Natural vectors of Dirofilaria: preliminary results in a risk area in Tuscany

ABSTRACT Entomological investigations by means of dog- and human-baited traps were carried out in summers 2000Ð2002 in urban and rural areas of the Tuscan region in central Italy. The aim of the study was to deÞne the mosquito species involved in the transmission of Dirofilaria nematodes and to assess the risk that their presence might represent for animal andhumanhealth. Nocturnal Þeldwork on host-seeking activity and feeding preferences was followed by microscopic identiÞcation of the mosquito species attracted and by molecular identiÞcation of Dirofilaria parasites in mosquitoes. In total, 3,611 mosquito females belonging to 12 species, largely represented by Culex pipiens L. and Aedes caspius (Pallas), were caught. Some females of each species collected fed on the dogs, indicating their possible role as an intermediate host, but Þlarial DNA was found only in Cx. pipiens, Anopheles maculipennis s.l. (Meigen), and Coquillettidia richiardii (Ficalbi). In rural environments, the DNA evidence indicated the presence of infective larvae of Dirofilaria immitis, whereas in urban areas, infective larvae of Dirofilaria repens were present. The role of Cx. pipiens as a vector for heartworm disease and subcutaneous infections in natural and artiÞcial environments was conÞrmed, whereas Ae. caspius seemed refractory to the infection. The different role of the collected species is discussed. The vector competence of An. maculipennis and Cq. richiardii needs further investigation, because the importance of these species poorly represented, and the role of species such as Aedes albopictus (Skuse), characterized by a dominant diurnal activity pattern, has to be evaluated