Veterinaria Italiana, 2011, 47 (2), 147‐153 © Istituto G. Caporale 2011 www.izs.it/vet_italiana Vol. 47 (2), Vet Ital 147 Detection of fowl poxvirus integrated with reticuloendotheliosis virus sequences from an outbreak in backyard chickens in India Sanchay K. Biswas (1) , Chandrakanta Jana (2) , Karam Chand (1) , Waseem Rehman (1) & Bimalendu Mondal (1) Summary Fowl poxvirus (FPV) infection was observed in unvaccinated backyard chickens. A total of 15 birds were affected in a flock of 37. Pock lesions were observed on the comb, eyelids, beak and wattles. The birds appeared sick with roughened feathers and stunted growth. No mortality was recorded. DNA was isolated from scabs and polymerase chain reaction (PCR) was performed to amplify the 4b core protein gene of FPV, the envelope (env) gene of reticuloendotheliosis virus (REV) and the region of FPV flanking REV 5´ long terminal repeat (LTR). Correct‐size PCR products of 578 bp, 807 bp and 370 bp, respectively, were observed in agarose gel electrophoresis. Sequence analysis of these products suggests that the virus was an FPV with a genome containing an integrated near full‐length REV provirus. Given the fact that REV has been associated with immunosuppression, its presence in the genome of FPV appears to play an important role in the pathogenesis of fowl pox and presumably prolongs persistence of FPV in bird populations. In the present case, fowl pox has been observed to have persisted for about three years in fowl that were reared in backyard systems in villages. Keywords Chicken, Fowl, India, Polymerase chain reaction, PCR, Poxvirus, Recurring infection, Reticuloendotheliosis virus, REV, Virus. Identificazione del diftero‐ vaiolo aviario riassortito con sequenze del virus della reticoloendoteliosi in un focolaio in polli da cortile in India Riassunto È stata riscontrata un’infezione da virus del diftero‐ vaiolo aviario (FPV) in polli da cortile non vaccinati. Gli esemplari colpiti sono stati 15 su un gruppo di 37. Sono state osservate lesioni cutanee vescicolari su cresta, palpebre, becco e bargigli. Gli esemplari colpiti hanno presentato arruffamento del piumaggio e ritardo nella crescita. Non si sono registrati casi mortali. Il DNA è stato isolato dalle croste ed è stata effettuata la PCR (reazione a catena della polimerasi) per amplificare il gene 4b che codifica per la proteina del “core” del FPV, il gene env del virus della reticoloendoteliosi (REV) e la regione adiacente REV 5´LTR del FPV. L’elettroforesi su gel di agarosio ha evidenziato prodotti di PCR delle dimensioni previste (1) Divisio n o f Viro lo g y, Ind ia n Ve te rina ry Re se a rc h Institute , Mukte sw a r C a m p us, Dist. Na inita l 263 138, Utta ra kha nd , Ind ia b im a le nd u.m @ e m a il.c o m (2) KVK Burd wa n, C e ntra l Re se a rc h Institute fo r Jute a nd Allie d Fib e rs, Bud b ud , Dist. Burd wa n 713403, We st Be ng a l, Ind ia