Warming Arctic temperatures can create an environment friendly to bacterial infections like anthrax, an infection spread by contact with bacterial spores, which plant-eating animals may eat or breathe in while grazing.
A recent outbreak of anthrax in western Siberia, which affected reindeer herds and resulted in 13 nomads being hospitalized, is believed to have stemmed from the thawing of a carcass of a reindeer that died of plague 75 years ago, according to an NBC News report.
But the likelihood of such outbreaks in Alaska, where there have been no diagnosed cases of anthrax reported, is low, says state veterinarian Dr. Robert Gerlach.
Anthrax is caused by the bacterium Bacillus anthracis, which can occur in skin, inhalation, intestinal and injection forms, and contact is spread by breathing, eating or through an area of broken skin.
The issue with anthrax is the spores survive for a long time, and there have been numerous outbreaks with cattle, Gerlach said. Once the bacteria leaves the body they form spores and those spores survive for decades in the soil, he said.
There have been anthrax outbreaks among cattle in certain areas of the American west, and among wood bison in parts of Canada, he said.
Moose, caribou, bison and deer, all grazing animals, are most susceptible, and the Alaska Department of Environmental Conservation lists the discovery of, or suspected existence of anthrax involving animals as one of six diseases that must be reported by day’s end. The others include avian influenza, swine vesicular disease, sylvatic plague, vesicular stomatitis, and West Nile virus.
Records dating back to when the state veterinarian’s office was established, shortly after statehood, show no cases of anthrax have ever been reported in Alaska.
Still Gerlach’s office works with reindeer herders and livestock ranchers in Alaska, and in conjunction with the Alaska Department of Fish and Game to diagnose mortality events among the state’s wildlife.
Gerlach’s office and ADF&G do investigate and evaluate any groups of animals that are sick and dying, from livestock to pets, he said. While the bacteria affects warm- blooded animals and some birds, it does not affect fish and shellfish, he said.
At this point though, there is more concern about diseases carried by insects and ticks, including tick borne diseases, he said. Winter ticks can cause death in grazing animals and livestock regulations require that cattle be treated for ectoparasites, such as fleas, who live on the outside of their host.
An anthrax vaccine is recommended for people at high risk of catching the anthrax bacteria, including people who work with animals, travelers, postal workers and military personnel, and immunizing animals against anthrax is recommended in areas where there have been previous anthrax infection spread.
That has not been the case in Alaska.
“The important thing the state tries to do is to work with all agencies on human and animal health to investigate illnesses,” Gerlach said.
That means an investigation any time there are a lot of animals sick or dying, to identify the cause and communicate that to all the people involved, he said.