Trypanosoma cruzi–Trypanosoma rangelico-infection ameliorates negative effects of single trypanosome infections in experimentally infectedRhodnius prolixus

Abstract

Trypanosoma cruzi, causative agent of Chagas disease, co-infects its triatomine vector with its sister species Trypanosoma rangeli, which shares 60% of its antigens with T. cruzi. Additionally, T. rangeli has been observed to be pathogenic in some of its vector species. Although T. cruzi-T. rangeli co-infections are common, their effect on the vector has rarely been investigated. Therefore, we measured the fitness (survival and reproduction) of triatomine species Rhodnius prolixus infected with just T. cruzi, just T. rangeli, or both T. cruzi and T. rangeli. We found that survival (as estimated by survival probability and hazard ratios) was significantly different between treatments, with the T. cruzi treatment group having lower survival than the co-infected treatment. Reproduction and total fitness estimates in the T. cruzi and T. rangeli treatments were significantly lower than in the co-infected and control groups. The T. cruzi and T. rangeli treatment group fitness estimates were not significantly different from each other. Additionally, co-infected insects appeared to tolerate higher doses of parasites than insects with single-species infections. Our results suggest that T. cruzi-T. rangeli co-infection could ameliorate negative effects of single infections of either parasite on R. prolixus and potentially help it to tolerate higher parasite doses.

Rhodnius stali: new vector infected by Trypanosoma rangeli (Kinetoplastida, Trypanosomatidae)

“…Moreover, it is known that the occurrence of T. cruzi and T. rangeli in the same geographical region, allows for the occurrence of mixed infections in both vertebrate hosts and vectors 1 , making it diffi cult to isolate and differentially diagnose the infection, leading to misdiagnoses of Chagas disease 15 . This situation is of concern, especially in regions where other vector species of T. rangeli are reported, such as the state of Acre, where they occur in addition to R. stali, for example, the species R. pictipes, R. robustus and R. montenegrensis 10,14 .…”

Trypanosoma cruzi Infection Does Not Decrease Survival or Reproduction of the Common Bed Bug, Cimex lectularius

“…36 In triatomine bugs, the known vectors of T. cruzi, some studies report that T. cruzi retards development time, reduces survival, decreases reproductive rates, and modifies other phenotypes in T. cruzi-infected bugs, [37][38][39][40] whereas others have reported no significant effects. [41][42][43] Life history variation in T. cruzi-infected triatomines has also been associated with insect age, sex, 39 T. cruzi strain, 44 parasite community within the host, 45,46 and temperature. 47 Cimex heterogeneity.…”

Broad patterns in domestic vector-borne Trypanosoma cruzi transmission dynamics: synanthropic animals and vector control

“…The probabilities of infection are unique to each infection class, while the contact rate is the same, as we assume homogeneous mixing. Our current model ignores co-infection at subsequent blood meals, a complexity that has been observed to give rise to more complex dynamics in T. cruzi -infected R. prolixus [ 20 ]. We assumed that infected vectors had slightly lower fitness than uninfected vectors [ 20 – 22 ], represented by a scalar term f that could take values between 0–1.…”