Research on Culicidae attracted to dog bait in Piedmont

Dog attracted mosquitoes were collected in Piedmont (NW Italy) in 1992 and 1993. Sampling sites where chosen on ecological and epidemiological basis, according to the results of a previous study on the distribution and prevalence of canine filariosis in this region. Dog baited traps were operated monthly (two nights/site from June to September) in six plain sites differing in the prevalence of heartworm infected dogs (including two sites where no positivity was recorded). A single capture was carried out in July-August in three more plain and four hill localities, as well as in a prealpine and a suburban zone inside the heartworm endemic area. The following species were collected (number of specimens in brackets): Aedes caspius (2255), Ae, cantans (1), Ae. cinereus (1), Ae, geniculatus (7), Ae. vexans (58), Aedes spp. (221), Anopheles claviger (1), An. maculipennis s.l. (405), Coquillettidia richiardii (16), Culex modestus (6361), Cx. pipiens (2032), Cx. territans (2), Culex spp. (94), Culiseta annulata (1). Cx. pipiens was captured in 15 sites, Cx. modestus and Ae. caspius in 13 and 12, respectively, An. maculipennis s.l. in 7, Ae. vexans in 6, Cq. richiardiiin 4, Ae. geniculatus in 3, Cx. territans in 2, Ae. cantans, Ae. cinereus, An. claviger and Cs. annulata in one. Species abundance and relative composition differed between habitats and between similar habitats with a different prevalence of microfillaraemic dogs. Regression analysis of heartworm prevalence vs. mosquitoes abundance demonstrated a positive linear relationship. Data suggest that four species (Ae. caspius, An. maculipennis s.l., Cx. modestus and Cx. pipiens) are playing a major role in the transmission of canine filariosis in Piedmont.