Infections linked to thawing show importance of Arctic surveillance
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In the summer of 2016, an outbreak of anthrax in the Russian Arctic that left dozens of people hospitalized and one 12-year-old boy dead was blamed on the thawing carcass of a reindeer that had died in the area’s previous anthrax outbreak in 1941.
According to CNN, The New York Times and other outlets, the hospitalizations followed the death of thousands of reindeer — deaths initially attributed to a heat wave and later to the thawed, infected carcass.
In a December 2018 article on Bacillus anthracis strains isolated from the Russian permafrost, Vatalii Timofeev, PhD, head of the anthrax laboratory at Russia’s Federal Budget Institution of Science, and colleagues said the outbreaks “show[ed] that such foci retain their epidemiological potential for a long time, and under favorable conditions, primarily in the thawing of permafrost due to local or global warming, they can become a source of infection, causing large-scale epidemics, resulting in casualties and significant economic costs.”
Importance of surveillance
“What the Russian Arctic anthrax outbreak highlights is the importance of public health surveillance to be able to identify and respond to situations like the one in Siberia,” the CDC’s Michael Bruce, MD, MPH, told Infectious Disease News.
Bruce is director of the CDC’s Arctic Investigations Program (AIP) in Anchorage, Alaska, which is part of the CDC’s Division of Preparedness and Emerging Infections. According to the CDC, the AIP conducts infectious disease surveillance, evaluates prevention services and conducts research to prevent infectious diseases in the Arctic and sub-Arctic. Around three dozen epidemiologists, laboratorians, research nurses, statisticians and other support staff are based at the facility on the Alaska Native Medical Center campus. Their areas of research include medical care, applied epidemiology, laboratory diagnosis, and biostatistical sciences. Surveillance data is shared with the U.S., Canada, Greenland, Iceland, Norway, Sweden and Finland.
The AIP monitors “invasive disease-causing bacteria” including Haemophilus influenzae, Streptococcus pneumoniae, Neisseria meningitidis, groups A and B Streptococcus and Helicobacter pylori. The program adopted five priorities for 2016 through 2020, including reducing the burden of disease and health disparities among Alaskans caused by respiratory infections and strengthening infectious disease monitoring in Arctic and sub-Arctic lands. The AIP also has focused on reducing and preventing infectious diseases disproportionately affecting American Indian and Alaska native people.
In addition to these projects, the AIP has joined with the Alaska Native Tribal Health Consortium to form a One Health group, which focuses on the interconnection between human health, animal health and the environment.
According to researchers, Alaska has warmed twice as fast as the rest of the United States, “bringing widespread impacts” that include receding sea ice, shrinking glaciers, thawing permafrost and a change in wildlife habitats. Writing in the International Journal of Circumpolar Health, researchers warned that “warmer temperatures may allow some infected host animals to survive winters in larger numbers, increase their population and expand their range of habitation, thus increasing the opportunity for transmission of infection to humans.” The researchers noted that beaver and muskrat populations in Alaska have been moving farther north, exposing humans in these areas to previously unencountered pathogens, such as Giardia.
According to the CDC, AIP scientists are working to address the potential for these climate-sensitive zoonotic threats, including the increased risk for intestinal giardiasis from the northward migration of beavers.
Other zoonotic diseases are known to occur in Alaska, including cryptosporidiosis and tularemia, the distributions of which also may be impacted by climate change, according to experts.
“There is concern and potential for zoonotic diseases to be affected by changes in weather and climate, both increasing and decreasing, but more information is needed,” Bruce said. “Increased surveillance is needed, along with an interdisciplinary approach, such as One Health, to bring together local communities, and health, wildlife and environmental professionals.”
Thawing-related threats
In Kivalina, Alaska, a small coastal Inupiat Eskimo community in the northwestern Alaska Arctic, thawing permafrost has led to erosion on the banks of the Wulik River and a decrease in water quality, making it difficult to treat water for consumption, according to researchers.
In a study published in the Journal of Water and Health, Bruce and colleagues examined rates of infections impacted by water quality in communities transitioning to in-home piped water in Alaska. According to the study, approximately 20% of rural Alaskan homes lack in-home piped water and people must haul water to their homes from outside sources.
They assessed rates of infections impacted by water quality and quantity in communities transitioning to in-home piped water, recording 5,477 person-years of observation from 1,032 individuals with 9,840 illness episodes. The study revealed 8,155 respiratory, 1,666 skin, and 241 gastrointestinal infections. After the change to in-home piped water, Bruce and colleagues noted declines in respiratory (16, 95% CI 11%-21%), skin (20, 95% CI 10%-30%) and gastrointestinal infections (38, 95% CI 13%-55%), reinforcing the importance of potable water.
“We know that increases in temperatures can affect water levels and result in erosion that can cause water and septic systems to fail,” Bruce said. “The effects of climate change and Arctic warming are already being seen in rural Alaskan coastal villages, where increased coastal erosion can cause severe infrastructure damage, potentially affecting water and sanitation.”
In Russia, Timofeev and colleagues examined the 2016 anthrax outbreak on the Yamal Peninsula — the first in the area since 1941. The district had been declared anthrax-free in 1968.
According to the study, officials were notified of the deaths of some private reindeer herds. The cause of death was initially believed to be heat stroke, because July 2016 had unusually warm temperatures, though the suspicion of B. anthracis was reported shortly thereafter, according to Timofeev and colleagues.
The researchers determined that the warm climate had led to the thawing of permafrost, exposing B. anthracis spores to the surface. According to the study, several strains were also isolated in samples from Yakutia, where miners were extracting mammoth tusks from permafrost and discovered two cave lion kittens frozen in ice. Timofeev said they were “surprised” by some of their findings, including the discovery of viable B. anthracis strains where anthrax outbreaks had not been recorded in the past.
“Studies of Yakut soil samples showed us that permafrost, at least in Eurasia, may be a reservoir of potentially viable pathogens, and its melting may theoretically be accompanied by disease outbreaks,” Timofeev said.
He said the outbreak also highlighted that, even the absence of outbreaks for more than 70 years, vaccinating livestock and people against pathogens is still important. Mandatory reindeer vaccination against anthrax was abandoned in the area in 2007, Timofeev and colleagues reported.
Such an outbreak is less likely to be caused by other pathogens, Bruce stressed.
“Anthrax is an unusual and especially hardy bacteria that is able to survive freezing and germinate when conditions are ideal again,” he said. “This is much less likely for other bacteria and viruses.” – by Caitlyn Stulpin
- References:
- Alaska Native Tribal Health Consortium. Climate change in Kivalina, Alaska. 2011. http://www.cidrap.umn.edu/sites/default/files/public/php/26952/Climate%20Change%20HIA%20Report_Kivalina.pdf. Accessed September 2, 2019.
- Hueffer K, et al. Int J Circumpolar Health. 2013;doi:10.3402/ijch.v72i0.19562.
- National Climate Assessment. Alaska. https://nca2014.globalchange.gov/report/regions/alaska#intro-section. Accessed September 2, 2019.
- Thomas TK, et al. J Water Health. 2016;doi:10.2166/wh.2015.110.
- Timofeev V, et al. PLoS One. 2018;doi:doi:10.1371/journal.pone.0209140.
- U.S. Climate Resilience Toolkit. Relocating Kivalina. 2017. https://toolkit.climate.gov/case-studies/relocating-kivalina. Accessed September 2, 2019.
Disclosures: Bruce and Timofeev report no relevant financial disclosures.