KOCHI: Extreme weather events like steep rise in temperature, flood and landslides have amplified the threats posed by infectious diseases. Citing global studies, experts point out that climate change could be behind the emergence of infectious diseases in Kerala, and have called for increased surveillance.
Unlike earlier times, with the viruses learning to survive high temperatures, it has now become difficult to predict infections and how they affect humans. Also, the loss of habitat due to climate change is forcing animals – carriers of multiple viruses – to move to human settlements, increasing the animal-human interface.
“Viruses are adapting to climate change, especially the rise in temperature due to global warming. Earlier, when the temperature rose during summers, viruses were rendered incapable of infecting humans. With temperature rising, they are mutating and learning to survive. Once they survive, they are able to multiply in the human body, causing infections,” said Dr Anup R Warrier, an infectious diseases expert based in Kochi.
A recent study published by the University of Hawaii highlighted that rising temperatures were the biggest driver of pathogenic diseases, followed by precipitation, flood and drought. “Climate hazards, loss of forest cover or changes in landscape are forcing animals to shift. As a result, the human-animal interface has increased, paving the way for more infections. For years, animals have been carrying several viruses. Since the interaction with the humans was low, it went unnoticed. Now humans are more exposed to viruses being carried by animals,” Dr Anup pointed out.
Emerging infectious diseases affect the humans in three ways. First, when the existing viruses affecting a group increase their area of impact, more people fall sick. Second, when virus-carrying animals move to human settlements, they carry the viruses too, exposing humans to the pathogens. Third, when a virus copes up with high temperature, it can turn into a new variant, causing diseases unknown till now. Also, the recent global studies have predicted that new viruses, like the one causing Covid, will arise.
“For instance, monkey fever (Kyasanur Forest disease) was rare and only affected those who interacted with animals. But monkeys are now forced to move into human settlements, exposing an entire community to infection. Scrub Typhus (tick-bite fever) is another such emerging infectious disease,” said Dr Mahesh P, an epidemiologist based in Thiruvananthapuram.
While the emerging diseases are mostly viral, fungal infections too are becoming a threat, said a health expert. “Though there is no animal-human or human-human transmission involved, controlling the infections is difficult,” he said.