Targeted Screening Strategies to Detect Trypanosoma cruzi Infection in Children

Abstract

BackgroundMillions of people are infected with Trypanosoma cruzi, the causative agent of Chagas disease in Latin America. Anti-trypanosomal drug therapy can cure infected individuals, but treatment efficacy is highest early in infection. Vector control campaigns disrupt transmission of T. cruzi, but without timely diagnosis, children infected prior to vector control often miss the window of opportunity for effective chemotherapy.Methods and FindingsWe performed a serological survey in children 2–18 years old living in a peri-urban community of Arequipa, Peru, and linked the results to entomologic, spatial and census data gathered during a vector control campaign. 23 of 433 (5.3% [95% CI 3.4–7.9]) children were confirmed seropositive for T. cruzi infection by two methods. Spatial analysis revealed that households with infected children were very tightly clustered within looser clusters of households with parasite-infected vectors. Bayesian hierarchical mixed models, which controlled for clustering of infection, showed that a child's risk of being seropositive increased by 20% per year of age and 4% per vector captured within the child's house. Receiver operator characteristic (ROC) plots of best-fit models suggest that more than 83% of infected children could be identified while testing only 22% of eligible children.ConclusionsWe found evidence of spatially-focal vector-borne T. cruzi transmission in peri-urban Arequipa. Ongoing vector control campaigns, in addition to preventing further parasite transmission, facilitate the collection of data essential to identifying children at high risk of T. cruzi infection. Targeted screening strategies could make integration of diagnosis and treatment of children into Chagas disease control programs feasible in lower-resource settings.

Triatomine Infestation in Guatemala: Spatial Assessment after Two Rounds of Vector Control

“…We show a straightforward approach to assess hotspots or areas of concern in terms of reinfestation after spray in the context of an extensive vector control intervention and highlight potential gains that can be captured through simple alterations to programmatic practices. It has been shown previously that spatial analysis can be used to improve and evaluate CD control programs by optimizing spraying strategies, 32,33 monitoring reinfestation, 34 and targeting screening for T. cruzi in children 35 as well characterizing discordant results of tests for T. cruzi infection. 36 In the future, it is critical that the time between spray and evaluation be systematized in accordance with the technical guidelines provided by the PAHO such that houses in need of subsequent sprays be administered insecticide in a timely manner.…”

To spray or not to spray? Understanding participation in an indoor residual spray campaign in Arequipa, Peru

“…The Arequipa IRS campaign originally focused on peri-urban districts, where 4.7% of children had become infected prior to control activities (Bowman et al, 2008; Levy et al, 2007). Based on unpublished data, we know that in these localities (treated prior to 2009) campaign participation rates were consistently above 80% (Barbu et al, 2014; Levy et al, 2006).…”

Autonomic Dysfunction and Risk Factors Associated with Trypanosoma cruzi Infection among Children in Arequipa, Peru

“…The study site and participants are described in detail elsewhere. [25][26][27] Most study children were recruited in public schools in periurban communities on the outskirts of Arequipa; 20% were recruited at their homes in Guadalupe, a community within the larger study area. We studied children, because most were born and likely infected with Arequipa, providing a better indicator of local transmission.…”

“…Targeted screening strategies may improve the efficiency of programs to detect infected children and facilitate early treatment. 27 Antitrypanosomal drug treatment is indicated for all T. cruzi infected individuals younger than 18 years, with a recent trend to treat adults as well, 44,45 introducing important ethical considerations when considering the possibility of longitudinal cohort studies to investigate the prognostic value of autonomic dysfunction to predict development or progression of cardiomyopathy.…”