Variabilidade dos casos de malária e sua relação com a precipitação e nível d’água dos rios no Estado do Amazonas, Brasil

Abstract

Variability in malaria cases and the association with rainfall and rivers water levels in Amazonas State, BrazilVariabilidade dos casos de malária e sua relação com a precipitação e nível d'água dos rios no Estado do Amazonas, Brasil Variabilidad de los casos de malaria y su relación con las precipitaciones y nivel del agua de los ríos en el estado del Amazonas, Brasil AbstractUnderstanding the relations between rainfall and river water levels and malaria cases can provide important clues on modulation of the disease in the context of local climatic variability. In order to demonstrate how these relations can vary in the same endemic space, a coherence and wavelet phase analysis was performed between environmental and epidemiological variables from 2003 to 2010 for 8 municipalities (counties) in the state of Amazonas, Brazil (Barcelos, Borba, Canutama, Carauari, Coari, Eirunepé, Humaitá, and São Gabriel da Cachoeira). The results suggest significant coherences, mainly on the scale of annual variability, but scales of less than 1 year and of 2 years were also found. The analyses show that malaria cases display a peak at approximately 1 and a half months before or after peak rainfall and on average 1-4 months after peak river water levels in most of the municipalities studied. Each environmental variable displayed distinct local behavior in time and in space, suggesting that other local variables (e.g. topography) may control environmental conditions, favoring different patterns in each municipality. However, when the analyses were performed jointly it was possible to show a non-random order in these relations. Although environmental and climatic factors indicate a certain influence on malaria dynamics, surveillance, prevention, and control issues should not be overlooked, meaning that government public health interventions can mask possible relations with local hydrological and climatic conditions.

Padrão sazonal dos casos de malária e a relação com a variabilidade hidrológica no Estado do Amazonas, Brasil

“…Wolfarth-Couto et al 32 , based on statistical analyses, showed that malaria peaks are reached, on average, between 1 and 4 months after the peak of river levels. Moreover, the authors suggested that the relationship between the variables may represent local actions concerning time and space, and that variables, such as topography, favor a differentiated initiative for each municipality.…”

A prospective cohort study linking migration, climate, and malaria risk in the Peruvian Amazon

“…Each of these occupations requires travel to work sites, which may depend on rainfall and river height as most of this travel occurs along the river system as roads are rarely available. Such movement may increase exposure to mosquitoes, of which vector reproduction rates and human-vector interactions have increased in part due to climate change and migration [15][16][17].…”

Seasonality modulates the direct and indirect influences of forest cover on larval anopheline assemblages in western Amazônia

“…We observed that rainfall plays an important role in the larval abundance of Anopheles in artificial larval habitats in Manaus. In addition, climatic factors such as rainfall and river levels are strongly associated with vector abundance and malaria cases in the region 54 , 55 . During the rainy season, increased water volume in artificial habitats provides more areas for distribution and development of mosquito species 56 and we detected a significant increase in abundance of A. triannulatus , A. darlingi and A. nuneztovari .…”