Lactate Dehydrogenase-Elevating Virus

Lactate dehydrogenase-elevating virus (LDV) is a mouse arterivirus, unusual in its extreme host specificity and its persistence in the circulation of the infected host that naturally infects wild mice. Although, probably not as frequent in laboratory mouse colonies as it used to be, LDV infection may affect experimental results, primarily through its effects on the host immune responses. On the other hand, because of its unique properties, LDV infections serve as a good animal model for viral persistence, virally induced immunomodulation, and pathogenic infection of neurons in the central nervous system. However, the inability of LDV to infect in transformed cell lines and to cause a detectable cytopathic effect in cell cultures in which it replicates, such as mouse peritoneal exudate cells, represents technical obstacles to the further analysis of this virus. Identification of the cell receptor utilized by LDV would constitute a major advance, since this might lead to the creation of a cell line permissive to LDV infection. Whereas LDV is a natural and sometimes pathogenic infectious agent of the mouse, it does not currently represent a major threat to animal facilities. The virus is not very contagious and there are a number of easy methods available to detect infected mice. Moreover, further study of the interaction between relatively silent viruses, such as LDV, and their host species should lead to new insights into the mechanisms by which viruses can establish and maintain relatively harmless, persistent infections in their hosts.