Thirteen people have been hospitalized amid an outbreak of anthrax in western Siberia, the governor’s office of the Yamalo-Nenets autonomous region reported Thursday. Experts with the Russian Ministry of Agriculture believe the cause of infection is the thawing of the frozen carcass of a reindeer that died 75 years ago.
Anthrax is a potentially deadly bacterial disease caused by Bacillus anthracis, according to the World Health Organization.
The hospitalizations came after up to 1,200 reindeer died over the past month, which officials originally blamed on a heat wave in the region. Unusually high temperatures of up to 35 degrees Celsius (95 degrees Fahrenheit) recorded over the past month might have weakened the reindeer.
Now, laboratory tests have confirmed that the reindeer died of anthrax, Gov. Dmitry Kobylkin’s office reported.
However, Moscow laboratories have not confirmed that the patients’ illnesses were caused by anthrax. But in the meantime, the patients are being treated as though they have the illness, including treatment with antibiotics.
Scientists speculated that the deer, weakened from the heat, ate the thawed remains of an infected reindeer carcass that had been frozen for many years. From there, the infection was passed to nomad herders.
An alternate theory proposed by some experts is that the deer picked up the infection from an abandoned cemetery in Halmer, where, in following an ancient tradition, the deceased have been placed in wooden boxes and set on the ground rather than buried. Soil samples in the area do not contain the pathogen.
This would be the first anthrax outbreak in the area since 1941, said Anna Popova, chief state sanitary doctor of Russia. The territory has been free of the infection since 1968.
Without firsthand knowledge of the Siberian outbreak, Dr. Peter Eichacker, a senior investigator at the U.S. National Institutes of Health clinical center, couldn’t say what type of anthrax infection may be occurring.
“It’s unclear, but it’s most likely the gastrointestinal tract form,” he said. In remote regions, he explained, people generally get one of two forms of anthrax infection: cutaneous, caused by anthrax spores infecting the skin around a cut or abrasion, or gastrointestinal, caused by eating infected meat. Symptoms include nausea, vomiting, diarrhea and abdominal pain.
Roughly 5% to 10% of those with cutaneous infections die, Eichacker said. No one knows the actual incidence and mortality rates for the intestinal form, but they are “much higher than cutaneous,” he said.
The autonomous region has more than 500,000 people, of whom 15,000 lead a nomadic way of life.
Kobylkin has enforced a mass evacuation of herders and their families in the Yamalsky district, in the northern Urals. Though anthrax is not passed from person to person, some residents may be flown to another part of the tundra for inoculations as a preventive measure.
All necessary assistance and measures for people and animals have been undertaken, Popova said, including the deployment of an on-site laboratory to conduct testing. People must be prepared for medical examinations and preventative vaccinations, she added. A quarantine may last until September.
“What (vaccines) specifically they would have in Siberia and Russia, we would not have any knowledge of,” said Dr. Natalya Serbina, principal scientist at Elusys Therapeutics, a private American company that developed the anthrax antitoxin Anthim for the U.S. Department of Health and Human Services.
“Most vaccines require three or four injections over a month,” Elusys CEO Dr. Elizabeth Posillico said, adding that an anthrax vaccine would not protect a person right away. It would take at least two weeks.
Meanwhile, officials have been vaccinating all the reindeer in the region. The mass vaccination should be completed within a day.
Popova said authorities will soon begin sanitation of the area, including recovery of animal corpses. Diesel fuel was delivered to the region to burn the infected carcasses, but officials have been hesitant to do so because of recent wildfires in the region, the governor’s office said.