Identification of bloodmeal sources of triatomines captured in the Paraguayan Chaco region of South America by means of molecular biology analysis

Fraenkel, Stefanía; Salvioni, Oscar Daniel; Arias, Antonieta Rojas de; Arze, Verónica Paola; Rolón, Míriam; Ramírez, Natalia Andrea; Gómez, Celeste Vega

doi:10.1080/20477724.2020.1716558

Cited by 9 publications

(5 citation statements)

References 21 publications

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“…The main blood meal source detected in domestic bugs was humans, whereas chickens and dogs were the main blood meal sources in the peridomestic ecotopes, as in other settings [27,28,[44][45][46][47]. Domestic T. infestans collected in the Paraguayan Chaco nearly exclusively fed on humans [48], in a context of strong vector control activities. In Avia Terai, chickens were relevant blood meal sources in all ecotopes across the rural-to-urban gradient, with the exception of urban domiciles where we found bugs only fed on humans and cats.…”

Section: Discussionmentioning

confidence: 99%

Trypanosoma cruzi infection in Triatoma infestans and high levels of human–vector contact across a rural-to-urban gradient in the Argentine Chaco

et al. 2021

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Background Peri-urban and urban settings have recently gained more prominence in studies on vector-borne transmission of Trypanosoma cruzi due to sustained rural-to-urban migrations and reports of urban infestations with triatomines. Prompted by the finding of Triatoma infestans across the rural-to-urban gradient in Avia Terai, an endemic municipality of the Argentine Chaco, we assessed selected components of domestic transmission risk in order to determine its variation across the gradient. Methods A baseline vector survey was conducted between October 2015 and March 2016, following which we used multistage random sampling to select a representative sample of T. infestans at the municipal level. We assessed T. cruzi infection and blood-feeding sources of 561 insects collected from 109 houses using kinetoplast DNA-PCR assays and direct enzyme-linked immunosorbent assays, respectively. We stratified triatomines according to their collection site (domestic or peridomestic), and we further categorized peridomestic sites in ecotopes of low- or high-risk for T. cruzi infection. Results The overall adjusted prevalence of T. cruzi-infected T. infestans was 1.8% (95% confidence interval [CI] 1.3–2.3) and did not differ between peri-urban (1.7%) and rural (2.2%) environments. No infection was detected in bugs captured in the urban setting; rather, infected triatomines were mainly collected in rural and peri-urban domiciles, occurring in 8% of T. infestans-infested houses. The main blood-feeding sources of domestic and peridomestic triatomines across the gradient were humans and chickens, respectively. The proportion of triatomines that had fed on humans did not differ between peri-urban (62.5%) and rural (65.7%) domiciles, peaking in the few domestic triatomines collected in urban houses and decreasing significantly with an increasing proportion of chicken- and dog- or cat-fed bugs. The relative odds ratio (OR) of having a T. cruzi infection was nearly threefold higher in bugs having a blood meal on humans (OR 3.15), dogs (OR 2.80) or cats (OR: 4.02) in a Firth-penalized multiple logistic model. Conclusions Trypanosoma cruzi transmission was likely occurring both in peri-urban and rural houses of Avia Terai. Widespread infestation in a third of urban blocks combined with high levels of human–triatomine contact in the few infested domiciles implies a threat to urban inhabitants. Vector control strategies and surveillance originally conceived for rural areas should be tailored to peri-urban and urban settings in order to achieve sustainable interruption of domestic transmission in the Chaco region.

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Section: Discussionmentioning

confidence: 99%

Trypanosoma cruzi infection in Triatoma infestans and high levels of human–vector contact across a rural-to-urban gradient in the Argentine Chaco

et al. 2021

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“…11 Of the 131 T. sordida from the eastern and 140 from the western region, analyzed by OM, the natural infection was detected in approximately 12% and 10%, respectively (Table 3). 10 ; 8 Fraenkel et al 24 ; D = domiciliary; FS = food source; IP = natural infection with T. cruzi in the region peridomiciliary; P = peridomiciliary; W = wild; I = natural infection with T. cruzi; II = natural infection with T. cruzi in the intradomiciliary region.…”

Section: Resultsmentioning

confidence: 99%

Chagas Disease Vectors of Paraguay: Entomoepidemiological Aspects of Triatoma sordida (Stål, 1859) and Development of an Identification Key for Paraguayan Triatomines Based on Cytogenetics Data

González-Brítez

Alevi

Garcia

et al. 2021

The American Journal of Tropical Medicine and Hygiene

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Approximately 150,000 people are living with Chagas disease in Paraguay. Although the country has been since 2008 considered as one of the countries that succeeded in interrupted the vector transmission of Chagas by Triatoma infestans in houses of the eastern region, there are nine other species notified in the country that are potential vectors and also deserve attention from vector control programs. Thus, we carried out an entomoepidemiological study of T. sordida in the eastern and western regions of the country and we developed an identification key for Paraguay's triatomines based on cytogenetic data. Between the years 2003 to 2004, 271 specimens of T. sordida were captured in domestic, peridomestic, and wild ecotopes, with 131 insects caught in the eastern (Alto Paraguay, Boquerón and Pte. Hayes) and 140 in the western region of Paraguay (Guairá and Paraguarí). High rates of peridomicillary infestation were observed for both regions. Besides that, the natural infection of the captured insects was detected by optical microscopy in 12% and 10%, and by PCR in 21% and 20% in the eastern and western regions, respectively. Based on cytogenetic data from nine of ten species notified in Paraguay, an identification key was developed to differentiate all taxa. Thus, given the vectorial importance of T. sordida, we highlight the need for continued attention from Paraguay's vector control programs for this species. Further, we provide a taxonomic key that assists in the correct classification of Paraguayan triatomines.

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Section: Discussionmentioning

confidence: 99%

“…Another study from this area detected T. infestans from 12J which had fed on human blood exclusively (53.3%), as well as on both humans and chickens (46.7%), establishing a link between these domestic and peridomestic transmission cycles [88]. In previous studies, sylvatic T. infestans from 12J have been collected from up to 2.5 km away from community dwellings and shown to have obtained blood meals from multiple sources, including chickens and humans, further demonstrating the capacity for these populations to mobilize, disperse widely and survive in different microhabitats [26].…”

Section: Plos Onementioning

confidence: 91%

Dynamics of Triatoma infestans populations in the Paraguayan Chaco: Population genetic analysis of household reinfestation following vector control

Arias¹,

Messenger

Rolón³

et al. 2022

PLoS ONE

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Background Although domestic infestations by Triatoma infestans have been successfully controlled across Latin America, in areas of the Gran Chaco region, recurrent post-spraying house colonization continues to be a significant challenge, jeopardizing Chagas disease vector control and maintaining active Trypanosoma cruzi transmission. Methodology/Principal findings To investigate the dynamics of triatomine reinfestation in a rural area of the Paraguayan Chaco, genetic characterization (based on 10 microsatellite loci and cytochrome B sequence polymorphisms) was performed on baseline and reinfestant T. infestans (n = 138) from four indigenous communities and adjacent sylvatic sites. House quality and basic economic activities were assessed across the four communities. Significant genetic differentiation was detected among all baseline triatomine populations. Faster reinfestation was observed in the communities with higher infestation rates pre-spraying. Baseline and reinfestant populations from the same communities were not genetically different, but two potentially distinct processes of reinfestation were evident. In Campo Largo, the reinfestant population was likely founded by domestic survivor foci, with reduced genetic diversity relative to the baseline population. However, in 12 de Junio, reinfestant bugs were likely derived from different sources, including survivors from the pre-spraying population and sympatric sylvatic bugs, indicative of gene-flow between these habitats, likely driven by high human mobility and economic activities in adjacent sylvatic areas. Conclusions/Significance Our results demonstrate that sylvatic T. infestans threatens vector control strategies, either as a reinfestation source or by providing a temporary refuge during insecticide spraying. Passive anthropogenic importation of T. infestans and active human interactions with neighboring forested areas also played a role in recolonization. Optimization of spraying, integrated community development and close monitoring of sylvatic areas should be considered when implementing vector control activities in the Gran Chaco.

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Identification of bloodmeal sources of triatomines captured in the Paraguayan Chaco region of South America by means of molecular biology analysis

Cited by 9 publications

References 21 publications

Trypanosoma cruzi infection in Triatoma infestans and high levels of human–vector contact across a rural-to-urban gradient in the Argentine Chaco

Trypanosoma cruzi infection in Triatoma infestans and high levels of human–vector contact across a rural-to-urban gradient in the Argentine Chaco

Chagas Disease Vectors of Paraguay: Entomoepidemiological Aspects of Triatoma sordida (Stål, 1859) and Development of an Identification Key for Paraguayan Triatomines Based on Cytogenetics Data

Dynamics of Triatoma infestans populations in the Paraguayan Chaco: Population genetic analysis of household reinfestation following vector control

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