Probable trajectories associated with the transport of Ochlerotatus albifasciatus during a strong wind event in Buenos Aires City (Argentina)

RUBÉN BEJARÁN; SYLVIA FISCHER; ALICIA DE GARIN; NICOLÁS SCHWEIGMANN

METEOROLOGICAL APPLICATIONS

Wiley Inter Science

Año: 2008 vol. 15 p. 243 - 248

1350-4827

Because of its capacity to infect human beings and domestic animals with a number of different viruses, Ochlerotatus albifasciatus Macquart, 1938 (Diptera: Culicidae) is an important mosquito from the sanitary point of view. The abundance peaks of this species after drought periods are well known in the provinces of Buenos Aires and Cordoba. This paper aims at explaining the presence of the high abundance of adult Oc. albifasciatus in Buenos Aires city in February 2005. As no breeding immatures were recorded during the previous weeks, the most likely hypothesis was that mosquitoes entered the city from breeding sites located in the surroundings. Wind observations and the existing knowledge on this species biology, atmospheric dynamic models and meteorological data were used to support this hypothesis and identify the source areas. Mass transport of these individuals was apparently the consequence of a convective process. The occurrence of a convective process was demonstrated, which transported air masses from the periphery toward the City of Buenos Aires. Air parcel trajectories, Ezeiza radar images and the flood zones observed in satellite images indicated the source was located in the lowlands of Ezeiza in the Rio Matanza basin, distant some 50 km to the southwest of the City. The evidence suggests that Oc. albifasciatus is transported by wind, and the trajectory models are a very useful tool to locate the sources of proliferation of these insects.