The eco-epidemiology of domestic Trypanosoma cruzi infection in rural communities of the humid Chaco of Argentina.

CARDINAL MV, OROZCO MM, ENRIQUEZ GF, CEBALLOS LA, GASPE MS, ALVARADO-OTEGUI JA, GUREVITZ JM, KITRON U, GÜRTLER RE.

Atlanta

Encuentro; 61st Annual Meeting of the American Society of Tropical Medicine and Hygiene; 2012

American Society of Tropical Medicine and Hygiene

&amp;lt;!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0mm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 30.0mm 70.85pt 30.0mm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --&amp;gt; Abstract Background: The eco-epidemiology of the domestic transmission of Trypanosoma cruzi in the humid Chaco region has seldom been investigated. We assessed the household distribution of bug, dog and cat infection between local ethnic groups (Tobas and Creoles) to investigate differences in transmission risks between them; tested the role of domestic dogs and cats as reservoir hosts, and identified transmission risk factors. Methodology/Principal Findings: We conducted a cross-sectional survey of house infestation with Triatoma infestans and T. cruzi infection in bugs, dogs and cats in a well-defined rural area in northeastern Argentina including 323 households. Bug infection prevalence among 1,869 bugs examined was highest in domiciles (43%) and in storerooms or kitchens (24%), and was marginal elsewhere (<3%). The composite prevalence of infection was similar among 481 dogs (26%) and among 87 cats (29%) examined by serological methods and/or xenodiagnosis. Vector and host infections were highly aggregated at the household level. Using a catalytic irreversible model, the annual force of infection in dogs was three times higher among Toba than Creole households, in agreement with other transmission indices. The demography of dogs and cats differed between ethnic groups in several respects. Random-coefficient multiple logistic regression analysis showed that infection in dogs increased significantly with age of the dog, the household number of infected dogs or cats, and the relative abundance of infected bugs. The fraction of infected bugs increased significantly with the household number of infected dogs in a dose-response fashion. Infected cats also increased transmission to bugs when no infected dog was present. Conclusions/Significance: Our results reveal the persistence of domestic transmission of T. cruzi in northern Argentina, especially among Tobas; the occurrence of a peridomestic transmission cycle, and the key role of dogs and cats as domestic reservoir hosts, risk factors and control targets in the humid Chaco.