8 research outputs found
Genotyping canine distemper virus (CDV) by a hemi-nested multiplex PCR provides a rapid approach for investigation of CDV outbreaks
CDVis a highly contagious viral pathogen causing a lethal systemic disease in dogs and other carnivores. Several lineages or
genotypes of CDV exist that are variously distributed throughout several continents. Legal or uncontrolled trading of animals
may modify the epidemiology of CDV, introducing novel strains in CDV-naı¨ve areas or accounting for the resurgence of CDVin
areas where vaccine prophylaxis was effective and successful to control the disease. A hemi-nested PCR system was developed
to genotype strains of the major CDV lineages, America-1, Europe, Asia-1, Asia-2 and Arctic. The assay was tested using a
collection of 27 laboratory and vaccine strains and of 36 field CDV strains. Distinct lineages could be differentiated by specific
primers targeted to the H gene. The method could be useful for molecular epidemiological studies of CDV, providing a tool for
large-scale studies, and for the diagnosis of vaccine-related disease
Roles of Macrophages in Measles Virus Infection of Genetically Modified Mice
Knowledge of the mechanisms of virus dissemination in acute measles is cursory, but cells of the monocyte/macrophage (MM) lineage appear to be early targets. We characterized the dissemination of the Edmonston B vaccine strain of measles virus (MV-Ed) in peripheral blood mononuclear cells (PBMC) of two mouse strains expressing the human MV-Ed receptor CD46 with human-like tissue specificity and efficiency. In one strain the alpha/beta interferon receptor is defective, allowing for efficient MV-Ed systemic spread. In both mouse strains the PBMC most efficiently infected were F4/80-positive MMs, regardless of the inoculation route used. Circulating B lymphocytes and CD4-positive T lymphocytes were infected at lower levels, but no infected CD8-positive T lymphocytes were detected. To elucidate the roles of MMs in infection, we depleted these cells by clodronate liposome treatment in vivo. MV-Ed infection of splenic MM-depleted mice caused strong activation and infection of splenic dendritic cells (DC), followed by enhanced virus replication in the spleen. Similarly, depletion of lung macrophages resulted in strong activation and infection of lung DC. Thus, in MV infections of genetically modified mice, blood monocytes and tissue macrophages provide functions beneficial for both the virus and the host: they support virus replication early after infection, but they also contribute to protecting other immune cells from infection. Human MM may have similar roles in acute measles