Trypanosoma cruzi transmission dynamics in a synanthropic and domesticated host community

Abstract

Trypanosoma cruzi is the causative agent of Chagas disease, a Neglected Tropical Disease affecting 8 million people in the Americas. Triatomine hematophagous vectors feed on a high diversity of vertebrate species that can be reservoirs or dead-end hosts, such as avian species refractory to T. cruzi. To understand its transmission dynamics in synanthropic and domesticated species living within villages is essential to quantify disease risk and assess the potential of zooprophylaxis. We developed a SI model of T. cruzi transmission in a multi-host community where vector reproduction and parasite transmission depend on a triatomine blood-feeding rate accounting for vector host preferences and interference while feeding. The model was parameterized to describe T. cruzi transmission in villages of the Yucatan peninsula, Mexico, using the information about Triatoma dimidiata vectors and host populations accumulated over the past 15 years. Extensive analyses of the model showed that dogs are key reservoirs and contributors to human infection, as compared to synanthropic rodents and cats, while chickens or other domesticated avian hosts dilute T. cruzi transmission despite increasing vector abundance. In this context, reducing the number of dogs or increasing avian hosts abundance decreases incidence in humans by up to 56% and 39%, respectively, while combining such changes reduces incidence by 71%. Although such effects are only reached over >10-years periods, they represent important considerations to be included in the design of cost-effective Integrated Vector Management. The concomitant reduction in T. cruzi vector prevalence estimated by simulating these zooprophylactic interventions could indeed complement the removal of colonies from the peridomiciles or the use of insect screens that lower vector indoor abundance by ~60% and ~80%. These new findings reinforce the idea that education and community empowerment to reduce basic risk factors is a cornerstone to reach and sustain the key objective of interrupting Chagas disease intra-domiciliary transmission.

Domestic host availability modifies human‐triatomine contact and host shifts of the Chagas disease vector Triatoma infestans in the humid Argentine Chaco

“…dogs and chickens) were assumed to increase bug carrying capacity (Spagnuolo et al ., 2012; Peterson et al ., 2015). Other modelling approaches also supported that increasing the number of dogs would amplify the intensity of domestic transmission (Fabrizio et al ., 2016; Flores‐Ferrer et al ., 2019). The latter model, fitted to the specific eco‐epidemiology of T. dimidiata and T. cruzi in Yucatan (Mexico), predicted that a large increase in the number of chickens would decrease bug and human infection in the long‐term.…”

Dynamics of food sources, ecotypic distribution and Trypanosoma cruzi infection in Triatoma brasiliensis from the northeast of Brazil

“…Additionally, the population must be aware of the potential risk of keeping sylvatic rodents as pets or for hunting-information provided by local people. For T. cruzi transmission by T. dimidiata in the Yucatan peninsula, Mexico, Flores-Ferrer and cols [37] developed sophisticated models of T. cruzi transmission in a multi-host combination. They suggested that vector reproduction and parasite transmission depend on the triatomine bloodfeeding preference.…”

“…cruzi transmission by T . dimidiata in the Yucatan peninsula, Mexico, Flores-Ferrer and cols [ 37 ] developed sophisticated models of T . cruzi transmission in a multi-host combination.…”

Dispersal patterns of Trypanosoma cruzi in Arequipa, Peru

“…However, epidemiological models suggest that infected hosts are likely to transmit T. cruzi to vectors given sufficient time and vector abundance. That is, one infected human infects 21 vectors on average while 100 vectors on average are needed to infect one human [37,38]. By sampling T. cruzi primarily from vectors we likely capture the least biased representation of the diversity in the city in order to determine how a single population of T. cruzi migrated through Arequipa.…”