The 9 killer viruses that pose greatest pandemic threats – from ear-bleeding fever to camel ‘flu’

WORLD leaders are convening this week to discuss concerns about the incoming pandemic.

Officials are coming together in Switzerland to discuss Disease X, a hypothetical, currently unknown pathogen.

It comes as the World Health Organisation (WHO) warned the disease could kill 20 times more people than the Covid-19 pandemic did.

Scientists have also said that Disease X is “as infectious as measles with the fatality rate of Ebola” and that preparations had started.

The  has reported that the WHO feels it “is more of a probability rather than possibility” that it will hit.

Kate Bingham, a former chair of the UK vaccine taskforce, said we may look back at the Covid pandemic like a "walk in the park.

"In a sense, we got lucky with Covid-19, even though it caused 20 million or more deaths worldwide.

“The point is that the vast majority of people infected with the virus managed to recover,” she told the . 

Kate added: "Imagine Disease X is as infectious as measles with the fatality rate of Ebola [67 per cent].

"Somewhere in the world, it’s replicating; sooner or later, somebody will start feeling sick.

"We need to take the first steps in dealing with the next pandemic right now - and that involves putting money on the table.”

What could the next pandemic be?

The WHO has compiled a list of animal viruses capable of infecting humans, known as the nine “”.

These diseases are believed to pose the "greatest public health risk due to their epidemic potential".

Disease X was added to the WHO's list of nine priority diseases in 2018.

Experts do not yet know what type of virus will trigger the next killer outbreak, but scientists have suggested that bird flu is the most likely contender.

The bug, which has been  for quite some time, is now regarded as a top threat for the next human pandemic.

Last year, the Sun revealed health officials had drawn up plans to stockpile vaccines in case of a bird flu pandemic in humans.

Four people in the UK tested positive for the bug last year.

According to United Nations agency, an updated threat list is now expected during the first half of 2024.

Here are the nine known pathogens global public health officials are currently keeping a watchful eye on:

1. Ebola and Marburg

Ebola and Marburg are severe and highly infectious viruses that come from bats and kill many they infect.

There have been several large outbreaks of both bugs in Africa over the last few years.

Both begin abruptly, with high fever and a severe headache.

Many patients develop severe haemorrhagic symptoms, including bleeding from bodily orifices, like the eyes, ears or internal organs.

On average, Ebola kills about 50 per cent of those it sickens, though case fatality rates have ranged from 25 per cent to 90 per cent, .

Marburg also kills around 50 per cent of those it infects, though case fatality rates range from around 24 per cent to 88 per cent, experts say. 

People can get infected with Ebola or Marburg viruses if they touch or handle items that have been in contact with an infected person.

2. Crimean-Congo hemorrhagic fever

Crimean-Congo haemorrhagic fever (CCHF) is a deadly tick-borne virus, endemic in places with warmer climates, such as Africa, the Balkans, the Middle East and Asia.

The disease, which is spread by ticks, kills up to 40 per cent of those who catch it, according to the WHO.

CCHF symptoms include fever, muscle ache, dizziness, light sensitivity and vomiting, and it can lead to organ failure and internal bleeding.

Scientists fear the disease could expand out of its usual territories and move towards Britain and France due to global warming.

3. Lassa fever

Lassa fever is an acute viral haemorrhagic illness which can lead to internal bleeding and affect multiple organ systems.

People usually contract the bug by being exposed to food or items covered in rat urine or faeces.

But it can also be spread through infected bodily fluids.

The virus - in the same family as Ebola, but not as deadly or infectious - has become endemic in a number of West African countries.

Most people with Lassa Fever make a full recovery, but some people can get severely ill.

Some people can experience a fever, physical fatigue, nausea, vomiting, diarrhoea, headaches, abdominal pains or sore throat.

It originated in the town of Lassa, northern Nigeria, which is its' namesake.

4. Severe Acute Respiratory Syndrome (SARS)

Severe acute respiratory syndrome (SARS) is a viral respiratory caused by the coronavirus, which also caused Covid-19.

Like other respiratory bugs such as flu and the common cold, SARS affects the airways in the lungs.

Symptoms can include a headache, body aches, mild respiratory symptoms, possible diarrhoea, an eventual dry cough, and pneumonia in most.

It's passed on through respiratory droplets produced when a person with the virus coughs or sneezes, or by contact with objects or surfaces containing the virus.

SARS showed how quickly infection can spread during its first reported outbreak in Asia in February 2003.

Over the next few months, the illness reached more than two dozen countries in North America, South America, Europe, and Asia before the SARS global outbreak of 2003 was contained. 

A total of 8,098 people worldwide became sick, and of these, 774 died.

Scientists say it is highly likely that the virus jumped from bats to cat-like civets before infecting humans.

A spillover could happen again.

5. Middle East respiratory syndrome coronavirus (MERS)

Middle East respiratory syndrome coronavirus (MERS), is a virus transmitted to humans via camels, hence the nickname, camel flu.

Most cases are reported in the Arabic world, but some have been discovered elsewhere - including one in the UK in 2018.

Its symptoms can range from mild to severe, including fever, cough, pneumonia and gastrointestinal issues.

The bugs kills about a third (35 per cent) of those infected, according to the WHO.

MERS was first identified by scientists in Saudi Arabia in 2012, and has since resulted in over 2,605 infections and 936 deaths.

6. Covid (SARS-CoV-2)

Coronavirus disease, or Covid-19, is an infectious disease caused by the SARS-CoV-2 virus. 

The first known case was identified in Wuhan, China, in December 2019.

The disease quickly spread worldwide, resulting in the Covid -9 pandemic, which led to at least seven million known deaths.

While the public health emergency of international concern (PHEIC) status was dropped in May 2023, WHO could always reinstate it if a new, more dangerous variant emerged.

Experts have recently warned the most recent variant, JN.1 could be the "biggest yet" due to several new mutations which make it better at spreading.

Most people infected with the virus will experience mild to moderate respiratory illness, much like flu or the common cold, and recover without requiring special treatment. 

However, some will become seriously ill and require medical attention.

7. Nipah

Experts have warned that Nipah, a virus that spreads from fruit bats or livestock, could also be the next pandemic.

The bug inspired the blockbuster film Contagion about a global pandemic.

It attacks the brain, causing it to swell and has a fatality rate up to 75 per cent.

Of those who survive it, around 20 per cent are left with long-term neurological conditions, including personality changes or seizure disorders.

It was first identified in pigs in Malaysia and Singapore in the late 1980s, though it originally came from fruit bats.

The virus predominantly affects Bangladesh, where outbreaks occur almost every year.

Last year, between January 4 and February 13, a total of 11 cases of Nipah, including eight deaths, were reported in the country.

Other regions at risk of infection include Cambodia, Ghana, Indonesia, Madagascar and Thailand.

8. Rift Valley fever

Rift Valley fever (RVF) is a viral disease primarily affecting domestic animals such as cattle, buffalo, sheep and goats.

But it can spread to humans via mosquitos or eating infected meat.

In humans, the disease ranges from a mild flu-like illness to severe haemorrhagic fever that can be lethal.

No human-to-human transmission of RVF has been documented. 

9. Zika virus

Zika virus is mainly spread by mosquitoes in certain parts of the world, including South and Central America, the Caribbean, the Pacific islands, Africa and Asia.

Most people with Zika virus infection do not develop symptoms.

Those who do typically have symptoms including rash, fever, conjunctivitis, muscle and joint pain, malaise and headache that last for a few days.

Severe diseases requiring hospitalization and deaths are uncommon.