At this year's World Economic Forum in Davos, held from January 14 to 19, a panel of health industry leaders pulled away from economics to discuss pre-planning for a hypothetical outbreak of "disease X."
Disease X is the World Health Organization (WHO) designation for an unknown infectious disease capable of causing an epidemic or pandemic. The idea is to be prepared so that when disease X does strike – which is inevitable – scientists are ready to roll out a vaccine quickly.
In fact, in 2018, WHO added disease X to its blueprint list of priority pathogens. The blueprint is a list of diseases that WHO urgently needs to accelerate research and development. The list will be updated again in 2024.
According to the World Health Organization, "X-disease represents the knowledge that a serious international epidemic may be caused by a pathogen of a currently unknown causative human disease."
While disease X is not yet known, what other diseases do WHO and other disease experts believe are most likely to cause the next pandemic? Let's find out.
The two diseases on WHO's Blueprint 2018 list are Middle East respiratory syndrome coronavirus (MERS-CoV) and severe acute respiratory syndrome (SARS), which have jumped from animals to humans and caused severe outbreaks over the past two decades.
We all know what happened in 2020, so it makes sense that the next pandemic could be another coronavirus.
In fact, all the debate about whether COVID-19 (SARS-CoV-2) escaped from a lab or came from animals somewhat obscures the fact that viruses and other pathogens have jumped from other animals to humans quite regularly.
Moreover, neither MERS nor COVID-19 is actually over. Wastewater data suggests that COVID-19 numbers are between 2 and 19 times higher than those officially reported.
As Dr Maria van Kerkhove, Head of WHO's Emerging Diseases and Zoonoses Unit, reminded at a press conference in January, the COVID-19 pandemic continues, officially killing around 10,000 people per month. However, since only a very small number of countries are still reporting deaths, the actual number is likely to be higher.
Van Kerkhove also noted that 6 to 10 percent of infected people will continue to have long-term effects. Perhaps even more worrying is that "the virus is spreading unscrupulously around the world, and we can emerge at any time a variant that will increase in severity."
Hemorrhagic fevers like Ebola (pictured) are scary, but fortunately do not spread quickly.
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Crimea-Congo (CCHF) is caused by a tick-borne virus (Nairovirus). A variety of wild and domestic animals, including cattle, sheep, and goats, can be reservoirs for ticks, and the virus is transmitted to humans through tick bites or contact with the blood of infected animals. Person-to-person transmission can also occur through close contact with the bodily fluids of an infected person.
Initial symptoms include fever, dizziness, headache, nausea, vomiting, diarrhea, and confusion. After two to four days, symptoms progress to drowsiness, hepatomegaly, severe rash, and mucosal bleeding. About 30% of those infected die.
The disease is endemic in Africa, the Balkans, the Middle East and Asian countries south of the 50th parallel, but there are concerns that a warming climate could expand the range of ticks.
Because of this risk, the UK is a country that struggles to prevent the possible spread of CCHF. They established vaccine development and evaluation centers to develop vaccines against potential future epidemics, including CCHF. A CCHF vaccine has entered phase I clinical trials.
Other types of hemorrhagic fevers, such as Ebola and Marburg, are even more deadly, but they tend not to spread to large populations.
One explanation for this is that the mucosa of the upper respiratory tract has been found to be much more susceptible to coronaviruses such as COVID-19 than Ebola. This allows the coronavirus to enter the host cell more quickly and spread the virus faster, leading to wider spread.
The Ebola virus is also not transmissible until symptoms appear, and can only be transmitted through direct contact with the bodily fluids of an infected person. Since it is fairly obvious when someone is infected with the Ebola virus, it is relatively easy to take precautions.
Measles paramyxovirus spreads easily and can be dangerous, but luckily there is a vaccine against it. singjai20 istock
Paramyxoviruses are a family of single-stranded RNA viruses that primarily cause infections in vertebrates. Various paramyxovirus diseases were once common. Diseases caused by subgroups include measles, mumps, parainfluenza virus, respiratory syncytial virus, and henipavirus (e.g., Nipah virus and Hendra virus).
Although paramyxoviruses have plagued humans for a long time, researchers still don't know how they get into new species, what mutations they need to become more transmissible, or why some paramyxoviruses produce only mild symptoms while others are deadly.
Paramyxoviruses, such as the flu and coronavirus, spread quickly in the air, but are usually easy to vaccinate. One exception is Nipa, the deadliest paramyxovirus, which emerged in Malaysia in the late 1990s and has a natural host in fruit bats.
Nipah virus causes respiratory illness and can progress to encephalitis and death, killing 45% to 75% of those infected. Although Moderna has developed a vaccine that is currently being evaluated, there is currently no licensed vaccine.
The flu is a tragic annoyance, but it has also proven deadly. Helaman istock
Most of us are familiar with the flu. It is a contagious respiratory illness caused by the influenza virus that can infect the nose, throat, and sometimes lungs, causing high fever, muscle or body aches, headaches, fatigue, and other symptoms. In healthy adults, it may be mild, but it also causes up to 650,000 deaths worldwide each year.
Most experts believe that the flu virus is mainly spread through tiny droplets produced when a person with the flu coughs, sneezes, or talks. These droplets can land in the mouths or noses of nearby people. Less commonly, a person may get the flu by touching a surface or object that has the flu virus on it and then touching their mouth, nose, or eyes.
Every year, the influenza virus mutates. While not on WHO's blueprint (in part because there are already significant resources dedicated to fighting influenza), influenza has led to past pandemics.
In 1918, a deadly influenza subtype called H1N1 led to a pandemic that could have killed up to 50 million people. That outbreak began as a milder form of the disease and quickly progressed into a more deadly form.
Although the H1N1 outbreak subsided after about two years, it was not the end of the deadly influenza epidemic.
1957 and 1968 (so-called "Hong Kong" flu; influenza A virus subtype H2N2) has led to an outbreak of another deadly influenza subtype (the so-called "Hong Kong" flu; The H3N2 strain of the influenza A virus, which is a descendant of H2N2), killed about 2 million people each time.
Avian influenza is another family of viruses associated with influenza that birds can transmit to humans, but rarely from person to person. It is divided into multiple subtypes (i.e., H5N1, H5N3, H5N8, etc.) and its genetic characteristics evolve rapidly.
Currently, it mostly kills birds, but if the virus mutates and can easily spread from person to person, it could be a good candidate for the next pandemic.
Mosquitoes can transmit Rift Valley fever and other diseases.
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This is another animal-borne disease that can be transmitted to humans through mosquitoes and blood-sucking flies, contact with the blood or organs of infected animals, or through ingestion of unpasteurized or undercooked milk from infected animals. This means that pastoralists, farmers, slaughterhouse workers and veterinarians are most at risk.
In humans, it can be a mild flu-like illness or a severe and fatal illness.
Although the disease was once confined to Africa, Saudi Arabia and Yemen have reported 2,000 cases.
Although human-to-human transmission does not appear to be happening, if these changes or disease-carrying ticks spread to other regions with global warming, Rift Valley could be a candidate for the next pandemic.
Currently, the Zika virus poses the greatest danger to unborn children.
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First identified in Uganda in 1947, Zika virus is a mosquito-borne virus that has been transmitted from animals to humans.
While most people infected with Zika virus either have no symptoms or only mild symptoms, infections during pregnancy can cause babies to be born with microcephaly (smaller than the normal head size) and other congenital malformations. The virus has also been linked to Guillain-Barre syndrome, neuropathy, and myelitis in children.
While Zika cases have declined globally since 2017, transmission remains low in Zika-endemic areas. Although 89 countries and territories have reported evidence of mosquito-borne Zika virus infection, global follow-up is limited.
There is currently no specific** method for Zika virus infection or disease.
Lassa fever is usually spread through food contaminated with rat urine or feces.
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Lassa fever is an acute viral bleeding disorder. It is endemic in some countries in West Africa, including Benin, Ghana, Guinea, Liberia, Mali, Sierra Leone, and Nigeria. Although it is a viral bleeding disorder, such as Ebola or Marburg, it has a much lower mortality rate than these diseases.
However, in some parts of Sierra Leone and Liberia, 10 to 16 per cent of hospitalized patients suffer from Lassa fever each year. This means that it has severely affected people, healthcare, and businesses in these areas.
Lassa fever is spread through food or household items contaminated with urine or feces from infected rodents. Person-to-person transmission can also occur through secretions from infected people. The mortality rate of hospitalized patients with severe Lassa fever is about 15%.
The good news is that the antiviral drug ribavirin has been used successfully for this disease. However, it is still possible for the disease to mutate into a more dangerous or resistant form.
Will the next pandemic come from**?
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As we can see, this is an unknown disease, there is no way to know when and where it may appear, only history tells us that it will eventually appear.
Recently, scientists have warned that an ancient virus frozen in the Arctic permafrost could be released as the climate warms and cause a pandemic. Researchers have isolated some of these so-called zombie viruses or Methuselah viruses, proving that they do exist.
Marion Koopmans, a virologist at Erasmus Medical Centre Rotterdam, was quoted in a recent Guardian article and explained: "We don't know what virus is lying in the permafrost, but I think there's a real risk that there could be a virus that can cause disease outbreaks – like an ancient form of polio." We have to assume that something like this could happen.
In fact, researchers are planning to develop an Arctic surveillance network to track the diseases caused by ancient microbes as soon as they appear.