Immunohistochemistry and molecular epidemiology of avian paramyxovirus 1 from formalin-fixed and paraffin-embedded sections of Japanese doves (Columba livia) affected with neurological signs

Four doves (Nos. 1–4 birds) affected with neurological signs (ataxia, circling and torticollis) were investigated pathologically and microbiologically. Viral isolation was tried from the tracheal and cloacal swabs of all 4 birds and from liver, spleen, kidney, heart, lung and brain of Nos. 1 and 2 birds. No viruses were isolated from 4 birds, but they had high serum antibody titers against avian paramyxovirus 1 (APMV-1). Histologically, they had the characteristic histological changes of pigeon APMV-1 infection; nonpurulent encephalitis and interstitial nephritis. Immununohistochemically, APMV-1 antigens were detected in the necrotic renal tubular epithelial cells of 1 bird of them (No. 3 bird). Detection of APMV-1 ribonucleic acid (RNA) from formalin-fixed and paraffin-embedded (FFPE) sections was attempted by reverse transcription-polymerase chain reaction (RT-PCR). Sequencing the RT-PCR product showed the virus RNA belonged to the same APMV-1 genotype (VI) as the strains isolated from the world previous cases of pigeon APMV-1 infection. The RT-PCR of FFPE sections and sequencing of RT-PCR products are useful for molecular epidemiology of the virus when viral isolation from fresh samples is unsuccessful.