In recent years, growing attention has been focused on the increasing threat of zoonoses – diseases that transmit from animals to humans. This article aims to provide an overview of the critical aspects of zoonoses, including their origin, impact on human health, and possible solutions.
Zoonoses: A Brief Introduction
Derived from the Greek words for “animal” and “sickness,” Zoonoses refer to diseases that are transmitted from animals to humans. These diseases can range from the often fatal Rabies, which spreads predominantly by rabid dogs, to diseases caused by microbes carried by mosquitoes like West Nile virus and the Zika virus. The most recent and globally impactful example of a zoonotic disease is Covid-19, believed to have originated from bats and/or pangolins.
Surprising Statistics about Zoonoses
A shocking fact about these diseases is that approximately one new infectious disease emerges in humans every four months. Research concluded before the recent Covid-19 pandemic found that rodents, primates, and bats are responsible for carrying three-quarters of the viruses that infect humans. Domestic animals also contribute significantly to disease transmission, carrying about 50% of identified zoonoses.
In 2016, it was reported by the United Nations Environment Programme (UNEP) that 75% of all emerging infectious diseases in humans are zoonotic, indicating a strong correlation between the health of ecosystems and these diseases.
Impact of Zoonoses on Human Life
While the ongoing Covid-19 pandemic has underscored their threat, zoonoses have long been a global health concern. Estimates by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) suggest that zoonoses kill around 700,000 people annually.
Connection between Ecosystem Changes and Zoonoses
Zoonotic diseases flourish when ecosystems change, particularly when alterations affect animal or human populations that serve as hosts for pathogens, or the disease-causing microorganisms themselves. The past century has seen considerable population growth, coupled with a decline in ecosystems and biodiversity, providing an increasingly conducive environment for pathogen transmission between animals and humans.
Human Activities: Catalysts for Zoonotic Diseases
When humans modify land for settlement, agriculture, logging, extractive industries, and related infrastructure, they inevitably disrupt and encroach upon animal habitats. This destruction of natural buffer zones, which typically separate humans from animals, creates opportunities for pathogens to infect humans. Climate change exacerbates these conditions, as shifts in temperature, humidity, and seasonality can directly affect microbial survival.
Global Initiatives against Zoonoses
To combat the threats posed by zoonoses, international organizations like UNEP and the UN Food and Agriculture Organization have launched a 10-year plan to counter habitat degradation. Known as the UN Decade on Ecosystem Restoration 2021-2030, this massive collaborative effort aims to restore humanity’s balance with nature.
Addressing the Problem
Dealing with zoonotic diseases requires a focus on their root cause – the impact of human activities on ecosystems. By restoring diverse ecosystems that naturally regulate diseases, the spread of pathogens can be limited. It is essential to recognize the interdependence of human, animal, and environmental health, necessitating a unified, multisectoral, transdisciplinary, and international approach to deal with the threat of zoonoses effectively.