Biological Factors Influencing Transmission of Trypanosoma rangeli by Rhodnius prolixus

Certain biological factors which might influence transmission of a Venezuelan strain of Trypanosoma rangeli by Rhodnius prolixus are presented with statistical evaluation of their significance. T. rangeli must invade the salivary glands of R. prolixus before transmission is possible. When 1st instar nymphs were exposed to an infected meal, survival during the nymphal stages decreased. This decrease was statistically significant and indicates that T. rangeli is pathogenic for R. prolixus nymphs. There was no indication that blood from different vertebrate hosts influenced survival. In adult survivors exposed as nymphs as well as in those exposed as adults the cycle progressed to the salivary glands in a significantly greater percentage of males than females. There was no significant difference in the percentage of mature infections between those exposed as 1st instar nymphs and those exposed as adults. There appeared to be no advantage in multiple infective feedings.