Eosinophilic Encephalomyelitis in a Raccoon Experimentally Infected with a Dog Isolate of Rabies Virus

Abstract

For the past decade, the mid-Atlantic region of the United States has been experiencing an epizootic of rabies in its wild raccoon (Procyon lotor) population. In 1987, there were 965 reported cases of rabid raccoons in this geographical location.* To counteract this epidemic, a genetically engineered vaccinia-rabies glycoprotein (V-RG) oral rabies vaccine has been developed and has been evaluated experimentally in raccoons. 10 It is now awaiting final government approval for field testing. An adult female raccoon used in a control group of animals for the experimental evaluation of the V-RG recombinant virus vaccine was presented to the Laboratory of Large Animal Pathology at the University of Pennsylvania for necropsy. The raccoon had been inoculated intramuscularly with 0.3 ml of rabies virus strain MD5951 (10 5.5 MICLD50), which had been isolated from a dog. 12 On day 12 postinoculation (PI) the raccoon had shown vague neurologic signs and was euthanized on the day of presentation (day 13 PI). Prior to euthanasia, blood samples were obtained for hematology and for the serum neutralization test for rabies antibody. 10