Epidemic and Endemic Malaria Transmission Related to Fish Farming Ponds in the Amazon Frontier

<div><p>Fish farming in the Amazon has been stimulated as a solution to increase economic development. However, poorly managed fish ponds have been sometimes associated with the presence of <i>Anopheles</i> spp. and consequently, with malaria transmission. In this study, we analyzed the spatial and temporal dynamics of malaria in the state of Acre (and more closely within a single county) to investigate the potential links between aquaculture and malaria transmission in this region. At the state level, we classified the 22 counties into three malaria endemicity patterns, based on the correlation between notification time series. Furthermore, the study period (2003–2013) was divided into two phases (epidemic and post-epidemic). Higher fish pond construction coincided both spatially and temporally with increased rate of malaria notification. Within one malaria endemic county, we investigated the relationship between the geolocation of malaria cases (2011–2012) and their distance to fish ponds. Entomological surveys carried out in these ponds provided measurements of anopheline abundance that were significantly associated with the abundance of malaria cases within 100 m of the ponds (<i>P</i> < 0.005; r = 0.39). These results taken together suggest that fish farming contributes to the maintenance of high transmission levels of malaria in this region.</p></div

Buffer zone from 100 to 1000m around breeding sites in the urban/periurban area of Mâncio Lima, and malaria cases in 2011 and 2012.

<p>Buffer zone from 100 to 1000m around breeding sites in the urban/periurban area of Mâncio Lima, and malaria cases in 2011 and 2012.</p

Distribution of Annual Parasitic Index by county in Acre State, from 2003 to 2013.

<p>API = 0: No risk; Low API: < 10 cases; medium API: ≥ 10 and < 50 cases; high API: ≥ 50 cases.</p

Hierarchical clustering of the 22 municipalities of Acre according to the similarity of the time series of malaria incidence (2003–2013).

<p>Hierarchical clustering of the 22 municipalities of Acre according to the similarity of the time series of malaria incidence (2003–2013).</p

Scatterplot of the number of malaria cases in 2011 and 2012 as related to the distance to the nearest fish ponds, in meters.

<p>Scatterplot of the number of malaria cases in 2011 and 2012 as related to the distance to the nearest fish ponds, in meters.</p

Time series of malaria autochthonous cases in Acre and per stratum, 2003–2013.

<p>(*) marks the 2006 epidemics when control actions were strengthened in this region.</p

Number of hectares of aquaculture in Mâncio Lima estimated from harvest data in 2003 to 2006, as related to the number of malaria cases in the county.

<p>Number of hectares of aquaculture in Mâncio Lima estimated from harvest data in 2003 to 2006, as related to the number of malaria cases in the county.</p

Additional file 2: Table S1. of Socioeconomic inequities and hepatitis A virus infection in Western Brazilian Amazonian children: spatial distribution and associated factors

Social inequities associated with being of indigenous ethnicity in children 12to 59 months old. Assis Brasil, 2011. (DOCX 19 kb

Additional file 1: Figure S1. of Socioeconomic inequities and hepatitis A virus infection in Western Brazilian Amazonian children: spatial distribution and associated factors

Spline correlograms, with 95 % pointwise bootstrap confidence intervals, of the Pearson residuals from the logistic regression models applied to “having anti-HAV antibodies”: (A) model with no covariates (null model) showing spatial correlation at distances less than ca 100 m; and (B) model with all covariates of the final model, indicating that no spatial structure remained in the residuals after the introduction of the explanatory variables. (TIFF 21 kb

Number of malarial infections diagnosed by conventional microscopy (CM) and quantitative real-time PCR (qPCR), according to the presence or absence of malaria-related symptoms, during 8 consecutive cross-sectional surveys in the population of Remansinho, Brazil (2010–13).

<p>Dates of cross-sectional surveys were: survey 1 1, March–May, 2010; survey 2, May–July, 2010; survey 3, October–November, 2010; survey 4, March–April, 2011; survey 5, October–November, 2011; survey 6, April–May, 2012; survey 7, October–November, 2012; survey 8, April–May, 2013. Polyethylene bed-nets treated with 2% permethrin (Olyset Net) were distributed to the entire study population in August, 2012.</p><p>Number of malarial infections diagnosed by conventional microscopy (CM) and quantitative real-time PCR (qPCR), according to the presence or absence of malaria-related symptoms, during 8 consecutive cross-sectional surveys in the population of Remansinho, Brazil (2010–13).</p