SEASONAL DISTRIBUTION OF MALARIA VECTORS (DIPTERA: CULICIDAE) IN RURAL LOCALITIES OF PORTO VELHO, RONDÔNIA, BRAZILIAN AMAZON.
Bottom Line: The present paper relates to the results of the survey of Anopheles fauna conducted in the state of Rondônia.Of these specimens, 95.1% consisted of Anopheles darlingi, 1.8% An. triannulatus l.s., 1.7% An. deaneorum, 0.8% An. konderi l.s., 0.4 An. braziliensis, 0.1% An. albitarsis l.s., and 0.1% An. benarrochi.An. darlingi was the only species found in all localities; the remaining species occurred in sites with specific characteristics.
Affiliation: Fundação Oswaldo Cruz, Porto Velho, RO, Brazil.
We conducted a survey of the malaria vectors in an area where a power line had been constructed, between the municipalities of Porto Velho and Rio Branco, in the states of Rondônia and Acre, respectively. The present paper relates to the results of the survey of Anopheles fauna conducted in the state of Rondônia. Mosquito field collections were performed in six villages along the federal highway BR 364 in the municipality of Porto Velho, namely Porto Velho, Jaci Paraná, Mutum Paraná, Vila Abunã, Vista Alegre do Abunã, and Extrema. Mosquito captures were performed at three distinct sites in each locality during the months of February, July, and October 2011 using a protected human-landing catch method; outdoor and indoor captures were conducted simultaneously at each site for six hours. In the six sampled areas, we captured 2,185 mosquitoes belonging to seven Anopheles species. Of these specimens, 95.1% consisted of Anopheles darlingi, 1.8% An. triannulatus l.s., 1.7% An. deaneorum, 0.8% An. konderi l.s., 0.4 An. braziliensis, 0.1% An. albitarsis l.s., and 0.1% An. benarrochi. An. darlingi was the only species found in all localities; the remaining species occurred in sites with specific characteristics.
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Mentions: We collected 2,185 anopheline mosquitoes belonging to seven species in the sixlocalities. Of the mosquitoes collected, 95.1% were identified as An.darlingi, 1.8% as An. triannulatus l.s. , 1.7% asAn. deaneorum, 0.8% as An. konderi l.s. , 0.4% asAn. braziliensis, 0.1% as An. albitarsis l.s. , and0.1% as An. benarrochi l.s. Anopheles darlingi wascollected in all localities. The remaining species were found in sites with uniquecharacteristics (e.g. , An. braziliensis was predominantly found inareas of secondary growth, such as forest clearings and pastures) (Table 1). Mutum Paraná, Porto Velho, and JaciParaná exhibited four of the seven collected species, whereas only two were found inExtrema, Vista Alegre do Abunã, and Vila Abunã. Moreover, although these areas had thesame number of species, their species composition (i.e. , species found in the area)significantly differed (PERMANOVA S.S = 1.37; Pseudo-F < 0.001).However, no significant differences in Anopheles spp. communityhomogeneity were observed among the study areas (Permdisp p = 0.34;Fig. 2). Analysis of the distribution patternsof the main malaria vectors showed that the number of An.darlingidiffered significantly among localities (ANOVA χ2 = 44.35,p < 0.001), with Porto Velho exhibiting the highest mean numberof individuals of this species (144.55 ± 59.81) and Vila Abunã exhibiting the lowest(5.66 ± 1.04). The mean distribution of An. darlingiamong thelocalities is summarized in Table 2. With theexception of Vista Alegre do Abunã, An. darlingi numbers weresignificantly higher in outdoor than indoor dwellings (ANOVA χ2 = 27.79, p < 0.001; Fig. 3).