-184- 



(Table 4-6). After about three days, long-slender and short- 

 broad promastigotes appeared in the abdominal midgut. In one four- 

 day infection, short- broad dividing forms were packed in the anterior 

 cardia and attached by their flagella to the stomodeal valve, as observed 

 in L mexicana infections. Parasites were not observed anterior to the 

 stomodeal valve and short-slender, highly active forms were not seen. 



Leishmania donovani infantum (strain untyped). Fifty-one (89.5%) 

 of 57 Lu. diabol ica became infected when fed on the ear and abdomen of 

 a dog naturally infected with visceral leishmaniasis, apparently due 

 to L d. infantum . The dog had lived in Sicily for three years. 

 Fourteen (24.6%) of the flies refed on uninfected hamsters. Twelve of 

 those that refed were found to be infected upon dissection. The 

 growth pattern of L d_. infantum in Lu. diabol ica paralleled almost 

 exactly that of L mexicana . These infections and transmission trials 

 with visceral leishmaniasis will comprise the subject of a later 

 paper. 



Concurrent infections . Large, peanut-shaped flagellates with 

 large eccentric nuclei were also observed in about 50% of Leishmania - 

 infected sand flies and in some uninfected flies (Fig. 4-lla). Their 

 movement was rather sluggish and they appeared to be more ameboid than 

 the smaller leishmanial forms, frequently changing their shape. They 

 did not occur in large numbers, with rarely more than a dozen seen in 

 a single fly. Without the flagellum they measured about 15 pm in 

 length and about 4 ym in width. The flagellum was about half as long as 

 the body, measuring 8 to 9 pm. Upon fixation in 100% methanol they 

 rounded up, losing their characteristic peanut shape (Fig. 4-llb). 

 Their presence did not appear to be deleterious to either leishmanial 



