Zombie Virus & Impacts of Climate Change on Re-Emergence of Viruses!

Following the outbreak of the COVID-19 pandemic, citizens worldwide have realized the damage a viral disease could cause, not only to the health sector but also to economies and impact the entire society as a whole. With the recent news of scientists reviving the 48,500-Year-Old ‘Zombie Virus’ buried in Ice, the Climate Fact Checks team investigated if climate change has induced the spread of viruses over the last few decades.

What is the Zombie Virus?

Zombie virus is the term used for viruses that have been dormant for many years due to being trapped inside the Ice and have come to life after the Ice melted.

Researchers from France, Germany and Russia revived 13 new types of viruses trapped under Ice in Siberian soil dating back 27,000 and 48,500 years. The evidence so far suggests that the so-called zombie viruses were not posing a threat to humans yet remained infectious despite being trapped under Permafrost for many millennia. These viruses were found to mainly impact micro-organisms, specifically amoeba.

But other pathogens released in future as permafrost melts could even pose risks to humans, say, scientists. Speaking to New Scientist, virologist Eric Delwart from the University of California states that” If the authors are indeed isolating live viruses from ancient Permafrost, it is likely that the even smaller, simpler mammalian viruses would also survived frozen for eons,”

More details about the zombie virus are documented here.

Climate change impacts leading to a faster rate of thawing of Permafrost have increased the probability of re-emergence of “zombie viruses.”

Scientists alert that almost one-fourth of the Northern Hemisphere is laden with Permafrost, which contains permanently frozen bacteria and viruses. In addition, as the climate is warming, Permafrost is thawing irreversibly, releasing organic matter frozen for millions of years. The organic matter also decomposes into methane and carbon dioxide, causing a greenhouse effect.

As a result of climate change, sudden temperature changes and more frequent extreme weather events, such as floods, hurricanes, and droughts, would be an ideal breeding ground conducive to virus modification and the emergence of infectious diseases.

However, the impacts of climate change, releasing unknown viruses trapped inside frozen Ice for many millennia, is not a new concern, especially since Permafrost is an excellent preserver of microbes.

In fact, there has already been an instance of a heat wave thawing frozen Permafrost, which led to an anthrax outbreak in 2016 Siberia. Even though this mainly infected thousands of raindeers and few humans were hospitalized, with one child death. The origins of the 2016 anthrax outbreak is linked to a dead reindeer carcass which had died after being infected with the virus and got trapped under Permafrost for over 75 years. More on this here

A study conducted on this anthrax outbreak had outlined how the Climatic Factors would Contribute to the Anthrax Outbreak, as seen below. A complete research paper can be read here.

As summarized by the European Society of Clinical Microbiology and Infectious Diseases, the key to understanding the relationship between climate change and the re-imergence of viruses is to recognize alterations in average temperatures, humidity levels, vegetation quality, and the large-scale movement of animals.

Furthermore, other factors related to climate change, like pollution and the deterioration of air quality, make us more susceptible to infectious respiratory diseases. This was evident during the 2002 SARS virus epidemic in China, where patients from regions with higher levels of air pollution were twice as likely to die after being infected compared to those with better air quality.

Increase in the spread of viral infections – Sri Lanka context

The CFC team spoke to Dr Mahen Kothalawala, a Clinical Microbiology and Infection Prevention Specialist at the Teaching Hospital, Kandy, regarding the matter. He highlighted that there is a minimum risk of new viruses infectious to humans popping up due to thawing permafrost.

He stated that several factors need to be fulfilled for a virus to transmit among humans. Accordingly, The first factor is the species barrier, which is the natural system that prevents diseases from spreading from one type of animal or plant to another. For example, the Covid19 virus SARS-CoV-2 has been seen crossing the species barrier, infecting humans from the wild with yet unclear source, spreading from humans to humans quickly, humans to animals, animals to animals, and is likely to spread from animals to humans even though minimally. Hence, the species barrier needs to be breached for the new viruses discovered to infect humans. 

The second factor is that even if there is a possibility of a viral infection spreading from the environment to humans, there is minimal potential for it to spread from one person to another. The third factor is that even if the viral infection spreads among humans, there is a minimum chance for it to cause a pandemic. He added that human and environmental factors need to coincide for a pandemic. For example, human behaviour and transmission mode need to align for a viral outbreak.

Dr Mahen Kothalawala mentioned that even though Sri Lanka is a country vulnerable to the impacts of climate change, the spread of viral infections has many other contributing factors, such as human behaviour, population exclusion and the development level of the health system. Therefore, climate change is a minimum contributory factor in spreading infectious diseases, and there is no direct association between climate change and viral infections.

He added that the Sri Lankan health system is not yet developed enough to identify and combat new viral infections, as the disease surveillance system in Sri Lanka is only designed to identify existing pathogens. He added that Sri Lanka lacked the infrastructure and technology to face new viral infections and requires global assistance in detecting them.