Amid Monkeypox outbreak, WHO warns about rising number of 'zoonotic' diseases. Here's what it means

Written By: Moohita Kaur Garg | Updated: Jun 02, 2022, 09:32 PM IST

World Health Organization's emergencies director Mike Ryan has warned that outbreaks of endemic diseases such as Monkeypox and Lassa fever are becoming more persistent and frequent than ever.

As climate change contributes to the rapidly changing weather, animals and humans are changing their behaviour. So are viruses and pathogens.

He asserts that diseases that normally infect animals are now infecting people due to 'ecologic fragility.' Monkeypox, which is currently ravaging the globe, is the most prominent example of this.

But did you know that there are other diseases that have crossed the species barrier from animals to humans? Here are a few:

What are Zoonotic diseases?

First of all let us understand what exactly are Zoonotic diseases.

People all across the world rely on animals for food, fibre, livelihoods, travel, sport, friendship, and education. However, as the WHO emergencies director said diseases that normally infect animals are now infecting people due to 'ecologic fragility'.

As per WHO Zoonotic diseases or Zoonosis "is an infectious disease that has jumped from a non-human animal to humans. Zoonotic pathogens may be bacterial, viral or parasitic, or may involve unconventional agents and can spread to humans through direct contact or through food, water or the environment. They represent a major public health problem around the world due to our close relationship with animals in agriculture, as companions and in the natural environment." 

Now, let's take a look as some zoonoses.



Novel coronavirus

The novel coronavirus that causes COVID-19 was initially discovered in Wuhan, China, at the end of December 2019, with officials suspecting the source was linked to a seafood market there. 

The virus's genetic analysis indicates that it originated in bats. Scientists believe an unidentified species acted as a go-between in transferring the coronavirus to people because no bats were sold at the seafood market at the outbreak's epicentre.

However, we are yet to know the source of the virus, there have been claims that it might actually be a lab-engineered strain.



Influenza first hit humans in 1918. Within months, the H1N1 pandemic swept the world killing 50 million people - which was more than any other illness in recorded history for the short time framed involved. It was of avian origin.

In 2009 another influenza virus, this one (H1N1)pdm09 cropped up, killing around 575,000 people. This strain had its origins in pigs.

(Image: Wikimedia Commons)


Bubonic Plague

The 14th century Bubonic Plague or Black death that killed 75 million people worldwide also has animal origins.

Plague is a bacterial disease cause by Yersinia Pestis. The bacteria is present in rodents (rats etc) and even cats can be carriers. It can be transmitted to humans via infected fleas. However the most deadly version of it like the one in 13th century was a mutated version that transmitted between humans. 

Even today it remains deadly if not treated.

(Image: Wikimedia Commons)



This deadly disease kills 55,000 people globally each year. Most of these are caused because of a bite by an infected pet. Wild animals, rodents also carry rabies.

(Image: Wikimedia Commons)



Did you know even AIDS had animal origins?

HIV the virus behind AIDS can be traced back to a type of Chimpanzee that is found in Central Africa. 

However, in the chimps it is a different variant called SIV or Simian immunodeficiency virus. It was likely passed on to humans via hunting and meat.

(Image: Wikimedia Commons)



This disease is a widespread threat to chimpanzees and gorillas in Central Africa. It might have gotten transmitted to humans via infected bats or infected non-human primates. 

It was first identified in 1976 near the Ebola river, hence the name.

(Image: Wikimedia Commons)


Lyme disease

This disease is caused by ticks. Black-legged ticks can transmit the bacteria that causes Lyme disease in humans.

As per CDC every year about 30,000 cases are reported in US alone.

(Image: Wikimedia Commons)


How many Zoonoses are there and how to safeguard against them?

The US Centers for Disease Control and Prevention on its website lists down dozens of such zoonoses. However, you don't need to be overly worried, if taken precautions you can protect yourself and your family.

Although zoonotic disease prevention approaches vary per pathogen, certain practises have been identified as beneficial in reducing risk at the community and individual levels.

- Keep your hands clean at all times. Even if you didn't touch any animals, washing your hands after being around them is one of the most critical things you can take to avoid getting sick and transmitting infections to others.

- Safe and effective animal care standards in the agricultural industry serve to limit the risk of foodborne zoonotic disease outbreaks via meat, eggs, dairy, and even some vegetables.

- Standards for safe drinking water and waste disposal, as well as environmental protections for surface water, are also important and effective.


Humans also infect animals

It's not just humans who can get sick with animal diseases, it can also happen vice versa.

There have been reports of chimps contacting polio for humans. Additionally, in West Africa chimps and gorillas were killed by outbreaks of anthrax, which is believed to have been originated from cattle herded by humans. 

In 2009, exposure to humans also led to respiratory disease in Chimpanzee of a Chicago zoo.