Co-infection with Marek’s disease virus and avian leukosis virus in the banat naked neck hens

Abstract

Marek’s disease virus and avian leucosis virus are causes of contagious, immunosuppressive, and oncogenic diseases. Many reports have described single virus infection, but detailed description of co-infection with Marek’s disease virus and avian leucosis virus has been provided in a few previous reports. The aim of this study was to determine the cause of health disorders in a flock of the Banat Naked Neck hens at the age of 11 weeks. Clinical examination of the flock showed signs of cachexia, apathy, dropped wings, nervous symptoms in the form of bilateral leg paresis, sporadic diarrhoea, and the mortality reaching 20%. Post-mortem examinations showed the following changes: chronic pseudomembranous typhlitis, intestinal ascaridiasis, splenomegaly, granulomatous pneumonia, multiple yellowish caseous foci in the liver, and white tumour masses in the heart. Histopathological examination of the spleen, proventriculus and heart tissue revealed polymorphic infiltrates, while granulomatous inflammation was observed in the lung and liver. Gomori methenamine silver stain method revealed septate and arborized hyphae resembling the Aspergillus spp. fungi in the liver and lung granulomas. Bacteriological examination of faeces revealed the presence of Escherichia coli, and parasitological examination of the small intestine determined the presence of oocyst of Eimeria acervulina and Eimeria tenella in the caecum. The genomes of Marek's disease virus and avian leucosis virus were determined by polymerase chain reaction in tissue samples. In this case, specific pathological lesions, as well as molecular finding confirmed co-infection with Marek’s disease virus and avian leucosis virus.

Virus Marekove bolesti i virus ptičje leukoze uzrokuju zarazne, imunosupresivne i onkogene bolesti. Mnoga izvješća opisuju infekciju pojedinim virusom, ali tek mali broj izvješća podrobnije opisuje koinfekciju virusom Marekove bolesti i virusom ptičje leukoze. Cilj ovog istraživanja bio je utvrditi uzrok zdravstvenih poremećaja u jatu kokoši pasmine Banatski gološijan u dobi od 11 tjedana. Klinički pregled jata pokazao je znakove kaheksije, apatije, spuštena krila, živčane simptome u obliku pareze nogu, sporadični proljev te 20%-tnu smrtnost. Postmortem pregledi pokazali su sljedeće promjene: kronični pseudomembranski tiflitis, crijevnu askaridijazu, splenomegaliju, granulomatoznu pneumoniju, višestruka žućkasta sirasta žarišta u jetri i bijele tumorske tvorbe u srcu. Patohistološki pregled tkivnih uzoraka slezene, proventrikla i srca otkrio je polimorfne infiltrate, dok je u plućima i jetri zabilježena granulomatozna upala. Metenamin srebrno bojenje po Gomoriju otkrilo je septirane i arborizirane hife nalik gljivama Aspergillus spp. u jetrenim i plućnim granulomima. Bakteriološke pretrage fecesa pokazale su prisutnost Escherichia coli, dok je parazitološka pretraga tankog crijeva utvrdila prisutnost oocita Eimeria acervulina te Eimeria tenella u cekumu. PCR-om su genomi virusa Marekove bolesti i virusa ptičje leukoze utvrđeni u tkivnim uzorcima. U ovom istraživanju su specifične patološke promjene i molekularni nalazi potvrdili koinfekciju virusom Marekove bolesti i virusom ptičje leukoze.