Transfusion-transmitted malaria in endemic zone: epidemiological profile of blood donors at the Fundação HEMOAM and use of rapid diagnostic tests for malaria screening in Manaus

OBJECTIVE: With 99% of the cases in Brazil, malaria is endemic in the Amazon region. Transfusion-transmitted malaria, an important risk in endemic areas, has been reported. The aim of this study was to describe the epidemiological profile of blood donor candidates at the Fundação de Hematologia e Hemoterapia do Amazonas and evaluate the efficacy of rapid diagnostic tests used for malaria screening of blood donors within endemic regions. METHODS: Between May 2008 and May 2009, 407 blood donor candidates were selected and grouped based on the Malaria Annual Parasite Index of the geographic area in which they originated: Group 1 (eligible donors - n = 265) originated from areas of low to medium risk of exposure to malaria and Group 2 (ineligible donors - n = 142) originated from high-risk areas. All samples were concurrently screened using two immunochromatic antigen-based rapid tests and by the thick smear test. RESULTS: All samples were negative by all three methods. The demographic profile indicated that the majority of participants were male, ages ranged from 18 to 39 years and less than half the candidates had only elementary schooling. Two issues need to be addressed: one is the ineligibility of donors and its impact on blood donor centers as, in this study, 22.7% of the donors were considered ineligible. The other is the limited sensitivity of the parasitological tests used, allowing a risk of false-negative results. CONCLUSION: New methods are needed to ensure transfusion safety without rejecting potential donors, which would ensure safe transfusion without harming the blood supply

Distribution of dengue vectors in neighborhoods with different urbanization types of Manaus, state of Amazonas, Brazil

Aedes aegypti   and Ae. albopictus are vectors of dengue viruses, which cause endemic disease in the city of Manaus, capital of the state of Amazonas, Brazil. More than 53 thousand cases have been registered in this city since the first epidemic in 1998. We evaluated the hypothesis that different ecological conditions result in different patterns of vector infestation in Manaus, by measuring the infestation level in four neighborhoods with different urbanization patterns, during the rainy (April), dry (August), and transitional (November) seasons. Ae. aegypti predominated throughout the study areas and sampling periods, representing 86% of all specimens collected in oviposition traps. High frequencies of houses positive for both species were observed in all studied sites, with Ae. aegypti present in more than 84% of the houses in all seasons. Ae. albopictus, on the other hand, showed more spatial and temporal variation in abundance. We found no association between infestation level and house traits. This study highlights the homogeneity of dengue vector distribution in Manaus

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

Abstract 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

MOESM4 of Socioeconomic and demographic characterization of an endemic malaria region in Brazil by multiple correspondence analysis

Additional file 4. Details of mixed logistic regression models analyzes