Spatial distribution and breeding site characteristics of Aedes albopictus and Aedes aegypti in Fortaleza, State of Ceará

Abstract

Introduction: Since the registration of Aedes albopictus in the municipality of Fortaleza in 2005, it has shown rapid dispersion. A study aiming to identify its occurrence areas, breeding sites and associations with Aedes aegypti and other culicids was carried out during 2008. Methods: Between January and July 2008, samples of immature forms of culicids were gathered from properties located in districts of Fortaleza. Certain features of the breeding sites were highlighted, such as location (indoors or outdoors), presence of covering (protection against impact of sunlight and rain), water turbidity (water clear or not clear), constituent material, volume, height above ground level and simultaneous presence of different species of culicids in the same breeding site. Results: Indoor location was an important factor for the breeding sites for Aedes albopictus [PR = 0.52; 95% CI: 0.33-0.81]. On the other hand, water turbidity and reservoir covering were not shown to be differentiators regarding infestation [p > 0.05]. Absence of water turbidity was significant for Aedes aegypti infestation in breeding sites [PR = 1.14; 95% CI: 1.06-1.22]. Conclusions: Absence of one of the species from the breeding sites enhanced the infestation by another species. Breeding sites that had not been infested by Aedes albopictus had a prevalence of infestation by Aedes aegypti that was 2.05 times greater [95% CI: 1.72-2.44]. There was no significant association between volume and height of the breeding sites and infestation by both species. Both species were found to be dispersed throughout the municipality, occupying a wide diversity of breeding sites. However, a slight physical separation could be identified, with higher infestation with Aedes albopictus outdoors.