First finding of Dirofilaria repens in a natural population of Aedes albopictus

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Abstract
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.