​8 viruses that can potentially cause a pandemic​

COVID pandemic was an eye opener for health agencies worldwide. For advance preparedness, the World Health Organisation (WHO) has been proactively updating the list of pathogens that are likely to cause pandemic in the future.

Few weeks ago the WHO shared a list of 30 pathogens that have the potential to cause the next pandemic. The new list of pathogens includes influenza A virus, dengue virus and monkeypox virus. It also has several strains of influenza A viruses, including subtype H5, which has recently caused an outbreak in cattle in the United States. Five new bacterial strains have been added, responsible for diseases such as cholera, plague, dysentery, diarrhea, and pneumonia.

The 1918 Spanish flu pandemic, caused by the H1N1 strain, remains one of the deadliest pandemics in history, killing an estimated 50 million people worldwide. The 2009 H1N1 pandemic, also known as swine flu, demonstrated the continued potential of influenza A viruses to cause pandemics. These viruses are known for their ability to undergo significant genetic changes, leading to novel strains that can cause widespread outbreaks. Currently, avian influenza strains are of particular concern due to their high mortality rates.

Coronavirus, the virus responsible for COVID, has already demonstrated its pandemic potential. Its high transmissibility, asymptomatic and presymptomatic spread, and ability to cause a wide range of symptoms from mild to severe contribute to its pandemic potential. The virus's ability to mutate has also led to the emergence of new variants, which can impact disease severity, transmissibility, and vaccine efficacy. New variants of COVID, such as the Omicron variant, have raised concerns about the virus's potential to evade immune responses and cause surges in cases.

Dengue virus, transmitted primarily by Aedes mosquitoes, poses a significant pandemic risk due to its widespread presence in tropical and subtropical regions. With over 400 million annual infections, dengue can cause severe flu-like symptoms and, in extreme cases, dengue hemorrhagic fever or dengue shock syndrome, which can be fatal. Rapid urbanization, climate change, and global travel facilitate its spread, increasing the risk of outbreaks in new areas. Its potential for widespread impact and the absence of a universally effective vaccine highlight the need for enhanced surveillance and mosquito control measures to mitigate the risk.

Monkeypox virus, though currently rare and geographically confined to Central and West Africa, has significant pandemic potential due to increasing global travel and interconnectedness. The virus spreads through close contact with infected individuals or animals, and recent outbreaks outside its traditional regions have heightened concerns. With symptoms resembling smallpox, including fever, rash, and swollen lymph nodes, monkeypox could strain healthcare systems if it spreads more widely. The WHO has recently declared it as a global health emergency.

Nipah virus can lead to severe respiratory illness and encephalitis. The virus was first identified during an outbreak in Malaysia in 1998-1999 and has since caused outbreaks in Bangladesh and India. It has a high mortality rate, with fatality rates ranging from 40% to 75%. It is transmitted through direct contact with infected animals, such as bats or pigs, and can spread between humans through respiratory droplets and bodily fluids.

Marburg virus can cause severe hemorrhagic fever with a high fatality rate. The virus was first identified in 1967 during an outbreak in Marburg, Germany, and has caused sporadic outbreaks in Africa. It is transmitted through direct contact with infected individuals or their bodily fluids and can cause severe symptoms, including hemorrhagic fever and organ failure.

Hantavirus causes hantavirus pulmonary syndrome (HPS) and hemorrhagic fever with renal syndrome (HFRS). Hantaviruses are transmitted through contact with rodent droppings, urine, or saliva and can cause severe respiratory or renal symptoms in humans. Hantavirus infections can have high mortality rates, especially in cases of HPS.

Zika virus is primarily transmitted by Aedes mosquitoes. While often asymptomatic or causing mild illness, Zika virus infection during pregnancy can lead to severe congenital abnormalities, including microcephaly and other neurological defects in infants. The global spread of Aedes mosquitoes and the virus's ability to cause significant birth defects make Zika a concern for potential outbreaks. The 2015-2016 Zika outbreak in the Americas highlighted the virus's impact on public health, particularly in terms of maternal and child health.

​​Monkeypox declared global public health emergency: What is it and why is it a global threat?​