The Covid-19 pandemic has drawn attention to the way new diseases emerge and spread amongst the human population. It may surprise you to know that many diseases were originally animal diseases which have been transmitted to humans.
According to the World Health Organization (WHO) ‘the source of SARS-CoV-2, the coronavirus (CoV) causing Covid-19 is unknown [ie not seen in humans before]. All available evidence suggests that SARS-CoV-2 has a natural animal origin and is not a constructed virus.’ More research will be needed to confirm the exact origin of the virus but currently the WHO believes bats are the most likely source.
Back in 2012, Dr Sally Best introduced us to the term ‘zoonosis’ in Footsteps 89 on Livestock. You might be surprised to learn how many diseases have animal origins:
‘A zoonosis is a disease or infection that is naturally transmitted between animals and humans. Zoonoses cause serious public health problems and often particularly affect poor communities. Although they are usually preventable, many zoonotic diseases continue to spread because they are neglected by national and international health systems. Zoonoses are also responsible for many new diseases. In fact, the majority of new diseases that have emerged over the last few decades have been passed from animals. Since they also affect animal health, they affect food production and international trade in animal products, which in turn affects economic development.
‘There are more than 200 known zoonotic diseases, caused by all sorts of germs which circulate in wildlife, domestic livestock or both. Examples of zoonotic diseases that can be passed from livestock to humans include bird flu, sleeping sickness, tick-borne diseases, tuberculosis and some worms. Rabies is another important zoonotic disease, although it is carried by dogs rather than livestock.
‘Zoonoses can pass between humans and animals by a variety of routes including direct and indirect exposure to animals, their products and/or their environment. For example, infection can occur by eating contaminated food, through animal bites, insect bites or contamination of the environment. Therefore methods to prevent human infection vary for different diseases. It is important to control animal diseases to prevent onward transmission to humans and to maintain healthy productive livestock.’
You can read more about other zoonoses such as rabies, human sleeping sickness and pork tapeworm here.
‘the majority of new diseases that have emerged over the last few decades have been passed from animals.’
Tearfund is working hard to respond to the Covid-19 pandemic, focusing on those living in poverty across Asia, Africa and Latin America. You can read more about our response here. On Tearfund Learn we have a new dedicated page with resources for Tearfund partners and others responding to the crisis. We are updating these regularly so do keep checking back for the latest information and advice.