Distribution of triatomine species in domestic and peridomestic environments in central coastal Ecuador

PLoS Negl Trop Dis. 2017 Oct 2;11(10):e0005970. doi: 10.1371/journal.pntd.0005970. eCollection 2017 Oct.

Abstract

Background: Although the central coast of the Ecuador is considered endemic for Chagas disease, few studies have focused on determining the risk of transmission in this region. In this study we describe the triatomine household infestation in Manabí province (Central Coast region), determine the rate of Trypanosoma cruzi infection and study the risk factors associated with infestation by Rhodnius ecuadoriensis.

Methodology/principal findings: An entomological survey found three triatomine species (Rhodnius ecuadoriensis, Panstrongylus rufotuberculatus and P. howardi) infesting domiciles in 47.4% of the 78 communities visited (total infestation rate of 4.5%). Four percent of domiciles were infested, and nymphs were observed in 77% of those domiciles. The three species were found in altitudes below 500 masl and in all ecological zones except cloud forest. Within the domicile, we found the three species mostly in bedrooms. Rhodnius ecuadoriensis and P. rufotuberculatus were abundant in bird nests, including chicken coops and P. howardi associated with rats in piles of bricks, in the peridomicile. Triatomine infestation was characterized by high rates of colonization, especially in peridomicile. Flagelates infection was detected in only 12% of the samples by microscopy and Trypanosoma cruzi infection in 42% of the examined triatomines by PCR (n = 372). The most important risk factors for house infestation by R. ecuadoriensis were ecological zone (w = 0.99) and presence of chickens (w = 0.96). Determinants of secondary importance were reporting no insecticide applications over the last twelve months (w = 0.86) and dirt floor (w = 0.70). On the other hand, wood as wall material was a protective factor (w = 0.85).

Conclusion/significance: According the results, approximately 571,000 people would be at high risk for T. cruzi infection in Manabí province. A multidisciplinary approximation and the adhesion to a periodic integrated vector management (IVM) program are essential to guarantee sustainable preventive and control strategies for Chagas disease in this region.

MeSH terms

  • Animal Distribution
  • Animals
  • Animals, Domestic
  • Chagas Disease / epidemiology*
  • Chagas Disease / parasitology
  • Chagas Disease / prevention & control
  • Chagas Disease / transmission
  • Chickens / parasitology
  • Cross-Sectional Studies
  • Ecosystem
  • Ecuador / epidemiology
  • Housing*
  • Humans
  • Insect Control / methods
  • Insect Vectors / parasitology
  • Insect Vectors / physiology*
  • Insecticides
  • Nymph / parasitology
  • Nymph / physiology
  • Panstrongylus / parasitology
  • Panstrongylus / physiology*
  • Population Density
  • Rats / parasitology
  • Rhodnius / parasitology
  • Rhodnius / physiology*
  • Risk Factors
  • Surveys and Questionnaires
  • Trypanosoma cruzi / isolation & purification*

Substances

  • Insecticides

Grants and funding

Financial support was received from Ohio University Heritage College of Osteopathic Medicine, Pontifical Catholic University of Ecuador Project (2009 – H14143, 2010 – H13026, H13042 and 2011-H13174), the European Commission Framework Programme 7 Project ‘‘Comparative epidemiology of genetic lineages of Trypanosoma cruzi’’ (ChagasEpiNet - Contract No. 223034), Children’s Heartlink, PLAN International Ecuador and the PEW Latin American Fellows Program in the Biomedical Sciences (18274). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.