A deadly virus has stricken Samson, the only elephant born at the Maryland Zoo in Baltimore in its 137-year history, but zoologists are hopeful that he will recover because the strain is thought to be less serious in his species. Samson also has survived longer than others with the virus.

Caretakers first noticed the soon-to-be-5-year-old male looking lethargic Feb. 26, and feared it was a sign of what is known as elephant endotheliotropic herpesvirus. They began treating him for the disease, which can kill within days, and tests confirmed the virus.

Samson has recovered dramatically, zoo officials said, but has at least several weeks of recuperation ahead. Since late February, the African elephant has undergone around-the-clock treatment that includes 40 times the human dose of herpes medication, gallons of diluted Gatorade and regular enemas.

Given the virus' severity, Samson's caretakers consider their 3,500-pound patient fortunate so far.

"We knew this virus existed in the world from the day he was born," said Mike McClure, the zoo's general curator and elephant manager. With that in mind, Samson was trained to take pills, open his mouth for oral exams and stand still for evaluations.

Without that training, McClure said, "I think it's questionable he would have even survived this."

Samson has been a zoo favorite during his young life. His birthday parties draw crowds of guests who sing to him, have their face painted and watch him eat cake made from cornmeal and vegetables (with carrots for candles).

He has grown up amid improving financial conditions at the zoo. At the time of his birth in 2008, the institution was in danger of losing its accreditation. Since then, attendance has risen to its highest levels since 2004, with more than 400,000 visitors in the fiscal year that ended June 30.

The herpes virus most commonly infects Asian elephants from ages 1 to 4, and is lethal 80 to 90 percent of the time, wrote Johns Hopkins University professor Gary Hayward in a February 2012 article in the scientific journal Veterinary Record. There have been 32 confirmed cases in North America and another 25 suspected infections in Europe, with more across the world. Among them, only 10 elephants have survived.

Left untreated, the infections cause internal bleeding and heart failure in elephants.

As with the human herpes viruses, the disease can remain latent inside the body only to reactivate occasionally. In elephants, it can be transmitted through trunk secretions and typically causes a mild initial infection that can be detectable in blood but is not symptomatic. Eventually, the virus is shed through the trunk secretions and becomes undetectable, but occasionally infections get out of control, Hayward said in an email.

The virus is rarer in African elephants like Samson. The strain detected in his blood has not shown to be dangerous to African elephants, which have been found to carry multiple strains of the virus without consequence, Hayward said.

But Samson's case is in some ways uncharted territory.

"This would be the first time it has been seen at this 'primary' stage in an African elephant calf and so it is prudent to monitor the situation carefully," Hayward said.

The first recorded case of the disease came in 1995, when Kumari, a 16-month-old Asian elephant at the National Zoo in Washington, died, baffling zookeepers. Scientists believed at the time that the virus was passed from African elephants to Asian elephants at the zoo.

Since then, infections have been reported in just two African elephants besides Samson, zoo officials said. One survived.

But much is still unknown about the virus. Paul Ling, an associate professor at the Baylor College of Medicine in Houston, said a greater understanding is key as zoos attempt to launch elephant breeding programs. Asian elephants are an endangered species.

"It's such a joy to have a baby elephant on one hand, and on the other, you live in fear of the day he or she doesn't act quite right," said Kari Johnson, who runs a private elephant ranch in Southern California with her husband, Gary.

Samson was born March 19, 2008, in a barn at the Druid Hill Park zoo. His mother, Felix, had arrived in Baltimore three months earlier from Arkansas. More than 12,000 votes were cast to choose his name, which means "of the sun" and is shared by the heroic Bible character.

Samson made his debut to visitors and flashing cameras in August of that year as a toddler, weighing 340 pounds. Male elephants are not considered mature until as late as age 30.

The zoo has three adult African elephants in addition to Samson and his mother — females Dolly and Anna and male Tuffy. Female African elephants have a median life expectancy of about 37 years; male life expectancy is not known.

Samson is not being isolated because his co-inhabitants, as well as zookeepers and visitors, aren't deemed at risk for the infection. It is assumed the elephants already carry one or more strains of the virus.

As Samson recovers, zoo officials hope the virus can become better understood.

"He's going to help a lot of elephants, I think," McClure said.

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