The study of histopathological changes caused by influenza A (H5N8) viral infection in bird species is essential for the understanding of their role in the spread of this highly infectious virus. However, there are few such studies under natural conditions in minor gallinaceous species. This article describes the pathomorphological findings in Colchis pheasants infected naturally with H5N8 during an epizootic outbreak in Bulgaria. Samples of internal organs of 10 carcasses were collected for histopathological and immunohistochemical evaluation, virus isolation and identification, and nucleic acid detection. Consistent macroscopic findings were lesions affecting the intestine, heart, lung, and pancreas. Congestion and mononuclear infiltrate were common findings in the small intestine, as were necrosis and lymphoid clusters in the lamina propria of the caeca. Congestion with small focal necrosis and gliosis with multifocal nonpurulent encephalitis were observed in the brain. Myocardial interstitial oedema and degenerative necrobiotic processes were also detected. Immunohistological analysis confirmed systemic infection and revealed influenza virus nucleoprotein in all analysed organs. Variable necrosis was observed in the brain, liver, trachea, heart, small intestine, and caeca. Viral antigen was commonly found in the brain, heart, lung and trachea. Contact with migrating waterfowls was suspected as a reason for the outbreak.

The study of histopathological changes caused by influenza A (H5N8) viral infection in bird species is essential for the understanding of their role in the spread of this highly infectious virus. However, there are few such studies under natural conditions in minor gallinaceous species. This article describes the pathomorphological findings in Colchis pheasants infected naturally with H5N8 during an epizootic outbreak in Bulgaria.

Inclusion of high-ionic strength buffers helped us to develop a sandwich ELISA to detect hemorrhagic septicemia virus (HSV) in cell culture and infected trout tissue extracts. For maximal sensitivity of 0.1 to 0.2 ng/well/100 microliter or about 10 to 50 TCID50/well/100 microliter, trout extracts were diluted 1:1 and assayed for the earliest synthesized nucleoprotein N. Simultaneous binding of the N protein from HSV in the sample to the wells coated with monoclonal antibody (2D5 against the N protein) and to the peroxidase-labeled monoclonal antibody (2C9 against the N protein) proceeded during a 2-hour incubation at 20 to 22 C (room temperature). The response was linear between 6 to 60 ng/well of purified virus. Monoclonal antibodies used were noncompetitive with each other and reacted with F1, F2, 23.75, and 5 Spanish isolates of HSV, but not with infectious hematopoietic necrosis or infectious pancreatic necrosis viruses. Tissue specimens with low content of HSV virus may now be assayed directly without use of cell culture, rapidly, and with high precision, during the acute phase of the disease in salmonid fishes.

Influenza A virus (IAV) infections are endemic in pork producing countries around the world. The emergence of the pandemic 2009 human H1N1 influenza A virus (pH1N1) raised questions about the occurrence of this virus in Brazilian swine population. During a 2009-2010 swine influenza virus research project at Embrapa Swine and Poultry (CNPSA), an outbreak of a highly transmissible H1N1 influenza A virus disease was detected in a pig herd in Santa Catarina State, Brazil. The virus caused a mild disease in growing pigs and sows without mortality. Three clinically affected piglets were euthanized. Gross lesions included mild to moderate consolidation of cranioventral areas of the lung. Microscopically, the lesions were characterized by necrotizing obliterative bronchiolitis and bronchointerstitial pneumonia. Immunohistochemistry using a monoclonal antibody against type A influenza virus nucleoprotein revealed positive staining in the nuclei of the bronchiolar epithelial cells. Lung tissue from three piglets and nasal swabs from five sows and four piglets were positive for influenza A by RT-PCR. Influenza virus was isolated from one lung, later confirmed by the hemagglutination test (HA titer 1:128) and RT-PCR. Sequence analyses of Hemmaglutinin (HA) and Matrix (M) genes revealed that the virus was consistent with the pandemic (A/H1N1) 2009 influenza virus strain that circulated in humans. This is the first report of an outbreak of pandemic A/H1N1 influenza virus in pigs in Brazil.

A infecção causada pelo vírus Influenza A (IAV) é endêmica em suínos no mundo inteiro. O surgimento da pandemia de influenza humana pelo vírus A/H1N1 (pH1N1) em 2009 levantou dúvidas sobre a ocorrência deste vírus em suínos no Brasil. Durante o desenvolvimento de um projeto de pesquisa do vírus de influenza suína em 2009-2010, na Embrapa Suínos e Aves (CNPSA), foi detectado em um rebanho de suínos em Santa Catarina, Brasil, um surto de influenza altamente transmissível causado pelo subtipo viral H1N1. Este vírus causou uma doença leve em suínos em crescimento e em fêmeas adultas, sem mortalidade. Tres leitões clinicamente afetados foram eutanasiados. As lesões macroscópicas incluiam consolidação leve a moderada das áreas cranioventrais do pulmão. Microscopicamente, as lesões foram caracterizadas por bronquiolite necrosante obliterativa e pneumonia broncointersticial. A imunohistoquímica, utilizando um anticorpo monoclonal contra a nucleoproteína do vírus influenza A, revelou marcação positiva no núcleo das células epiteliais bronquiolares. O tecido pulmonar de três leitões e os suabes nasais de cinco fêmeas e quatro leitões foram positivos para influenza A pela RT-PCR. O vírus influenza foi isolado de um pulmão, mais tarde sendo confirmado pelo teste de hemaglutinação (título HA 1:128) e por RT-PCR. A análise das seqüências de nucleotídeos dos genes da hemaglutinina (HA) e proteína da matriz (M) revelou que o vírus isolado foi consistente com o vírus pandêmico A/H1N1/2009 que circulou em humanos no mesmo período. Este é o primeiro relato de um surto de influenza causado pelo vírus pandêmico A/H1N1 em suínos no Brasil.