The MERS virus may be coming back

The first case of MERS was confirmed in 2012.
Over the next nine years, the virus that causes the disease has infected about 6,000 people, killing 2,000 of them.
Such a high death toll is striking for a virus that has yet to evolve the ability to transmit effectively from person to person, and scientists cannot rule out the possibility of widespread human-to-human transmission in the future.
We still don’t have an effective vaccine or drug for it.
Worse, as the climate warms, the chances of the virus spreading widely among humans are rising sharply.

Millicent Minayo is not the first person to be kicked by a camel.
These seemingly benign mammals can become extremely irritable.
Don’t believe it?
Try taking a nasal swab.
“It will kick you,” Minayo said. “It will spit at you.
It also piss on you.

“Anyone who comes into contact with them can get infected.”

Minayo has long studied camels in Marsabit, Kenya.
The large animals that roam the desert carry an almost invisible danger: the Middle East Respiratory Syndrome (MERS) coronavirus.
Unlike the novel coronavirus (SARS-CoV-2) that recently ravaged the world, MERS has a fatality rate of more than 30 per cent.
According to the World Health Organization (WHO), about 35 percent of those infected with MERS have died.
By contrast, the fatality rate for novel coronavirus infections is less than 3% in most countries.

The MERS virus, first identified in Saudi Arabia in 2012, infected nearly 1,000 people and killed at least 300 in just two years.
Fortunately, the virus does not appear to spread from person to person unless there is close contact.
At present, the MERS virus is most commonly transmitted from camels to humans, which could explain the more severe MERS outbreak in the Middle East.

So far, MERS has been transmitted from camel to camel, from camel to camel and from person to person in countries and regions.

But here’s the bad news: Recent analysis suggests the MERS virus may be making a comeback.
The culprits behind this are humans themselves.

The spread of drought

Animals are “natural storage pools” for coronaviruses.
Coronaviruses, including the novel coronavirus, SARS and MERS viruses, have in some ways jumped from animals to human populations.
The most likely source of the novel coronavirus is bats, as is the MERS virus.
Published in the journal of virology a traceability paper combines evidence, obtained “with MERS virus virus to recent evolutionary relationship with bat from the long-term living in Africa” in the conclusion, and collection of evidence to suggest that serum from camel, the virus has originated from the bats in the Middle East more than the camel body existed for more than 20 years.
The analysis showed that camels, the intermediate host, had already transmitted the MERS virus to camel breeders around 2010.

Once in the body, the MERS virus first infects epithelial cells inside the bronchus.
At first, because of the MERS and SARS viruses’ similarity, immunologists thought they were invading human cells using the same receptor, the type 2 angiotensin-converting enzyme receptor.
However, after the failure of drugs to block the binding of the MERS and ACE2 receptor, scientists discovered that the MERS virus uses a type 4 dipeptidylpeptidase (DPP4) receptor, which is very similar in bats, camels and humans. It is not surprising that MERS can invade human cells.
The body’s defence against viruses is highly dependent on interferon;
After the cell is infected by the virus, can secrete interferon rapidly, make the cell expression around antivirus protein, block the pace that virus infects diffuses.
But the MERS virus effectively neutralizes the interferon secreted by cells, causing this first line of defense to collapse, which is one reason MERS is so deadly.
And that’s all thanks to the long evolution of the virus in bats.

Predictably, such a zoonotic virus requires prolonged contact between humans and host animals to spread, and Africa and the Middle East provide the perfect conditions for the virus to do so.
These areas naturally have high numbers of camels, high density, and long contact with humans.
There are more than 3 million camels in Kenya alone, and 10 times that number in the world.
Masabit, who work in Minayo alone, has more than 224,000 camels, just over twice the official population of 460,000.

Unlike the rest of Kenya, Masabit has no developed tourism industry and 80 percent of its residents live below the poverty line.
This has indirectly led to the local people’s reliance on livestock such as camels.
In Massabit, camels are hard currency, used as dowries and for children’s education.
But in recent years, local residents’ degree of dependence on camels grow only: years of drought of thirst for many other animals, only a camel standing – these huge animals have special, for desert “customize” the fluid system, so it is highly resistant to water, when the loss of water equal to 30% of the weight can survive;
Not only that, they also have highly efficient insulation and thermoregulation systems.
Under the influence of the drought, local people have gradually shifted their livestock from other animals, which are prone to thirst, to camels in order to ensure their economic income.

In Massabit, in northern Kenya, the wasteland is littered with animal bones.
Many of the moors were once lush pastures.
(Credit: Anthony Irungu)

Droughts, which are becoming more common, have boosted residents’ reliance on camels, increasing their exposure to them.
Higher dependence means more people use camels as “hard currency”.
As a result, the Masabit often have to travel from village to village with their camels, which makes it easier for the camels to come into contact with the wild animals that live between villages.
“Diseases can go from wild animals to camels, and then from camels to humans,” said Dawn Zimmerman of the Global Health Program. “Those diseases are always out there in the wild.
Given the opportunity, they can spread [across species].”

Both Zimmerman and Minayo are members of the PREDICT project, of which Zimmerman is the leader of the Kenyan branch.
Over the past several years, the Forecast Project has studied zoonoses in more than 30 countries worldwide and has identified 1,166 zoonotic viruses, of which only 217 are animal viruses previously known to infect humans.

The invisible “killer”

The scientists involved in the prediction project need to be fully armed when sampling.
Goggles are a must, not to mention masks and full-body dust suits.
Of course, they also need to wear protective masks, rubber boots and gloves to do everything they can to minimize the risk of infection.

None of this equipment is available to the locals, leaving the camel-dependent population exposed to countless invisible killers.
“Camels can sneeze, they can cough,” Minayo said. “Unlike humans, camels don’t wear masks.”
The MERS outbreak in Saudi Arabia alone in 2018 infected nearly 200 people and killed 56 — a staggering number for a virus that has yet to transmit effectively from person to person.

While many experts assumed for years after MERS was identified that the virus would not evolve the ability to transmit effectively from person to person in the short term, scientists have identified several mutations that the virus has made so far that may be associated with greater pathogenicity and infectivity.
Therefore, all the evidence shows that there has not yet been a large-scale human-to-human transmission, and the academic community can not rule out the possibility of such a phenomenon in the future.
“You never know what the next mutation will bring,” Dr. Zimmerman said. “That’s why it’s so important to fund research.”

The Masabit’s reliance on camels has increased with each passing year.
(Credit: Jacob Kushner)

In addition to promoting research on zoonoses, it is also important to educate people at high risk and to provide protective devices.
Marsabit residents rely on camel’s milk: “camel’s milk is everything”.
Many local people rely on camel milk to buy things.
They drink camel’s milk, use camel’s milk to make milk tea, and sell camel’s milk for money.
While milking, however, Marsabit residents do not wear gloves and often have no gloves to wear.

Opportunities for contact with camels do not end there, of course.
Camels, like most livestock, eat grass.
In order to find grass for the camels in the increasingly arid wilderness, they have to travel with their camels for days without returning home.
Every night out, these camel owners need to sleep on their camels to keep warm.
In the daytime, camel breeders live on camel milk.
The equipment is so heavy that camel milk can only be drunk raw — the norm for local camel breeders.
Of course, these journeys come with the risk of the deadly spread of MERS from camels to camel owners.

“We tell them [locals] what to do to protect themselves,” said Dub Wato, a local colleague of Minayo’s. “Like avoid close contact;
If you have to, wear a mask.
After close contact, wash your hands and disinfect them — no different from fighting SARS.”
In addition, boiled milk is also an important defense against MERS: Rraw milk can contain a variety of zoonotic viruses carried by camels, and high temperatures inactivate all known viruses.

The PREDICT team sampled a camel.
(Credit: Jacob Kushner)

Scientists are doing what they can to prevent the next outbreak: sending more doctors and researchers to high-risk areas, sampling camels to prevent widespread infection, educating locals about the disease.
These are necessary and effective preventive measures, but the problem may not be so simple.
As mentioned above, years of drought have made camels more accessible and exposed for longer to communities that depend on them.
Another result of the drought is that it has lengthened the journey that camel breeders make with their camels to find grass.
According to a Kenyan government report, “the frequency of droughts has increased to one every one to three years,” while the United Nations expects Kenya’s temperature to rise by 2 degrees Celsius by 2050.
So for the foreseeable future, camel owners are only going to spend more time with camels.

In the meantime, hungry camel breeders on the journey still have to eat raw meat from thirsty camels.

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