RESUMO
Histologic and ultrastructural changes were observed in the respiratory portions of lung in five 29-40-month-old Aruba Island rattlesnakes, Crotalus unicolor, that were inoculated with an Aruba Island Rattlesnake virus (AIV) strain of ophidian paramyxovirus (OPMV) isolated from an Aruba Island rattlesnake. Lungs from one non-infected and three mock-infected Aruba Island rattlesnakes were examined also. From 4 to 22 days following intratracheal inoculation, progressive microscopic changes were seen in the lung. Initially, increased numbers of heterophils were observed in the interstitium followed by proliferation and vacuolation of epithelial cells lining faveoli. The changes appeared to progress from cranial to caudal portions of the respiratory lung following inoculation. Beginning at 4 days postinoculation, viral antigen was demonstrated in epithelial cells lining faveoli with an immunofluorescent technique using a rabbit anti-AIV polyclonal antibody. Electron microscopy revealed loss of type I cells, hyperplasia of type II cells, and interstitial infiltrates of heterophils and mononuclear cells. Viral nucleocapsid material was seen within the cytoplasm and mature virus was seen budding from cytoplasmic membranes of infected type I and type II cells from 8 to 19 days after infection. A virus consistent with AIV was isolated from lung tissues of infected rattlesnakes, thus fulfilling Koch's postulates.
Assuntos
Crotalus , Pulmão/patologia , Pulmão/virologia , Pneumonia Viral/veterinária , Infecções por Respirovirus/veterinária , Respirovirus/patogenicidade , Animais , Animais de Zoológico , Divisão Celular/fisiologia , Epitélio/patologia , Epitélio/ultraestrutura , Epitélio/virologia , Feminino , Técnica Indireta de Fluorescência para Anticorpo , Pulmão/ultraestrutura , Masculino , Microscopia Eletrônica/métodos , Microscopia Eletrônica/veterinária , Antilhas Holandesas , Pneumonia Viral/patologia , Pneumonia Viral/virologia , Coelhos , Respirovirus/isolamento & purificação , Respirovirus/ultraestrutura , Infecções por Respirovirus/patologia , Infecções por Respirovirus/virologiaRESUMO
Venezuelan hemorrhagic fever (VHF), a newly described disease caused by an arenavirus (Guanarito), has resulted in multiple human deaths in Venezuela. To develop an animal model of this disease, strain 13 and Hartley strain guinea pigs were inoculated subcutaneously with Guananto strain 95551 of arenavirus in a pilot study to determine susceptibility of the species to the virus. All animals were killed when moribund 12-14 days following inoculation. Animals were necropsied and tissues were fixed and examined by both light and electron microscopy. Viral antigen was demonstrated in the tissues by immunohistochemistry at both the light and electron microscopic levels. Lesions were characterized by single cell necrosis of epithelium of the gastrointestinal tract, interstitial pneumonia, lymphoid and hematopoietic cell necrosis, and the presence of platelet thrombi in occasional blood vessels associated with hemorrhage. Viral antigen was demonstrated in lymphoid tissues and macrophages, endothelial cells of multiple organs, pulmonary epithelium, epithelium of the gastrointestinal tract, and in miscellaneous other tissues and cells. Intact virions and typical arenavirus inclusions were demonstrated by immunoelectron microscopy in these tissues. Based on these findings, the guinea pig appears to be a valid animal model of the human disease.
Assuntos
Arenavirus , Modelos Animais de Doenças , Febres Hemorrágicas Virais , Animais , Antígenos Virais/isolamento & purificação , Arenavirus/imunologia , Arenavirus/isolamento & purificação , Suscetibilidade a Doenças , Cobaias , Febres Hemorrágicas Virais/imunologia , Febres Hemorrágicas Virais/patologia , Febres Hemorrágicas Virais/virologia , Microscopia Imunoeletrônica , Projetos Piloto , VenezuelaRESUMO
Oliveros virus is an agent isolated in cell culture from Bolomys obscurus (Rodentia, Muridae, Sigmodontinae) captured on the central Argentine pampa. Oliveros virus was shown to be related to members of the Tacaribe complex of the family Arenaviridae by immunofluorescent antibody (IFA) tests, electrophoretic pattern of viral proteins, and morphology as observed by electron microscopy. It was distinct from 12 other arenaviruses by a combination of plaque-reduction neutralization tests, comparison of endpoint titers among cross-IFA tests, and comparison of viral RNA sequence data. This agent is the third new arenavirus from South America described within the last three years.