Elucidating the Mechanism of Trypanosoma cruzi Acquisition by Triatomine Insects: Evidence from a Large Field Survey of Triatoma infestans.

Aaron W Tustin,Ricardo Castillo-Neyra,Michael Z Levy,Katty Borini-Mayorí,Renzo Salazar,Laura D Tamayo

doi:10.3390/tropicalmed5020087

Abstract

Blood-sucking triatomine bugs transmit the protozoan parasite Trypanosoma cruzi, the etiologic agent of Chagas disease. We measured the prevalence of T. cruzi infection in 58,519 Triatoma infestans captured in residences in and near Arequipa, Peru. Among bugs from infected colonies, T. cruzi prevalence increased with stage from 12% in second instars to 36% in adults. Regression models demonstrated that the probability of parasite acquisition was roughly the same for each developmental stage. Prevalence increased by 5.9% with each additional stage. We postulate that the probability of acquiring the parasite may be related to the number of feeding events. Transmission of the parasite does not appear to be correlated with the amount of blood ingested during feeding. Similarly, other hypothesized transmission routes such as coprophagy fail to explain the observed pattern of prevalence. Our results could have implications for the feasibility of late-acting control strategies that preferentially kill older insects.

Highlights

Trypanosoma cruzi, the protozoan parasite that causes Chagas disease, is transmitted to humans via the feces of blood-sucking triatomine insects (Hemiptera: Reduviidae) such as Triatoma infestans, the major vector of Chagas disease in much of South America [1]
In this report we show the stage-prevalence of T. cruzi in a large sample of T. infestans captured during vector control and surveillance activities in Arequipa, Peru
In a large field survey of Triatoma infestans captured in Arequipa, Peru, we demonstrate that the probabMiliotydeolfNTarympeanosoma crFuizttieadcPqauriasmitieotenr is the samBeeastt-eFaitcPhadraemveetleorp(m95e%ntal staAgIeC

Summary

Introduction

Trypanosoma cruzi, the protozoan parasite that causes Chagas disease, is transmitted to humans via the feces of blood-sucking triatomine insects (Hemiptera: Reduviidae) such as Triatoma infestans, the major vector of Chagas disease in much of South America [1]. All triatomine stages are at risk for acquiring T. cruzi because they all ingest blood meals. In this report we show the stage-prevalence of T. cruzi in a large sample of T. infestans captured during vector control and surveillance activities in Arequipa, Peru.

Results

Conclusion