PIROPLASMOSIS. 523 



grass; and it is resident in localities where horse-sickness is un- 

 known. Mr. D. Hutcheon, C.V.S., Cape Town, tells us (" Veterinary 

 Record," 5th April,,^ 1902), that " in the Cape Colony it is more 

 prevalent in the Cape Peninsula, and along the East Coast, extend- 

 ing about 100 miles inland, than elsewhere, but its area of infection 

 has been increasing, and cs/ses are now met with all over the South 

 African Colonies." Dr. Theiler was the first to observe micro- 

 organisms in the blood of horses affected with this South African 

 disease, and Mr. W. Robertson, M.R.C.V.S., in 1900, found in the 

 red blood corpuscles of such animals, protozoa closely resembling 

 those of human malarial fever; hence this disease is nearly allied 

 to Indian malarial fever. It is most prevalent during summer and 

 autumn. " Imported horses are more subject to it than Colonial 

 bred. Horses which are brought to the coast from the high inland 

 districts, where the disease is rarely met with, are also more 

 susceptible to an attack than those bred on the coast. T know of 

 several farms where almost every strange horse which is brought 

 there during the summer or autumn months contracts the disease. 

 Horses are liable also to a second attack, but such horses in my 

 experience have been removed from the infected centre subsequent 

 to the first attack, and become reinfected on their return. Horses 

 reared continuously on the same farm do not contract the disease 

 a second time, and, many horses, which are bred and reared on 

 such farms, do not become visibly affected with the disease at all " 

 (Hutcheon). 



The disease is sudden in its attack. The horse is depressed, 

 breathing and pulse quickened, and temperature very high. The 

 loss of appetite is more or less dependent on the severity of the' 

 symptoms, but there is almost always considerable thirst. The 

 lining membrane of the eyelids assumes a bright yellow colour, 

 and the mucous membrane of the lips becomes tinged with yellow; 

 hence the name of " biliary fever." The bowels are constipated, 

 as a rule, and sometimes the animal suffers from colic. The urine 

 is frequently amber-coloured, red, and blackish. Urticarial wheals 

 appear on the chest and abdomen, and may remain for weeks. 

 '■ Usually the fever lasts from four to seven days, although some 

 cases may last much longer. In the great majority of cases that 

 are properly attended to and recover, the temperature usually 

 begins to fall on the third day, and the animal may be apparently 

 all right by the sixth day. In fatal oases, the temperatiu-e remains 

 high, the breathing becomes quicker and more distressing, and the 

 general uneasiness greater until the end ; death may take place 

 from the fourth to the eighth day " (Hutcheon). We thus see that 

 equine malarial fever resembles human malarial fever, as regards 

 its acquired immunity and bilious symptoms, which appear to be 



