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Abad-Franch F.,Instituto Leonidas e Maria Deane Fiocruz Amazonia | Valenca-Barbosa C.,Instituto Oswaldo Cruz Fiocruz | Sarquis O.,Instituto Oswaldo Cruz Fiocruz | Lima M.M.,Instituto Oswaldo Cruz Fiocruz
PLoS Neglected Tropical Diseases | Year: 2014

Control agents conducted triplicate vector searches in 414 man-made ecotopes of two rural localities. Ecotope-specific ‘detection histories’ (vectors or their traces detected or not in each individual search) were analyzed using ordinary methods that disregard detection failures and multiple detection-state site-occupancy models that accommodate false-negative and false-positive detections. Mean (±SE) vector-search sensitivity was ∼0.283±0.057. Vector-detection odds increased as bug colonies grew denser, and were lower in houses than in most peridomestic structures, particularly woodpiles. False-positive detections (non-vector fecal streaks misidentified as signs of vector presence) occurred with probability ∼0.011±0.008. The model-averaged estimate of infestation (44.5±6.4%) was ∼2.4–3.9 times higher than naïve indices computed assuming perfect detection after single vector searches (11.4–18.8%); about 106–137 infestation foci went undetected during such standard searches.Vector-borne diseases are major public health concerns worldwide. For many of them, vector control is still key to primary prevention, with control actions planned and evaluated using vector occurrence records. Yet vectors can be difficult to detect, and vector occurrence indices will be biased whenever spurious detection/non-detection records arise during surveys. Here, we investigate the process of Chagas disease vector detection, assessing the performance of the surveillance method used in most control programs – active triatomine-bug searches by trained health agents.We illustrate a relatively straightforward approach to addressing vector detection uncertainty under realistic field survey conditions. Standard vector searches had low sensitivity except in certain singular circumstances. Our findings suggest that many infestation foci may go undetected during routine surveys, especially when vector density is low. Undetected foci can cause control failures and induce bias in entomological indices; this may confound disease risk assessment and mislead program managers into flawed decision making. By helping correct bias in naïve indices, the approach we illustrate has potential to critically strengthen vector-borne disease control-surveillance systems. © 2014 Abad-Franch et al. Source

Santarem M.C.A.,Instituto Oswaldo Cruz Fiocruz | Santarem M.C.A.,Federal University of Rio de Janeiro | Farias E.S.,Instituto Leonidas e Maria Deane Fiocruz Amazonia | Felippe-Bauer M.L.,Instituto Oswaldo Cruz Fiocruz
Anais da Academia Brasileira de Ciencias | Year: 2015

A new species of the reticulatus species group, C. castelloni Santarém and Felippe-Bauer, is described and illustrated based on female specimens from the state of Amazonas, Brazil. A systematic key, wing photographs and table with numerical characters of females and a synopsis of 24 species of the Culicoides reticulatus group are presented. This paper presents further new records for seven species of the reticulatus group. © 2015, Academia Brasileira de Ciencias. All rights reserved. Source

Espinoza N.,University of Valencia | Borras R.,University of Valencia | Abad-Franch F.,Instituto Leonidas e Maria Deane Fiocruz Amazonia
PLoS Neglected Tropical Diseases | Year: 2014

Background:Chagas disease has historically been hyperendemic in the Bolivian Department of Cochabamba. In the early 2000s, an extensive vector control program was implemented; 1.34 million dwelling inspections were conducted to ascertain infestation (2000-2001/2003-2011), with blanket insecticide spraying in 2003-2005 and subsequent survey-spraying cycles targeting residual infestation foci. Here, we assess the effects of this program on dwelling infestation rates (DIRs).Methodology/Principal Findings:Program records were used to calculate annual, municipality-level aggregate DIRs (39 municipalities); very high values in 2000-2001 (median: 0.77-0.69) dropped to ~0.03 from 2004 on. A linear mixed model (with municipality as a random factor) suggested that infestation odds decreased, on average, by ~28% (95% confidence interval [CI95] 6-44%) with each 10-fold increase in control effort. A second, better-fitting mixed model including year as an ordinal predictor disclosed large DIR reductions in 2001-2003 (odds ratio [OR] 0.11, CI95 0.06-0.19) and 2003-2004 (OR 0.22, CI95 0.14-0.34). Except for a moderate decrease in 2005-2006, no significant changes were detected afterwards. In both models, municipality-level DIRs correlated positively with previous-year DIRs and with the extent of municipal territory originally covered by montane dry forests.Conclusions/Significance:Insecticide-spraying campaigns had very strong, long-lasting effects on DIRs in Cochabamba. However, post-intervention surveys consistently detected infestation in ~3% of dwellings, underscoring the need for continuous surveillance; higher DIRs were recorded in the capital city and, more generally, in municipalities dominated by montane dry forest - an eco-region where wild Triatoma infestans are widespread. Traditional strategies combining insecticide spraying and longitudinal surveillance are thus confirmed as very effective means for area-wide Chagas disease vector control; they will be particularly beneficial in highly-endemic settings, but should also be implemented or maintained in other parts of Latin America where domestic infestation by triatomines is still commonplace. © 2014 Espinoza et al. Source

A wave of Haitian immigration into Brazil began in February 2010 through three northern border states: Acre, Rondônia, and Amazonas. Focusing on the state of Amazonas, the article uses an ethnographic approach to explore the social networks involved in this immigrant issue and examines how Brazil’s Sistema Único de Saúde (SUS) responded to the demands placed by this unexpected contingent of new users visà- vis the system’s guiding constitutional principles, particularly equity. A picture is painted of some aspects of the most critical immigration period (March 2010-March 2012) and of the public healthcare system’s reception of these Haitian newcomers. © 2016, Fundacao Oswaldo Cruz. All rights reserved. Source

Rojas de Arias A.,Chilean Center of Nanosciences and Nanotechnology | Abad-Franch F.,Instituto Leonidas e Maria Deane Fiocruz Amazonia | Acosta N.,National University of Asuncion | Lopez E.,National University of Asuncion | Gonzalez N.,National University of Asuncion
PLoS Neglected Tropical Diseases | Year: 2012

Background: Chagas disease prevention critically depends on keeping houses free of triatomine vectors. Insecticide spraying is very effective, but re-infestation of treated dwellings is commonplace. Early detection-elimination of re-infestation foci is key to long-term control; however, all available vector-detection methods have low sensitivity. Chemically-baited traps are widely used in vector and pest control-surveillance systems; here, we test this approach for Triatoma spp. detection under field conditions in the Gran Chaco. Methodology/Principal Findings: Using a repeated-sampling approach and logistic models that explicitly take detection failures into account, we simultaneously estimate vector occurrence and detection probabilities. We then model detection probabilities (conditioned on vector occurrence) as a function of trapping system to measure the effect of chemical baits. We find a positive effect of baits after three (odds ratio [OR] 5.10; 95% confidence interval [CI95] 2.59-10.04) and six months (OR 2.20, CI95 1.04-4.65). Detection probabilities are estimated at p ≈ 0.40-0.50 for baited and at just p ≈ 0.15 for control traps. Bait effect is very strong on T. infestans (three-month assessment: OR 12.30, CI95 4.44-34.10; p ≈ 0.64), whereas T. sordida is captured with similar frequency in baited and unbaited traps. Conclusions/Significance: Chemically-baited traps hold promise for T. infestans surveillance; the sensitivity of the system at detecting small re-infestation foci rises from 12.5% to 63.6% when traps are baited with semiochemicals. Accounting for imperfect detection, infestation is estimated at 26% (CI95 16-40) after three and 20% (CI95 11-34) after six months. In the same assessments, traps detected infestation in 14% and 8.5% of dwellings, whereas timed manual searches (the standard approach) did so in just 1.4% of dwellings only in the first survey. Since infestation rates are the main indicator used for decision-making in control programs, the approach we present may help improve T. infestans surveillance and control program management. © 2012 Rojas de Arias et al. Source

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