Avian Pneumovirus infection in turkery and broiler farms in Italy: a virological, molecular and serological field survey [Veneto]

Avian pneumovirus (APV) is the casual agent of turkey rhinotracheitis (TRT) and also causes a respiratory infection in chickens, which can result in swollen head syndrome. A survey of APV infection in Italian turkey and broiler farms, in a highly populated area of Northern Italy (Verona province), is reported. Nine turkey farms and 6 broiler farms were sampled. Sixteen birds from each group were doubly swabbed from choanal cleft for virus isolation on tracheal organ cultures (TOC) and RT nested PCR (A and B type specific) using extracted RNA. At the same time, blood samples were collected for a blocking ELISA assay. The broiler samples for virological assays were treated with Infectious bronchitis virus (IBV) antiserum raised against serotypes prevalent in the sampled areas, to avoid competitive growth of IBV on TOC. Ciliostasis on TOC was taken as indicator of the virus occurrence and confirmation was obtained by indirect immunofluorescence. APV was isolated and detected by RT-PCR in 19 day-old turkeys and in 34, 42 and 48 day-old broilers. All APV strains were found to be type B. All turkeys more than 4 week-old resulted APV positive by ELISA. APV infection was found to be widely spread in the sampled area and the protocol used for virus isolation was shown to be effective. Turkey rhinotracheitis first appeared in Italy in late eighties and the involved APV isolates were subsequently characterised as B types. Our results confirm that APV B type is present in Italy, but the limited findings to date need to be extended by further surveys in other Italian regions Il Pneumovirus aviare (APV) è causa, nel tacchino, di una infezione delle prime vie respiratorie, nota come rinotracheite del tacchino (TRT), mentre nel pollo è responsabile di una forma respiratoria lieve, che può sfociare nella sindrome della testa gonfia. Nel presente lavoro è riportata un'indagine sulla presenza di APV in allevamenti di tacchini e polli da carne della provincia di Verona. Sono stati considerati 9 allevamenti di tacchini e 6 di polli. Sono stati eseguiti tamponi rinofaringei da 16 soggetti/gruppo, per isolamento virale su colture di anelli tracheali di embrione di pollo (TOC) ed RT-nested PCR sottotipo specifica. Dagli stessi soggetti sono stati raccolti campioni di sangue per evidenziare anticorpi per APV mediante ELISA. I campioni per gli esami virologici prelevati dai polli da carne erano previamente trattati con antisieri specifici nei riguardi dei ceppi di virus della bronc