High levels of human infection with Trypanosoma cruzi associated with the domestic density of infected vectors and hosts in a rural area of northeastern Argentina.

CARDINAL MV; SARTOR PA; GASPE MS; ENRIQUEZ GF; COLAIANNI I; GÜRTLER RE

PARASITES AND VECTORS

BIOMED CENTRAL LTD

Lugar: Londres; Año: 2018 vol. 11 p. 492 - 492

1756-3305

usually lack an active surveillance system that copes with house reinvasion. Following an insecticide campaign withno subsequent surveillance over a 12-year period, we implemented a longitudinal intervention programmeincluding periodic surveys for Triatoma infestans, full-coverage house spraying with insecticides, and selectivecontrol in a well-defined rural area of the Argentinean Chaco inhabited by Creoles and one indigenous group(Qom). Here, we conducted a cross-sectional study and report the age-specific seroprevalence of human T. cruziinfection by group, and examine the association between human infection, the onset of the intervention, therelative density of infected domestic bugs, and the household number of infected people, dogs, or cats.Results: The seroprevalence of infection among 691 residents examined was 39.8% and increased steadily withage, reaching 53?70% in those older than 20 years. The mean annual force of infection was 2.5 per 100 personyears(95% CI: 1.8?3.3%). Infection in children younger than 16 years born before the intervention programme wastwo to four times higher in houses with infected T. infestans than in houses without them and was six times higherwhen there were both infected dogs or cats and bugs than when they were absent. The model-averaged estimateof the intervention effect suggests that the odds of seropositivity were about nine times smaller for those bornafter the onset of the intervention than for those born before it, regardless of ethnic background, age, gender,household wealth, and cohabitation with T. cruzi-infected vectors or human hosts. Human infection was also closelyassociated with the baseline abundance of infected domestic triatomines and the number of infected cohabitants.Two of 43 children born after interventions were T. cruzi-seropositive; since their mothers were seropositive andboth resided in apparently uninfested houses they were attributed to vertical transmission. Alternatively, these casescould be due to non-local vector-borne transmission.