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Discussion and Conclusions 



Infection of Sand Flies and Parasite Development 



General observations. A key factor in successful experimental 

 transmission studies is obtaining a high leishmanial infection rate to 

 produce large numbers of heavily infected sand flies, thus increasing 

 the probability of transmission. Several methods of infecting sand 

 flies from histiocytomas on hamsters have been used with varying 

 degrees of success. Johnson and Hertig (1970) restrained sand flies 

 in small cages made of bolting-cloth stretched over a wire frame. The 

 cages were fitted over the head or leg of the infected hamster and 

 fastened with a drawstring, thus confining the flies to the general 

 area of the lesion. They obtained infection rates of 22 to 66%, with 

 four leishmanial strains in Lu . sanguinaria (Fairchild and Hertig) and 

 Lu . gomezi (Nitz.), respectively. Lainson et aj_. (1977) obtained only 

 a 10% infection rate in Ltu 1 ongi pa 1 pi s (Lutz and Neiva) following 

 blood meals on L chagasi -infected hamsters. Because of this low 

 infection rate they resorted to a less natural method of feeding the 

 flies on amastigote suspensions through chick-skin membranes, and 

 obtained a 100% infection rate. Tesh and Modi (1984) fed amastigote 

 suspensions of six species of Leishmania to Phlebotomus papatasi 

 Scopoli and Lu. 1 ongi pal pis through a chick-skin membrane and obtained 

 high rates of infecton (73-100%) with all but two of the Leishmania 

 species. Christensen and Herrer (1980) obtained 88.9% and 82.6% 

 infection rates in Lu. sanguinaria and Uk gomezi , respectively, by 

 feeding the flies on anesthetized hamsters with histiocytomas of the 

 nose, feet and ears. Perkins (1982) found that when an anesthetized 



