Baltimore (WHTM) It’s called Elephant Endotheliotropic Herpesvirus, or EEHV for short. It comes in a number of strains, infects both Indian and African elephants, and left untreated it can be fatal.

On October 10 Samson, a 15-year-old bull African elephant at the Maryland Zoo, was diagnosed with the illness.

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EEHV occurs naturally in both wild elephants and those in human care. There are currently fourteen EEVH viruses identified, of which seven are particularly worrisome. Four usually affect African elephants, while the other three affect Asian elephants. It is believed that most elephants live with one or more strains and periodically shed the virus in body secretions. (There is no evidence that the disease can cross over to humans.)

According to Dr. Ellen Bronson, Sr. Director of Animal Health, Conservation & Research at the Maryland Zoo, “EEHV is a highly fatal disease that progresses rapidly and affects blood vessels throughout the body, causing severe hemorrhagic disease, “That’s why regular blood testing and preparedness are so important.”

In fact, it was a routine blood test that detected Samson’s illness. The zoo regularly collects blood samples from all their elephants, which are sent to the National Elephant Herpesvirus Laboratory at the National Zoo in Washington (or to use its full name, the Smithsonian’s National Zoo and Conservation Biology Institute.) The Laboratory tests for EEHV, and on October 10 they informed the Maryland Zoo that Samson had a severe infection of the strain EEHV6, a relatively rare form of the disease which has affected only a few African elephants so far.

Because EEHV is so dangerous to elephants, Maryland Zoo has a standing operating procedure ready should a case arise. “Our elephant and medical teams are highly trained so that, should the time ever come, they are prepared to work together around the clock to provide the necessary therapy,” said Margaret Rose-Innes, General Curator at the Maryland Zoo. The Zoo keeps a four-day supply of antiviral medicines so it can begin treatment as soon as the disease is diagnosed.

Several weeks of intense treatment later, Samson’s bloodwork shows both improved blood cell counts and reduced viral loads, signs that the infection is waning. (This is actually Samson’s second episode of EEHV. He survived a different strain of this same virus (EEHV3b) when he was 5 years old, becoming the first elephant clinically diagnosed with that strain at the time.) Maryland Zoo officials have kept in constant contact with leading EEHV experts to discuss his case and share observations. Looking to the future, the Zoo is sharing blood samples and trunk washes with researchers, which they hope will ultimately lead to improved diagnostics and treatment for this disease.

The National Elephant Herpesvirus Laboratory has a FAQ page about EEVH. You can read it here.