Man Attacked by Monkeys Catches Rare, Life-Threatening B Virus

A Hong Kong man’s scrape with monkeys led to him contract a potentially deadly germ. This week, local health officials reported a case of B virus in a 37-year-old man—the first ever reported in the region. Human B virus infections are rare, and they can be life-threatening without urgent treatment. The man is currently in an intensive care unit.

B virus is related to the two viruses that cause oral and genital herpes in humans (it’s also known as herpesvirus simiae). Much like herpes in humans, B virus is very commonly found in its natural host animals, macaques, a broad genus of Old World monkeys. In macaques, the infection is similar to oral herpes, either causing no symptoms or cold sores around the mouth. But when it infects humans, B virus can wreak havoc on the nervous system, causing problems like severe encephalitis (brain swelling). Without treatment, it’s estimated to have an 80% fatality rate. The virus is often present in the saliva, urine, and poop of infected macaques, and human infections are usually caught from monkey bites and scratches.

Hong Kong’s Center for Health Protection (CHP) reported the case Wednesday, after a test of the man’s spinal fluid confirmed his B virus infection. According to the CHP’s investigation, the man was visiting the Kam Shan Country Park in late February when he was wounded by monkeys. A month later, he was admitted to the emergency department of Yan Chai Hospital with fever and decreased consciousness. As of now, he remains in critical condition.

Scary as the B virus is, it’s a very rare danger. This is the first ever local case detected and reported by the CHP, officials said. Since its discovery in 1932, only around 50 cases worldwide have been documented, with cases in the U.S., Canada, and mainland China. Of these, 21 people have died. Though most macaques are thought to carry B virus (70% to 80%, based on studies), the infection doesn’t seem to be that easily transmitted, since even monkey attack victims seldom contract the virus. Only one case of human-to-human transmission has ever been reported.

Still, CHP officials are reminding the public to stay away from macaques and especially to avoid touching or feeding them. People who do get attacked by monkeys should wash their wounds with running water and seek immediate medical attention, they said.