Affinity and diversity indices for anopheline immature forms

Abstract

As for the entire Amazon Region, malaria continues to be a major health public problem in Roraima that presented an Annual Parasitic Index of 85.4 in 2005, the highest in Brazil. Information on anopheline breeding sites is an essential component in malaria control strategies. Aiming to contribute to the limited knowledge on anopheline immature forms in Roraima, collections and breeding site observations were performed in 10 breeding sites around the capital city Boa Vista. Collections were carried out in the rainy and dry season periods between April 2004 and January 2005. Breeding sites comprised natural and artificial water reservoirs. A total of 623 immature forms were collected belonging to Anopheles albitarsis s.l., An.triannulatus s.l., An. nuneztovari/dunhami, An. braziliensis, An. evansae, An. oswaldoi s.l., An. strodei and An. darlingi. An. albitarsis and An. braziliensis were the most frequently found species. Eight larvae of An. darlingi were found in only one breeding site located in the forest. An. triannulatus/An. nuneztovari and An. albitarsis/An. braziliensis were the pairs of species that mostly occurred together. Both pair of species displayed the highest affinity index what might indicate a high compatibility for the same breeding conditions and/or a synergistic co-occurrence. Species diversity index was higher for the dry season.

Deforestation and Malaria on the Amazon Frontier: Larval Clustering of Anopheles darlingi (Diptera: Culicidae) Determines Focal Distribution of Malaria

“…24,25 The preference of A. darlingi for sites with lower luminosity may help explain the absence of the species in deforested areas, as well as in the largely treeless savanna in Suriname, 26 English Guyana, 27 and in northern Roraima. 16,28 The species reappears in patches of forests and alluvial forests. 16 The preference for lower luminosity has been suggested to be a behavioral characteristic of the forest-adapted ovipositing female.…”

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

“…In 2005, several immature specimens of malaria vectors were described in areas surrounding Boa Vista, especially in the dry season, but anopheles darling larvae were found rarely. The authors discuss the usual persistence of malaria transmission even under these conditions (Nagm et al 2007). Another study showed the impact of human settlements and other anthropogenic changes on the environment and how climate variability affected both population density and relative abundance of these vectors (Gomes et al 2008).…”

Ecological Suitability and Spatial Distribution of Five Anopheles Species in Amazonian Brazil

“…goeldii) has been described as a species readily able to colonize and dominate in altered environments 33 as a result of its ability to survive in a variety of conditions, such as sunlit or shaded sites, fresh, clear, still, or flowing water 34 and occasionally in turbid and polluted sites. 35 The Albitarsis complex consists of at least eight species and a new lineage 36,37 ; only some of these have been incriminated as malaria vectors. The medical importance of Anopheles oryzalimnetes (Wilkerson and Motoki), previously Anopheles albitarsis B, is largely unknown, although this species has been attracted to human bait.…”