SHORT COMMUNICATION First finding of Dirofilaria repens in a natural population of Aedes albopictus G. CANCRINI, R. ROMI * , S. GABRIELLI, L. TOMA * , M. DI PAOLO y and P. SCARAMOZZINO y Parasitology Section, Department of Public Health Science, University of Rome ‘La Sapienza’, * Parasitology Laboratory, Istituto Superiore di Sanita` and y Istituto Zooprofilattico Sperimentale del Lazio e della Toscana, Rome, Italy Abstract. The invasive mosquito Aedes albopictus (Skuse) (Diptera: Culicidae) has become widespread in Italy during the past decade. Also Italy has foci of canine filariasis caused by Dirofilaria (Spirurida: Onchocercidae), due to subcutaneous D. repens Railliet & Henry as well as the dog heartworm D. immitis (Leidy) transmitted by various vector mosquitoes (Diptera: Culicidae). In 2002, at Fiumicino, west of Rome (Lazio Region), 17% of dogs were found to have D. repens microfilariae in peripheral blood. To evaluate the role of Ae. albopictus as a vector of Dirofilaria in this area, female mosquitoes were collected daily, June–October 2002, landing on dog or human bait in a rural house at Focene. Mosquitoes were maintained at 27  C and 70% RH for 6 days, to allow development or purging of filaria larvae, then identified and frozen for subsequent molecular assay with filaria-specific ribosomal S2-S16 primers. To distinguish specimens harbouring infective L3 Dirofilaria larvae, DNA was extracted separately from the mosquito abdomen and head-thorax. Dirofilaria species were identified by sequencing, confirmed by polymerase chain reaction of positive specimens using primers specific for D. immitis and D. repens. Dirofilaria DNA was detected in 3/154 (2%) of Ae. albopictus females examined: D. repens DNA in head-thorax and abdomen of one collected 27th July; D. immitis in the abdomen of one collected 24th September; DNA of both D. immitis and D. repens in the head-thorax of one collected 11th October 2002. Thus Ae. albopictus is a potential vector of both Dirofilarias in Italy, representing risks for veterinary and human health. Key words. Aedes albopictus, Dirofilaria immitis, D. repens, canine subcutaneous dirofilariasis, dog heartworm, filaria vector, filariasis, infective larva, invasive mosquito, molecular diagnostics, natural vector, Fiumicino, Italy. The ‘Asian Tiger Mosquito’ Aedes albopictus was first reported in Italy by Sabatini et al. (1990) and has spread to most parts of the country (Fig. 1) apparently dispersed mainly by the tyre trade (Dalla Pozza et al., 1994; Romi, 2001). It reached Rome in 1997 and, within 3 years, became established throughout the city and suburbs as well as towns on the coastal plain to the west (Di Luca et al., 2001). Apart from being a biting nuisance, the vector com- petence of Ae. albopictus for dengue and other arboviruses (Mitchell, 1995) brings new potential threats to human health in Italy. Canine dirofilariasis is endemic in northern Italy and other Eurasian foci (Avdiukhina et al., 1997; Muro et al., 1999), involving both Dirofilaria immitis (the dog heartworm) and D. repens (causing human conjunctival/subcutaneous as well as canine subcutaneous dirofilariasis) transmitted by various species of mosquitoes and possibly other vectors (Noe` , 1901; Coluzzi, 1964; Coluzzi & Trabucchi, 1968; Cancrini et al., 1995; Pampiglione & Rivasi, 2001). Among the natural vectors of dirofilariasis in other parts of the world, Ae. albopictus transmits both D. immitis (Suenaga & Correspondence: Dott. ssa Paola Scaramozzino, Istituto Zoo- profilattico Sperimentale del Lazio e Toscana, Via Appia Nuova 1411, 00178 Rome, Italy. E-mail: pscaramozzino@rm.izs.it Medical and Veterinary Entomology (2003) 17, 448–451 448 # 2003 The Royal Entomological Society