Urbanisation, risk stratification and house infestation with a major vector of Chagas disease in an endemic municipality of the Argentine Chaco

GASPE, MARÍA SOL; FERNÁNDEZ, MARÍA DEL PILAR; CARDINAL, MARTA VICTORIA; ENRIQUEZ, GUSTAVO FABIÁN; RODRÍGUEZ-PLANES, LUCÍA INÉS; MACCHIAVERNA, NATALIA PAULA; GÜRTLER, RICARDO ESTEBAN

PARASITES AND VECTORS

BIOMED CENTRAL LTD

Año: 2020 vol. 13

1756-3305

Background: The occurrence of the major vectors of Chagas disease has historically been linked to poor rural housing,but urban or peri-urban infestations are increasingly being reported. We evaluated a simple risk index to detecthouses infested with Triatoma infestans and tested whether house infestation and vector abundance increased acrossthe urban-to-rural gradient in Avia Terai, an endemic municipality of the Argentine Chaco; whether the associationbetween infestation and selected ecological determinants varied across the gradient; and whether urban and periurbaninfestations were associated with population settlement history.Methods: We conducted a screening survey of house infestation in 2296 urban, peri-urban and rural dwellings toidentify high-risk houses based on a simple index, and then searched for triatomines in all high-risk houses and in asystematic sample of low-risk houses.Results: The risk index had maximum sensitivity and negative predictive value, and low specificity. The combinednumber of infested houses in peri-urban and urban areas equalled that in rural areas. House infestation prevalencewas 4.5%, 22.7% and 42.4% across the gradient, and paralleled the increasing trend in the frequency of domesticanimals and peridomestic structures. Multiple logistic regression analysis showed that house infestation was positivelyand significantly associated with the availability of poultry and bug refuges in walls, and was negatively associatedwith domestic insecticide use. Several pieces of evidence, including absence of spatial aggregation of house infestation,support that T. infestans has been a long-established occupant of urban, peri-urban and rural settings in AviaTerai.Conclusions: An integrated vector management strategy targeting chicken coops and good husbandry practicesmay provide more cost-effective returns to insecticide-based vector elimination efforts.