Larval habitats of Anopheles species in a rural settlement on the malaria frontier of southwest Amazon, Brazil

DENISE PIMENTEL BERGAMASCHI; NICOLÁS SCHWEIGMANN; PAULO RUFALCO-MOUTINHO; MARIA ANICE MUREB SALLUM

ACTA TROPICA

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2016 vol. 164 p. 243 - 258

0001-706X

disturbancesin the natural environment, thus affecting the ecology of the species of Anopheles and thus the malariatransmission. Larval habitats are important sources for maintenance of mosquito vector populations, andholding back a natural watercourse is a usual process in the establishment of rural settlements, since theformation of micro-dams represents a water resource for the new settlers. Identifying characteristics ofthe larval habitats that may be associated with both the presence and abundance of Anopheles vectorsspecies in an environment under ecological transition is background for planning vector control strate-gies in rural areas in the Amazon. Anopheles larvae collections were performed in two major types ofhabitats: natural and flow-limited water collections that were constructed by holding back the originalwatercourse. A total of 3123 Anopheles spp. larvae were captured in three field-sampling collections. Themajority of the larvae identified were taken from flow-limited water collections belonged to species ofthe Nyssorhynchus subgenus (92%), whereas in the natural larval habitats a fewer number of individu-als belonged to the Stethomyia (5%) and Anopheles (3%) subgenera. The total of Nyssorhynchus identified(1818), 501 specimens belonged to An. darlingi, 750 to An. triannulatus and 567 for others remainingspecies. In addition, 1152 could not be identified to subgenus/species level, because they were either inthe first-instar or damaged. The primary vector in areas of the Amazon river basin, An. darlingi, was foundexclusively in man-made habitats. Statistical analysis display An. triannulatus with specialist behaviorfor characteristics of man-made habitats. Modifications in the natural environment facilitate the rise oflarval habitats for species with epidemiological importance for malaria in the region. This study showedthat man-made habitats flow-limited water collections from dry lands could be a factor associated withthe increase of An. darlingi and An. triannulatus populations, and other Nyssorhynchus species as well inendemic areas of the Amazon Region.