Vector Relationships in the Trypanosomatidae

This chapter discusses the interaction between trypanosomatid flagellates and their invertebrate hosts—the majority of those discussed are vectors. It also discusses the lower vertebrate trypanosomes and their vectors and mammalian trypanosomes and their vectors. Trypanosoma (Herpetosorna) rangeli (T. Rangeli) is one of the most interesting of mammalian trypanosomes. It is a parasite of man and various mammals in Central and South America and is transmitted by the bite of reduviids, usually Rhodnius prolixus. T. (H.) rangeli is pathogenic to its vector. The relationship between mammalian and reptilian Leishmania may prove to be of importance in understanding the epidemiology of the human disease. The chapter elaborates on the monoxenous trypanosomatid in insects. Under natural conditions, there are several situations in which an individual vector may be infected with more than one species of trypanosomatid. Thus, the effects of one parasite on another may be important in the context of competition for sites of establishment and available vector resources or because one species may be pathogenic to the vector, thus reducing the transmissibility of both parasites. Mixed infections between trypanosomes and monoxenous flagellates will occur in many situations, but few have been discussed in the chapter.