Survey of Italian veterinary practioners on D. immitis and D. repens

Dirofilarial infections (D. immitis, D. repens) are vector-borne parasitic diseases mainly of dogs and cats. Moreover, they are zoonotic and endemic areas of both are expanding. The experience of veterinarians is very important for correct prevention and diagnosis. To evaluate this, an electronic questionnaire was sent to all Italian veterinary facilities. In the first months of 2018 a questionnaire was sent by e-mail to 2795 veterinary facilities (surgeries, clinics, hospitals and public facilities). The 31 questions were mainly about in which province the facilities were located, and about diagnosis, prevention and treatment for D. immitis and D. repens in dogs and cats. In addition, it was asked if they knew the Dirofilariosis societies and if they had attended lectures and/or congresses on the topic. Among 662 responses (27%), 33.7% facilities reported infections only of D. immitis, 3.2% only of D. repens, 10.7% mix infections and 52.4% no cases of either parasite in the last year. Dirofilaria immitis infections were observed above all in the northern and central Italy. However, also many regions of the south and the islands (Sicily and Sardinia) reported heartworm infections. Dirofilaria repens is fairly evenly distributed throughout Italy mainly in co-infections with D. immitis. The most frequent diagnostic method used in dogs was the antigen test, 24.0%, followed by the fresh blood smear together with the antigen test 23.3%, aid of a diagnostic laboratory 8.3%, and Knott test together with the antigen test 4.7%. For D. repens in dogs results were: diagnostic laboratory 33.8%, skin biopsy 10.8% and fresh blood smear 9.8%. The most frequently diagnostic technique for D. immitis in cats was: diagnostic laboratory 27.3%, serological test 26.9% and fresh blood smear 8.2%. For treatment of canine heartworm infection, more then 25% used ivermectin + doxycycline or melarsomin and ivermectin + doxycycline 11%; while more than 50% did not do any treatment in the cat. Prevention was started in the dog in April-May, 54.8%, while 10.3% treated for all year. Finally, more than 70% knew the American Heartworm Society (AHS), while 69% knew the European Society of Dirofilariosis and Angiostrongylosis (ESDA). Our data show how D. immitis and D. repens are distributed in most of the Italian provinces. Furthermore, the diagnosis is often underestimated and mainly relegated just to serology. This type of research can be a good starting point for scientific societies and to get updated risk maps.