Drivers of canine distemper virus exposure in dogs at a wildlife interface in Janos, Mexico.

Background: Human population expansion has increased the contact between domestic animals and wildlife, thereby increasing the transmission of infectious diseases including canine distemper virus (CDV). Here, we investigated the risk factors associated with CDV exposure in domestic and wild carnivores from the Janos Biosphere Reserve (JBR), Mexico.

Methods: A cross-sectional household questionnaire study was performed in four rural towns to investigate the risk factors associated with the presence of CDV in domestic and wild carnivores from the JBR, Mexico.

Carnivore Protoparvovirus 1 at the Wild-Domestic Carnivore Interface in Northwestern Mexico.

Eighty-three wild and domestic carnivores of nine species from Janos Biosphere Reserve (JBR), Mexico, were tested by serologic and molecular assays to determine exposure and infection rates of carnivore protoparvovirus 1. Overall, 50.8% (33/65) of the wild carnivores and 100% (18/18) of the domestic dogs tested were seropositive for Canine protoparvovirus 1 (CPV), while 23% (15/65) of the wild carnivores and 22.

Kinetics of antibody-induced modulation of respiratory syncytial virus antigens in a human epithelial cell line.

Background: The binding of viral-specific antibodies to cell-surface antigens usually results in down modulation of the antigen through redistribution of antigens into patches that subsequently may be internalized by endocytosis or may form caps that can be expelled to the extracellular space. Here, by use of confocal-laser-scanning microscopy we investigated the kinetics of the modulation of respiratory syncytial virus (RSV) antigen by RSV-specific IgG. RSV-infected human epithelial cells (HEp-2) were incubated with anti-RSV polyclonal IgG and, at various incubation times, the RSV-cell-surface-antigen-antibody complexes (RSV Ag-Abs) and intracellular viral proteins were detected by indirect immunoflourescence.

Interleukin-8 mRNA synthesis and protein secretion are continuously up-regulated by respiratory syncytial virus persistently infected cells.

The aim of this study was to investigate whether respiratory syncytial virus persistence regulates interleukin 8 (IL-8) mRNA synthesis and protein secretion in a human lung epithelial cell line (A549). Therefore, we established RSV persistence in these cells (A549per) and determined the levels of interleukin-8 mRNA by RT-PCR and of protein through ELISA. Interleukin-8 mRNA synthesis and protein secretion were continuously up-regulated in A549per cells during passages and in A549 cells that had been incubated with supernatants (cA549per) obtained from A549per passages.

Characteristics of a respiratory syncytial virus persistently infected macrophage-like culture.

A persistently infected culture obtained from immortalized murine macrophage-like cells, which survived respiratory syncytial virus (RSV) infection at multiplicity of one, was established and characterized. The presence of RSV through the passages was confirmed and monitored by (a) detection of infectious virus by TCID(50)/ml, (b) defective particles by viral infectivity interference and buoyant density determinations, (c) cell surface antigen by indirect immunofluorescence and FACS, and (d) expression of a viral gene by RT-PCR. Moreover, cell morphology changes by comparison of macrophage area and perimeter were determined.