Next month, during the Islamic pilgrimage known as the Hajj, 3 million people will pour into the holy city of Mecca in Saudi Arabia. They will worship, pray, and be within 50 miles of the first identified case of the fatal infectious disease, Middle East Respiratory Virus (MERS). Discovered in 2012 at a hospital in Jeddah, a port city and entry point to Mecca, MERS has infected 840 people worldwide. Nearly 30 percent of them have died, most suffering fevers, cough, and a terrifying shortness of breath.

It’s a frightening scenario: one of the world’s largest human migrations is about to settle in an area that’s home to a deadly virus without a cure or vaccine. As recent studies have shown, modern transportation, notably international ports and travel hubs, can be a viral expressway to pandemics. MERS has already traveled by foot, car, and plane to more than a dozen countries on four continents, including the United States, where two healthcare providers, hospitalized, have recovered.

But a curious thing happened on the path to an international outbreak. In May, when the World Health Organization (WHO) convened a special panel and stopped just short of dubbing MERS a global emergency, the number of cases spiked. But since July only two new MERS cases have been reported. A rocketing epidemic had disappeared. What happened? In Saudi Arabia, officials are taking credit for breaking the virus’ routes of transmission. If so, their work lends hope and lessons to officials scrambling to contain other epidemics, such as the raging Ebola fire in West Africa. But could a deadly contagious virus really be stopped that quickly, or does it lurk just beneath the surface?

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Tariq Madani, Special MERS-Coronavirus Consultant to Saudi Arabia’s Ministry of Health, says the nation has averted disaster. International Health Regulations require all WHO member countries, including Saudi Arabia, to report on disease outbreaks, and Madani says they’ve obliged. In an email, he writes that the Saudi health ministry’s success can be attributed to the attention it’s paid to how the virus spreads within hospitals. “We implemented a number of strict new controls that contributed to the cessation of transmission,” Madani writes. The health ministry has constructed a triage system to isolate suspected patients; set up laboratories within four hours of every town in Saudi Arabia to enable quick detection of the virus; rolled out a campaign to prevent infection of healthcare workers; and improved capacity for MERS patients.

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“It’s become very clear that hospital practices, as for other diseases such as Ebola and SARS, are very important in transmission,” says David Heymann, an infectious disease epidemiologist at the London School of Hygiene and Tropical Medicine. The Saudi health ministry has taken steps to block that amplification, he says, and “it looks like that has been paying off.”



But Ian Lipkin is not relieved. Lipkin has fought contagious diseases for 30 years and now directs the Center for Infection and Immunity at Columbia University’s Mailman School of Public Health. He developed the technology used to characterize more than 400 viruses. He has tracked down microbes lurking in New York City’s bed bugs and others in forest-dwelling primates of Asia. He was the chief scientific consultant for the 2011 medical thriller Contagion.

In early August, sitting in his office overlooking the George Washington Bridge, Lipkin expresses frustration that his Saudi counterparts had taken the previous six weeks off, first for Ramadan, then for summer vacation. “The virus doesn’t take vacations,” he says. Plans for handling the dangers of the upcoming Hajj had lain idle and he had been unable to reach his Saudi contacts. “I think [the Saudis] have a responsibility to be proactive,” he says.

With communication cut off for so long, could the virus still be spreading undetected or unreported? By late August, in an email to Nautilus, Lipkin wrote: “I don’t know the extent to which the decreased number of cases reported reflects a true decrease in incidence or a failure in ascertainment.” But by September he decided the decrease was likely real.

Lipkin still fears MERS, however, because of the virus’ zoonotic nature. It’s a promiscuous bug, able to jump from animals into humans, like the microbes that cause malaria, the Plague, Lyme disease, and Ebola. Last February, he showed that dromedary camels in Saudi Arabia had carried the MERS coronavirus since at least 1992.1 (The coronavirus family includes Severe Acute Respiratory Syndrome, SARS, which killed about 800 people worldwide in 2003.)

The first reported case of MERS, in 2012, was from a Saudi man from Bishah, a small city southeast of Jeddah, who owned camels. He developed a bad cough and died a few days later. Since then, contact with camels and camel-products has been noted as a common thread among many MERS patients.

It seems the virus has made the jump between species multiple times, but why remains unknown. As a precautionary measure, the WHO now warns against drinking unpasteurized camel milk, eating undercooked camel meat, or consuming camel urine, which is sometimes done for folk-medicinal purposes.

This spring, most cases were acquired from human-to-human contact. The MERS virus attaches to lung cells with spikes on its outer shell. When a person coughs or sneezes, some of these cells might be aerosolized, along with the infectious virus. In this manner, a person may pass the infection to their neighbor though the air. This makes MERS somewhat more worrying than Ebola—at least as far as person-to-person transmission is concerned. With Ebola, the virus hides out within organs, and it’s only passed through direct contact with a person’s urine, feces, or other bodily fluids. “From a pandemic vantage point, I’m more concerned about MERS than I am about Ebola,” he says.

During the SARS outbreak in 2003, a biotech firm called Chiron began developing a vaccine, but by the time the drug could be tested in animals, the outbreak had ended.

Luckily, MERS doesn’t seem to pass from person to person all that often. In a study of 280 people living alongside 26 people with MERS, only about 4 percent of them ended up getting the disease.2 One reason the current MERS virus may not be transmitted more frequently is that it appears to only infect cells deep in the lung, as opposed to cells closer to the surface of the lungs that might be coughed up more regularly, says Christian Drosten, a virologist at the University of Bonn Medical Center in Germany, who led the study. Another possibility, he adds, is that the virus seems highly susceptible to immune system proteins called interferons, so we often kill it before it has a chance to replicate.

Like Ebola, there are no specialized treatments or vaccines for MERS; the most health care workers can do is treat symptoms such as breathing problems and high fevers. A few antiviral drugs are showing promise in animal studies and preliminary human trials, says Darryl Falzarano, a virologist at Rocky Mountain Laboratories, an infectious disease branch of the National Institutes of Health in Montana. “The people treated early [in the disease course] seem to have done better, but it’s such a small number that there’s not really much more than that known,” Falzarano says.

That probably won’t change soon. Testing a vaccine or drug candidate takes years and a tremendous amount of money. During the SARS outbreak in 2003, a biotech firm called Chiron began developing a vaccine, but by the time the drug could be tested in animals, the outbreak had ended. The quick demise of MERS is likely to dampen any enthusiasm there was on the part of drug companies, Falzarano says.

Since MERS made headlines this spring, Ebola has supplanted it in the public consciousness. The African virus has killed and sickened more people. The apparent success with MERS suggests that public health strategies such as isolating patients, disrupting lines of transmission, and cutting off animal reservoirs can work for Ebola, too. But infrastructure in West Africa is far weaker than in Saudi Arabia, a wealthy country. In Liberia, Guinea, and Sierra Leone, there is a shortage of trained nurses and doctors, and the few hospitals that exist lack basic supplies, like rubber gloves, hospital gowns, and disinfectants. “We know what to do, we know how to do it,” Margaret Chan, director-general of the WHO, said of Ebola at a press conference in early September. “But we do need to coordinate global efforts to deal with this.”

In preparation for the Hajj, which will be held the first week in October, Saudi Arabia has added measures to ensure that MERS or any other disease doesn’t spread among pilgrims. Airports will screen arriving passengers for fevers, isolation facilities are available, and several vaccinations are required of visitors to combat the spread of other communicable diseases. “We are taking precautions to minimize the risk of the spread of infectious disease,” Madani says. The Saudis’ apparent success in stopping hospital transmissions of MERS gives hope that their efforts will be enough during the massive pilgrimage.

Halting the virus itself, though, and preventing a new outbreak, is another matter. “I’m not relaxed, because MERS can re-emerge,” Lipkin says. “These viruses live in wildlife and they can move from animals to people again. The rules of good behavior are not followed by microbes.”





Karen Weintraub is an independent health/science journalist based in Cambridge, Massachusetts.





References

1. Alagailli, A.N., et al. Middle East Respiratory Syndrome coronavirus infection in dromedary camels in Saudi Arabia. mBio 5, e00884-14 (2014).

2. Drosden, C., et al. Transmission of MERS-coronavirus in household contacts. The New England Journal of Medicine 371, 828-835 (2014).