Correction to: Socioeconomic and demographic characterization of an endemic malaria region in Brazil by multiple correspondence analysis.

After publication of the article [1], it has been brought to our attention that the y-axis of Fig. 6 has been labeled incorrectly. It should read "linear predictor". This has now been corrected in the original article.

Socioeconomic and demographic characterization of an endemic malaria region in Brazil by multiple correspondence analysis.

BACKGROUND: In the process of geographical retraction of malaria, some important endemicity pockets remain. Here, we report results from a study developed to obtain detailed community data from an important malaria hotspot in Latin America (Alto Juruá, Acre, Brazil), to investigate the association of malaria with socioeconomic, demographic and living conditions. METHODS: A household survey was conducted in 40 localities (n = 520) of Mâncio Lima and Rodrigues Alves municipalities, Acre state. Information on previous malaria, schooling, age, gender, income, occupation, household structure, habits and behaviors related to malaria exposure was collected. Multiple correspondence analysis (MCA) was applied to characterize similarities between households and identify gradients. The association of these gradients with malaria was assessed using regression. RESULTS: The first three dimensions of MCA accounted for almost 50% of the variability between households. The first dimension defined an urban/rurality gradient, where urbanization was associated with the presence of roads, basic services as garbage collection, water treatment, power grid energy, and less contact with the forest. There is a significant association between this axis and the probability of malaria at the household level, OR = 1.92 (1.23-3.02). The second dimension described a gradient from rural settlements in agricultural areas to those in forested areas. Access via dirt road or river, access to electricity power-grid services and aquaculture were important variables. Malaria was at lower risk at the forested area, OR = 0.55 (1.23-1.12). The third axis detected intraurban differences and did not correlate with malaria. CONCLUSIONS: Living conditions in the study area are strongly geographically structured. Although malaria is found throughout all the landscapes, household traits can explain part of the variation found in the odds of having malaria. It is expected these results stimulate further discussions on modelling approaches targeting a more systemic and multi-level view of malaria dynamics.

Prenatal care and childbirth assistance in Amazonian women before and after the Pacific Highway Construction (2003-2011): a cross-sectional study.

BACKGROUND: Attention to prenatal care and child delivery is important for the health of women and children, but in the Amazon these indicators tend to be historically unfavorable, in part by geographical and political isolation. In 2003 both Brazilian and Peru governments have finished paving an international road connecting remotes areas in the Brazilian Amazon to the Pacific coast in Peru. METHODS: The situation of prenatal care and child delivery with mothers of children under 5 years old living in the urban area of Assis Brasil, Acre was assessed in two cross-sectional studies performed in 2003 and 2011, corresponding to the period before and after the Pacific highway construction. RESULTS: In 2003, most mothers were of black/Afro-American ethnicity, or "pardos" (the offspring of a Caucasian with a African descendant) (77.69 %), had more than 4 years of schooling (73.40 %) and had a mean age of 22.18 years. In 2011, the number of as a migration of indigenous women increased from 0 to 14.40 % of the respondents, because of migration from communities along the rivers to urban areas, with no other significant changes in maternal characteristics. No significant improvement in childbirth assistance was noticed between 1997 and 2011; only the percentage of in-hospital vaginal deliveries performed by doctors increased from 17.89 to 66.26 % (p <0.001) during this period. Access to prenatal care was associated with white ethnicity in 2003, and higher socioeconomic level and white ethnicity in 2011, while the higher number of prenatal visits was associated with higher maternal education and higher socioeconomic levels in 2011. Vaginal child delivery at a hospital facility was associated with maternal age in 2003, and year of birth, being of white ethnicity and higher level of education in 2011. CONCLUSIONS: The indicators of prenatal care and child delivery were below the national average, showing that geographical isolation still affects women's health care in the Amazon, despite the construction of the highway and governmental health protocols adopted during this period.

Socioeconomic inequities and hepatitis A virus infection in Western Brazilian Amazonian children: spatial distribution and associated factors.

BACKGROUND: Hepatitis A is still a neglected health problem in the world. The most affected areas are the ones with disadvantaged socioeconomic conditions. In Brazil, seroprevalence studies showed that 64.7 % of the general population has antibodies against HAV (hepatitis A virus), and the Amazon region has the highest seroprevalence in the country. METHODS: In the present study the seroprevalence of total HAV antibodies in children between 1 and 5 years old residing in the urban area of Assis Brasil, Acre was measured and spatial distribution of several socioeconomic inequities was evaluated. RESULTS: In the year of 2011, seroprevalence rate was 16.66 %. Factors associated with having a positive serology identified by multivariate analysis were being of indigenous ethnicity [adjusted Odds Ratio (aOR) = 3.27, CI 1.45-7.28], usage of water from the public system (aOR = 8.18, CI 1.07-62.53), living in a house not located in a street (aOR = 3.48, CI 1.54-7.87), and child age over 4 years old (aOR = 2.43, CI 1.23-4.79). The distribution of seropositive children was clustered in the eastern part of the city, where several socioeconomic inequities (lack of flushed toilets, lack of piped water inside the household and susceptibility of the household to flooding during rain, low maternal education, having wood or ground floor at home, and not owning a house, lack of piped water at home, and type of drinking water) also clustered. CONCLUSIONS: The findings highlight that sanitation and water treatment still need improvement in the Brazilian Amazon, and that socioeconomic development is warranted in order to decrease this and other infectious diseases.

Vivax malaria in an Amazonian child with dilated cardiomyopathy.

A child living in the Brazilian Amazon region who had had vivax malaria at the age of 11 months was admitted three months later with a history of progressive dyspnoea and fever, which culminated in respiratory distress and severe dilated cardiomyopathy at hospital admission in a malaria-free area. She received treatment for cardiac insufficiency and was tested for malaria with two thick blood smears, which were negative. There was general improvement of cardiorespiratory function in the next two weeks, but in the third week of hospital admission, there was re-appearance of fever, severe anaemia, severe plaquetopaenia, and respiratory distress. A third thick blood smear was positive for Plasmodium vivax mono-infection, which was confirmed by molecular methods. A serological panel with the most prevalent infectious agents known to cause myocarditis was performed, and specific anti-cytomegalovirus (CMV) IgM and elevated levels of anti-CMV IgG were also detected in the serum. After treatment for malaria, there was improvement of respiratory distress, although cardiac function did not recover. She was discharged home with drugs for cardiac insufficiency and is currently under follow-up with a paediatric cardiologist as an outpatient. This report presents a young child with several episodes of vivax malaria who suffers from cardiac insufficiency, probably related to CMV-induced myocarditis.

Hepatitis A and E seroprevalence and associated risk factors: a community-based cross-sectional survey in rural Amazonia.

BACKGROUND: Hepatitis A virus (HAV) and hepatitis E virus (HEV) are both transmitted by the faecal-oral route, and represent common causes of acute hepatitis in developing countries. The endemicity of HAV infection has shifted from high to moderate in Brazil. Human cases of HEV infection seem to be rare, although the virus has been detected in swine livestock and effluents of slaughterhouses. This study was to determine the epidemiology of hepatitis A and E in one of the largest agricultural settlements in the Amazon Basin of Brazil. METHODS: Serum samples collected from 397 individuals aged between 5 and 90 years during a population-based cross-sectional survey were tested for anti-HAV and anti-HEV antibodies. Associated risk factors and spatial clustering of HAV and HEV seropositivity were also analyzed. RESULTS: The overall rate of HAV seropositivity was 82.9% (95% confidence interval (CI), 79.2-86.6%). Multilevel logistic regression analysis identified increasing age (in years; odds ratio (OR), 1.097; 95% CI, 1.050-1.147; P < 0.001) and crowding (OR, 1.603; 95% CI, 1.054-2.440; P = 0.028) as significant risk factors for HAV seropositivity. Anti-HEV IgG was detected in 50/388 settlers (12.9%, 95% CI, 9.5-16.2%). Anti-HEV IgM was detected in 7/43 (16.3%) anti-IgG positive samples, and 4 of them had a confirmed result by immunoblot. Increasing age was the only significant determinant of HEV seropositivity (OR, 1.033; 95% CI, 1.016-1.050; P < 0.001). No significant spatial clustering of HAV and HEV seropositivity was detected in the area. CONCLUSIONS: Both HAV and HEV are endemic, with differing rates of infection in children and adults in this rural setting of the Brazilian Amazon. Anti-HEV prevalence was considerably higher than those previously reported in Brazil. The detection of HEV- specific IgM antibodies in four asymptomatic individuals is highly suggestive of the circulation of HEV in this rural population.

Socioeconomic inequalities are still a barrier to full child vaccine coverage in the Brazilian Amazon: a cross-sectional study in Assis Brasil, Acre, Brazil.

INTRODUCTION: Vaccines are very important to reduce morbidity and mortality by preventable infectious diseases, especially during childhood. Optimal coverage is not always achieved, for several reasons. Here we assessed vaccine coverage for the first 12 months of age in children between 12 and 59 months old, residing in the urban area of a small Amazonian city, and factors associated with incomplete vaccination. METHODS: A census was performed in the urban area of Assis Brasil, in the Brazilian Amazon, in January 2010, with mothers of 282 children aged 12 to 59 months old, using structured interviews and data from vaccination cards. Mixed logistic regression was used to determine factors associated with incomplete vaccination schemes. RESULTS: Only 82.6% of all children had a completed the basic vaccine scheme for the first year of life. Vaccine coverage ranged from 52.7% coverage (oral rotavirus vaccine) to 99.7% coverage (for Bacille Calmette-Guérin). The major deficiencies occurred in doses administered after the first six months of life. Incomplete vaccination was associated with not having enough income to buy a house (aOR = 2.12, 95% CI 1.06-4.21), low maternal schooling (aOR = 2.60, 95% CI 1.28 - 5.29) , and time of residence of the child in the urban area of the city (aOR = 0.73, 95% CI 0.55 - 0.95). CONCLUSIONS: This study showed that vaccine coverage in the first twelve months of life in Assis Brasil is similar to other areas in the Amazon and it is below the coverage postulated by the Brazilian Ministry of Health. Low vaccine coverage was associated with socioeconomic inequities that still prevail in the Brazilian Amazon. Short and long-term strategies must be taken to update child vaccines and increase vaccine coverage in the Amazon.

Fy(a)/Fy(b) antigen polymorphism in human erythrocyte Duffy antigen affects susceptibility to Plasmodium vivax malaria.

Plasmodium vivax (Pv) is a major cause of human malaria and is increasing in public health importance compared with falciparum malaria. Pv is unique among human malarias in that invasion of erythrocytes is almost solely dependent on the red cell's surface receptor, known as the Duffy blood-group antigen (Fy). Fy is an important minor blood-group antigen that has two immunologically distinct alleles, referred to as Fy(a) or Fy(b), resulting from a single-point mutation. This mutation occurs within the binding domain of the parasite's red cell invasion ligand. Whether this polymorphism affects susceptibility to clinical vivax malaria is unknown. Here we show that Fy(a), compared with Fy(b), significantly diminishes binding of Pv Duffy binding protein (PvDBP) at the erythrocyte surface, and is associated with a reduced risk of clinical Pv in humans. Erythrocytes expressing Fy(a) had 41-50% lower binding compared with Fy(b) cells and showed an increased ability of naturally occurring or artificially induced antibodies to block binding of PvDBP to their surface. Individuals with the Fy(a+b-) phenotype demonstrated a 30-80% reduced risk of clinical vivax, but not falciparum malaria in a prospective cohort study in the Brazilian Amazon. The Fy(a+b-) phenotype, predominant in Southeast Asian and many American populations, would confer a selective advantage against vivax malaria. Our results also suggest that efficacy of a PvDBP-based vaccine may differ among populations with different Fy phenotypes.

Nutritional status of children under 5 years of age in the Brazilian Western Amazon before and after the Interoceanic highway paving: a population-based study.

BACKGROUND: The aim of this study was to analyse the prevalence of undernutrition, overweight and associated factors, before and after the implementation of the Interoceanic Highway. METHODS: A population-based cross-sectional study on children under 5 years of age was conducted in the municipality of Assis Brasil, AC, Brazil, in 2003 and 2010. Prevalence of undernutrition was observed by using height-for-age Z-scores (HAZ) and adopting a cut-off point equal to or lower than a -2 Z-score. Overweight prevalence was defined by a cut-off point equal to or greater than a +2 Z-score of the WHZ index. Z-scores were calculated relative to WHO 2006 reference data. Semi-structured questionnaires were applied to the children's guardians, investigating family socio-economic and demographic characteristics, morbidities, access to services and child care. Associated factors were identified by hierarchical multiple logistic regression analysis. RESULTS: The prevalence of low HAZ (undernutrition) was 7.0% in 2003 and 12.2% in 2010. The prevalence of high WHZ (overweight) was 1.0% and 6.6% for 2003 and 2010, respectively. It was not possible to adjust the multiple model for the year 2003. The factors associated with low HAZ in 2010 were: wealth index, the situation of living with biological parents, maternal height and presence of open sewage, whereas the factors associated with a high WHZ in the same year were: child's age, mother's time of residence in the location, mother's body mass index. CONCLUSIONS: Overweight increase within this undernutrition scenario reveals that the process of nutritional transition began in this Amazonian city only in the last decade, and therefore, it is delayed when compared to overweight in other parts of Brazil. Such nutritional transition in Assis Brasil may have been facilitated by the construction of the Interoceanic Highway.

Trajetorias: a dataset of environmental, epidemiological, and economic indicators for the Brazilian Amazon.

The Trajetorias dataset is a harmonized set of environmental, epidemiological, and poverty indicators for all municipalities of the Brazilian Legal Amazon (BLA). This dataset is the result of a scientific synthesis research initiative conducted by scientists from several natural and social sciences fields, consolidating multidisciplinary indicators into a coherent dataset for integrated and interdisciplinary studies of the Brazilian Amazon. The dataset allows the investigation of the association between the Amazonian agrarian systems and their impacts on environmental and epidemiological changes, furthermore enhancing the possibilities for understanding, in a more integrated and consistent way, the scenarios that affect the Amazonian biome and its inhabitants.

Time Trend of Overweight and Obesity in Adults from Rio Branco, Acre, Western Brazilian Amazon (2006-2020).

This study aimed to analyze overweight trend and obesity in adults from Rio Branco, Acre, Western Brazilian Amazon, from 2006 to 2020. This is a time series study, with data from Surveillance System for Risk and Protective Factors for Chronic Diseases by Telephone Survey (VIGITEL). To estimate annual percentage change (APC) and 95% confidence intervals, the software Jointpoint Regression Analysis v.4.6.0.0., was used. In Rio Branco, overweight prevalence ranged from 44.0% in 2006 to 58.9% in 2020, with a bigger frequency among men than that among women. Obesity prevalence has increased from 12.5% in 2006 to 21.4% in 2020, similar between both sexes. From 2006 to 2020, overweight APC was 5.2% (95% CI: 1.4; 9.1) by 2010, and decreased to 1.3% by 2020. Public policies to control obesity and its risks must be both, implemented as strengthened.

Single-nucleotide polymorphism, linkage disequilibrium and geographic structure in the malaria parasite Plasmodium vivax: prospects for genome-wide association studies.

BACKGROUND: The ideal malaria parasite populations for initial mapping of genomic regions contributing to phenotypes such as drug resistance and virulence, through genome-wide association studies, are those with high genetic diversity, allowing for numerous informative markers, and rare meiotic recombination, allowing for strong linkage disequilibrium (LD) between markers and phenotype-determining loci. However, levels of genetic diversity and LD in field populations of the major human malaria parasite P. vivax remain little characterized. RESULTS: We examined single-nucleotide polymorphisms (SNPs) and LD patterns across a 100-kb chromosome segment of P. vivax in 238 field isolates from areas of low to moderate malaria endemicity in South America and Asia, where LD tends to be more extensive than in holoendemic populations, and in two monkey-adapted strains (Salvador-I, from El Salvador, and Belem, from Brazil). We found varying levels of SNP diversity and LD across populations, with the highest diversity and strongest LD in the area of lowest malaria transmission. We found several clusters of contiguous markers with rare meiotic recombination and characterized a relatively conserved haplotype structure among populations, suggesting the existence of recombination hotspots in the genome region analyzed. Both silent and nonsynonymous SNPs revealed substantial between-population differentiation, which accounted for ~40% of the overall genetic diversity observed. Although parasites clustered according to their continental origin, we found evidence for substructure within the Brazilian population of P. vivax. We also explored between-population differentiation patterns revealed by loci putatively affected by natural selection and found marked geographic variation in frequencies of nucleotide substitutions at the pvmdr-1 locus, putatively associated with drug resistance. CONCLUSION: These findings support the feasibility of genome-wide association studies in carefully selected populations of P. vivax, using relatively low densities of markers, but underscore the risk of false positives caused by population structure at both local and regional levels.

Variant-specific antibodies to merozoite surface protein 2 and clinical expression of Plasmodium falciparum malaria in rural Amazonians.

Naturally acquired antibodies to five variants of the merozoite surface protein 2 (MSP-2), a target of clinical immunity to Plasmodium falciparum malaria, were measured in a cohort of rural Amazonians. Local MSP-2 variants comprised both highly divergent families of alleles (FC27 and 3D7). Total IgG antibodies to two FC27-type antigens were found in 22-28% of subjects at baseline, with substantial cross-reactivity between variants and stable concentrations and specificities over time. The IgG antibodies to three 3D7-type antigens were less prevalent (6-7%), less cross-reactive, and short-lived; subsequent exposure to 3D7-type parasites rarely elicited homologous response. The clinical spectrum of 109 incident P. falciparum infections in our cohort ranged between asymptomatic infection and fully symptomatic but uncomplicated disease. Parasitemia at the time of diagnosis, rather than cumulative malaria exposure or acquired immunity (presence of variant-specific antibodies matching the MSP-2 type in infecting parasites), was a major predictor of perceived symptom severity.

Anemia and iron deficiency in school children, adolescents, and adults: a community-based study in rural Amazonia.

We investigated the prevalence and risk factors of anemia and iron deficiency in 389 [corrected] rural Amazonians aged 5-90 years in Acre, Brazil. Anemia and iron deficiency were diagnosed in 16% and 19% of the population, respectively. Anemia was likely to have multiple causes; although nearly half of anemic school children and women had altered iron status indicators, only 19.7% of overall anemia was attributable to iron deficiency. Geo-helminth infection and a recent malaria episode were additional factors affecting iron status indicators in this population.

Child health and nutrition in the Western Brazilian Amazon: population-based surveys in two counties in Acre State.

The article presents prevalence rates for malnutrition, intestinal parasitic infections, anemia, and iron deficiency in under-five children in a population-based cross-sectional survey performed in the urban area of two counties in the Western Brazilian Amazon, Assis Brasil (n = 200) and Acrelandia (n = 477). Available data included: (a) weight and height measurements, standardized as z-scores using the 1977 NCHS reference population, (b) diagnosis of current intestinal parasitic infection, (c) blood hemoglobin levels, and (d) plasma ferritin and soluble transferrin receptor levels. Overall prevalence rates of low weight-for-height, low weight-for-age, and low height-for-age were 3.7%, 8.7%, and 7.5%, respectively, with similar figures in the two towns. Intestinal parasites were detected in 32.5% children; helminths were uncommon. Anemia and iron deficiency were diagnosed in 30.6% and 43.5% of the children, respectively. Evidence of anemia was found in only 47.6% of the children with depleted iron reserves, indicating that hemoglobin measurement alone would severely underestimate the magnitude of iron deficiency in this population. In both towns, anemia and malnutrition were significantly more prevalent among children in the lowest socioeconomic stratum.

Prevalence and spatial distribution of intestinal parasitic infections in a rural Amazonian settlement, Acre State, Brazil.

A population-based survey of the prevalence and spatial distribution of intestinal parasitism was carried out in an agricultural settlement in the Amazon Basin of Brazil (Granada, Acre State). More than half (53.4%) of the 429 stool specimens from subjects in all age groups, living in 113 households, had cysts, ova, or larvae of intestinal parasites. The most prevalent parasites were Giardia duodenalis (19.6%) and soil-transmitted helminths (12.7%); 105 (24.5%) subjects were infected with more than one species of parasite. Significant age-related differences in prevalence were only found for G. duodenalis (children < 1 year and adults > 30 years were less affected). Six households (5.3%), situated within a radius of 690m, comprised 48.1% of all subjects harboring soil-transmitted helminths in our study area. Households within this cluster were poorer and more crowded than those outside the cluster. The observed spatial clustering of infections with soil-transmitted helminths provides valuable information for the spatial targeting of sanitary interventions in this area.

Multi-character population study of the vir subtelomeric multigene superfamily of Plasmodium vivax, a major human malaria parasite.

Plasmodium vivax, the most widely distributed human malaria parasite, contains the subtelomeric multigene vir superfamily corresponding to circa 10% of its coding genome. In this work, we used a multi-character strategy to study the vir gene repertoire circulating in natural parasite populations obtained directly from 32 human patients from endemic regions of Brazil and Sri Lanka. Cladistic analysis confirmed the existence of vir subfamilies, which varied in size and allele polymorphisms. Moreover, different motifs, protein domain, and secondary structures were predicted for each subfamily. Of importance, not all vir sequences possess a recognizable Pexel motif recently shown to be important, though not essential, signal for transportation to the cell membrane of infected red blood cells. Furthermore, subfamilies A and D display common structural features with the recently described P. falciparum SURFIN and Pfmc-2tm subtelomeric multigene families. These results suggest that VIR proteins can have different subcellular localizations and functions. This is the first study on a population level of the P. vivax vir subtelomeric multigene superfamily.

Hepatitis A seroprevalence in preschool children in Assis Brazil, Acre, Brazil, in 2003 and 2010.

BACKGROUND: The Amazon region has the highest seroprevalence of hepatitis A virus (HAV) in Brazil. METHODS: In the present study, the seroprevalence of total HAV antibodies in two groups, composed of 147 and 254 children between 1 and 5 years old in Assis Brasil, Acre, was measured in 2003 and 2010, respectively, and compared with socio-economic changes in the city. RESULTS: In 2003, the HAV seroprevalence rate was 26.5%, while in 2010, it was 22.4%. There was an overall improvement in socio-economic and sanitary conditions, with the exception of open sewage. In 2003, factors associated with positive serology were child age (aOR [adjusted odds ratio] 1.84; 95% CI: 1.28-2.64), having a latrine or not having a toilet at home (aOR 4.73; 95% CI: 1.06-21.17) and the treatment of drinking water with chlorine (aOR 0.26; 95% CI: 0.07-0.92). In 2010, the main factors associated with positive serology were using rivers, streams and rainwater as sources of water for domestic purposes (aOR 24.36; 95% CI: 3.69-160.85); having a wooden or ground floor at home (OR 2.51; 95% CI: 1.11-5.69) and child age (aOR 2.33; 95% CI: 1.66-3.28). CONCLUSIONS: In the Brazilian Amazon, sanitation and water treatment still require improvement and socio-economic development is warranted in order to decrease hepatitis A transmission.

Stunting in children under five years old is still a health problem in the Western Brazilian Amazon: a population-based study in Assis Brasil, Acre, Brazil.

Despite the process of nutritional transition in Brazil, in some places, such as the Amazon region, stunting is still an important public health problem. We identified the prevalence and factors associated with stunting in children under five years old residing in the urban area of Assis Brasil. A survey was conducted in which a questionnaire on socioeconomic, maternal and children's conditions was applied, and height or length was measured. The children with height for age index below -2 Z-scores were considered stunted, according to the criteria by the World Health Organization. Four hundred and twenty-eight children were evaluated. Of these, 62 were stunted. Factors associated with stunting, according to adjusted models, were: the presence of open sewer, the wealth index for households, the receipt of governmental financial aid and the mother's height, age and education. Therefore, it was observed that family and the mother's characteristics as well as environmental and socioeconomic factors were closely related to the occurrence of stunting in the population studied, and such nutritional disturbance is still a health problem in the Brazilian Amazon.

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

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 Anopheles 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 (P < 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.