Re-emerging threat of Trypanosoma cruzi vector transmission in El Salvador, update from 2018 to 2020

Abstract

Background Since the late twentieth century, Chagas disease gained global attention to suppress the vector burden as a main control strategy in endemic countries. In Central America, multi-national initiative successfully achieved significant reduction in the estimated disease prevalence as well as elimination of the region’s principal vector species at the time in 2012. While the last decade has witnessed significant changes in ecosystem—such as urbanization and replacement of the main vector species—that can possibly affect the vector’s habitation and residual transmission, the up-to-date vector burden in the region has not been evaluated thoroughly due to the cessation of active vector surveillance. The aim of this study was to update the risk of vector-borne Trypanosoma cruzi infection in El Salvador, the top Chagas disease-endemic country in Central America. Methods A nationwide vector survey was conducted in the domestic environment of El Salvador from September 2018 to November 2020. The selection of the houses for inspection was based on expert purposeful sampling. Infection for T. cruzi was examined by microscopic observation of the insects’ feces, followed by a species confirmation using PCR. The data were analyzed using R software version 4.1.3. Proportion estimates with 95% confidence intervals were inferred using the Jeffrey’s method provided under the epiR package. Results A total of 1529 Triatoma dimidiata was captured from 107 houses (infestation rate, 34.4%; 107/311) in all the fourteen departments of the country visited within the period; prevalence of T. cruzi infection was as high as 10% (153/1529). In the country, domestic T. dimidiata infestation was distributed ubiquitously, while T. cruzi infection rates varied across the departments. Five out of fourteen departments showed higher infection rates than the average, suggesting sporadic high-risk areas in the country. Conclusions Our comprehensive study revealed substantial T. cruzi infection of T. dimidiata across the country, indicating potential active transmission of the disease. Therefore, strengthened surveillance for both vector and human infection is required to truly eliminate the risk of T. cruzi transmission in Central America.

Chagas Disease Maternal Seroprevalence and Maternal–Fetal Health Outcomes in a Parturition Cohort in Western El Salvador

“…As clustering of disease cases frequently occurs with T. cruzi infection, results of this study support prior evidence that ongoing vector-borne transmission is still occurring and a portion of pediatric cases in this region of El Salvador could possibly be contributed to congenital infection. A recent publication of T. dimidiata dispersion found a 10% overall T. cruzi infection rate within the disease vector and an elevated infection rate in the departments of Ahuachapan and Sonsonate [36]. The study further found >34% of surveyed houses had triatomine domiciliation.…”

“…The study further found >34% of surveyed houses had triatomine domiciliation. Adobe houses were most highly colonized by triatomines followed by mud and brick [36]. Substandard living conditions and socioeconomic limitations in certain parts of the western departments create risk for exposure to infected insects.…”

Identification of a triatomine infected with Trypanosoma cruzi in an urban area of the state of Veracruz, Mexico: A comprehensive study

“…The connectives present a yellow–orange coloration and with a very extensive characteristic dark central spot. Previous reports have shown the existence of species similar to T. dimidiata (Dorn et al, 2018; Lima‐Cordón et al, 2019), but due to the characteristics of the pronotum, legs and abdomen, the specimen corresponds to T. dimidiata ; this group of insects was mainly associated with sylvatics environments; however, it has expanded its habitat to domestic areas, through adaptation processes to environmental changes, increasing its interaction with humans (Dorn et al, 2007; Rodríguez et al, 2022). In addition, due to the position and magnitude of the central spots characterized by the Feret diameters; observed in the specimen, indicate its correspondence to a specimen of T. dimidiata of haplogroup 2 (Figure 2a), these spots are significantly different between T. dimidata haplogroups (Cruz et al, 2021).…”

Salvadoran Celastraceae Species as a Source of Antikinetoplastid Quinonemethide Triterpenoids

“…Between 2018 and 2020, a study in El Salvador, covering 107 households, revealed a 34.4% infection rate among approximately 1500 examined triatomines, vectors of the Chagas disease, and no less than 10% of them having the potential to transmit T. cruzi to humans [7]. In 2018, a surveillance study in western El Salvador found that the seropositivity rate for pediatric Chagas disease in the Sonsonate Department was 2.3%, surpassing the reported national adult rate of 1.7% [8].…”