EFFECT OF THE VEGETATION ANO THE SHADE ON THE ABUNDANCE OF BREEDING SITES OF Aedes aegypti IN A CEMETERY OF BUENOS AIRES CITY, ARGENTINA.

VEZZANI D.; RUBIO A.; VELÁSQUEZ S.M.; SCHWEIGMANN N.

Buenos Aires

Congreso; V Congreso Argentino de Entomología.; 2002

Buenos Aires

Buenos Aires city is at the southern limit of the distribution of Aedes aegypti,vector of dengue and yellow fever. September to May is the favorable season for its developmentin this temperatezone, with maximumabundanceduring , March and April. The objective of this work was to evaluate the effect of the vegetation and the shade on the abundance of breeding sites in an environment with limitless container availability (cemetery). On March 2001, we performed a spatial census of all containers present in a small patch of 0,7 hectares, discriminating those with water and those´that also contained immature stages of the vector. The vegetation and the projection of their shade (from 10 to 16 hs) were measured in the field and represented on a map scale 1:700. The proportion of breeding sites found in different microenvironments (under vegetation, under shade, sun).was compared with a test of proportions. Out of 752 water-filled containers examined, 101 (13,4%) contained immature stages of Ae. aegypti. The proportion of breeding sites under vegetation (17,5%: 55/314) and shade (17,6%: 35/199) did lÍot significantly differ, but both were higher (p<0,OOO1)than the ratio registered ´at sun (4,6%: 11/239). Our results suggest that microenvironments under shade and under vegetation are the most favorable´ for Ae. aegypti, probably due to the high temperatures of the water in containers exposed to the sun. Considering these results, we would advise to concentrate vector control in those neighborhoods with greater vegetation cover in the city.