While climate change contributes to the upsurge in disease outbreaks across the world, the current rate of environmental degradation and biodiversity loss will worsen future pandemics like the coronavirus, scientists have said.
Even though climate change did not cause the emergence of COVID-19 they said it could indirectly make the effects of a current or future pandemic worse.
This position was pushed by Arthur Wyns who specialises on climate change, environment and human health with the World Health Organisation (WHO).
Mr Wyns who spoke in his personal capacity with PREMIUM TIMES in April said, climate change “undermines the environmental conditions we need for good health—access to water, clean air, food and shelter—and places additional stress on the health system.”
The Nigeria Meteorological Agency (NiMet) has said Nigeria is already being hit hard by climate change through rising temperatures and lowered rainfall.
NiMet has also pointed out that these hotter and drier conditions which Nigerians are exposed to will exacerbate floods, droughts and heat waves and hamper agricultural production, which many rely on for their livelihoods.
These changing climatic conditions are already causing a rise in malaria and other diseases.
A research titled; Global trend on emerging infectious diseases notes that the total number of disease outbreaks has more than tripled each decade since the 1980s.
It said more than two thirds of the diseases originated in animals and most of those were directly transmitted from wildlife to people.
Habitat destruction like deforestation and agricultural development on wildland are increasingly forcing disease-carrying wild animals closer to humans, allowing new strains of infectious diseases to thrive.
Also, the World Resources Institute said only about 15 per cent of the world’s forests, which are key to maintaining biodiversity, remain intact after degradation from logging, fires and agricultural expansion. Millions of animal and plant species currently face extinction because of habitat destruction.
Meanwhile, some scientists have said the COVID-19 pandemic is the most recent instance of how human degradation of wildlife habitats is linked to the spread of infectious diseases.
Tierra Smiley, an epidemiologist at the University of California was quoted by CNBC news to have said, “Preserving habitats for wildlife and preserving our world is a human health issue.” He also said the orangutans in Indonesia have been known to be on the verge of extinction as a result of deforestation and poaching.
Also, Roger Frutos, infectious disease researcher in France told CNBC, “when you cut down trees and remove the forest, you eliminate the natural environment of some species. But those species don’t just disappear.”
He said “we should instead create a patchwork, a mosaic of their environment that’s closer to ours, with houses that attract insects or sheds where bats can rest and find shelter.”
Research has found that COVID-19 likely originated in a horseshoe bat and was then transmitted through another animal.
Mr Frutos said bats are less likely to transmit viruses to humans when they are in wild habitats, but land conversion has increased their exposure to humans and upped the chances of virus transmission.
“There’s now a higher density of bat-borne viruses and pathogens near human dwellings worldwide.”
Some researchers estimate that more than 3,000 strains of coronaviruses could already exist in bats and could be transmitted to humans.
According to Ms Smiley, “when you’re building human homes right up on forest edges, you’re destroying wildlife habitats and squeezing animal habitats into smaller areas leading to a more likely transmission of disease to humans.”
“Preserving habitats for wildlife and preserving our world is a human health issue, not just a wildlife or environmental issue,” she said .
Scott Weaver, director of the Institute for Human Infections and Immunity at the University of Texas, said deforestation will increase the risk of many mosquito-borne viruses in areas like the tropics, Latin America and South-east Asia.
“Poorer countries will suffer the most from diseases made worse by climate change, since warmer temperatures will increase the spread of viruses like dengue fever in places where people can’t afford air conditioning and general protections against disease exposure,” he said.
For instance, the West Nile virus, a mosquito-borne disease, replicates a lot faster in hotter climates. Researchers believe that global warming is allowing the virus to spread more efficiently in wild birds, who then infect people.
Mr Weaver also said “we’re in this predicament with the coronavirus because we’ve under invested in public health across the world and we haven’t taken scientific information into account in political decisions”.
“Hopefully the awakening from this pandemic will get people paying more attention to scientists telling us about these risks that could spill over into vector-borne diseases,” Mr Weaver added.
According to the International Livestock Research Institute(ILRI), diseases that are transmitted between animals and humans are called zoonoses. Past zoonoses have included bird flu, SARS, MERS-CoV and Ebola.
The institute said people can acquire zoonoses from direct or indirect contact with animals and from livestock products. In some cases, when a disease jumps species from animals to humans it becomes adapted to humans as it spreads as a human-only disease.
It said HIV was originally a zoonotic disease which mutated to become a human-to-human disease. In other cases, such as rabies, animals remain the source of infection.
The ILRI said zoonoses are more common than most people realise. On average, a new zoonosis emerges every four months, although few in recent memory have been as globally threatening as COVID-19.
Also, the Institute noted that the emergence of COVID-19 underlines the importance of taking a ‘one health approach’, based on the premise that animal and human health coupled with the ecosystems they share are inextricably linked and must be addressed together.
Nigeria groping in dark
Meanwhile, Tunde Amole, the country’s director, ILRI, who spoke with PREMIUM TIMES in April, said for Nigeria to get things right in the livestock industry, and ensure healthy meat consumption in the country, it must pass the Food Safety Bill that has been in the National Assembly since 2016.
He said this will help checkmate the killing and selling of unhealthy wild animals in the country.
According to data from Worldometer, which tracks coronavirus globally, the COVID-19 has affected 212 countries and territories around the world and two international conveyances.
With over 4.2 million confirmed cases so far, the world has witnessed 287,355 fatalities and 1,529,606 recoveries.