Time trends and changes in the distribution of malaria cases in the Brazilian Amazon Region, 2004-2013

Recent efforts to reduce malaria incidence have had some successes. Nevertheless, malaria persists as a significant public health problem in the Brazilian Amazon. The objective of this study was to describe changes in malaria case characteristics and to identify trends in malaria incidence in the Brazilian Amazon. This study used data from the Malaria Epidemiological Surveillance and Case Notification Information System from 2004 to 2013. The annual parasite incidence (API) was calculated and joinpoint regression was used to assess the trends in API over time. There was a sharp increase in API in the state of Acre, followed by two periods of decrease. Pará also presented inconsistent decreases over the study period. Amapá, Amazonas, Rondônia, and Roraima showed statistically significant decreases over the period. The sharpest decrease occurred in Rondônia, with a reduction of 21.7% in the average annual percent change (AAPC) (AAPC: -21.7%; 95% confidence interval: -25.4%, -17.8%; p < 0.05). This panorama of malaria incidence highlights the importance of integrating evidence-based malaria surveillance and control. Malaria is highly preventable, and eliminating its transmission should be a goal in coming decades.

Factors associated with timely treatment of malaria in the Brazilian Amazon: a 10-year population-based study / Factores asociados con el tratamiento oportuno de la malaria en la Amazonia brasileña: estudio de 10 años basado en la población / Fatores associados ao tratamento precoce da malária na Amazônia brasileira: um estudo populacional de 10 anos

ABSTRACT Objective To identify factors associated with timely treatment of malaria in the Brazilian Amazon. Malaria, despite being treatable, has proven difficult to control and continues to be an important public health problem globally. Brazil accounted for almost half of the 427 000 new malaria cases notified in the Americas in 2013. Methods This was a cross-sectional study using secondary data on all notified malaria cases for the period from 2004 - 2013. Timely treatment was considered to be all treatment started within 24 hours of symptoms onset. Multivariate logistic regression was used to identify independent factors associated with timely treatment. Results The proportion of cases starting treatment on a timely basis was 41.1%, tending to increase in more recent years (OR = 1.40; 95%CI: 1.37 - 1.42 in 2013). Furthermore, people starting within < 24 hours were more likely to: reside in the states of Rondônia (OR = 1.50; 95%CI: 1.49 - 1.51) or Acre (OR = 1.53; 95%CI: 1.55 - 1.57); be 0 - 5 years of age (OR = 1.39; 95%CI: 1.34 - 1.44) or 6 - 14 years of age (OR = 1.34; 95%CI: 1.32 - 1.36); be indigenous (OR = 1.41; 95%CI: 1.37 - 1.45); have a low level of schooling (OR = 1.20; 95%CI: 1.19 - 1.22); and be diagnosed by active detection (OR = 1.39; 95%CI: 1.38 - 1.39). Conclusion In the Brazilian Amazon area, individuals were more likely to have timely treatment of malaria if they were young, residing in Acre or Rondônia states, have little schooling, and be identified through active detection. Identifying groups vulnerable to late treatment is important for preventing severe cases and malaria deaths.

RESUMEN Objetivo Determinar los factores asociados con el tratamiento oportuno de la malaria en la Amazonia brasileña. La malaria, a pesar de que es tratable, ha resultado difícil de controlar y sigue siendo un problema importante de salud pública mundial. En Brasil se notificaron casi la mitad de los 427 000 nuevos casos de malaria en la Región de las Américas en el 2013. Métodos Se realizó un estudio transversal que utilizó datos secundarios de todos los casos notificados de malaria en el período 2004-2013. Se entendió como tratamiento oportuno todo tratamiento iniciado en las 24 horas posteriores a la aparición de los síntomas. Para determinar los factores independientes asociados con el tratamiento oportuno, se usó el método de regresión logística multifactorial. Resultados La proporción de casos en los que se inició el tratamiento oportunamente fue de 41,1%, con una tendencia ascendente en los últimos años (razón de posibilidades [OR] = 1,40; IC 95%: 1,37 - 1,42 en el 2013). Además, en las personas que comenzaron el tratamiento menos de 24 horas después de la aparición de los síntomas era mayor la probabilidad de que residieran en los estados de Rondônia (OR = 1,50; IC 95%: 1,49 - 1,51) o Acre (OR = 1,53; IC 95%: 1,55 - 1,57); también era mayor la probabilidad de que tuvieran entre 0 y 5 años (OR = 1,39; IC 95%: 1,34 - 1,44) o entre 6 y 14 años (OR = 1,34; IC 95%: 1,32 - 1,36); fueran indígenas (OR = 1,41; IC 95%: 1,37 - 1,45); tuvieran un nivel bajo de escolarización (OR = 1,20; IC 95%: 1,19 - 1,22) y hubieran sido diagnosticadas por detección activa (OR = 1,39; IC 95%: 1,38 - 1,39). Conclusiones En la zona de la Amazonia brasileña, era más probable que las personas que iniciaban oportunamente el tratamiento contra la malaria fueran jóvenes, residieran en los estados de Acre o Rondônia, tuvieran un nivel bajo de escolarización y fueran detectadas mediante la detección activa. La identificación de los grupos vulnerables al tratamiento tardío es importante para prevenir los casos graves y las muertes por malaria.

RESUMO Objetivo Identificar os fatores associados ao tratamento precoce da malária na Amazônia brasileira. Embora seja tratável, a malária tem sido difícil de controlar e continua a representar um importante problema de saúde pública em escala mundial. Em 2013, o Brasil registrou quase a metade dos 427.000 novos casos de malária notificados nas Américas. Métodos Este foi um estudo transversal que utilizou dados secundários sobre todos os casos de malária notificados no período de 2004 a 2013. O tratamento precoce foi definido como todo tratamento iniciado nas primeiras 24 horas desde o surgimento dos sintomas. Utilizamos a regressão logística multivariada para identificar fatores independentes associados ao tratamento precoce. Resultados A proporção de casos que iniciaram tratamento precoce foi de 41,1%, tendendo a aumentar em anos mais recentes (odds ratio [OR] = 1,40; IC 95%: 1,37 - 1,42 em 2013). Além disso, as pessoas que iniciaram o tratamento em menos de 24 horas tiveram maior probabilidade de: residir nos estados de Rondônia (OR = 1,50; IC 95%: 1,49 - 1,51) ou Acre (OR = 1,53; IC 95%: 1,55 - 1,57); ter entre 0 e 5 anos de idade (OR = 1,39; IC 95%: 1,34 - 1,44) ou entre 6 e 14 anos de idade (OR = 1,34; IC 95%: 1,32 - 1,36); ser indígena (OR = 1,41; IC 95%: 1,37 - 1,45); ter um baixo nível de escolaridade (OR = 1,20; IC 95%: 1,19 - 1,22); e ser diagnosticado por meio da detecção ativa (OR = 1,39; IC 95%: 1,38 - 1,39). Conclusão Na região da Amazônia brasileira, as pessoas têm uma maior probabilidade de receber tratamento precoce para a malária se forem jovens, residirem nos estados do Acre ou de Rondônia, tiverem um baixo nível de escolaridade e forem identificadas através da detecção ativa. A identificação de grupos vulneráveis ao tratamento tardio é importante para prevenir os casos graves e as mortes decorrentes da malária.

Factors associated with the occurrence of Triatoma sordida (Hemiptera: Reduviidae) in rural localities of Central-West Brazil

This study estimates the factors of artificial environments (houses and peridomestic areas) associated with Triatoma sordida occurrence. Manual searches for triatomines were performed in 136 domiciliary units (DUs) in two rural localities of Central-West Brazil. For each DU, 32 structural, 23 biotic and 28 management variables were obtained. Multiple logistic regression analysis was performed in order to identify statistically significant variables associated with occurrence of T. sordida in the study areas. A total of 1,057 specimens (99% in peridomiciles, mainly chicken coops) of T. sordida were collected from 63 DUs (infestation: 47%; density: ~8 specimens/DU; crowding: ~17 specimens/infested DU; colonisation: 81%). Only six (0.6%) out of 945 specimens examined were infected with Trypanosoma cruzi. The final adjusted logistic regression model indicated that the probability of T. sordida occurrence was higher in DU with wooden chicken coops, presence of > 30 animals in wooden corrals, presence of wood piles and presence of food storeroom. The results show the persistence of T. sordida in peridomestic habitats in rural localities of Central-West Brazil. However, the observed low intradomestic colonisation and minimal triatomine infection rates indicate that T. sordida has low potential to sustain high rates of T. cruzi transmission to residents of these localities.