T

here is too much rinderpest lurking in laboratories around the world, a new report from the World Organization for Animal Health concludes.

The livestock disease has been eradicated, and labs that are keeping unnecessary samples constitute a risk that the virus could be reintroduced to the world, said the report, published Thursday in the journal Emerging Infectious Diseases.

Destroying virus samples kept in laboratory freezers is a critical step in ensuring that a disease that took years to eradicate remains gone. It’s a job 20 countries now need to do for rinderpest, and many more will need to do in the months ahead with type 2 polioviruses, which were recently declared eradicated. (One other of the original three types is likely also gone, but polio won’t be declared vanquished until type 1 viruses are extinct.)

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These containment projects won’t be easy, people familiar with the process warn.

“I think it’s going to be quite a challenge,” said David Salisbury, a member of the Global Commission for the Certification of Poliomyelitis Eradication. Individual countries are going to need to work with their science communities to identify, destroy, or securely contain supplies, he said. “Most labs are not going to want to put themselves through what they will have to do to show that they’ve complied with containment.”

To date, only two diseases have been consigned to the history books as a result of human actions. Smallpox was the first, declared gone in 1980. It remains the only human disease that has been eradicated, though after many years and massive efforts, programs to wipe out polio and Guinea worm appear to be closing in on their goals.

Rinderpest was declared eradicated in 2011. A relative of the human measles virus, it wrecked havoc when it struck. Rinderpest could kill as many as nine of 10 infected cattle during an outbreak.

Though gone from nature, the virus still exists in 27 research facilities in 24 countries — an unacceptably high number, the OIE report said. (The Paris-based agency’s acronym is derived from the French version of its name.)

Earlier this year the OIE’s annual meeting authorized the establishment of five institutions that could hold samples of the virus for now: two in Japan and one each in the United States, Britain, and Ethiopia.

One-third of the facilities presently holding onto samples are storing them at biosecurity level 2 — too low, said the report. First author Keith Hamilton, who teaches at the veterinary school at Kansas State University in Manhattan, Kansas, said the report deliberately does not name names, preferring not to provide information on where rinderpest virus can be found.

Hamilton, who was working at the OIE when he co-wrote the report, said the agency has been warned by the World Health Organization that it should move swiftly to deal with the issue of the remaining samples in the hopes it can avoid a protracted debate like the one that has occurred on the human health side.

“We hope that we won’t have the same experience as smallpox,” he admitted in an interview with STAT.

Dead oxen, some partly buried, thought to have died from rinderpest, ca. 1900.
Dead oxen, some partly buried, thought to have died from rinderpest, ca. 1900. Reinhold Thiele/Getty Images

Lab-based outbreaks

Though it was originally envisaged that all samples of smallpox would be destroyed after the final chains of transmission were broken, that hasn’t happened. Every two years the World Health Assembly — the WHO’s equivalent of the UN General Assembly — debates whether the final stocks should be destroyed. The United States and Russia retain samples and have fought to keep them.

Concern about viral relics is not merely an academic debate. If a virus that had been halted was re-established through a laboratory error, it would be an unimaginable and enormously expensive tragedy. The world has spent $11 billion so far trying to get rid of polio, and the job is still several years and several billion dollars from being completed.

And lab accidents happen. It’s widely thought that H1N1 flu viruses, which had stopped circulating after the 1957 H2N2 flu pandemic, re-emerged in 1977 as the result of a lab accident. Genetic analysis of the viruses suggested they had not been spreading undetected for two decades; it was as if the virus had been frozen in time.

The last cases of SARS — severe acute respiratory syndrome — were the result of a lab accident in China. And while the last case of smallpox in the wild occurred in Somalia in 1977, the last person killed by the virus was a British lab worker who infected herself by accident in 1978.

That latter event galvanized world leaders, said Dr. D.A. Henderson, who led the smallpox eradication campaign. “They were really frightened at that point.” And yet stores of smallpox remain — to Henderson’s enduring frustration.

Prospects for polio

Now at the UPMC Center for Health Security in Baltimore, Henderson said the polio eradication effort is going to have a hard time corralling, containing, and destroying stocks of poliovirus from labs around the world.

For one thing, laboratories don’t always know what they have, said Henderson, recalling an effort he made to inventory the holdings in the labs of Johns Hopkins’ School of Public Health when he was dean. “At the time we were dealing with a couple of buildings of labs. Not huge. But oh my goodness, we had deep freezers everywhere.”

That’s still a problem, as evidenced by the 2014 announcement by the National Institutes of Health in Bethesda, Md., that it had found six vials of live smallpox in a cardboard box in a cold room that was being cleaned out. The NIH was not supposed to have any smallpox; the stores the US holds are in safekeeping at the Centers for Disease Control and Prevention in Atlanta.

With polio, the task will be further complicated by the fact that many laboratories that collect stool samples could conceivably have polioviruses. (People infected with polio shed the viruses in their stool.)

“I think there will undoubtedly be people like gastroenterologists who have got freezers with samples that they collected years ago in places like Pakistan or Bangladesh where they were looking for rotavirus or other gastrointestinal infections … and it didn’t dawn on them that their samples could have poliovirus in them,” Salisbury said.

Hamilton said the rinderpest team is trying to impress upon countries and research facilities that holding on to the virus is all-risk, no-benefit. “If there is an accident or someone gets their hands on it, then it’s pretty embarrassing for that facility and undermines decades of work that went into eradicating it. We’re saying: ‘Look, there’s no value hanging on to this virus. So just get rid of it or send it to one of the approved facilities.’ ”

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