CANINE MALARIA 343 
Geographical distribution. This disease has been found in several 
places in Africa, India, Italy and France. 
In 1908 Phillips and Miceeompbell reported an outbreak of piro- 
plasmosis in dogs from Ohio. 
Etiology. The Piroplasma canis is the cause of this -affection. 
Like Piroplasma bigeminum it appears in two forms, round and pear- 
shaped. They nearly always occur in the red blood corpuscles. It 
varies in its morphology. According to Marchoux Piroplasma canis 
in France is larger than Piroplasma bigeminum and single parasites 
occur more frequently. They vary in size from 2 to 44. At the 
beginning of the disease usually single large round forms appear. It 
is said by Nocard and Motas not to be pathogenic for other species of 
animals. The parasite is said to be transmitted by means of certain 
insects. Lounsbury has demonstrated that Pulex serra liceps, which 
is very abundant in certain localities, plays a réle in its transmission. 
In Italy Piroplasma canis is supposed to be transmitted by Ixodes 
ricinus. In France it is supposed to be conveyed by Dermacentor 
reticulatus. In South Africa it is conveyed by Haemaphysalis leachi. 
The parasite appears in the blood in from two to four days after 
artificial infection. 
Graham-Smith did not find the parasites in films from the peri- 
pheral circulation when stained by Leishman’s method until several 
days after infection. The earliest day on which they appeared was 
the sixth day and the latest the thirty-sixth day. In most cases they 
were observed between the eighth and twelfth days after infection. 
In a few cases he worked out the percentage of red blood corpuscles 
that were infected. He found that it varied from .3 to 1.4%. Free 
parasites were seldom encountered in the earlier stages but later they 
became more numerous. The day before death he found one free 
parasite to 23 infected corpuscles, and the day of death the free para- 
sites were still more numerous. He found little evidence of phagocy- 
tosis in the cases examined. Nucleated red corpuscles appeared in 
films from three dogs the day before death, and in three other dogs they 
appeared six days before death. Blood pigment was present in nearly 
all samples of urine. Young dogs are more susceptible than old ones. 
It is possible that the piroplasma of dogs is of different species in 
different countries. M’Fadyean and Nuttall found dogs that had 
recovered from piroplasmosis in India to be susceptible to the African 
infection. 
