Loss of biodiversity forces microbes to “hitchhike” on humans: researchers
A research paper published by the Indian Journal of Medical Research in April 2021 called Hitchhiking microbes: Declining biodiversity and emerging zoonoses sheds light on the role of declining biodiversity and emerging diseases on humans which has led to new diseases like Covid-19 being passed on to humans.
This research was presented on the occasion of the international day for biological diversity on May 22 by Gurudas Nulkar, Madhura Bedarkar of Symbiosis International University (SIU) and Symbiosis Institute of Business Management (SIBM) along with Ketaki Ghate, Oikos for Ecological Services, Sakshi Nulkar, intern and wildlife researcher, ecological society, Pune.
The research paper argues that microbes which were found in animals, have jumped on to other animals, because of habitat loss and food loss, this is why we now see microbes hitchhiking, for example, the way Covid has jumped from bats to human beings.
“The connection between nature conservation and human wellbeing is well known, however, the role of declining biodiversity and emerging diseases is relatively less studied. The presence of a thriving biological diversity is known to have therapeutic effects on human health, but economic activities have contributed to a sharp decline in species, resulting in poor ecosystem health. Several studies have shown how microorganisms have switched from animals to humans, leading to novel diseases and we have presented studies on zoonotic diseases and biodiversity, with examples from India,” said Nulkar.
According to Nulkar, the biodiversity in the city is undergoing a change which can be seen in bird species seen in the city.
“We have more crows, mynas and squirrels seen in the city while in wilderness, you will come across flycatchers, thurshes and other birds which are now completely missing from the cityscape. This is because of urbanization, deforestation and infrastructure that have changed the biodiversity in the city,” he said.
Earlier too, we witnessed diseases such as rabies, leptospirosis, plague, scrub typhus, Nipah virus, Kyasanur forest disease, Japanese encephalitis, and various types of influenza are causing small and consistent outbreaks in animal and human populations across India.
“Rabies, another disease with a 100 per cent fatality rate, is not an emerging infectious disease, but has existed for a long time. As a rabies-endemic country, India is estimated to have 20,000 rabies deaths every year, among 20 million dog bite cases a year. Nearly 36 per cent of the world’s rabies deaths occur in India every year. This disease has the potential to spillback into healthy populations of wild canids, small mammals and bat species through dog bites, as free ranging dogs are increasingly found to have conflicts with wild animals,” said the research.
It also highlights that increasing mining has led to a sharp decline in natural forests, which has forced out apex predators and increased human-animal conflicts. This has denuded millions of hectares of forests all over the world.
“Three major infrastructure projects sanctioned in 2020 in Goa will go through the Mollem National Park, diverting over 250 hectares of forest land for commercial purposes. Of this, 170 hectares falls within protected areas. Mollem is host to a large biodiversity and several threatened species are found here. The proposed Hubballi-Ankola rail project in North Karnataka will divert 727 hectares of pristine forests and 2.2 lakh trees will be fallen. This is part of the ecologically fragile Western Ghats, home to rare and endangered flora and fauna,” said Nulkar.
Viruses, bacteria and other types of microbes are capable of inflicting diseases in plants, animals and humans. In a healthy ecosystem, they are usually constrained geographically and seasonally by ecological relationships and the regulatory functions of ecosystem services. Researchers have established an association between biodiversity loss and human health.
Biodiversity must be conserved even in urban environment, with patches of wilderness given importance, like for example leaving the Tekdis alone and not building any infrastructure that could imbalance the biodiversity.
It is argued that conservation of biodiversity and ecosystems and changes in economic activities must be made to ward off new diseases, and this is why cooperation between ministries is critical to restrict the decline of biological diversity in a megadiverse country like India.
The diversity of potential disease-causing organisms is also greater, only a fraction of which are currently known to science. The zoonotic disease outbreaks in India like Covid- 19, Nipah virus, Swine flu, KFD among others have pointed to a need for continuous surveillance for detecting zoonoses early and initiating timely and efficient management of these diseases.
However, the field of studies concerning zoonotic diseases and their implications are largely isolated, institutionally, with studies undertaken by ecologists, public health experts, and agriculturists, all working in isolation and there is hardly any public awareness and engagement seen.
In the recent national budget of 2021-2022, the government has made a provision for establishing the Institute of One Health, to manage endemic and emerging epidemic threats of zoonotic diseases, where it offers a holistic approach for combating the emerging global health concerns with transdisciplinary efforts, especially with respect to zoonotic diseases.