Trypanosoma cruzi transmission in a Colombian Caribbean region suggests that secondary vectors play an important epidemiological role

Abstract

BackgroundColombia, as part of The Andean Countries Initiative has given priority to triatomine control programs to eliminate primary (domiciliated) vector species such as Rhodnius prolixus and Triatoma dimidiata. However, recent events of Trypanosoma cruzi transmission in localities where R. prolixus and T. dimidiata are not present suggest that other species are involved in the T. cruzi transmission cycle.MethodsWe studied T. cruzi transmission on Margarita Island, located on the Magdalena River in the Colombian Caribbean region, where a high number of non-domiciliated triatomines infected with T. cruzi inside human dwellings have been observed. A cross-sectional survey including serological studies in humans and parasitological and molecular methods in vectors and reservoirs was conducted. We investigated risk factors for human infection and house infestation, and evaluated the association between abundance of wild triatomines in palm trees (Attalea butyracea) across municipalities, seasons and anthropogenic land use.ResultsThe T. cruzi seroprevalence rate in humans was 1.7% (13/743) and autochthonous active T. cruzi transmission was detected. The infection risk was associated with the capture of triatomines in human dwellings. Five wild mammal species were infected with T. cruzi, where Didelphis marsupialis was the main reservoir host with an 86.3% (19/22) infection rate. TcIb was the only genotype present among vectors. Triatomine abundance was significantly higher in Ecosystem 2, as well as in the dry season. Despite the absence of triatomine domiciliation in this area, T. cruzi active transmission was registered with a human seroprevalence rate similar to that reported in areas with domesticated R. prolixus.ConclusionsThis study illustrates the importance of secondary and household invading triatomines in Chagas disease epidemiology in the Caribbean lowlands of Colombia.

Detection of high percentage of Trypanosoma cruzi infection, the etiologic agent of Chagas disease, in wild populations of Colombian Caribbean triatomines

“…Recently, abundance of wild triatomines in five municipalities on Margarita Island, located on the Magdalena River in the Colombian Caribbean region, were reported by Cantillo- Barraza et al (2014). This locality was not included in our study.…”

Eco-epidemiological study of an endemic Chagas disease region in northern Colombia reveals the importance of Triatoma maculata (Hemiptera: Reduviidae), dogs and Didelphis marsupialis in Trypanosoma cruzi maintenance

“…However, recent studies have suggested its epidemiological relevance in the lowland Caribbean region of Colombia and the eastern Colombian plains [4, 5, 10, 42]. In a recent study [15], our group discussed the vectorial relevance of T. maculata based on a) the household-invading behaviour of infected adults, b) transmission in children less than fourteen years old, and c) an epidemiological association between the presence of this species in houses and human seropositivity [10, 15]. The present work provides new evidence supporting this argument.…”

“…The population is approximately 30,000 inhabitants, and the economy depends on subsistence agriculture. Previous studies performed in Talaigua Nuevo and Mompós, reported the presence of infected household-invading T. maculata and R. pallescens [6, 15]. …”

“…Among them, T. maculata, was often considered to be of little epidemiological relevance due to its low infection rates and apparently ornithophilic preferences [5, 7, 9]. However, recent studies in the Colombian Caribbean region reported the occurrence of active transmission, and infection risk was associated with highly infected T. maculata in peridomestic human dwellings [6, 10, 14, 15]. The differential relevance of T. maculata in transmission cycles from distinct geographical areas, suggests the ability of this vector to adapt to a variety of environments and its distinct ecological behaviours have different epidemiological implications [7, 16].…”

Risk of transmission of Chagas disease by intrusion of triatomines and wild mammals in Bucaramanga, Santander, Colombia

“…En este contexto, es necesario centrar la atención en el orden de los marsupiales y el género Didelphis, el cual es reconocido por su comportamiento sinantrópico, ya que visita o anida en el peridomicilio o en el domicilio en zonas rurales o urbanas, lo cual lo expone a picaduras de triatominos silvestres o domésticos (10,12,30,31).…”