ABSTRACT
Canine herpesvirus (CHV) is a member of the alphaherpesvirus subfamily, which can cause severe hemorrhagic diseases in neonatal pups as well as mild or subclinical respiratory infections in adult dogs. We examined the effects of cold stress on disease progression of CHV, an alphaherpesvirus, in neonatal puppies. Eight puppies were challenged intranasally with CHV suspension and divided into a cold stress treatment group and a hyperthermal group. Four pups were left uninoculated as controls and divided into cold and hyperthermal groups. In the challenged cold treatment group, all pups showed CHV-related disease within 5 days; pathological changes were observed in organs of puppies showing clinical symptoms. Grossly, numerous petechial red foci were scattered throughout lungs, kidneys, livers, and intestines of all CHV-infected puppies exposed to cold stress. Most puppies showed typical clinical signs and macroscopic lesions, and CHV infection was confirmed by isolation of the virus. However, in the challenged hyperthermal group, only one of the pups showed mild symptoms of CHV-induced disease. None of the puppies in the uninoculated group showed abnormal signs, although they were exposed to cold stress. These findings indicate that cold stress can cause rapid disease progression of CHV, an alphaherpesvirus.
Subject(s)
Adult , Animals , Dogs , Humans , Disease Progression , Hemorrhage , Intestines , Kidney , Liver , Lung , Respiratory Tract InfectionsABSTRACT
Descrevem-se os achados clínicos e patológicos e os exames laboratoriais de filhotes de cães com diagnóstico post mortem de infecção por herpesvírus canino. Os casos ocorreram em duas propriedades da Cidade de Porto Alegre, Rio Grande do Sul, em abril de 2007 e julho de 2008. Clinicamente, os cães apresentaram anorexia, apatia, choro e dispneia. A morte dos cães ocorreu após 24-72 horas do início dos sinais clínicos. Na necropsia observaram-se hemorragia multifocal renal e hepatomegalia com petéquias e pontos brancos na superfície natural do fígado. Os pulmões se apresentaram não-colapsados e vermelhos. Havia esplenomegalia e, em alguns cães, petéquias na superfície capsular do baço. Aumento dos linfonodos mesentéricos e do timo foi observado. Lesões microscópicas incluíram hemorragia e necrose multifocal em células epiteliais tubulares renais, hepatócitos e tecidos linfoides. Nos pulmões, havia necrose alveolar multifocal acentuada com abundante material fibrinoso e infiltrado inflamatório misto de intensidade variada. Ocasionais corpúsculos de inclusão intranucleares em áreas periféricas à necrose foram identificados em hepatócitos, células epiteliais de túbulos renais e células alveolares. Amostras de fígado, rim e pulmão foram positivas na imunofluorescência direta para herpesvírus canino tipo 1 (CHV-1). O diagnóstico de infecção por herpesvírus foi baseado nos achados de necropsia, histológicos e de imunofluorescência positiva em tecidos usando anticorpo anti-CHV-1. De nosso conhecimento, este é o primeiro relato da identificação do CHV-1 no Brasil, embora achados clínico-patológicos anteriores já sugerissem a presença do agente na população canina do país.
The clinic and pathological findings and laboratorial testing of puppies with postmortem diagnosis of canine herpesvirus infection are described. The cases occurred in two households of Porto Alegre, RS, in April 2007 and July 2008. The puppies presented anorexia, depression, cry and dyspnea, followed by death about 24-72 hours after the onset of clinical signs. At necropsy multifocal pin point hemorrhages were observed in the kidneys. The liver was enlarged with petechiae and white foci on the surface. The lungs were red and did not collapse. The spleen was enlarged and, in some cases, with petechiae on the capsular surface. Mesenteric lymph nodes and thymus were enlarged. Microscopic lesions included hemorrhages and multifocal necrosis of the renal tubular epithelial cells, hepatocytes and lymphoid tissues. In the lungs there was severe multifocal alveolar necrosis with abundant fibrin deposits and a mixed inflammatory infiltrate of variable intensity. Intranuclear inclusion bodies were identified in the periphery of necrotic areas in hepatocytes, renal tubular epithelial cells and alveolar cells. Samples of liver, kidney and lung were positive in the direct immunofluorescence test for canine herpes virus type 1 (CHV-1). The diagnosis was based on epidemiological data, necropsy findings, histological lesions and positive immunofluorescence results using CHV-1 antibody in tissue samples. To our knowledge, this is the first report of the identification of CHV-1 in Brazil, although previous clinic and pathological findings already suggested the presence of the virus in Brazilian canine population.
Subject(s)
Animals , Dog Diseases/diagnosis , Herpesvirus 1, Canid , Massive Hepatic Necrosis/diagnosis , Dogs , Fluorescent Antibody Technique/methodsABSTRACT
Two non-radioactive probes using digoxigenin or biotin were developed for detecting canine herpesvirus (CHV) and compared for their sensitivities by in situ hybridization (ISH) in formalin fixed, paraffin embedded sections, which has been used routinely in veterinary fields. Sections of the CHV-infected cell preparation were subjected to several different ISH protocols using digoxigenin- or biotin-labeled probe respectively. Results were compared for the hybridization and background signal intensities. The best result was obtained by the optimized ISH protocol using digoxigenin-labeled probe for detection of CHV DNA. The optimized ISH assay, which developed in this study, may be a valid tool for the study of pathogenesis and diagnosis of CHV infection.