Emerging Infectious Diseases: The Threat of Pandemics and Mutations

2023-09-02 03:05:00

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A ‘disaster’ if an influenza mutation with strong human-to-human transmission appears
Corona may also come out with Corona 19 mutations or new species

“The COVID-19 pandemic is neither the first nor the last.” This is a message issued by the Global Vaccine Immunization Alliance (GAVI) warning of an upcoming pandemic. Humans who have invaded animal habitats in the name of development have increased opportunities to come into contact with carriers of infectious diseases such as bats, mosquitoes and ticks. As a result, we are living in an era of infectious diseases that mankind has never experienced, such as COVID-19. The Coalition for Epidemic Preparedness Innovations (CEPI) diagnosed that ‘a new era of infectious diseases has entered’, and the British Medical Journal (BMJ) even published a special article titled ‘What will be the next pandemic?’

For a specific infectious disease to become a pandemic, three conditions must be met. First, it must be a new species that is not immune to humans. In addition, the virulence must be strong enough to cause severe and fatal damage, and the ability to transmit from person to person must be high. An infectious disease that meets these conditions, like Corona 19, can become a pandemic at any time. Kim Woo-joo, professor of infectious medicine at Korea University Guro Hospital, said, “If we combine the three conditions of the pandemic and past experiences, we can predict the future. In other words, an RNA virus that is good at mutating and a respiratory virus that is highly contagious will be the next pandemic, and influenza and coronavirus are likely. Highly pathogenic avian influenza has spread to all continents in the world except for Australia, so it occurs sporadically every year. Swine flu, which was recently reported in the United States and transmitted to humans, is also a candidate for a pandemic. These influenza did not develop into a pandemic because of their weak ability to transmit from person to person, but if a mutant with that ability appears one day, a catastrophic pandemic might come. In addition, the corona virus steadily appeared as SARS and MERS, and eventually became a pandemic as Corona 19. Whether a new species emerges or a major mutation occurs in Corona 19, the possibility of a’second pandemic’ is high,” he warned.

On March 10, 2020, in the early days of the Corona 19 pandemic, the screening clinic installed in Sindolim-dong, Seoul was crowded with people trying to get tested. ⓒ Sisa Journal Park Jeong-hoon

Influenza and coronavirus that mutate every year

Influenza has caused flu every year over the past century and has become a pandemic four times: the 1918 Spanish flu, the 1957 Asian flu, the 1968 Hong Kong flu, and the 2009 swine flu. Experts predict influenza as the greatest risk of causing a pandemic over the next few decades. It has a short incubation period of less than a week, spreads rapidly, and causes many deaths. In particular, avian influenza is likely to become a pandemic. Avian influenza, which originated in wild waterfowl, was originally prevalent only in birds, but one day it found a way to transfer to humans following mutating through poultry such as chickens and ducks and mammals such as pigs. Human-to-human transmission is weak, so it has not become a pandemic. However, since it develops every year, mutations with high human-to-human transmission may emerge one day. Experts are keeping an eye on H5N1 and H7N9 in particular. H5N1 infected 861 people between 1997 and 2019, and 455 people died, recording a fatality rate of 53%.

Considered a low-grade pathogen causing mild symptoms, the coronavirus sent a warning to humans with SARS (Severe Acute Respiratory Syndrome) in 2002 and MERS (Middle East Respiratory Syndrome) in 2012. All of them have infected thousands in more than 20 countries and put many to death. SARS and MERS did not have strong human-to-human transmission power, so they did not become a pandemic and died out. Then, a new mutation with rapid human-to-human transmission appeared in 2019 and maintained the Corona 19 pandemic for more than three years. Hundreds of coronaviruses are currently circulating in animals such as pigs and bats. In fact, 80% of animals from a farm sold in a Chinese wildlife market have been found to have coronavirus antibodies. We do not know what variations may appear in these animals.

Hemorrhagic fever with a fatality rate of up to 90%, a threat to human society

Hemorrhagic fever is an infectious disease accompanied by bleeding and high fever. Hemorrhagic fever has a very high fatality rate, so if it becomes a pandemic, it will be a disaster for mankind. In fact, if the fatality rate is too high, the transmission power is weak because the host dies before it can spread. Therefore, the possibility of becoming a pandemic is reduced. However, the outbreak itself can have a strong enough impact on human society. Examples of such hemorrhagic fevers include Nipah, Ebola, Lassa, Marburg, yellow fever, Crimean-Congo hemorrhagic fever, Chikungunya, and Rift valley fever. There are no vaccines or treatments for most of them.

Nipah virus has been prevalent almost every year in Asia since it was first discovered in pig farms in Malaysia in 1999. In 2018, 19 people were infected and 17 died in India. The fatality rate is as high as 40-70%. The epidemic areas are Bangladesh, India, Malaysia, the Philippines, Thailand, etc. In particular, there is a so-called ‘Nipa belt’ where Nipah frequently occurs on the border of Bangladesh and India. The natural host of nipa is the fruit bat. Because bats frequently come into contact with humans and animals, mutations with strong human-to-human transmission may emerge. Then, one person was found to infect 12 to 18 people. Since the Nipah outbreak is related to pigs and fruit bats, the World Health Organization (WHO) recommends that each country establish a surveillance system for livestock and wildlife.

Ebola, which has a fatality rate of up to 90%, was discovered in 1976 near the Ebola River in Congo. The most recent large-scale outbreak occurred in Guinea, Liberia and Sierra Leone between 2014 and 2016, infecting 28,616 people and killing 11,310. Because the fatality rate is so high, there is little chance of transmission because patients become incapacitated or die in the early stages of infection. In addition, there are vaccines approved by Europe and the United States in 2020, so the possibility of a pandemic is low. However, since the natural host is a fruit bat, no one knows what mutations will emerge. It spreads mainly through bodily fluids from person to person, but in rare cases, it has spread through respiratory droplets. If a mutation that spreads through the respiratory tract becomes the dominant species, it might have a great impact on human society.

During the Ebola epidemic in West Africa from 2014 to 16, deaths from Lassa, which is similar to Ebola, increased one following another in the neighboring country of Benin. The large spread was prevented with the usual training of Ebola countermeasures. Lhasa, first reported in 1969, is endemic to West Africa, infecting 100,000 to 300,000 people each year and killing regarding 5,000. Lassa virus, which has a fatality rate of regarding 35%, is transmitted through human-to-human contact with certain wild mice. It has a long incubation period of up to three weeks and 80% of infected people are asymptomatic, so it is easy to spread around the world through overseas travel. There are cases of influx into the United States and Europe.

Ebola’s cousin, Marburg, also has a fatality rate of regarding 90%. Marburg infection killed 31 people in Belgrade and Germany in 1967 when they collapsed bleeding from their nose and mouth. In Angola in 2004, 90% of the 250 infected people died. Most die within 8-9 days following infection. Even following recovery, the virus can survive in the eyes, testicles, and breast milk. The virus, which was transmitted to humans through bats, green monkeys, and pigs, is transmitted from person to person through blood or bodily fluids. The incubation period is long, ranging from 2 to 21 days, so it can spread worldwide by moving abroad. There are also cases of outbreaks in Europe and the United States. The world’s medical community is keenly aware of the occurrence of Lassa and Marburg mutations that spread through easier ways, such as through the respiratory system.

In March 2020, many shops and restaurants were closed due to the COVID-19 pandemic. ⓒ Sisa Journal Choi Jun-pil

“We need to prepare first before responding to the epidemic of infectious diseases”

Yellow fever, which claimed thousands of lives in Europe, Africa, and the United States in the 19th century, is endemic to Africa and Central and South America, with regarding 90% occurring in Africa. About 200,000 people are infected each year and 30,000 die, with a fatality rate of 20-50%. The problem is that the habitat of Aedes aegypti mosquito, which transmits yellow fever, is expanding. Aedes aegypti mosquito already lives in the Asia-Pacific region, where regarding 2 billion people live. Some experts argue that an epidemic of yellow fever in Asia, where there is no immunity to yellow fever, would be so shocking that Ebola would be nothing. There is a vaccine, but the supply is not large, so when a pandemic occurs in the Asia-Pacific region, a vaccine shortage occurs.

Crimean-Congo hemorrhagic fever (CCHF) drew attention in 2008 when a butcher in Sudan died five days following developing diarrhea and nosebleeds. The main vectors are ticks. It spreads from person to person through blood, bodily fluids, and contact, and there is a risk of airborne infection. In fact, relatives and nurses who were caring for the butcher shop owner, as well as other inpatients and nurses’ families, were also infected. CCHF has been found in Europe, China, Central Asia, Africa, and India. The US National Institute of Allergy and Infectious Diseases has designated CCHF as one of the highest risks to national security and public health.

First discovered in 1952, Chikungunya originally did not affect the northern hemisphere, but has recently begun to be discovered in Asia, Europe and the Americas. In Africa, most cases of chikungunya are infected following being bitten by Aedes gnat, but the problem is that the habitat of Aedes gnat, which carries this virus, is spreading to the northern hemisphere. Aedes aegypti mosquitoes can also be found in forests and residential areas in Korea. Although the fatality rate is low, chronic joint pain can linger for years.

Rift valley fever, which is prevalent in livestock such as cattle, sheep, goats, and camels, is claimed to be a great disaster in itself when passed to humans. Although the fatality rate is less than 1%, this is because it adversely affects the nervous system. A 2019 study found that 90 to 100 percent of pregnant cows with Rift Valley fever had miscarriages or stillbirths. In humans, it means that it poses a threat to the fetus. After first identifying the virus in sheep living in the Rift Valley in Kenya in 1931, it spread to Africa and the Arabian Peninsula, and has now been found in regarding 30 countries. There are regarding 50 species of mosquitoes that can spread this virus, and Aedes mosquitoes in particular already live in Europe, America and Asia. No cases of human-to-human transmission have yet been reported, but there is a possibility that medical personnel treating infected people can become infected through blood and tissue contact.

Infectious diseases are usually prevalent every 10 to 30 years, but the cycle is getting shorter. Even if you look at the coronavirus alone, the cycle of SARS-H1N1-MERS-Corona 19 has narrowed from 6 to 4 years. As much as that, we must hurry up to prepare for the ‘second Corona 19’. Professor Kim Woo-joo said, “Korea is good at responding, but the contrast seems rather weak. So, in the early days of Corona 19, everyone emphasized preparation for infectious diseases, but now no one is talking regarding preparing for infectious diseases. In order to reduce damage from the next infectious disease pandemic, preparations such as tracking, monitoring, and evaluating the virulence and transmission power of infectious diseases through genetic sequencing, etc., should be prepared,” he stressed.

© Sisa Journal Unauthorized reproduction and redistribution prohibited

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#pandemic #Avian #influenza #coronavirus #potential