Thinking about the next pandemic keeps many researchers busy.
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Peter Zeray Images/Getty Images
Thinking about the next pandemic keeps many researchers busy.
Peter Zeray Images/Getty Images
Just three years ago, on January 30, 2020, the Director-General of the World Health Organization made a milestone declaration: The ‘novel coronavirus’, first identified in China, has now escalated into a ‘Public Health Emergency of International Concern (PHEIC)’.
The virus currently known as SARS-CoV-2, which causes COVID-19, is still widespread. But for those who study infectious diseases, it is necessary to talk about the possibility of the next pandemic.
Hidden Viruses: How Pandemics Really Start
NPR is running a series on spillover viruses. This is when animal pathogens jump into humans. Researchers thought spillovers were rare occurrences. It is now clear that they are happening all the time. This has changed the way scientists look for deadly new viruses. I went to Guatemala and Bangladesh, Borneo and South Africa to find out more.
Questions about spillovers should be sent to [email protected] with “Spillover” in the subject line. I’ll answer your questions in a follow-up post when the series concludes in his mid-February.
That is why the World Health Organization maintains a list of viruses and bacteria with pandemic potential. Jill Weatherhead The Baylor College of Medicine professor said disease prioritization is generally based on two factors.
This list will help scientists, governments, and organizations invest energy and money to study the pathogens most likely to cause the greatest devastation to humans. Developed by WHOBlueprintIt shows strategic goals and research priorities for each disease on the list.
The diseases currently on the list are: A revised list is expected in the coming months. Late 2022the World Health Organization convened more than 300 scientists to evaluate and update the list.
NOTE: Infrastructure for disease detection varies in different parts of the world, as does the fact that mild cases of disease may not be known or reported. Fatality rates are based on best available data.
Nipah virus
Which animal carries it: Flying foxes, including those called flying foxes, and farm animals such as pigs, horses, cats, and dogs
How it spreads: Nipah virus can be transmitted to humans from animals or contaminated food. It can also be transmitted directly from person to person.
Its Toll: 40% to 75% lethality. The virus can also cause encephalitis, or swelling of the brain.
Medical toolbox: There are no vaccines for humans or animals. Monoclonal antibody therapy is under development.
Pandemic Potential: Although parts of Asia experience outbreaks almost every year, there are known ways to prevent the spread of the virus. Prevention efforts include avoiding contact with bats and sick animals, avoiding eating fruit that bats may have nibbled on, and not drinking certain raw juices from fruits eaten by bats. . Washing these fruits and fruit products thoroughly and peeling them before eating can reduce the risk of cross-border transmission.
Crimean-Congo hemorrhagic fever
Which animal carries it: mites, livestock
How it spreads: Humans usually get the virus from contact with ticks or infected livestock. Acquiring the virus from another person requires close contact with the blood or other bodily fluids of an infected person.
Its Toll: 10% to 40% fatality rate. The disease is endemic and occurs regularly in Africa, the Balkans, the Middle East and Asia. This virus causes severe outbreaks of viral hemorrhagic fever. This is a condition that can damage the body’s organ systems and cardiovascular system and is often accompanied by severe bleeding.
Medical toolbox: The vaccine is used in Bulgaria, but no studies have been published on its efficacy and it is not licensed in other countries. Other vaccines are in development, and an antiviral drug called ribavirin appears to help treat infections.
Pandemic Potential: Determining when an animal is infected is difficult and should be avoided, and the WHO says ticks that carry the virus are numerous and widespread. Avoiding tick bites and wearing gloves and other protective clothing when near livestock can reduce the threat.
Lassa fever
Which animal carries it: Mice and other rodents
How it spreads: The virus is endemic in parts of West Africa. Rats excrete the virus, and humans pick up the virus through direct contact with rat urine or feces or by eating contaminated food. It can also spread from person to person through direct contact with secretions (blood, urine, faeces) of an infected person, sexual contact, and in healthcare settings through contaminated equipment.
Its Toll: 1%, but up to 15% in severe hospitalizations. It can be fatal in the third trimester of pregnancy and for the fetus. In addition to death, a common complication is hearing loss, which can be permanent.
Medical toolbox: Although there is no vaccine, ribavirin appears to help treat infections.
Pandemic Potential: Since the primary method of transmission is exposure to certain types of rats, the potential for the disease to spread is most likely limited to countries where rats live.
rift valley fever
Which animal carries it: mosquito. Insects can transmit viruses to both humans and their offspring. Livestock such as cattle, sheep, goats, buffalo, and camels can also become infected.
How it spreads: It spreads to humans through contact with the blood, other body fluids, or tissues of infected animals.
Its Toll: Although the case fatality rate is less than 1% and the illness is mild for most people, about 8% to 10% of those infected develop severe symptoms such as eye lesions, encephalitis, and hemorrhagic fever.
Medical toolbox: A vaccine is being developed, but not yet licensed or available.
Pandemic Potential: Rift Valley fever has spread from Africa to Saudi Arabia and Yemen. Flooding appears to be contributing to the increase in Rift Valley fever as the number of mosquitoes infected with the virus increases after heavy rains. Rapid case detection, including rapid laboratory testing of symptomatic people, has limited recent outbreaks.
Zika fever
Which animal carries it: mosquito
How it spreads: In addition to being bitten by mosquitoes, the virus can be spread from a pregnant person to an unborn child. The disease can also be transmitted through sex and possibly blood transfusions.
Its Toll: Although rarely fatal, Zika can cause severe brain damage, including microcephaly, in fetuses. It is also associated with miscarriage, stillbirth and other birth defects.
Medical toolbox: No cure, no vaccine
Pandemic Potential: So far, it has been confined to areas inhabited by Zika-carrying mosquitoes.
Ebola and Marburg disease
Animals that carry them: Bats and non-human primates are thought to harbor viruses of the Filoviridae family that cause these hemorrhagic fevers.
Diffusion method: Both viruses are believed to spread equally. After the initial spillover from animals, humans spread the virus to others through direct contact with the blood and other bodily fluids of symptomatic or deceased persons. The virus can also be spread through objects and surfaces contaminated with bodily fluids and through the semen of people who have recovered from an illness.
Their Toll: The average case fatality rate is about 50%, but has ranged from 25% to 90% in past outbreaks.
Medical toolbox: Vaccines are in use against Ebola in Guinea and the Democratic Republic of the Congo. A monoclonal antibody approved by the Food and Drug Administration in 2020 could also help treat Ebola. A Marburg virus vaccine is under development.
Pandemic Potential: These viruses can spread rapidly in healthcare settings, especially if proper sterilization is not used.
MERS (Middle East Respiratory Syndrome)
Which animal carries it: camel
How it spreads: After the initial camel-to-human transmission event, the coronavirus can spread from person to person through close contact with an infected person.
Its Toll: According to WHO, the reported case fatality rate is 35%.
Medical toolbox: Several vaccines are in development, but none have been approved.
Pandemic Potential: Since 2012, 27 countries have reported infections. Unlike SARS-CoV-2, the coronavirus that causes MERS multiplies deep in the respiratory tract, making it much less likely to be transmitted by sneezing or coughing.
SARS (severe acute respiratory syndrome)
Which animal carries it: Civet cats were the main cause of the 2003 epidemic. Bats and other wildlife also carry it.
How it spreads: After an initial animal-to-human spillover event, SARS can spread from person to person through close contact with an infected person. It is usually thought to be spread through droplets from coughs and sneezes, and can also be spread through surfaces touched by an infected person.
Its Toll: Less than 1% fatality rate
Medical toolbox: There are no approved treatments or vaccines.
Pandemic Potential: Unlike SARS-CoV-2, which can spread before people know they are infected, this SARS virus is usually only spread by people with known symptoms, so it can be contained through public health measures such as quarantine. much easier. The 2003 outbreak was contained after causing approximately 8,000 cases and 700 deaths in 29 countries.
disease X
The WHO says it does not rank the diseases in order of potential threat, but acknowledges that as-yet-unknown diseases can cause severe pandemics.
of Her research on bat virusesFor example, Cornell University’s Raina Plowright says that animals carry thousands of viruses, even in a small fraction of the bat species studied. “We don’t have the technology to take the sequence and determine for sure if it’s contagious or if it’s passed from person to person. We’re really blind.”
It goes without saying that subspecies pose a threat, she says. “A very small genetic change can have a big impact. [a pathogen] Efficiently infected with 50% lethality?”
Sheila Mulrooney Eldred is a freelance health journalist from Minneapolis. She has written about her COVID-19 in many publications including: new york timesKaiser Health News, Medscape, Washington Post. more sheilaeldred.pressfolios.com. on Twitter: @milepostmedia.
