Covid-19: Why vet scientists should check livestock
Years back, while in veterinary school, our public health professor of zoonosis warned that failure to recognise diseases in wild and domestic animals that could be transmitted to humans was the greatest sin a vet could commit.
The diseases are called zoonoses. He further told us that such diseases did not necessarily have to be initially infective to humans, but human exposure could make disease-causing organisms, called pathogens, change their genetic code or adapt to infect the human host.
As I analysed the current coronavirus outbreak, I recalled these words as if he spoke yesterday.
Since the outbreak of the virus, it has spread rapidly to all corners of the globe. The World Health Organisation (WHO) has since declared the disease a global pandemic and instituted measures to contain further spread and eventually control it.
Zoonoses include infections such as rabies, tuberculosis, brucellosis and ebola. Most of these diseases are caused by viruses and bacteria.
The current coronavirus outbreak is suspected to have emanated from bats and snakes sold as food in a meat market in Wuhan, China.
Scientists determined that the human body had not been exposed to the virus before and named it Covid-19. Such viruses are new to medical science.
The coronavirus family is well known to medical scientists in both human and animal health, but Covid-19 is a new strain to both scientists and the human body.
The corona family causes many diseases in children and young animals, adult humans and animals. These include diarrhoea in children and young animals, common cold in humans and gut infection and pneumonia in adult pigs.
Apart from Covid-19, other coronavirus strains have jumped species from animals and infected humans, causing severe disease and mortality in the recent past. Other outbreaks In 2002, there was an outbreak of the Severe Acute Respiratory Syndrome (SARS), which emanated from a Chinese wet meat market and was traced to wild civet cats.
There was also the Middle East Respiratory Syndrome (MERS) outbreak in 2012. The virus was traced back to camels in Saudi Arabia.
Though these previous outbreaks spread from the epicentre to many other countries, they were put under control before they could become pandemics. That was mainly because they were not very easily passed from one person to another.
The major challenges with Covid-19 are its ease of personto-person transmission and its long incubation period of up to two weeks. During this period, the infected person does not show signs of the disease.
It, therefore, means that infected people can travel long distances and to many places before they are diagnosed with the infection. This is one of the reasons there is rapid spread of the disease.
I am motivated to write about Covid-19 because of the many questions I have received from readers, especially via WhatsApp.
First, I must say that Covid19, as it is now, is a human pandemic because transmission is between people. However, we also can reasonably speculate that susceptible animals could get infected from humans since the disease initially came from animals.
Therefore, as human medical scientists deal with the disease in people, veterinary scientists must also check vulnerable animals to prevent spread.
There’s the need to check animals close to humans, such as pets and livestock because there is the possibility that they can be infected by the virus and they become mechanical carriers without symptoms.
At a social function, a farmer asked whether Covid-19 could affect cattle, sheep and chickens if an outbreak occurred in a family.
Most farmers live close to their animals due to space and security constraints. Currently, the virus is not known to affect livestock.
Scientists are still studying the pathogen to understand it better. However, it is advisable for infected people to distance themselves from animals until the extent of the virus range and activity is understood.
This piece is an edited version of what appeared in the Daily Nation of Kenya.