Deadly new MERS virus traced to Egyptian tomb bat

A 100% genetic match for Middle East Respiratory Syndrome (MERS) has been discovered in an insect-eating bat in close proximity to the first known cas...
Taphozous perforates, the Egyptian Tomb bat, has been found to carry Middle East Respiratory Syndrome (MERS) virus. Photo courtesy of Jonathan H. Epstein / copyright EcoHealth Alliance 2013

A deadly new virus that has killed 47 people has been traced to an Egyptian Tomb Bat, researchers reported on Wednesday.

The virus causes Middle East respiratory syndrome, MERS for short, and it’s sickened 96 people with links to the Middle East – most of them in Saudi Arabia. It’s a coronavirus, a distant relative of the SARS virus that caused a global outbreak of severe acute respiratory syndrome in 2003. 

Experts had long suspected bats, and a team led by Dr. Ian Lipkin of Columbia University started testing animals in Saudi Arabia soon after the virus killed its first known victims last year. Now they’ve found it, in a species of bat called Taphozous perforates. The infected bat was found just a few miles from the first victim’s home, they report in the journal Emerging Infectious Diseases.

“There have been several reports of finding MERS-like viruses in animals,” Lipkin says. “None were a genetic match. In this case we have a virus in an animal that is identical in sequence to the virus found in the first human case. Importantly, it’s coming from the vicinity of that first case.”

Lipkin says only one bat was found to carry the virus, out of hundreds tested. But now scientists can monitor bats and keep an eye out for potential outbreaks of the virus. West Nile virus first appeared in the United States in 1999, and once researchers discovered which birds and mosquitoes carried the virus, they started monitoring them to predict when the virus would start being a threat to people.

The news was announced just as the Saudi deputy health minister, Dr. Ziad Memish, was speaking to a gathering of experts hosted by the University of Pittsburgh Medical Center’s Center for Health Security in Washington.

“I think we suspected from day one …this had something to do with bats,” Memish told the gathering. But he doubts the bats directly infected the victims. “There must be something in the middle. Is it food? Is it something else?”

The tomb bat, found across Africa and the Middle East, lives in caves and stone buildings, especially deserted buildings. It eats moths and beetles.

Lipkin’s team and Saudi experts have been looking at food, at other animals including camels, goats, sheep and cattle. They plan to report more findings soon. Earlier this month a European team reported they had found antibodies to a virus similar to MERS in camels from Oman – but MERS hasn’t been reported in people in Oman.

The tests were not very conclusive, Memish says. “Camels apparently have the most complicated immune systems,” he said. They have antibodies to a number of coronaviruses, he said, so it’s not clear if they are carrying the MERS virus and if they might be infecting people.

“We think bats are the source but we need an intermediate host,” Memish said. “We have not been able to document the relationship between the patients and the bats.”

The first victim, an elderly man, died last summer, but it took several weeks to identify the virus that killed him, Memish says. As soon as it was identified, the health ministry contacted Lipkin, whose team has experience searching for viruses that jump from animals to people.

“I got a call at 2 o’clock in the morning,” Lipkin said. “They were on the ground in a week,” Memish added.

“It took a while because collecting bats is not an easy process,” Memish said. “You’re trying not to kill the bats, collecting samples.”

The virus seems to be especially dangerous to people who are already sick, Memish says. Many of the patients have had diabetes or kidney disease – one cluster was traced to a dialysis clinic. Dialysis clinics in Saudi Arabia now follow careful infection control procedures.

MERS spread to Britain, France, Jordan and elsewhere, but all the patients had traveled to the Middle East. It does not seem especially infectious – seven nurses who treated one patient showed evidence that they had been infected, but none of them ever got sick. And several of the victims lived in large extended families, but only infected a few other family members.

A 100% genetic match for Middle East Respiratory Syndrome (MERS) has been discovered in an insect-eating bat in close proximity to the first known cas...
The Egyptian Tomb Bat has been found to carry Middle East Respiratory virus (MERS) Photo courtesy of Jonathan H. Epstein / copyright EcoHealth Alliance 2013

It might be in part because it doesn’t cause some of the typical symptoms that help other viruses spread. Memish says patients do not develop upper respiratory symptoms such as sneezing. Instead, the infection takes hold deep in the lungs. It also causes gastrointestinal symptoms.

The good news is that no one appears to have been infected during the Hajj – the annual mass pilgrimage to Mecca that faithful Muslims undertake. Fifteen million people made the pilgrimage last October, five million from outside Saudi Arabia, Memish said. “Not a single case of MERS coronavirus was reported,” he says.

This year, Saudi authorities are telling anyone with a chronic disease or immune deficiency to delay the pilgrimage until another time, just to be safe, Memish says.

Coronaviruses are a big family and they usually cause common cold-like symptoms in people. But in some cases they can cause very severe infections – and MERS is one of these.