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 RICO 1 
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 
