Parasites and parasitic diseases of cattle in Puerto Rico

PUERTO RICO AGRICULTURAL EXPERIMENT STATION
MAYAGUEZ, PUERTO RICO

Under the supervision of the
UNITED STATES DEPARTMENT OF AGRICULTURE

BULLETIN No. 36

PARASITES AND PARASITIC DISEASES
OF CATTLE IN PUERTO RICO

By
H. L. VAN VOLKENBERG

Parasitologist

Issued October 1934

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UNITED STATES DEPARTMENT OF AGRICULTURE

OFFICE OF EXPERIMENT STATIONS

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JACKSONVILLE, FLORIDA

PUERTO RICO AGRICULTURAL EXPERIMENT STATION, MAYAGUEZ

[Under the supervision of the Office of Experiment Stations, United States Department

of Agriculture]

James T. Jardine, Chief, Office of Experiment Stations

STATION STAFF

H. Atherton Lee, Director.

H. L. Van Volkenberg, Parasitologist.

R. L. Davis, Agronomist.

J. O. Carrebo, Assistant Chemist.

A. Arroyo, Minor Scientific Helper.

J. Brtjnet, Minor Scientific Helper.

A. Diaz, Assistant Field Aide.

C. Alemar, Jr., Principal Clerk.

PUERTO RICO AGRICULTURAL EXPERIMENT STATION
MAYAGUEZ, PUERTO RICO

Under the supervision of the
UNITED STATES DEPARTMENT OF AGRICULTURE

BULLETIN No. 36

Washington, D.C.

October 1934

PARASITES AND PARASITIC DISEASES OF CATTLE
IN PUERTO RICO1

By H. L. Van Volkenberg, parasitologist

CONTENTS

Page
General characteristics and effects of para-
sites 1

Kinds and locations of parasites 1

Damage by parasites 2

Susceptibility to parasites 2

Symptoms of parasitism 2

Life history of internal parasites 3

Influence Of climate and topography on

parasites 3

Relation of parasites to livestock improve-
ment in Puerto Rico 4

General parasite control measures 5

Disposal of manure 5

Role of forage grasses in parasite control-.. 5

Pasture management 6

Construction of pens for young stock 7

Medicinal treatment 7

Other control measures 8

Page

Diseases of cattle caused by protozoa 9

Piroplasmosis, tick fever, or "Fiebre

Tejana"- 9

Anaplasmosis 11

Coccidiosis 12

Worm parasites -. 13

The stomach worm 13

The nodular worm 15

• Hookworm 16

Thread lungworm.. 17

Liver fluke, "lingua "or "cucaracha" 18

Tapeworm 19

Other worm parasites. 20

External parasites 21

Cattle tick or garrapata 21

Hornfly 22

Other external parasites 23

Eradication of parasites. 26

GENERAL CHARACTERISTICS AND EFFECTS OF PARASITES

KINDS AND LOCATIONS OF PARASITES

The term parasite as used here refers to lower forms of animal
life which, for the purpose of livelihood, exist on or in the bodies
of the higher animals, which are known as host animals.

Parasites may be divided into three general groups: (1) Protozoa,
including such groups as the hemosporidia and coccidia, the former
located in the blood stream, the latter in the intestinal tract; (2)
worms, including flukes, tapeworms, and roundworms, located usu-
ally in the intestinal tract, lungs, or liver, although mature worms
of the various species or their larvae may invade other organs and
tissues of the body; and (3) arthropods, including ticks, certain
flies, lice, and mites, located usually on or in the skin.

1 The internal parasites described in this bulletin have been identified by members
of the Zoological Division, Bureau of Animal Industry, and the external parasites have
been identified by members of the Bureau of Entomology, U.S. Department of Agriculture.
Acknowledgment is made especially of the constructive and very helpful criticism of
the manuscript by Dr. Maurice C. Hall, Chief of the Zoological Division.

G7b*60— :!4— — 1

2 BULLETIN 36, PUERTO RICO BXPERIMEX1 STATION

DAMAGI in i-ak LBITEfl

llic seriousness of parasites depends on the kind or kinds and the
numbers present as well as the Length of time the animals are in-
fested. Parasites may cause injury or death to the bost in one or
more of the following ways: (1) Loss <d* blood; (2) interference
with digestion ; (3) damage or destruction of tissue ; I i) secretion or
excretion of toxins which may be absorbed by the h< con-

stant irritation, itching, pain, etc.; (<>) transmission <d' dis<
directly or indirectly.

The death rate from parasitic infestations may uot he high, but
results from slow and stunted growth, uneconomical use of iwd.
Lowered capacity for work, reduced production, and condemnation of
the meat carcasses in whole or in part. A heavily parasitized ani-
mal Is likely t<> be more susceptible t<> bacteria] injections and other
diseases, and such an animal becomes a " poor risk " when treatment
is attempted with drugs and biologies.

SUSCEPTIBILITY TO PARAS1 I i -

The damage from parasites is greatest as a rule among young

animal-, as they seem to become more easily infested than older
animal.-, and young tissues are more easily injured. As growth must
be made in youth and cannot be made up later, it i- important to
pay special attention to the care of young >tock.

In Puerto Rico calve- suffer more from parasites than from dis-
eases due to other causes, with the possible exception of morbid col
ditions caused by improper feeding. Mature cattle are injured by
externa] parasites and protozoan diseases, hut are Less susceptible to
the worm parasites. The liver fluke seems to he the only serious
worm parasite <>f older cattle.

SYMPTOMS OF PARASITISM

The symptoms of parasitic worm diseases are usually less noti *-
able than those from infectious diseases caused by bacteria, because
the onset is seldom noticeable and the symptoms are usually more
vague. The presence of worm parasites may he suspected where
there is a lack of growth or a loss in weight, distended abdomen, and
diarrhea or constipation with little or no fever.

Anemia and edema are characteristic of the bloodsucking para-
sites. Anemia is shown by thinness of the blood and paleness or
whitening of the mucous membranes revealed by examining the in-
side of the mouth and inner surface of the eyelid-. Edema i> a
swelling caused by an accumulation of fluid in the tissues, usually
m the pendent portions of the body such as underneath the jaw or
in the lower abdominal region. Heavily parasitized work animals
such as oxen and horses tire easily and frequently are unable to
stand heavy work.

Protozoan diseases are more like specific bacterial diseases in that
they usually run a more definite and acute cour-e and -how charac-
teristic symptoms. Stockmen are more or less familiar with the
arthropod- or external parasites and the injuries produced by them.

PARASITIC DISEASES OF CATTLE IN PUERTO MOO 6

LIFE HISTORY OF INTERNAL PARASITES

Protozoa multiply within the body, so that one organism may give
rise to a large number of organisms. Adult worm parasites in their
definite host do not multiply in the body, as a rule, as each egg or
young parasite which gains entrance into the body develops usually
'into only one worm and multiplication depends on the eggs or young
worms produced by such a parasite. As most of the mature worms
live in the digestive tract or in organs in communication with the
digestive tract, the eggs or young worms are passed with the feces.

It is possible, by making 'a microscopic examination of the fresh
dung of the animal, to determine the presence of parasites and
approximately the amount of infestation. The eggs or young worms
as they are passed are not capable of infesting an animal, but must
pass through a stage of development outside of the body, in water,
-oil. or manure piles, or wherever the proper conditions are found.
Some species must pass a period of development in such lower ani-
mals as insects or snails. Warmth, moisture, and shade are necessary
for this development on the ground. Shade for the microscopic
free-living forms may be provided by any covering that conserves
moisture and prevents the penetration of the direct rays of the sun.

If conditions are favorable the infective stage is reached in a few
davs or a few weeks. This infective stage is more resistant to
unfavorable conditions than are the fresh ova or intermediate stages.
The infective larvae of several species are capable of crawling up the
blades of grass when these are wet with rain or dew. The host
animal becomes infested by grazing or by ingesting contaminated
water and green forage or by picking up the infective stages that
have developed on the floors and walls of the pens or stables. Con-
trol measures are concerned with breaking this cycle of development
by preventing infestations or by eliminating the worms from the
host.

INFLUENCE OF CLIMATE AND TOPOGRAPHY ON PARASITES

In the temperate zones, the freezing temperatures have a very
appreciable effect in limiting and destroying pasture and field infes-
tations with parasites. In the climate of Puerto Rico there are two
important limiting factors. One is a lack of moisture and another
is an excess of moisture. The dry season provides a limiting factor
through the lack of moisture. The southern coast, during 6 months
of the year, is semiarid, and parasites do not thrive under arid
conditions. The heat and drying tend to desiccate the worm eggs
and larvae on the ground so that, practically speaking, pastures and
fields are sterilized as far as parasites are concerned. This is as
unfavorable for worms as freezing temperatures elsewhere. In por-
tions of the other coastal areas, with a few inches of rainfall dis-
tributed over a period of several months and with the amount of
evaporation exceeding the precipitation, similar although less notice-
able results occur over a snorter season. In those areas, such as on
the western coast, where the rainfall is more evenly distributed
throughout the year and where the rate of evaporation is lower, this
limiting factor is less apparent.

I BULLETIN 36, PUERTO RICO EXPERIMENT STATION

A not hti- limiting factor in the more humid areas during the rainy
season is the torrential showers, which have a decidedly cleansing
action in washing down and carrying oil' the source of infection, such
as the eggs ana larvae of parasites. This infective material is
either washed into streams and destroyed or is deposited on the more
level lowlands. The abundant moisture which remains after the
ii of heavy rains is very favorable for parasites and usually it
i- during this time that the heaviest infestations are obtained.

( )n the basis <>f variation in rainfall and differences in topography,
Puerto Rico may he divided into three parts— the wet coastal plains
of the north, east, and west; the Avy southern coastal plain: and the
central mountain area subject to torrential rainfall. The [sabela
district on the northern coast and the island of Vieques are other dry
area-, -mailer hut similar to the southern coast.

In general, livestock of the wet coastal plains suffer more from
worm parasites than those of the other areas. The abundant mois-
ture and the more level lands which tend to retain moisture are more
favorable for the development of parasites. The southern coast
area is the most favorable for raising cattle. The dry season with
its destructive influence on parasites, and the rich limestone soils are
very favorable, especially for young growing animals. This area
appears to be especially suited as a breeding area for improved
dairy cattle. However, the light and variable rains characteristic of
the wet season in this area are favorable for several species of round-
worms, and preventive measures and treatment are necessary. Seri-
ous infestations with roundworms among calves of this area have
been especially noticeable during and following the unusual heavy
rains of 1933.

The mountain areas where suitable grasses are grown are favor-
able for raising livestock, even though the rainfall may be very
abundant. Hillsides or mountain slopes carry less infestation than
bottom lands because they benefit by the cleansing action of the rain
and the following run-off, as well as b}' holding less moisture. The
benefit of the natural advantages, however, is often lost by allowing
the young stock access to the stream beds and low areas.

As these differences in the climate and topography result in con-
siderable variation in the prevalence of parasites and also some
variation in the parasitic fauna, the methods used in control of
parasites must vary somewhat in different parts of the island and
at different time- of the year.

RELATION OF PARASITES TO LIVESTOCK IMPROVEMENT IN PUERTO RICO

Stockmen and both Insular and Federal Government agencies have
imported livestock of the improved breeds in order to develop better
and higher producing animals. New importations and the progeny
of those already introduced are replacing the native animals. The
higher producing animals are very susceptible to parasites and para-
sitic diseases. The recommendations in regard to control of para-
sites are directed especially toward the animals of the improved
breeds because of their rapidly increasing numbers, higher value,
and need for better care and management. The same methods.
however, can be used to advantage with the native stock.

PARASITIC DISEASES OF CATTLE IN PUERTO KICO •>

GENERAL PARASITE CONTROL MEASURES

DISPOSAL OF MANURE

A> manure is the direct or indirect source of most of the common
parasites, its proper disposal is an important factor in control.
Fresh manure or unrotted manure from an open pile, from infested
animals, should not be spread on pastures or on land which is to be
used for growing forage, especially the smaller grasses, unless it is
plowed under. Plowing buries the eggs and larvae and apparently
they do not get back to the surface in sufficient numbers to cause
serious trouble. Horse manure may be spread on pastures or grass
fields to be used by cattle, and vice versa. With 1 or 2 minor excep-
tions the internal parasites of horses are not transmissible to cattle,
and horses are not susceptible to those of cattle.

A dangerous practice which is equivalent to feeding the animals
from the top of a manure pile is sometimes followed. The forage is
fed from piles on the ground. The left-over grass accumulates and
becomes mixed with the manure. These piles retain moisture and
provide favorable conditions for the larval forms of parasites. As
soon as a light rain or heavy dew occurs the larvae may come to the
surface and contaminate the fresh grass. The forage should always
be fed from tight mangers and any left over should be disposed of
with the manure.

ROI.E OF FORAGE GRASSES IN PARASITE CONTROL

The roughage for livestock in Puerto Rico other than pasturage
consists of soiling, usually a forage grass cut and fed in a fresh,
green condition. Dried or stored roughages such, as hay and silage,
which carry very little if any parasitic infestation, are not used to
any extent. Therefore the selection of the soiling grass is very
important from a parasitological viewpoint.

The giant or rank-growing grasses such as Guatemala, elephant,
and sugarcane carry very little parasitic infestation in comparison
with the smaller grasses such as malojillo (Para grass) or guinea
grass or other similar grasses even though fresh contaminated
manure is spread on the fields in which the larger grasses are grown.
As the stalks of these giant grasses grow upright and are compar-
atively few in number the infective eggs and larvae of parasites are
less likely to be present on them.

Malojillo grass is more apt to carry these infective stages than
other grasses because it grows in more direct contact with the ground
and thrives only on marshy land very favorable for the development
and perpetuation of parasites. Malojillo fields cannot be protected
from contamination by the usual measures because infective material
may be washed onto them with every fall of rain. Malojillo grass
should be regarded as being unsafe to feed to calves. The cleaner
giant grasses may be fed to calves, goats, and horses, but malojillo
grass should be fed only to older cattle.

Guinea grass, or other small grasses grown on fields which have
not been fertilized with fresh cow manure and where there is no
danger of contamination by drainage from adjacent land on which
infested animals are maintained, may be fed to calves without danger
of infesting them with parasites.

6 BULLETIN 36, PUERTO BICO EXPERIMENT STATION

Molasses or Yaragua grass [MeUma mintU Is another grass

that may assist in parasite control. The fine hairs with which this

is covered and it- sticky exudation hinder seed ticks from

climbing upon the plant and so act as a deterrent to the spread of the

attle tick.

PASTURE MANAGEMENT

Statements in regard to pastures apply principally to the dry
area- and mountain sections. Foung calves cannot be pastured
successfully in the wet coastal areas because of the greater abundance
of parasites. Older cattle may be pastured in these wet areas with
considerable safety, if proper measures are used in controlling the
liver fluke.

( Overstocking of pasture, a common practice in Puerto Rico, favors
the infection of animals by parasites. Heavy stocking means more
manure and this in turn results in heavier concentration of parasite

and larvae. Animal- grazing on such pastures have
opportunity for picking up parasite eggs and larvae. How
overstocking is sometimes a relative term. During the drv season a
pasture may l>e overstocked, hut during the wet season with a much
heavier growth of grass the same pasture may have a much higher
carrying capacity. The overstocking in the dry season may not
cause the same amount of infestation as a similar overstocking in the
rainy season, owing to the presence of fewer parasib

Pasture rotation is an excellent method of parasite control.
prevent setting up dangerous infestations, it i> advisable that calves
he moved every '2 week- to clean pastures, during the wet season, and
should not he returned to the same pasture for at Least v months.
Such a system of management requires considerable fencing and
more land than i- usually available. Consequently a modification
of this program or other control measures are necessary. However,
any rotation is valuable, especially with heavy stocking. The more
often calves can he moved into (dean pastures, the more effectively
infestation will be kept down.

Stock rotation is another mean- of helping to control paras
Horses ami cattle are maintained in separate pastures and alternated
twice a year. Theoretically the changes should l>e made about the
middle of both the dry and wet seasons. The saying, u Permanent
pastures perpetuate parasites ", applies here as elsewhere, especially
as pastures in this climate are used throughout the year, and there
are no crops or land available for temporary pastures.

Location of the pasture is important in controlling parasites.
Pastures, especially for calves, should be confined to the hillside-.
because bottom land-, being less thoroughly drained and receiving
the wash from the hillsides, are likely to he more highly infested with
eggs and larvae of parasites than the hill land-. Calves should
l»e kept away from low -pot- in the pasture by fencing and should
be watered in troughs from which there i- no overflow. A .-mall
surrounding a watering trough or spring may provide sufficient
moisture for the propagation of parasites and thus serve m- a con-
stant source of infestation. The bottom land- may he used for held
crops or if necessary for pasturing mature cattle.

PARASITIC DISEASES OF CATTLE IN PUERTO ItICO /

CONSTRUCTION OF PENS FOR YOUNG STOCK

Dark, damp, and dirty pens or stables provide conditions favor-
able for the development of parasites. Therefore, the proper con-
struction of pens for confined animals is an important factor in the
control of parasites and disease. The open-shed type of building in
common use is well adapted for local conditions. Advantage should
be taken of the fact that the sun shines nearly every day throughout
the year in Puerto Eico. The sun's rays provide an efficient and
inexpensive drier and disinfectant and are very destructive to the
eggs and larvae of parasites. The pen should face east and west and
the sides and roof should be so constructed that the direct rays
of the sun can reach the entire floor space. Tight floors, preferably
of concrete with drainage facilities, are essential. The mangers

Figure 1. — A sanitary calf pen with movable roof. Exercising yard in foreground.

and troughs should be protected from fecal contamination. A yard
or corral may be used in connection with the pens, provided it is a
bare lot, unshaded, and with good drainage. Young animals should
have plenty of exercise and direct sunlight.

A modified type of such a pen (fig. 1) has been constructed for
trial at the station. The roof of this pen is built lower than an
ordinary roof. It covers one-half the pen and it is set on rollers.
Each day as the pen is cleaned the roof is moved over to cover the
opposite half of the pen. Thus all parts of the pen are exposed to
the sun on at least alternate days. Such a construction provides
sufficient shelter for this climate and allows the sun to shine directly
into the pen for a greater length of time than the ordinary type of
roof.

MEDICINAL TREATMENT

The factors involved in the treatment of parasites, including the
diagnosis, the specific drug to be used, the dose, and administration,
usually require the knowledge, skill, and also the equipment of a

8 BULLBTI M'KIMMKM -

veterinarian. If a veterinarian is n«»t available the owner must use
bis <»wn judgment in determining whether be can recognize the
trouble and administer the remedy.

The most common method 01 administering remedies used by
stockmen Lb drenching or giving the medicine as a solution from a
Long-necked bottle, by way of the mouth. The animal should remain
on all four legs with the head held horizontally and in line with
the body. The practice of elevating the head as high as possible,
twisting the neck, closing the nostrils, and then pouring the drench
rapidly into the mouth may result in all or part of the solution going
into tie.- Lungs and either drowning the animal or producing
pneumonia.

Pasting or withholding food for a certain Length of time (p. 13)
before and after the administration of worm remedies is quite im-
portant and should not be neglected. The bulk of the conter:
the digestive tract is thereby reduced, thus allowing the dru.
reach the parasites more certainly and effectively. A program of
regular treatments should be adopted. The usual procedure for the
parasites of calves and goats is to dose once a month or more often
if necessary. Judgment based on experience is more valuable than
any general rule.

OTHER CONTROL MEASURES

From the standpoint of parasites and diseases, calves and all
young animals should be separated from older animals when they
are a few days old and should not come in contact with them. Older
animals carry and spread parasites and diseases, and the areas
occupied by them are infested. The local custom of allowing calve-
to start the milk flow and to strip the udder of their dams during
the entire lactation period is a poor dairy practice and dangerou- to
the calf. Goats, both young and old. should not be brought into
contact with calves, as goats are usually infested with stomach worms
and other worms common to calves. Stray animals may be another
source of infestation.

Calves up to 3 or 4 weeks of age should be kept in individual pens,
and may then be placed in larger pens with other calves of the same
age. Calves raised in the wet coastal area should not be placed on
pasture until they are at least 1 year of age. At this age a healthy
calf seems to have gained sufficient resistance to the roundworm
that very little injury is caused by them. However, if calves of
this age or older are for any reason in poor physical condition, their
resistance is reduced and they may suffer from intestinal paras

The practice of placing caives less than 1 year of age on pasture
and treating them regularly with anthelmintics every few weeks has
not been successful. The calves usually become heavily infested with
injurious worms, such as lungworms and nodular worms, which are
not readily destroyed by treatment. A few dairymen have avoided
the difficulties of raising calves in the wet coastal areas by placing
the animals on pastures in the dry areas or mountain sections.

The pens and exercising yards for calves should be cleaned every
day in order to prevent the development of parasite eggs and larvae
in them. A supply of fresh clean water should be available at all
times. Salt and a mineral mixture should be provided. The latter

PARASITIC DISEASES OF CATTLE IX PUERTO RICO \j

not only supplies minerals that are often lacking in local soils but
also helps to prevent the calves from licking the walls and floors of
the pen and picking up parasites and disease germ-.

Improper feeding and management, as well as parasitic diseases,
cause unthriftiness, emaciation, and stunting in calves. Among the
causes of failure to raise normal, healthy calves is the common prac-
tice of feeding them largely or solely on fresh grass. The low-
protein, bulky forage grasses in common use are unsuited to the
limited capacity of the stomach of the young calf. These grasses
should be supplemented with larger proportions of skim milk and
grain. There are more difficulties to overcome in raising young stock
in Puerto Rico than in many other localities and climates.

DISEASES OF CATTLE CAUSED BY PROTOZOA

PIROPLASMOSIS, TICK FEVER, OR " FIEBRE TEJANA "

Tick fever is caused by Piroplasma bigeminum, a microparasite
located in the blood (fig. 2, Aa). These organisms enter the red
blood corpuscles and cause them to disintegrate.

Life history. — The piroplasma are transmitted by the common
cattle tick. The tick becomes infected from the blood of an animal
that harbors the organism, and the infection is carried through the
egg to the young ticks of the next generation. These young ticks
may infect any susceptible animal (bovine) to which they become
attached.

Importance. — About one-third of the imported cattle from tick-free
localities are said to die from this disease. Native cattle, especially
the higher-bred dairy cattle, suffer from the disease, although the
attacks are usually of short duration and death does not occur
as a rule.

Symptoms. — The first symptom usually noticed is extreme dullness,
loss of appetite, and, in milking cows, a decided drop in production.
Other symptoms are a fever temperature which may be as high as
41.5° to 42.2° C. (107° to 108° F.), constipation, and loss of flesh.
The feces are usually heavily stained with bile and sometimes with
blood. The blood itself is pale and watery. A coffee-colored or
blood-colored urine is characteristic of the disease.

Treatment. — The sick animal should be placed immediately in a
cool, shady pen and the ticks removed from the skin. The back and
sides of the animal may be covered with a thickness of burlap and
sprinkled frequently with water. Unnecessary driving or rough
handling should be avoided. A small dose of a saline purge may
be given if there is constipation. Stimulants to support the heart
action are indicated.

Intravenous injections of trypan-blue have been used with good
results in Africa and South America. The usual dose is 1 gram
dissolved in 100 cubic centimeters of a sterile physiologic salt solu-
tion. It should be administered as soon as possible after the symp-
toms appear.

Pre rent /on. — This disease can be eliminated by eradicating the
cattle ticks from the island (p. 22). Cattle, become immune to tick
fever after recovery from an acute attack. This fact has led to
the development of several methods of immunizing cattle to the

67666—34 2

10

BULLETI] . PUERTO RICO EXPERIMENT STATION

FiGURi 2. — 1'rotozoan and external paraail rto Etican cattle: A.a, >d evils

showing tick-fever parasites (from Btilea, 1931). l<< . Red blood ceiis sh<
plasma (from Btilea, 1931). C, Coccidia from cattle, x ''»•"»" (from Wilson. 1931).
I>. Cattle tick female, -4 (from UraybiU). F. Hornfly, <5 (from Riley

and Howard). Q-, Extracting a grab or warble from a cow's back (from Bisbopp.
Laake, and Wells). //. Tail louse, B. /. Bhort-nosed ox Lous* - /, Leeches
anengorged with blood. A". Btahle fly, adult female, side view; with blood,

(from Biabopp). /.. Screw-worm maggot, sid<> view, • 5 (from Bisbopp, Mitchell.
and Parman). .1/. Psoroptic mange mite, female; dorsal view, ■ 4<» (after Salmon and
Still

PARASITIC DISEASES OF CATTLE IN PUEBTO RICO 11

disease. Probably the safest method for pure-bred cattle is by in-
jecting blood from immune animals into those that arc susceptible.

To insure the success of this method, natural infestations with the
tick must be avoided. It is recommended that animals from 6 to L5
months of age be selected for inoculation, as they are more readily
immunized than adults. The treatment with trypan-blue should
be used to ease the severe reactions and to reduce the Losses result-
ing from the immunization.

A control measure that has been tried in Puerto Rico, with vary-
ing results, is to allow only a limited number of ticks to infest the
susceptible imported animals. These animals are isolated, at the
time of arrival, in a stable or bare corral, and sprayed every week
or two with an arsenical solution. They become infested with a few
or several ticks for a short interval, and the disease is produced, but
the proportion of deaths is usually small when compared with the
fatalities among uncontrolled animals. The ticks infesting these
animals are picked up from the forage grasses. The animals should
receive medicinal treatment as soon as they show signs of the
disease.

Calves of 1 year of age or less can be introduced with considerable
safety, as the disease is usually mild and less fatal in young ani-
mals. The importation of mature cows in an advanced stage of
pregnanc}r should be avoided, as they are likely to succumb to the
disease.

ANAPLASMOSIS

The organism Anaplaxma marginale associated with anaplas-
mosis (fig. 2, Be) appears in stained blood smears, as a small, dark,
dotlike object, usually on the margin of the red blood cells. The
disease itself resembles piroplasmosis in many respects, and the two
diseases are being confused.

Life history. — The disease is spread by cattle ticks and other ticks.
As in the case of piroplasmosis, the cattle tick (Boophilus cmnulatus)
engorged on anaplasmosis carriers can transmit the disease to sus-
ceptible animals in the next generation. Various biting flies have
also been reported as carriers of the disease. In connection with
the transmission of this disease it should be mentioned that anaplas-
mosis can be carried from one animal to another by instruments
such as hypodermic needles, lancets, and dehorning shears.

Importance. — Apparently this disease occurs much more frequently
among native and acclimated cattle than does piroplasmosis. Among
these animals the percentage of fatalities is low. The higher pro-
ducing milk cows seem to be more predisposed to the disease and
are often attacked at the time of parturition. Animals may recover
from the disease, but the milk production is lowered or may cease,
and is not resumed until the next parturition. As with piroplas-
mosis, the disease may spread rapidly among susceptible imported
cattle and may result in a high mortality. As the period of incu-
bation of anaplasmosis is longer than that of tick fever, an imported
animal may recover from the latter and then in a few days or a
few weeks suffer from an attack of anaplasmosis.

Symptoms. — The symptoms are similar to those of tick fever ex-
cept that the urine is rarely, if ever, blood-colored, although it may

12 BULLETIN 36, PUERTO BICO EXPERIMENT STATION

be darker than aormaJ due to the presence of bile pigment An accu-
liagnosis of the disease can be made by microscopic examination
of the blood.

Treatment.- The management and treatment of sick animals is the
same as thai recommended for piroplasmosis except that trypan-blne
Is of no value. There is do known specific for treating this di»
A veterinarian should be called at once as delay may result in the
death of sick animals.

Prevention. — Susceptible imported cattle should be managed as
described under piroplasmosis. Any Instrument which may carry or
inoculate the fresh blood 6f one animal into that of another, such as
dehorning instruments, syringe needle-, etc.. should be cleaned and
disinfected after each operation. A> the carriers of this dig
imperfectly known, the control measures recommended at this time
are incomplete.

The prevention of both anaplasmosis and piroplasmosis in native
cattle is practically impossible under existing conditions. A- b
result of lowered vitality caused by some other disease, by parturi-
tion, or by exposure, privation, injury, and rough handling, the
immunity of the animal becomes reduced and finally overcome and
one or the other of these disea>e> may occur. ( )ften there is no indi-
cation of an impoverished condition. The most that can be done is
to avoid anything that may tend to lower the resistance of the animal.
The high-producing milk cow should have a long rest period and
should be fed well and carefully handled previous to parturition.
The cattle tick should be controlled by frequent dipping or spraying.

COCCIDIOSIS

The coccidia Eimeris spp. (tin". ~. ( ). are microscopic round or

oval organisms which attack the mucosa or lining of the intestine.

Life hfeto7y. — Infection is conveyed by contaminated food and
water. The coccidia in the body multiply in large numbers, but
after several generations an encysted stage is produced which passes
out in the feces. The disease is self-limited and ultimately dies out
in the absence of reinfection.

Importance. — Coccidia are often found in feces of cattle, especially
during and following the wet season. The finding of these organ-
isms indicates that the animal has zoological coccidiosis, but not
ssarily clinical coccidiosis as coccidia may occur in apparently
normal animals. This is usually a disease of young stock but also
occurs in older animals. This disease seems to be uncommon
although it is possible that it is not always recognized.

Symptoms. — Coccidiosis is an acute disease and often terminate-
fatally. The first noticeable symptom is a diarrhea in which the
contain mucus and blood. Later there i> a loss of appetite,
of flesh, and a slight U>\<>\\ A fetid, bloody diarrhea may

lop.

Treatment. — Preventive treatment seems to be the only feasible
program known at present Medicinal treatment should be given by
i veterinarian. As the seriousness of the disease depends consider-
ably on the Dumber of organisms taken into the body, measures
should he taken to keep the numbers ingested at a minimum. The

PARASITIC DISEASES OF CATTLE IN PUBBTO HTCO 13

sick animal should be placed in a clean dry pen. Either dry hay or
clean fresh grass obtained from a hillside or dry held should lie fed.
The animal may be muzzled after eating and drinking. The pens
should be scrubbed, sprayed with a hot disinfectant, and dried.
The organism is very resistant to ordinary disinfectants, but it can
be destroyed by heat and drying.

Pn v ration. — Cattle should be kept away from low. wet pastures.
An open manure pile draining into a pasture or grass field is danger-
ods. The ingestion of dirty- water from pools and marshes must be
avoided. For confined calves, clean fresh grass, clean water, and
clean dry pens should be provided.

WORxM PARASITES

THE STOMACH WORM

The stomach worm (Haemonehus contortus) (fig. 3, A) is a round-
worm found in the fourth stomach (abomasum) of cattle. The
worms are 12 to 30 millimeters (y2 to 1*4 inches) long and about
as thick as an ordinary pin. The female worms are larger than the
males and have a spiral striping. The smaller male may be dis-
tinguished by the fact that the posterior or tail end of the body is
flattened and expanded.

Life history. — The eggs are passed in the feces and develop on the
ground. In 10 days or sooner the infective larvae crawl up on
the blades of grass when there is a rain or dew. Animals become
infested by grazing, by eating contaminated forage grasses, or by
picking up the larvae which have developed in damp and dirty
pens.

Importance. — The stomach worm is one of the most common and
most serious parasites of cattle in Puerto Rico. Calves of less than
(3 months of age are more susceptible to and more seriously injured
by infestation than older animals. Healthy calves of 1 year of age,
or older, which are fed properly, become quite resistant to inf<
tion. Mature cattle often harbor a few stomach worms but are
rarely injured by them.

Symptoms and lesions. — The worm attaches itself to the lining of
the stomach and sucks blood, producing pin-point punctures with
hemorrhages. The first symptoms are dullness and unthriftiness,
and, later, anemia and edema. The condition knoAvn as " papera " in
which there is a swelling underneath the jaw (fig. 4) is a sign of
infestation by this parasite. This swelling is also found in infesta-
tions with the hookworm and liver fluke.

Treatment. — A satisfactory treatment is by drenching with a 1-per-
cent solution of copper sulphate. The dose for a calf 3 months of
age is 60 cubic centimeters (2 ounces), and for each additional month
of age add 15 cubic centimeters, or at the rate of approximately V/2
ounces per 100 pounds (1 cubic centimeter per kilogram) of live
weight. All food should be withheld 18 hours before, and both
food and water 4 to 6 hours after, treatment.

To make a 1-percent solution of copper sulphate dissolve 100 grams
of copper sulphate in 1 liter of boiling water and add 9 liters of
cold water, or at the rate of one-fourth pound of copper sulphate to
3 gallons of water. Select only the clear blue crystals of copper

11

BULLETIN 36. PUERTO RICO EXPEBIMENT STATION

sulphate, discarding those thai have turned white. Porcelain or
enamel-ware receptacles should be used in preparing and handling
the solution, ;»- it will corrode metals. If a large Dumber of animals

1

1

l$H

H

mfin

3

mtfmr

Figure 3. -Worm parasites of Puerto Rican cattle: .i. Stomach worms; B, nodular
worms; r, hookworms; U, lungworms; /.'. whipworms; I', laryngeal worms; O, tape
worm; //, liver Bakes; /. Btomach flakes. All Datura] siz.-.

are to be treated the device described by Hall -' may be used. For
stockmen that have a comparatively small number of animals, but

'-'llu.r M C. PABA8ITE8 AND PABA81TIC DI8BA8E8 OF SHEEP. U.S. Dept. Agr. Farmers'
:ul. 1330, 6 » pp., lllus 192a.

PARASITIC DISEASES OF CATTLE IN PUERTO RICO 15

who wish to dose regularly, a concentrated stock solution may be
made by dissolving 200 grams of copper sulphate in 1 Liter of
distilled water or rain water. Such a solution will retain its
strength indefinitely. In making the dilution for administration,
add 50 cubic centimeters of the stock solution to 950 cubic centimeters
of water, or in this proportion.

Prevention, — Confined calves should be provided with dry sanitary
pens and should be fed on uncontaminated grass. Pastured animals
should be given a wide range on dry hillside pastures. If necessary,
both the confined and pastured animals should be treated. Periodic
treatments, every 2 or 3 wreeks, should be given instead of waiting
until the animals show symptoms of the disease. On some pastures
where heavy stocking is practiced, it is necessary to dose every 2
weeks during the wet season.

Figuke 4.— Calf with "papera" or edematous swelling underneath the jaw. This calf
was infested with stomach worms.

THE NODULAR WORM

The nodular worm (Oesophagostomum radlatum) is about 15 milli-
meters (five-eighths of an inch) long. It has a characteristic solid
white body. The adult worms live in the large intestine. The lar-
val worms live in nodules in the wall of the intestines and occasion-
ally make their way to the mesenteric lymph glands, the omentum,
or the liver. The nodules are usually found in the terminal portions
of the small intestine.

Life history. — The eggs are passed with the manure and the young
worms are hatched and undergo some development on the ground.
When swallowed by cattle, the young worms enter the walls of the
intestine and remain for a few days and then return to the lumen
of the large intestine, where they reach maturity. Following this
encysted stage in the walls of the intestine, the nodules formed
often increase in size and contain a yellowish or greenish, cheesy or
calcareous material.

1() BULLET] . PUERTO RICO EXPERIMENT STATION

Importance. — The oodular worm is common and serious especially
in the \\< t coastal area- and lower mountain regions. It occur- in
cattle of the southern coastal plain, but it is considerably Less im-
portant in this area. Similar to other roundworms, young calves
arc more susceptible to an<l more seriously injured by infestation
with nodular worms than older cattle.

Symptoms "/>// lesions. — The injury by this parasite seems t«>
occur Largely from the nodules. The Large Dumber of nodules result-
ing from a heavy infestation prevents the intestine from functioning

] roperly, and they are a constant source of irritation to the sensitive
tissue of the intestinal tract. Because of the permanent natui
the nodules, calves may recover slowly from a heavy infestation.
The symptoms are dullness, lack of thrift, ami diarrhea.

Treatment. — Preventive measures must he relied on for controlling
this parasite. There is no known remedy that will reach the young
worms in the nodules. As the injury by the parasite is Largely from
the nodules, medicinal treatment cannot relieve or improve this con-
dition. A drug to destroy the mature worms in the large intestine,
which is both efficient and safe for cattle, has not been found. Such
a drug would be valuable in eliminating the ova-producing worms
and thus assisting in the control of pasture, field, and stable infes-
tations.

Pn vention.- — Pasturing young calves in the areas most favorable
for this parasite should not be attempted. In the other areas calves
should be maintained on dry hillsides. If dry pastures are not
available, calves should be confined during the wet season. Confined
calves can be protected from infestation by feeding the giant gi
or other clean grasses and by providing clean, dry pens and corral-,
i use this worm is very common and serious, and medicinal treat-
ment is unsatisfactory, careful preventive measures are essential.

HOOKWORM

The hookworm {Bunostomum phlcbotoimun) is located in the
small intestine. The female hookworm is about 2 centimeters
(three-fourths of an inch) long, and the male is shorter and more
-lender.

Lift history. — The life history is similar to that of the stomach
worm. Infestation is by way of the mouth and possibly the larvae
are capable of penetrating the skin.

Importance. — The hookworm is not as widely distributed as either
the stomach or nodular worms. Considering the island as a whole,
it is more common and serious among calves of the southern CO
area. This parasite shows a preference for porous soils. At Maya-
guez, where the soils are mostly a heavy clay, the worm is more
common among the calves raised on the sandy soils near the
shore.

Symptoms and h sions. — The worm is a bloodsucker, and the symp-
- and lesions are similar to those of the stomach worm.

Treatment. — A solution containing the copper sulphate solution,
as described for the stomach worm [p. 13), combined with nicotine,
is effective for hookworms. To make this solution, add 1 ounce of
LO-percent nicotine sulphate to 1 gallon of 1-percent copper sulphate
(10 cubic centimeters to 1 liter). The dose for this combination is

PARASITIC DISEASES OF CATTLE IN PUERTO RICO 17

the same as for the copper sulphate alone. However, this combina-
tion is more toxic and the amount given should be diminished if the
full close produces unpleasant symptoms. It should not be given
to very young animals nor to animals suffering from disease condi-
tion other than those of parasitic origin. Calves which are in poor
condition because of improper feeding and infestations with para-
sites should be given small doses of this combination. The strength
of these animals should be built up by supplying sufficient amounts
of suitable concentrates. Animals frequently show symptoms of dis-
tress after the first few dosings with this combination, but tolerate
it better later. Alternating the use of this solution with the straight
copper sulphate solution is a good practice.

Prevention. — Same as for the stomach worms and nodular worms.

THREAD LUNGWORM

The lungworm (Dictyocaulus viviparus) (fig. 3, D) is found in
the air passages, bronchi, and bronchioles of the lungs. They are
rather large worms, ranging from 4 to 8 centimeters in length.

Life history. — The eggs hatch in the lung and the larvae ascend
the trachea and are expelled in coughing or swallowed and passed
in the feces. The infective stage may be reached in 10 days or
less. The infective larvae climb up the blades of grass when they
are wet, as do the larvae of stomach worms and here they are taken
in by grazing calves and make their way to the lungs. Infection
may also be obtained from contaminated grass and from the larvae
that have developed in damp and dirty pens. However, this is
usually a pasture disease, and confined calves, regardless of the sys-
tem of management, seem to be less subject to infestation with lung-
worms than with some of the other roundworms.

Importance. — Heavy infestations with this lungworm are not so
common as with some of the intestinal worms. However, on many
farms it is one of the most serious parasites of calves. Attempting
to pasture young calves in the wet coastal areas usually results in
massive infestations. In the dry' areas and mountain sections, calves
having access to low, wet pastures may also become heavily infested.

Symptoms and lesions. — The first symptom is a husky cough which
may be followed by difficulty in breathing. The animal may die
from suffocation, or a fatal pneumonia may develop. In the more
common prolonged cases, the animal becomes emaciated, anemic, the
eye sunken, and there is loss of appetite. Diarrhea is a common
symptom.

Treatment. — Nursing treatment appears to be the safest and most
satisfactory in most cases. Infested calves should be confined and
provided with a safe drinking water and a plentiful supply of dry
hay or clean grass and concentrates. Sanitary measures should be
taken to prevent fresh infestations in the pen. The animals should
be treated with the copper sulphate-nicotine sulphate solution to
remove the gastro-intestinal worms that are usually present with
this worm.

Prevention. — Medicinal treatment, if attempted, should be given
by a veterinarian. In the wet coastal areas, calves up to 1 year
of age should be confined. The confined calves should be fed on the

Is BULLETIN 36, PUERTO RICO EXPERIMENT STATION

iriant grasses and provided with clean, dry pens. In the dry areas
and mountain regions, calves should be pastured ou the hillsides
and should n<»t have access t<> wei <»r marshy land.

UVEH FLIKK. - UNGUA " OR " ( l( ARACHA "

The liver fluke {FascMa hepatica) (tin-. :;. // i \s found usually in
the canals and duct- of the liver, although the flukes may occur as
wandering parasites in the lungs and elsewhere. This fluke is a
flattened, leaflike, brown animal about 1 inch long.

Lifi history. — The eggs pa— out in the feces ;md. if they get to
water, they develop in about 3 weeks and release a motile embryo.
This embryo swims about and enters a snail (Lymnaea oube\
in which another stage of development take- place. A small fluke-
like cercaria with a tail is produced in the snail, and this cercaria
emerges and swims about and in a short time encysts. This en-
cysted form may float on water or it may become attached to grass.
When these are swallowed by cattle or other suitable h<>.-t animals.
the larval flukes escape into the digestive tract and bore their way
through the intestinal walls to the body cavity. A> a rule, they per-
forate the capsule of the liver and enter the bile ducts, while a lew
may perforate the diaphragm, getting into the lungs.

Importance. — The liver fluke is a common and serious pest of
cattle in the wet coastal and lower mountain areas. This parasite
also infests the goat, pig. horse, and man. Mature animal- as well
as the young may suffer serious injury or die from infestation. In
daiiy cows there is a loss in milk production and breeding efficiency.
Work bulls are weakened and made unfit for service. There is
another loss in that all infested livers are condemned at the
abattoirs.

Symptoms end lesions. — Loss of condition, anemia, and edema are
associated with this parasite. The fluke causes considerable dam-
age to the liver, which in cattle especially is of a permanent nature.
since heavy infestation in cattle is followed by a calcification of the
bile ducts. Complete recovery is hardly possible because of the
permanent injury to the liver tissue.

Treatment. — Xo treatment is recommended for flukes in cattle.
The permanent injury to the liver cannot he relieved or improved
by treatment. Infections in cattle may be controlled by destruction
of the snails responsible for carrying the young fluke-.

Prevention. — The snail which is essential to complete the life cy-
cle of this fluke can be destroyed by proper drainage or by treating
the water and mud with copper sulphate. This snail lives in the
mud. in stagnant fresh water, and in sluggish streams and drai]
ditches hut not in swift -running water or in gravelly stream beds.
A mixture of 1 part powdered copper sulphate to 4 or v part- of
dry -and may he broadcast by hand over the snail-infested areas at
the rate of :> to 6 pounds of copper sulphate to the acre.

The snails in streams and ditches may he destroyed by putting
a gunny sack containing crystals of copper sulphate in the head
water-. Damming the stream- at intervals aids in destroying snails
along the hanks. The copper sulphate is capable of destroying the
-nails in a stream as far down a- the water retain- a bluish color.

PARASITIC DISEASES OF CATTLE IN PTJEBTO UICO 19

Technically, the amount to use is 12 pounds of copper sulphate per
second-foot of flow for running water and about 6 pounds per acre-
foot of water for marshy land. As this amount of copper sulphate
is too small to distribute evenly, it should be mixed with a carrier.
If the copper sulphate is distributed uniformly, there is little danger
of animals being poisoned by it.

The best season of the year for the treatment is a short time after
the heavy rains of the rainy season. As the land gradually dries off,
the remaining water tends to collect in depressions or pools and the
snails follow the water line and become concentrated in these centers.
Later, if treatment is not undertaken, the snails disappear in cracks
and holes in the soil and cannot be reached by ordinary methods.
Until island-wide eradication measures are undertaken, it will be
necessary to repeat the operation every year or as often as the snails
reappear. If live snails are found after an application, the treat-
ment should be repeated. Usually one treatment at the right time
of the year is sufficient for that year. At the experiment station at
Mayaguez the pastures and malojillo vegas are treated some time
during November or December.

TAPEWORM

The tapeworm (Monieza expansa) (fig. 3, G) is a whitish, seg-
mented worm which may attain a length of several feet. It is found
in the small intestine.

Life history. — Unknown.

Importance. — This worm is very common in some districts. Of
the cattle slaughtered at Mayaguez, this tapeworm seems to be more
common in those obtained from the district of San Sebastian. The
heaviest infestations occur more frequently among pastured animals.
Confined calves that are kept in sanitary pens and fed on the clean
grasses occasionally become infested.

Symptoms and lesions. — The worm causes obstruction of the intes-
tine and irritation, and infested animals become unthrifty, weak, and
emaciated. Diarrhea is a common symptom. Occasionally the pres-
ence of the worm is detected by the passage of several or many of the
end segments in the feces.

Treatment. — Various treatments have been recommended. How-
ever, most of the recommended drugs are unsafe for the young stock
which harbor the heaviest infestations and are in greatest need of
treatment. Care must be used also in giving any anthelmintic, as
many of the young animals besides harboring various kinds of para-
sites are improperly nourished and thus are poor subjects for treat-
ment with any potent drug.

Kamala administered in capsules in doses of 1 to 2 drams (4 to 8
grams) for calves up to 1 year of age may be used. It should not
be given to very young animals or to those in a weakened condition.
Periodic treatment with the copper sulphate-nicotine sulphate com-
bination as recommended for the hookworm seems to reduce infesta-
tions with this tapeworm.

Prevention. — Xo dependable preventive measures against these
tapeworms can be recommended, owing to the fact that the life
history is unknown. However, as the ova are the starting point of

20 16, PUERTO BXC0 EXPERIMENT STATION

new infestations and these are eliminated with the manure, any
measures which are taken in regard to the proper disposal of manure
will aid in preventing infestations with this tapeworm.

OTHBB WORM PARASH

The whipworm {Trichuris ovis) (fig. 3, E) is found in the La
intestine 01 cattle and goats. This worm i- common in calves. T&
body of the worm is thick posteriorly and very slender anteriorly,
the anterior portion of the body being 2 or '■'> times a- long as the
posterior portion. Whipworms set up an inflammation, with the
likelihood of the Lining of the intestine being infected by bacteria.
Because of their location, treatment with anthelmintic- i< not very
effective. The preventive measures as given for stomach worms
(]). 15) and other worms should be followed.

Syngamosis caused by the worm Syngwmus laryng&as (fig. 3,
F ) in the larynx, occurs in cattle and iroats. The worm appear- to
be double-headed and Y-shaped because the shorter male is attached
to the larger female worm. It appear- to give rise only to a local
lesion at the point of attachment. Infestations by 1 or '1 worm-, in
man. have caused considerable irritation. The worm is common and
lather conspicuous and, because of its location, stockmen are likely
to ascribe to it the symptoms of lungworm infestation.

The stomach fluke (C otylophoron cotylophorum) (fig. 3, /) is
found attached among the papillae of the rumen or paunch of cattle.
It is about 1*2 millimeters (one-half inch) in length and conical in
shape. This conical fluke is found in the same districts as the liver
fluke. Similar to the liver fluke it is common in both young and
mature animals. It is usually considered as not impairing the health
of the host but massive infestations, which sometimes occur, appar-
ently cause emaciation. Infestations can be prevented by destroying
the snails as described for the liver fluke.

Several other kinds of roundworms have been found in the stomach
(abomasum) and small intestine of cattle. The species have been
identified as Haemonclms similis, Ostertagia ostertagL Trichostro/,-
gylus axek Cooperia punctata, Capillar* a brevipes, and Strongy-
loides papillosum. These worms may be overlooked if they occur in
small numbers together with infestations of the more conspicuous
stomach worms or hookworms. Most of these worms, and probably
all of them, are injurious, but at present they are. so far as known.
of relatively less importance in comparison with stomach worms.
hookworms, and nodular worms. The method of prevention as
recommended for stomach worms, and other worm-, will help t<>
protect cattle from infestations with these worms.

The bladderworm (Gysticercm bovis) i^ about the size of a pea
and is grayish white in color. It may be found in any organ but
usually in the muscles of the jaw. tongue, heart, and diaphra
It is apparently uncommon locally in cattle and i- rarely det<
in the slaughtered animal. The prevention of infestation in cattle
is dependent upon the proper disposal of the excrement of man. The
bladderworm is the intermediate stage of the beef tapeworm (Taenia
saginata) in man. In Puerto Rico the beef tapeworm is said to
he more common than the pork tapeworm. Eating raw or partially

PARASITIC DISEASES OF CATTLE IN PUERTO RICO 21

cooked beef containing the bladderworms may result in infestation
with the tapeworm. A man infested with a tapeworm expels several
hundred proglottids a month, each containing many thousands of
eggs. Cattle are infested by eating human excrement or by swallow-
ing the eggs in contaminated feed and water. All beef should be
thoroughly cooked before it is eaten in order to destroy this inter-
mediate stage or else subjected to adequate meat inspection by com-
petent veterinarians.

The threadworm (Setaria labiato-papillosa) is a slender, whitish
worm from 2 to 5 inches in length. It usually occurs in the peri-
toneal cavity. A few of these worms are often found in cattle.
These worms do not appear to do much damage and are not known
to cause any definite symptoms.

The neck threadworm (Onchocerca gutturosa) is found in the
large ligament of the neck. This is a slender, whitish worm from
1 to 2 inches or more in length. Most of the cattle that are slaugh-
tered for meat purposes are infested with this worm. As far as can
be determined, this worm is not harmful to the animal aside from
causing a slight local irritation.

EXTERNAL PARASITES

CATTLE TICK OR GARRAPATA

The North American cattle tick (Boophilus annulatus) (fig. 2, D)
and the Australian cattle tick (B. annulatus australis) are found
attached to the skin of cattle and occasionally goats and horses.
These are the common ticks found on cattle. At Mayaguez, the
Australian variety is more common than the other.

Life history. — Both ticks mature on cattle and horses and the
Australian tick matures on goats as well. The engorged female
drops from the animal to the ground where it may deposit from a
few hundred to more than 3,000 eggs. The eggs hatch in 2 weeks
or longer, depending on external conditions. The young seed ticks
are capable of living 3 or 4 months on the ground, if they do not
become attached to a suitable host. After attachment the tick may
become mature within 1 month. The entire life cycle may be
completed within 6 weeks.

Importance. — These ticks are very abundant and are one of the
most serious parasites of cattle. In addition to causing direct in-
juries, they transmit the diseases piroplasmosis and anaplasmosis.

Symptoms and lesions. — The direct injury by the cattle ticks is
chiefly the drawing of blood from the host. As a result, growth is
retarded, work animals are weakened, and milk production is
reduced.

Treatment. — The ticks are controlled by " tickicides " used as
sprays or dips. At present concentrated proprietary arsenical solu-
tions are used almost exclusively. As these preparations and infor-
mation concerning their use are readily available to stockmen, details
in regard to treatment are not given.

Precautions should be used in the handling and dilution with
water of the dips. Often animals are poisoned from too high a
concentration of the arsenic in the solution. An animal mav ab-

22 nru.K'i; PUERTO BIOO EXPERIMENT STATION

sorb sufficient arsenic through the skin to cause death. This usually
occur- when the preparation is applied as a spray and the dilutions
arc made by persons unfamiliar with the danger involved. The
dilution- stipulated l>y the manufacturer must be closely 1<>11. .
A recommended dilution of 1 part of the stock solution to 155 part-
id' water is much less concentrated than the 1- to 3-percent solution
of a disinfectant ordinarily used in the stable.

Prevention. — The most feasible method of control usually
reduce the infestations t<> a minimum by routine dipping of cattle
;i- often a- accessary. Individual premises can he freed of ticks
and maintained tick-free by proper dipping and quarantine meas-
ures, hut cattle raised on these premises would he nonimmune t«»
tick fever and thus the owner would he handicapped in selling ani-
mal- other than for meat purposes.

The complete eradication of the cattle tick from the island would
enable dairymen to hrim: in pure-bred animal- for replacements
and to improve the native stock without danger of death from
tick fever.

Further information concerning treatment, eradication, and the
diseases transmitted by this tick i- available in various bulletins
published by the United State- Department of Agriculture.

HORNFLY

The hornfly < H<i> n,<it<>hni serrata) (tin. 2, F) i- a bloodsucking fly
that attack- cattle and also horses. This fly i- about one-half the size
of the common house fly. It is easily determined by it- size and
by the fact that it always bites or suets blood with it- wings spi
and with the head toward the ground and in the same direction as
the hair of the animal.

Lifi history. — The fly deposits it- eggs in fresh cow manure,
larvae remain in the manure for :'> t<> 5 days before they burrow into
the drier -oil underneath to pupate. The adult fly emerges in 1<» t.»
II day- after the eggs are deposited.

Importance. — In the southern coastal area of Puerto Rico this
fly i- very common and a very serious pest of cattle. Attacks
myriads of these flic- are common. In the wet coastal area- it is
considerably Less important, hut it i> common at times, and control
measures are necessary.

Symptoms <in<I lesions. — The fly puncture.- the -kin and sucks
blood. The loss of blood is considerable where it attacks in large
numbers. Animal- sometimes lacerate the -kin of the Hank- with
their horns while fighting the fly.

Treatment. — A spray consisting of a kerosene extract of pyre-
thrum i> very effective in destroying these flies. Spraying morn-
ing and evening protects the animal from infestation and greatly
reduces the number of flies.

Prevention. — The manure collected from stables should t>
in fly-tight pit- or bins or spread immediately on fields. In dairy

1 CHAPIN, B M FKVKi; TICKS \M> METHODS OF EftADI-

,•' \_ Farmers' Bui. 1067, '■'<- pp.. Ulus. 1919.

M'.iu.i ::. .1. R n- b rsvBB U.S. Dept. A-r Farmers' Bui. 1625. :'.<» pp., illus.

StilbSj G w. Jr. w\ :\ cattle. I'.s. Dept. Agr. Circ. i~.4. i<» pp

PARASITIC DISEASES OF CATTLE IN PUERTO RICO 2^

herds, the fly can he controlled by scattering all of the fresh drop-
pings in the yards and pastures with a rake or other implement.
The scattered 'manure dries out rapidly and the larvae die for la«'k
of the moisture required for their development. Hogs and poultry
assist in control by scattering the droppings and by eating the
maggots.

OTHER EXTERNAL PARASITES

Common scab or " soma" of cattle. — The mange mite (Psoroptes
communis) (fig. 2. M) is found on the surface of the skin. It is a
very small animal, which may be seen with the naked eye if placed
on a dark background. Psoroptic mange is comparatively common,
but in the climate of Puerto Rico it rarely becomes a serious disease.
However. heav}r infestations have been found among animals which
were crowded together in small enclosures. The mite pricks the skin
and sucks the blood serum. The first symptom noticed is itching,
and later there is formation of scales and scabs and thickening of
the skin.

Dipping or spraying with the lime-sulphur dip and the nicotine
sulphur dip are effective remedies for this mange. Proprietary
brands of these preparations, ready for use, are available. Cattle
which are dipped regularly for ticks do not become infested with
this kind of mange mite. For eradication of the mange the treat-
ments must be repeated at intervals of 10 days. Two dippings may
usually be depended on to cure ordinary cases. Four or more dip-
pings may be necessary in chronic cases. After treatment the pens
or stables housing the infested animals should be left vacant for a
time or should be cleaned and disinfected with a strong solution of
cresol to destroy the stray mites. Experiments carried out by the
Bureau of Entomology. United States Department of Agriculture, in
cooperation with the Texas Agricultural Experiment Station have
shown that the longest period during which a pen remained infective
was 10 days.

Sarcoptic mange caused by another variety of mite also occurs in
cattle. This mite burrows into the skin, usually in locations where
the skin is tender and the hair is thin. This disease is more serious
than common scab because it is more severe in its effects and more
difficult to eradicate. Sarcoptic mange of cattle is a rare disease,
but local veterinarians report that infestations have occurred. The
treatment is the same as given for psoroptic mange but it requires
persistent, thorough, and frequent application of these preparations.
A veterinarian should be consulted if the presence of this mange is
suspected.

The screw worm. — The screw worm (Cochliomyia arm ricana) (fig.
2. L) is the maggot of a blowfly which may attack any open wound
of animals. The fly itself is not often noticed, but the maggots of
this species are distinguished from the larvae of other common blow-
flies by their habit of penetrating practically sound tissue. The fly
deposits its eggs in wounds, in masses of from 40 to 250 eggs. These
eggs hatch in 3 hours or less and the maggots burrow into the wound
and grow rapidly and become completely developed in 4 or 5 days.
The injury is due to the eating away of the tissues and also to toxic-
secretions produced by the maggot. There is also serious danger

24 BULLBT] . PI7E8T0 BIOO EXPERIMENT STATION

from hemorrhage and infection, Attacks from screw-worm flies
may occur at any time of the year but arc more frequent after the
end of the rainy season.

The best treatment for an infested wound is to pour in benzol or
chloroform, later remove the maggots, and apply pine-tar <»il to
prevent fresh attack-. The Bureau of Entomology, United States
Department of Agriculture, recommends the use 01 ! ommercial pine-
tar oil with a specific gravity of L.065to L.085. Probing and opening
the burrows arc regarded as inadvisable. All fresh wound- should
be coated with pine-tar oil to prevent fly blow. The navel of ca
at time of birth as well as the vulva of fresh cows having a retained
afterbirth should be protected from attack.

The maggots of other blowflies may infest the wounds of animal-.
There arc several- species of these flies in Puerto Rie<» but they are
of minor importance. The maggots arc usually Located only in old
: iiiLr wounds or the young are deposited after a -ore has been
infested with screw worms. Tin- control is the same a- for the -
worm-.

Large tail louse of cattle. — The sucking louse ( //
tubercvla&us) (fig. 2, H) is found in colonies in the switch of the
tail. On the continent this louse is called the buffalo louse. It is
found on the American bison. It is bluish gray in color and large
in size in comparison with other lice. The hairs of the switch of
the tail may be lined with the nits or ova. Occasionally the
are found attached to the hairs on the inside edge of the
Heavy infestations are found especially in dairy cows and calves
that are confined in stables and corrals. This louse is very common
on cattle of the southern coast. If the lice are numerous they
abstract considerable blood and lymph from the host and
itching and irritation and the formation of abrasions and sores.

The official arsenical solutions used for cattle ticks are very effec-
tive for eradicating lice. If cattle are sprayed, the switch and end
of the tail should be immersed in the solution for a minute or two,
as spraying is not as effective in control as dipping. Several dairy-
men have reported that this louse can be controlled by using the
kerosene-pyrethrum extract sprays. To eradicate lice it is usually
necessary to dip or spray at Least twice, with an interval of IT to 16
days between applications, since these preparations cannot be de-
pended upon to kill the eggs. After treatment the stables and pens
should be cleaned and disinfected with strong solutions of coal-tar
preparations.

Short-nosed ox Iou.<e. — A -mailer sucking louse. II. < wrysU i
is sometimes found on imported cattle and heavy infestations are
found occasionally on native cattle. This louse is located on the
body. Colonies of the lice may be found on the eyelids.

The stable fly. — The stable fly {Stomoxys ccHcitrans) (fi°;. 2, K)
is a bloodsucking fly that readily attacks horses and mules, but is
also common on cattle. This fly resembles the common house fly,
but, among other differences, it has a long slender proboscis, pro
big down and forward from the head. The fly deposits its egg- in
damp fermenting collections of grass, in cane trash, and in hoi -
cow manure that contains considerable straw. In the dry area- this

PARASITIC DISEASES OF CATTLE IN PUERTO RICO 25

fly is unimportant in cattle in comparison with the hornfly, but in
the other areas, at times, it is as common and serious as the hornfly.
The treatment is the same as for the hornfly (p. 22). All decaying
vegetable material around the stables should be cleaned up every
few days and placed with the manure in fly-tight bins or pits.

Mosquitoes. — Various species of mosquitoes attack animals, espe-
cially horses and cattle. The actual damage caused by them is not
known, but it may be considerable where mosquitoes are numerous.
Investigators connected with the Bureau of Malaria Control of
Puerto Rico have found by actual count that the two species of
mosquitoes transmitting malaria show rather a decided preference
for feeding upon horses and cattle as compared with man. No
practical method has been found for protecting livestock from
mosquitoes. Destroying the breeding places by drainage or treat-
ment with oil or paris green or by impounding water and using cer-
tain species of small fish which eat the wrigglers or larvae are always
important control measures for mosquitoes.

Fleas. — Occasionally fleas attack young stock which are confined,
in sufficient numbers to cause considerable irritation and a loss in
condition. These pests can be controlled by spraying with kerosene
or with the kerosene-pyrethrum extract sprays. First cleaning up
the litter and then spraying the floors and walls of the stable with
kerosene are also important control measures.

The leeches or " sangruijuelas." — The leeches (fig. 2, J) should be
mentioned as occasional parasites of some importance. They are
very abundant in swampy land. They attach themselves to any
part of the body of the host animal which they can reach, while the
animal is standing in water, and occasionally enter the mouth or
nostril while the animal is drinking.

Leeches not only suck considerable blood, increasing enormously
in size, but make wounds from which there is some hemorrhage after
the engorged leeches become detached. Leeches can be destroyed
by treating the water with copper sulphate, as described for the
snail transmitting the liver fluke.

Poisonous arthropods. — According to the unpublished statement
of one authority,4 there are a number of arthropods reputed to be
poisonous, among which may be mentioned the so-called tarantulas
of the family Avicuiaridae ; large centipedes; several species of
-scorpions; and at least one species of whip scorpion known locally
as the " guava." The " guavii " is probably the most dangerous of
the group. Owing to lack of scientific investigations it is impossible
to make any definite statements as to the exact degree of their ven-
omous qualities. However, there is little or no direct evidence that
the poisonous arthropods in Puerto Rico, except for occasional and
unimportant injuries, are dangerous to cattle or other animals.

Exotic parasites. — Both external and internal parasites have been
found in imported cattle. Among these, the cattle grubs. Hypo-
derma spp., the larvae of warble flies, are common and conspicuous.
Small tumors or lumps are found in the skin of the back, which con-
tain the larvae (fig. 2, G). There is no authentic record of these flies
having reproduced themselves in this climate.

* Stuart Danforth, professor of zoology, University of Puerto Rico.

26

i;i LLETIN 36, PUERTO RICO EXPERIMENT STATION

ERADICATION OF PARASITES

The only effective means of control of some of the diseases and par-
asites i- by island-wide eradication campaigns. Such campaigns are
comparatively simple because Puerto Rico is an island and the terri-
tory to be covered is small. The cattle tick and liver fluke are two
serious parasites thai should be eradicated ;it this time. In the
United States the eradication of the cattle tick Is being accomplished
by proper dipping of all cattle and horses in a given ana. nt 1 1-day
intervals over a period of 9 month-. The State of California has
completed a campaign of eradication of the liver fluke in sheep by
destroying the snail which transmits the parasite. Puerto Rico
needs more and better Livestock and a Larger and better dairy in-
dustry, and these objects can be promoted greatly by eradication of
the tick and liver fluke.

US GOVERN*!1." rt N"SG OFFICE: 1934

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