The next pandemic: What scientists know so far

As Covid-19 continues ravaging the world, people wait for answers. But as scientists look for solutions to this pandemic, they are also working to avert the next one.

Early this year, the Health ministry announced that the International Livestock Research Institute (Ilri) would be carrying out research on Covid-19 variants through genome sequencing in the country.

Although Covid-19 affects humans, it originated from animals.

The Sars-Cov-2 virus is linked to a live animal market in Wuhan, China, but since December 2020 the virus has been spreading from person to person.

Many health experts believe that the coronavirus likely originated from bats or pangolins.

This happens when zoonotic pathogens directly jump from an animal species to infect humans such as HIV/Aids, which is believed to have originated from primates, or through other animal species. The animals either act as an intermediate connector host or bridge.

There is also the case where the amplifier hosts of pathogens are transmitted to humans as in the case of Nipah virus from bats, multiplied in pigs; influenza viruses mixing between human, pig and poultry populations in East and Southeast Asia.

The approach to prevent or eliminate the problem has made it impossible for experts to stay exclusively in their fields, requiring a well-coordinated approach in humans and animals.

This is why international organisations have come together to launch the One Health High-Level Expert Panel to improve the understanding of how diseases with the potential to trigger pandemics, emerge and spread.

‘One Health’ is an approach to design and implement programmes, policies, legislation and research in which multiple sectors communicate and work together to achieve better public health outcomes.

It recognises that human beings and animals share the same environment and the interactions between the three provides many opportunities for diseases to pass between animals and people.

Scientists believe that in the future we are likely to see many pandemics that come as a result of this interaction between man, animals and the environment.

The world is preparing for epidemic threats. Countries like Kenya are preparing in different ways based on their interpretation of disease risks and international agreements such as the International Health Regulations (IHR).

The regulations were introduced in 1969 to prevent the spread of specific serious diseases between countries and set out preparedness measures at international borders.

Future responses

In 2020, the UN’s expert panel on biodiversity warned that pandemics will be more frequent and deadly in the future due to increased contact between wildlife, livestock and humans as a result of environmental destruction. “There is a renewed interest in everything to do with viruses and zoonotic diseases because of Covid-19,” says Eric Fèvre, referring in particular to funding problems.  “This renewed interest is doing us a favour by helping us to do this very important work.”

According to The Lancet, the recent outbreaks of Ebola, Middle East Respiratory Syndrome Coronavirus (Mers-Cov), the coronavirus, and yellow fever reflect this changing context of disruptions requiring dynamic responses.

Dr Athman Mwatondo, a medical epidemiologist working for the Health ministry’s Zoonotic Diseases Unit (ZDU) says there are emerging viruses and they are currently setting up systems for future responses.

“We have a collaboration between the veterinarian team and medical doctors and we are currently doing an after action review to see how we did after every outbreak,” he says.

Dr Mwatondo says during the outbreak of the avian influenza, Severe Acute Respiratory Syndrome (Sars), Ebola and Marburg that have occurred in neighbouring countries like Uganda, the ZDU has provided Kenya with an institutional framework to highlight the public health importance of endemic and epidemic zoonoses.

They include Rift Valley Fever (RVF), rabies, brucellosis, Mers-Cov, anthrax and other emerging issues such as anti-microbial resistance. The plan involved training programmes, surveillance, workforce development, research, coordinated investigation and outbreak response.

“We spent time to prepare on how we respond since we have been surrounded by these disease providing us with an improved outbreak response,” he said.

The latest work they have done involves generating data including the discovery of new pathogens which has informed disease control programmes to reduce burden of and enhance preparedness for endemic and epidemic zoonotic diseases such as RVF in northern Kenya.

People can become infected with RVF after being bitten by an infected mosquito or through close contact with acutely infected animals or their tissues.

RVF is a vector borne, viral zoonosis that causes significant public health and economic impacts in animals and people. Kenya has experienced several RVF outbreaks since 1931, the most notable ones being the 1997–1998 and 2006–2007 outbreaks.

Severe disease

The occurrence of the disease is associated with heavy rainfall and flooding which provides ideal conditions for mosquito vector breeding, multiplication and disease emergence. Mosquitoes of the Aedes species are the primary vectors while the Culex and Anopheles species and other biting flies are secondary, amplifying vectors that propagate transmission.

The researchers, however, are now looking at an emerging disease that is likely to cause even more harm than the coronavirus.
Mers-Cov, a deadlier cousin of the coronavirus, is cited as the next pandemic. It is a zoonotic virus, believed to have been transmitted from camels. It causes similar symptoms to Covid-19 in humans: fever, coughing and respiratory difficulties.

While primary cases of Mers-Cov have been confined to six countries in the Middle East – Saudi Arabia, United Arab Emirates, Qatar, Jordan, Oman and Kuwait – travel related cases have been identified in Tunisia, the UK, France, Germany and Italy.

The most common comorbidities for Mers-Cov cases have been diabetes, hypertension, obesity, cancer, and chronic kidney, heart and lung diseases.

Human coronaviruses were first identified in the mid-1960s; Mers-Cov was first reported in 2012 in Saudi Arabia. Coronaviruses can also infect animals. Named for the crown-like spikes on their surface, coronaviruses are common in people, usually causing mild to moderate upper-respiratory tract illnesses. Two exceptions are Mers-Cov and the Sars-Cov.

Dromedary camels, which Kenya is also home to, are considered the source of zoonoses and natural reservoir hosts of Mers-Cov. A total of 2,589 cases were reported between April 2012 and April 2021, including 940 deaths. Most of these cases have an estimated fatality of 35 per cent, according to Gavi and have been on the Arabian Peninsula.

In people, the disease manifests as a mild influenza-like syndrome in over 80 per cent of cases or a severe disease with haemorrhagic fever, encephalitis or retinitis in a few cases.

In 2013, Ilri began researching camels. This is a year after the appearance in Saudi Arabia of Mers, a coronavirus which kills an estimated 35 per cent of those it infects, according to the World Health Organization.

Washington State University (WSU) and One Health team are currently conducting studies in Northern Kenya due to the huge number of camels there.  Kenya has about three million camels, which is about 10 per cent of the entire camel population.
Scientists suspect Mers-Cov could be the source of the next global pandemic.

Dr Isaac Ngere, a researcher with WSU, says they have done extensive research in Marsabit over the past few years on the virus in camels to try and learn more about it.

“We enrolled a cohort of 243 infant camels (0-24 months old) and 262 camel handlers who had intense contact with camels from 33 herds in Marsabit. We visited and collected samples from camels and human handlers every two week for the entire period,” he says.

Camel vaccine

He says that Mers-Cov has been known to exist in Kenyan camels from early 1990s, but no studies have determined if humans who take care of these camels could be getting infections.

“We tested over 10,000 samples collected from camels and humans in laboratories based at the Kenya Medical Research Institute here in Kenya, at CDC (Centers for Disease Control and Prevention) in Atlanta, Washington State University in the US and at Hong Kong University,” he says.

Their study reveals that up to 706 per cent of camels have been infected with Mers-Cov by the time they reach adulthood.
“For the first time, we have been able to demonstrate an outbreak of Mers-Cov affecting many different camels in Marsabit. We detected widespread outbreak of Mers-Cov infection affecting 45 per cent of enrolled herds,” he tells HealthyNation.

“Our study showed that young camels get multiple repeated infections during outbreaks, meaning the immunity that they develop may be short-lived or weak, underpinning the need for studies on camel immunity and the need for a camel vaccine,” adds Dr Ngere.

The study by WSU also revealed that three camel herders were infected with Mers-Cov. “However, these people were young and did not have any symptoms at the time we visited them,” he says.

Dr Ngere reckons that because people have not been testing for Mers-Cov there could be even more who have had the virus without being aware of it.

“We are continuing to follow up the camels and people and also study patients in major hospitals in northern Kenya who have respiratory illness to see if any of them could be infected with Mers-Cov. For now, we think this variant is not easily transmissible to humans and may not cause severe disease,” says the researcher.

He says the variant they tested was different from the Saudi strain, but equally lethal. “The virus we obtained from Kenyan camels was very slightly different from the variants in the Middle East and the rest of Africa,” he says. “But, the fact that there are many camel infections yet few human infections is to be approached with caution."