The potential risk of enzootic Trypanosoma cruzi transmission inside four training and re-training military battalions (BITER) in Colombia

Abstract

Background Colombia’s National Army is one of the largest military institutions in the country based on the number of serving members and its presence throughout the country. There have been reports of cases of acute or chronic cases of Chagas disease among active military personnel. These may be the result of military-associated activities performed in jungles and other endemic areas or the consequence of exposure to Trypanosoma cruzi inside military establishments/facilities located in endemic areas. The aim of the present study was to describe the circulation of T. cruzi inside facilities housing four training and re-training battalions [Battalions of Instruction, Training en Re-training (BITERs)] located in municipalities with historical reports of triatomine bugs and Chagas disease cases. An entomological and faunal survey of domestic and sylvatic environments was conducted inside each of these military facilities. Methods Infection in working and stray dogs present in each BITER location was determined using serological and molecular tools, and T. cruzi in mammal and triatomine bug samples was determined by PCR assay. The PCR products of the vertebrate 12S rRNA gene were also obtained and subjected to Sanger sequencing to identify blood-feeding sources. Finally, we performed a geospatial analysis to evaluate the coexistence of infected triatomines and mammals with the military personal inside of each BITER installation. Results In total, 86 specimens were collected: 82 Rhodnius pallescens, two Rhodnius prolixus, one Triatoma dimidiata and one Triatoma maculata. The overall T. cruzi infection rate for R. pallescens and R. prolixus was 56.1 and 100% respectively, while T. dimidiata and T. maculata were not infected. Eight feeding sources were found for the infected triatomines, with opossum and humans being the most frequent sources of feeding (85.7%). Infection was most common in the common opossum Didelphis marsupialis, with infection levels of 77.7%. Sylvatic TcI was the most frequent genotype, found in 80% of triatomines and 75% of D. marsupialis. Of the samples collected from dogs (n = 52), five (9.6%; 95% confidence interval: 3.20–21.03) were seropositive based on two independent tests. Four of these dogs were creole and one was a working dog. The spatial analysis revealed a sympatry between infected vectors and mammals with the military population. Conclusions We have shown a potential risk of spillover of sylvatic T. cruzi transmission to humans by oral and vectorial transmission in two BITER installations in Colombia. The results indicate that installations where 100,000 active military personnel carry out training activities should be prioritized for epidemiological surveillance of Chagas disease. Graphical abstract

Interrogating the transmission dynamics of Trypanosoma cruzi (Trypanosomatida, Trypanosomatidae) by Triatoma venosa (Hemiptera: Reduviidae) after the elimination of vector transmission by Rhodnius prolixus in Boyacá eastern Colombia

“…The municipalities of Chinavita, Garagoa and Sutatenza were certified free of R. prolixus intradomiciliary T. cruzi transmission in 2017 by PAHO, while Guateque, Somondoco and Tenza will be evaluated for certification in 2022 by PAHO. From each municipality, villages with household with T. venosa infestation reports after chemical-intervention for elimination of R. prolixus were selected for evaluation ( Table 1 ) ( Cantillo-Barraza et al., 2021 ). In addition, Triatomine Collection Stations (PITs-acronym in Spanish) for regular community surveillance activities were installed at each study location, as described by Cantillo-Barraza ( Cantillo-Barraza et al., 2021 ).…”

“…Boyacá department has 24 municipalities recently certified by PAHO-WHO as free of T. cruzi transmission through the elimination of intradomiciliary R. prolixus ( Cantillo-Barraza et al., 2021 ; Velásquez-Ortiz et al., 2022 ). However, recent evidence suggests that T. cruzi transmission risk maintained by other triatomine species, considering they can take advantage of the available niche, following the R. prolixus elimination ( Cantillo-Barraza et al., 2020a ; Cantillo-Barraza et al., 2021 ). The Tenza Valley, located in the southwest of the department, is a subregion Included in the elimination initiative ( Corredor et al., 1990 ; Guhl et al., 2007 ).…”

“…The chemical intervention for vector control performed in these municipalities developed by the Boyacá Health Department Service (BDHS) resulted in the elimination of R. prolixus . However, entomological surveillance between 2017 and 2018 following the chemical intervention showed the presence T. venosa inside the households ( Cantillo-Barraza et al., 2021 ).…”

“…Several evidence showed that T. dimidiata is now the most important vector in this department ( Cantillo-Barraza et al., 2021 ; Velásquez-Ortiz et al., 2022 ). However, the potential role of T. venosa in T. cruzi transmission is not yet clear ( Vargas et al., 2006 ; Cantillo-Barraza et al., 2021 ). Therefore, this study aimed to describe the ecological characteristics of T. cruzi transmission in areas with reinfestation by T. venosa to estimate the potential risk of this triatomine species in the resurgence of CD transmission.…”

Technological advances in the serological diagnosis of Chagas disease in dogs and cats: a systematic review

“…Recently, anti-T. cruzi antibodies were detected in 50% (17/34) of dogs from two rural settlements in the Sierra de Los Tuxtlas, Veracruz, Mexico [44]. In Costa Rica, 5.2-27.7% of dogs were seropositive in endemic areas [45][46][47], whereas in Colombia the prevalence ranged from 9.6% to 34% [48][49][50][51][52]. In the US, a study with 86 working dogs reported a seroprevalence of 14.1% [53], whereas other studies reported a lower prevalence [54][55][56][57].…”