Detection and genetic characterization of canine distemper virus isolated in civets in Vietnam.

Canine distemper (CD), caused by the canine distemper virus (CDV), is a lethal systemic disease to a wide range of wild and domestic carnivorous hosts, including civets. In this study, a possible CD outbreak in a backyard farm with 32 diseased civets (Viverricula indica) in Hanoi, Vietnam, was investigated. The sick civets showed CD-like clinical signs such as anorexia, sedentary behavior, diarrhea, dermatitis, nasal, and footpad hyperkeratosis. Various tissue samples collected from the dead civets were utilized for molecular screening of CDV and histopathological examination. The genetic detection and characterization confirmed that samples collected from dead civets tested positive for CDV. The phylogenetic analysis based on the full-length H gene sequences indicated that all CDV strains isolated from civets belonged to the Asia-1 lineage and were closely related to the CDV strains previously reported from dogs in Thailand, China, and Vietnam. Histopathological examination showed severe interstitial pneumonia, hemorrhagic alveolar septa, necrotic alveolar epithelial cells, necrotic, degenerated, or lost Purkinje cells, eosinophilic intracytoplasmic inclusion bodies, edema, and perivascular cuff. This study confirmed the detection of CDV in civets for the first time in Vietnam.

Differential resistance/susceptibility patterns to pneumovirus infection among inbred mouse strains.

Respiratory syncytial virus (RSV) is a prominent cause of airway morbidity in children under 1 yr of age. It is assumed that host factors influence the severity of the disease presentation and thus the need for hospitalization. As a first step toward the identification of the underlying genes involved, this study was undertaken to establish whether inbred mouse strains differ in susceptibility to pneumonia virus of mice (PVM), the murine counterpart of RSV, which has been shown to accurately mimic the RSV disease of children. With this purpose in mind, double-chamber plethysmography and carbon monoxide uptake data were collected daily for 7 days after inoculation of PVM in six inbred strains of mice. In parallel, histological examinations and lung viral titration were carried out from day 5 to day 7 after inoculation. Pulmonary structure/function values reflected the success of viral replication in the lungs and revealed a pattern of continuous variation, with resistant, intermediate, and susceptible strains. The results suggest that SJL (resistant) and 129/Sv (susceptible) strains should be used in crossing experiments aimed at identifying genes controlling pneumovirus replication by the positional cloning approach. Similarly, crossing experiments using BALB/c or C57BL/6 (resistant) and DBA/2 or 129/Sv (susceptible) will allow the identification of the genes involved in the control of pulmonary inflammation during pneumovirus infection.

Sendai virus-induced alterations in lung structure/function correlate with viral loads and reveal a wide resistance/susceptibility spectrum among mouse strains.

The Paramyxoviridae family includes some of the most important and ubiquitous disease-causing viruses of infants and children, most of which cause significant infections of the respiratory tract. Evidence is accumulating in humans that genetic factors are involved in the severity of clinical presentation. As a first step toward the identification of the genes involved, this study was undertaken to establish whether laboratory mouse strains differ in susceptibility to Sendai virus, the murine counterpart of human type-1 parainfluenza virus which, historically, has been used extensively in studies that have defined the basic biological properties of paramyxoviruses in general. With this purpose in mind, double-chamber plethysmography data were collected daily for 7 days after inoculation of Sendai virus in six inbred strains of mice. In parallel, histological examinations and lung viral titration were carried out from day 5 to day 7 after inoculation. Pulmonary structure/function values closely reflected the success of viral replication in the lungs and revealed a pattern of continuous variation with resistant, intermediate, and susceptible strains. The results unambiguously suggest that BALB/c (resistant) and 129Sv (susceptible) strains should be used in crossing experiments aimed at identifying the genes involved in resistance to Paramyxoviridae by the positional cloning approach.