On the way to the next pandemic

With the Covid-19 pandemic heading for a vaccine showdown that it is likely to lose, many experts in the field of emerging infectious diseases are already focused on preventing the next one.

They fear another virus leaps from the animal kingdom into humans that is far more deadly but spreads just as easily as SARS-CoV-2, the strain of the coronavirus that causes Covid-19. Such a virus could change the path of life on the planet, experts say.

“What keeps me up at night is that another coronavirus like MERS, which has a much, much higher mortality rate, is becoming as transmissible as Covid,” said Christian Walzer, Executive Director of Health at the Wildlife Conservation Society. “The logistics and the psychological trauma would be unbearable.”

SARS-CoV-2 has an average death rate of less than 1%, while the death rate for the Middle East Respiratory Syndrome (MERS), which spreads from camels to humans, is 35%. Other viruses that have crossed the species barrier for humans, such as bat-borne nipah, have a mortality rate of up to 75%.

“There are a wide variety of viruses in nature and the possibility exists of having the goldilocks traits of pre-symptomatic transmission with a high death rate,” said Raina Plowright, viral researcher at the Bozeman Disease Ecology Lab in Montana. (Covid-19 is highly transmissible before symptoms appear, but luckily it is far less deadly than some other known viruses.) “It would change civilization.”

For this reason, the Federal Foreign Office and the Wildlife Conservation Society hosted a virtual conference called One Planet, One Health, One Future in November to help tackle the next pandemic and convey to world leaders that killer viruses like SARS-CoV -2 – and many other less deadly pathogens – are unleashed into the world through the destruction of nature.

In light of the global attention drawn by the spread of the coronavirus, infectious disease experts are redoubling their efforts to reveal the robust link between the health of nature, wildlife and humans. It’s a concept known as One Health.

Although the idea is widely accepted by health officials, many governments have not included it in politics. Therefore, the conference was timed to coincide with the meeting of the world’s economic superpowers, the G20, to urge them to recognize the threat that wildlife pandemics pose not only to people but also to the global economy.

The Wildlife Conservation Society – America’s oldest conservation organization founded in 1895 – has partnered with 20 other leading conservation groups to urge government leaders to “prioritize the protection of highly intact forests and other ecosystems, and specifically to work to encourage commercial trade and the markets for wild animals to end human consumption as well as all illegal and unsustainable trade in wild animals, “reads a recently published press release.

Experts predict that implementing these and other measures would cost about $ 700 billion, according to the Wildlife Conservation Society. On the other hand, Covid-19 has cost an estimated $ 26 trillion in economic damage. Additionally, the solution offered by those advocating the One Health Goals would also mitigate the effects of climate change and loss of biodiversity.

The increasing invasion of natural environments as the world’s population grows makes another deadly pandemic a question of when and not if, experts say – and it could be far worse than Covid. The spread of animal or zoonotic viruses to humans causes around 75% of newly emerging infectious diseases.

But a variety of unknown viruses, some of which may be highly pathogenic, live in wildlife around the world. Infectious disease experts estimate that there are 1.67 million viruses in nature; only about 4,000 have been identified.

SARS-CoV-2 likely originated from horseshoe bats in China and was then transmitted to humans, possibly via an intermediate host such as pangolin – a scaly animal that is often hunted and eaten.

While the source of SARS-CoV-2 is uncertain, the animal-to-human route has been known for other viral epidemics, including Ebola, Nipah, and MERS. Viruses that circulate in wildlife and mutate in wildlife, especially bats, which are numerous and highly mobile around the world, leap into humans where they find a susceptible immune system and cause a deadly outbreak of infectious diseases.

“We have gone deeper into environmental zones that we had not previously occupied,” said Dennis Carroll, a seasoned emerging infectious disease expert with the US Agency for International Development. He sets up the Global Virome Project to catalog viruses in wildlife to predict what could trigger the next pandemic. “The flagship for this is the raw materials industry – oil and gas and minerals – and the expansion of agriculture, especially cattle. That’s the biggest predictor of where you’ll see an overflow. “

When these things happened a century ago, the person who contracted the disease likely died there. “Now an infected person can be on a plane to Paris or New York before they know they have it,” he said.

Meat consumption is also increasing, and that means either more domestic animals raised in cleared forests or “bushmeat” – wild animals. Both can lead to overflow. The AIDS virus is believed to originate from wild chimpanzees in central Africa that were hunted for food.

A case study of how viruses turn from nature to epidemic is the Nipah virus.

Nipah is named after the village in Malaysia where it was first identified in the late 1990s. Symptoms include brain swelling, headache, stiff neck, vomiting, dizziness, and coma. It is extremely fatal, with a death rate of up to 75% in humans compared to less than 1% for SARS-CoV-2. Since the virus never became highly transmittable among humans, it has only killed 300 people in around 60 outbreaks.

A critical feature prevented nipah from spreading. “Nipah’s viral load, the amount of virus someone has in their body, increases over time,” and is most contagious at the time of death, said the plow lawyer at the Bozeman Laboratory who studied Nipah and Hendra. (These are not coronaviruses, but henipaviruses.) “With SARS-CoV-2, your viral load peaks before you develop symptoms. So you’ll be working and interacting with your family before you know you’re sick. “

If an unknown virus, as deadly as Nipah but as transmissible as SARS-CoV-2, jumped from an animal into humans before an infection was known, the results would be devastating.

Plowright has also studied the physiology and immunology of viruses in bats and the causes of spillover. “We’re seeing spillover events due to stresses on the bats from habitat loss and climate change,” she said. “Then they are drawn into human realms.” In the case of Nipah, fruit bats raised in orchards near pig farms passed the virus on to the pigs and then to humans.

“It’s linked to a lack of food,” she said. “If bats could feed in native forests and move nomadically through the countryside to get the food they need, we wouldn’t see an overflow.”

Behind the campaign to raise awareness for One Health there is a growing understanding of ecological changes as the cause of many diseases.

A health policy is being expanded in places where human pathogens are likely to be found in wildlife or domestic animals. Doctors, veterinarians, anthropologists, wildlife biologists, and others are trained and trained to provide sentinel skills to detect these diseases as they occur.

However, the scale of prevention efforts is far smaller than the threat posed by these pathogens, experts say. They need government support to identify the problem and incorporate the cost of any possible epidemic or pandemic into the development.

“A road will make it easier to move goods and people, and create economic incentives,” said Walzer of the Wildlife Conservation Society. “But it will also provide an interface through which people interact and the likelihood of overflow is higher. Such costs were never taken into account in the past. And that has to change. “

The one-health approach also advocates the comprehensive protection of nature in areas with high biodiversity, where overflow is a risk.

Joshua Rosenthal, an expert on global health at Fogarty International Center at the National Institutes of Health, said that while these ideas are conceptually sound, they are an extremely difficult task. “These things are all managed by different agencies and ministries in different countries with different interests, and getting them on the same page is a challenge,” he said.

Researchers say the clock is ticking. “We have high population densities, high livestock densities, and high deforestation rates – and these things bring bats and humans in closer contact,” Plowright said. “We are rolling the dice faster and more often. It is really very simple. “

Kaiser Health News (KHN) is a national health policy news service. It is an editorially independent program of the Henry J. Kaiser Family Foundation that is not affiliated with Kaiser Permanente.


This story can be republished for free (details).

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