Distribution of Borna disease virus in the brain of rats infected with an obesity-inducing virus strain

Experimental infection of Lewis rats with Borna disease virus (BDV), a nons egmented, single-stranded RNA virus, usually causes an immune-mediated biph asic neurobehavioral disorder, Such animals develop a persistent infection of the CNS with viral antigen expression in all brain regions and a dissemi nated nonpurulent meningoencephalitis, Interestingly, intracerebral infecti on of Lewis rats with a BDV-variant (BDV-ob) causes a rapid increase of bod y weight with the development of an obesity syndrome without obvious neurol ogical signs, The obese phenotype is correlated with a characteristic distr ibution of inflammatory lesions and BDV-antigen in the rat brain, Infiltrat ion with mononuclear immune cells and viral antigen expression are restrict ed to the septum, hippocampus, amygdala and ventromedian tuberal hypothalam us. Therefore, infection with the obesity-inducing BDV-ob results most like ly in neuroendocrine dysregulations leading to the development of an obesit y syndrome. This might be due to the restriction of viral antigen expressio n and inflammatory lesions to brain areas which are involved in the regulat ion of body weight and food intake. The BDV-induced obesity syndrome repres ents a model for the study of immune-mediated neuroendocrine disorders caus ed by viral infections of the CNS.