THE PATHOGENIC PROTOZOA 187 



The Piroplasmata. 



Piroplasma bigeminum, the cause of Texas fever or 

 bovine malaria, develops in the red blood- corpuscles, first 

 as a minute double body like a diplococcus, which ulti- 

 mately grows into two pear-shaped bodies. The disease 

 is transmitted through the ticks (Rhipiceplialus annulatus] 

 which live on the beasts. The female ticks feed on infected 

 animals, and after impregnation fall off and lay their 

 eggs, from which the young ticks develop. The infection 

 passes from the mother through the egg to the young tick, 

 which then infects the animal on which it feeds. It is 

 probable that the parasite passes through a developmental 

 cycle in the ticks. Cattle indigenous to the district are 

 immune. 



Piroplasma parvum is found in Rhodesia (red-water) 

 fever of cattle. Prophylactic vaccination is successful. 



Amakebe, a disease affecting calves in Uganda, has as 

 the chief symptom the swelling of the lymphatic glands. 

 After recovery from the disease a calf is immune for life. 

 In addition to P. bigeminum and P. mutans, to which 

 diseases Uganda cattle are immune, the blood contains a 

 small piroplasm indistinguishable from Piroplasma parvum, 

 and the Blue Bodies of Koch are found in the spleen. 

 Rhipicephali are carriers of the disease (R.A.M.C. Journal, 

 May, 1910). 



Piroplasmosis of dogs, horses, and sheep are caused 

 respectively by P. canis, P. equi, and P. ovis. 



The Microsporidia. 



Nosema apis causes the ' Isle of Wight ' bee disease 

 (microsporidiosis). Certain bees act as parasite ' carriers.' 



Nosema bombycis causes pebrine in silkworms. It 

 occurs as small glistening, roundish corpuscles, in the 

 caterpillar, butterfly, and egg. 



For further information on protozoan diseases see 

 Castellani and Chalmers' ' Manual of Tropical Medicine ' 

 Bailliere, Tindall and Cox (1913). 



