Seasonal variations of Triatoma dimidiata demography and Trypanosoma cruzi transmission within its multi-host community in the Yucatan Peninsula, Mexico: Insights from an integrative SIR eco-epidemiological modelling

Résumé fourni par la source

Chagas disease is a zoonotic disease affecting 7 million people worldwide, mostly in Latin America. The causative agent, Trypanosoma cruzi, is transmitted by triatomine vectors feeding on a high diversity of vertebrate species. To understand its complex transmission dynamics is critical to assess disease risk and potential control strategies. We expanded a previous SI model of T. cruzi transmission in a typical synanthropic and domesticated host community into a SIR model to account for the effect of seasonal variations in the stage-structured vector demography and for the within-host parasite dynamics. The model was parameterized by using data on Triatoma dimidiata and hosts populations accumulated over the past 20 years in villages of the Yucatan peninsula, Mexico. Our modelling successfully reproduced 86.5% of the seasonal variations in vector abundance typically observed in those villages, with a peak of abundance during the warm and dry season (March to May), and it provided the first predictions of seasonal variations in the local T. cruzi transmission. Along with their abundance, vector infection was anticipated to rise by 23% from March to June, which closely matches a 19% increase in the field and led to a higher risk of T. cruzi transmission to all competent hosts. During this 3-months period, we predicted a two-fold increase in the incidence of T. cruzi, so that 39% of the yearly new infections occurred. Finally, sensitivity analyses provided evidence that reducing by 50% the current abundance of dogs, rodents, and increasing the current abundance of avians by 50% could reduce T. cruzi yearly incidence by up to ~38%, ~ 95%, and ~83%, respectively, supporting a promising potential for zooprophylactic control strategies that remain to be validated by empirical field studies. These findings strongly support the implementation of educational and empowerment strategies embedded in One Health approach to sustainably interrupt Chagas disease intra-domiciliary transmission.

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