Biting Indices, Host-seeking Activity and Natural Infection Rates of Anopheline Species in Boa Vista, Roraima, Brazil from 1996 to 1998

Abstract

The epidemiology of the transmission of malaria parasites varies ecologically. To observe some entomological aspects of the malaria transmission in an urban environment, a longitudinal survey of anopheline fauna was performed in Boa Vista, Roraima, Brazil. A total of 7,263 anophelines was collected in human bait at 13 de Setembro and Caranã districts: Anopheles albitarsis sensu lato (82.8%), An. darlingi (10.3%), An. braziliensis (5.5%), An. peryassui (0.9%) and An. nuneztovari (0.5%). Nightly 12 h collections showed that An. albitarsis was actively biting throughout the night with peak activities at sunset and at midnight. An. darlingi bit during all night and did not demonstrate a defined biting peak. Highest biting indices, entomological inoculation rates and malaria cases were observed seasonally during the rainy season (April-November). Hourly collections showed host seek activity for all mosquitoes peaked during the first hour after sunset. An. darlingi showed the highest plasmodial malaria infection rate followed by An. albitarsis, An. braziliensis and An. nuneztovari (8.5%, 4.6%, 3% and 2.6%, respectively). An. albitarsis was the most frequently collected anopheline, presented the highest biting index and it was the second most frequently collected infected species infected with malaria parasites. An. albitarsis and An. darlingi respectively, are the primary vectors of malaria throughout Boa Vista

Malaria entomological inoculation rates in gold mining areas of Southern Venezuela

“…Moreover, those studies were conducted mostly in the Brazilian Amazon and French Guyana; Soares Gil et al (2003) reported an EIR of 10 infective bites/person/year for An. darlingi in RO, while in urban areas of Boa Vista, Silva-Vasconcelos et al (2002) reported that the highest EIR was in An. albitarsis s.l.…”

The importance of Anopheles albitarsis E and An. darlingi in human malaria transmission in Boa Vista, state of Roraima, Brazil

“…Study sites -For continuity with and an extension of the study by Silva-Vasconcelos et al (2002) we collected in two localities, 13 de Setembro (along the Rio Branco) and Caranã (along the Rio Cauamé). We chose four additional localities (Cauamé, Jardim da Copaiba, Caçari, and Distrito Industrial) where malaria cases had recently (2000)(2001) been reported to the Secretaria Municipal de Saúde in Boa Vista.…”

“…marajoara appears to be the primary malaria vector in Serra do Navio, state of Amapá (Póvoa et al 2000b well as in Boa Vista, state of Roraima (Silva-Vasconcelos et al 2002). An.…”

“…The state of Roraima, which persists in having one of the highest annual parasitic indices (API; number of cases/1000) for malaria in Brazil (Silva-Vasconcelos et al 2002) is the most northern Brazilian state, sharing international borders with Guyana and Venezuela. The capital of Roraima, Boa Vista, is in the savannah ecoregion of Rubio-Palis and Zimmerman (1997) and is characterized by: a long rainy season (April-November), a short dry season (DecemberMarch), a mean annual temperature of 27.8°C, and a mean rainfall of 429 mm (Silva-Vasconcelos et al 2002).…”

Anopheles darlingi bionomics and transmission of Plasmodium falciparum, Plasmodium vivax and Plasmodium malariae in Amerindian villages of the Upper-Maroni Amazonian forest, French Guiana

“…Great differences in biting activity patterns have been reported throughout the An. darlingi geographic distribution, from very pronounced crepuscular to almost exclusively nocturnal activity (Forattini 1987, Lourenco-de-Oliveira et al 1989, da Silva-Vasconcelos et al 2002, Moreno et al 2007). In the coastal areas of French Guiana, Pajot et al (1977) showed that An.…”