34 CIRCULAR 338, U. S. DEPT. OF AGRICULTURE 



CANINE PIROPLASMOSIS 



Cause. — Piroplasmosis in the dog is due to the presence in the 

 red blood cells of a small protozoan parasite related to the organism 

 causing tick fever of cattle. This parasite is transmitted from 

 infected to healthy dogs through the bites of ticks. Several ticks have 

 been incriminated as vectors of canine piroplasmosis in various parts 

 of the world and among them is the brown dog tick, Rhipicephalus 

 sanguineus. It is probable that R. sanguineus is the important 

 vector of the disease in the United States, since this tick is common 

 in some parts of this country. (See p. 12.) The extent of canine 

 piroplasmosis in dogs in this country is not known, but one case in 

 Florida has recently come to the attention of the writers. 2 Cats are 

 not known to be susceptible. 



Symptoms. — Canine piroplasmosis may be either acute or chronic. 

 In the acute form of the disease the infected animal may show increase 

 in temperature, reddening of the mucous membrances, increased 

 pulse and respiration, loss of appetite, and increased thirst. Jaundice 

 is present in about 50 percent of the cases. Acute cases frequently 

 terminate in death. 



In chronic cases fever may be present during the first days of the 

 infection, and in rare cases there may be an intermittent fever. The 

 animals become listless and the mucous membrane pale; jaundice h 

 usually absent in chronic cases. There is a diminished appetite, and 

 the infected animals become greatly emaciated. A positive diagnosis 

 can be made only by microscopic examination of the blood and finding 

 the parasites in the red corpuscles. 



Treatment. — Trypan blue is said to be a specific in some forms of 

 canine piroplasmosis. The drug is used in the form of a 2-percent 

 solution in sterile distilled water. It is recommended that the powder 

 be finely triturated with a small quantity of cold water in a mortar and 

 more water added gradually until the dye enters completely into 

 solution, which is then made up to the desired percentage. The 

 solution should be filtered through filter paper and the filtrate auto- 

 claved at a temperature of 120° C. for 20 minutes. When cool, the 

 solution is transferred to sterile bottles which should be carefully 

 sealed. The dose of the solution that has been suggested for a dog of 

 average weight is 5 to 6 cubic centimeters injected intravenously. 

 One dose of trypan blue is usually sufficient to effect a cure in 

 infections with Babesia canis, one of the species causing canine 

 piroplasmosis. 



Tryparsamide has been reported also as being effective in the treat- 

 ment of canine piroplasmosis. The dose of the drug for a 25-pound 

 dog is given as 0.85 gram dissolved in 5 cubic centimeters of sterile 

 distilled water, administered intravenously. Best results are ob- 

 tained following the use of 5 injections with an interval of 5 days 

 between each injection. Other arsenical preparations also have been 

 recommended in the treatment of canine piroplasmosis. 



2 This report is based on a case diagnosed by Dr. Paul Eaton of the Florida Department of Heahh, the 

 diagnosis being confirmed by Dr. G. Dikmans, of the Federal Bureau of Animal Industry. 



