THE PIROPLASMASIDA 



313 



Pathogenesis : Corridor disease is 

 similar to East Coast fever and tropical 

 gonderiosis in its manifestations, G. 

 lawrencei is highly pathogenic for cattle, 

 the mortality being about 80%. African 

 buffaloes, however, are highly resistant 

 and serve as the reservoir of infection for 

 cattle. 



The incubation period following tick 

 transmission is 12 to 20 days, with a mean 

 of 15 days. The disease itself lasts 5 to 

 15 days, with a mean of 10 days. Peracute, 

 acute, subacute and mild forms have been 

 described. The acute form is the usual one. 



There is usually no anemia, altho 

 oligocythemia may occur. Icterus may be 

 present, but hematuria is not. The lymph 

 nodes, spleen and liver are often swollen, 

 edema of the lungs is pronounced, char- 

 acteristic ulcers are usually present in 

 the abomasum, and infarcts are some- 

 times present in the kidneys. 



Immunity : Animals which recover 

 from infection with G. lawrencei are pre- 

 mune. There is no cross-immunity be- 

 tween this species and G. miitans, but 

 there is partial or complete cross-immun- 

 ity between it and T. parva. 



Diagnosis : Same as for other species 

 of Gonderia and Theileria. 



Treatment : No effective drugs are 

 known for the treatment of Corridor dis- 

 ease, but there is some evidence that 

 chlortetracycline may suppress the dis- 

 ease if given repeatedly during the incu- 

 bation and patent periods. 



Prevention and Control : These de- 

 pend upon tick control and upon prevention 

 of association between cattle and African 

 buffaloes. 



GONDERIA HIRCI 

 (DSCHUNKOWSKY AND 

 URODSCHEVICH, 1924) 



Synonyms : Theileria hirci, Theil- 

 eria ovis du Toit, 1918; non T. ovis 

 Rodhain, 1916. 



Disease: Malignant ovine and cap- 

 rine gonderiosis, malignant ovine and 

 caprine theileriosis. 



Hosts : Sheep, goat. 



Location : Lymphocytes, erythro- 

 cytes. 



Geographic Distribution : North 

 Africa, southeastern Europe, southern 

 USSR, Asia Minor. 



Morphology : The erythrocytic 

 stages are about 80% round or oval, 18% 

 rod-shaped and 2% anaplasma-like. The 

 round forms are 0.6 to 2.0jj. in diameter 

 and the more elongate ones about 1.6/j, 

 long. Binary or quadruple fission takes 

 place in the erythrocytes. 



Koch bodies are common in the 

 lymphocjrtes of the spleen and lymph node 

 smears or free in these organs. They 

 average 8)iji in diameter but may range up 

 to 10 or even 20):x . They contain 1 to 80 

 reddish purple granules from 1 to 2(i in 

 diameter. Both macroschizonts and mi- 

 croschizonts can be found. These produce 

 merozoites 1 to 2;i in diameter. 



Life Cycle : The vector is unknown, 

 but is possibly Rhipicepfialus bursa. 



Pathogenesis : This species is highly 

 pathogenic for sheep and goats, mortal- 

 ities of 46 to 100% having been reported 

 in these animals. The disease is rela- 

 tively mild in young lambs and kids in 

 endemic areas. 



The incubation period is unknown. 

 The disease itself lasts 5 to 42 days. 

 Acute, subacute and chronic forms have 

 been described, the acute form being the 

 usual one. 



The disease resembles tropical bovine 

 gonderiosis in its manifestations. There 

 is fever following by listlessness, nasal 

 discharge, atony of the rumen and weak- 

 ness. Affected animals are anemic, and 

 icterus is frequently present. There is 

 often a transitory hemoglobinuria. The 

 lymph nodes are always and the liver 



