Comparative study of distribution of anopheline vectors (Diptera: Culicidae) in areas with and without malaria transmission in the highlands of an extra-Amazonian region in Brazil.

摘要

This study compares the distribution of anopheline mosquitoes in a malaria-endemic municipality (MAL) and a malaria-free municipality (FREE) in an area of the Atlantic Forest in Brazil. Simultaneous quarterly nightly captures were made in three locations in each municipality. One Shannon light trap (Shannon light traps were home made according to specifications published in Am. J. Trop. Med. 1939; 19: 131-140) (SLT) and five CDC light traps (a kind of automatic trap fed by batteries of 12 V and 7 amp/h, with dry ice as a source of CO₂; John W. Hock Company, Gainesville, FL) (CLT) (two in the canopy and three at ground level) were operated from 6:00 p.m. to 6:00 a.m. More specimens were captured in MAL (362 in SLTs and 126 in CLTs) than in FREE (66 in SLTs and 59 in CLTs). For the SLTs, Simpson's dominance index was similar in MAL and FREE (D=0.15 versus D=0.203, P>0.7), but Shannon's diversity index was higher for MAL (H=1.969 versus H=1.641, P<0.01). For the CLTs, Simpson's dominance index was higher in MAL (D=0.416 versus 0.2688, P<0.001), and the Shannon diversity index was higher in FREE (H=1.5222 versus H=1.115, P<0.01). In SLTs, Anopheles (Kerteszia) cruzii s.l. frequencies were higher in MAL ( chi 2=23.39; P=0.000001). In CLTs, An. cruzii s.l. was present in all strata in MAL but only in the canopy inside the forest in FREE (17 specimens). An. cruzii s.l. represented a higher proportion of anophelines in MAL ( chi 2=31; P<0.000001). The factors that differed in these two areas were anopheline species density and An. cruzii s.l. abundance and distribution.