The virus is morphologically, biologically, and antigenically similar to herpes simplex virus. It produces mild disease in monkeys, usually in the form of small ulcers in the mouth. Antibody that reacts with the virus has been seen in the majority of tested monkeys that were caged in colonies, but it is much less common among animals in the wild. In humans, however, it causes acute ascending myelitis, which leads to death from respiratory paralysis.
Cardiopulmonary support is the most important aspect of management.
Only four survivors, however, are documented among the nearly 20 cases identified, and all four had significant neurologic residua. Immune globulin from vaccinated laboratory workers or survivors of infection has been recommended, as has high-dose acyclovir or ganciclovir. Monkey handlers should wear protective clothing and a face mask. These viruses are all members of the poxvirus family, Poxviridae, and have structures resembling those of smallpox and vaccinia viruses. Cowpox is caused by vaccinia virus and produces vesicular lesions on the hands.