The story so far: Reports of an emergent viral infection transmitted from pigs in China dominated the news earlier this week. Newspapers and television channels reported that a new strain of H1N1 (also known as swine flu) had started infecting workers and the recommendations of scientists were that it must be controlled with a great deal of urgency as it had the potential of becoming yet another pandemic.
What are the risks from emerging pathogens?
At this stage, potential harm from G4 EA H1N1, the new strain, has just been flagged by scientists who predict risk from emerging pathogens. Knowledge of the existence of the virus in pig farms in China has been present since 2016. But a new study (“Prevalent Eurasian avian-like H1N1 swine influenza virus with 2009 pandemic viral genes facilitating human infection”) published in the Proceedings of the National Academy of Sciences , U.S. (https://bit.ly/2ZuLy7O), said it replicates efficiently in human airway paths and so far, has infected a few people without actually making them ill. They found antibodies for the virus in the blood of pig farm workers, none of whom was sick.
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The authors, who are researchers based in China, recorded in the article: “Pigs are intermediate hosts for the generation of pandemic influenza virus. Thus, systematic surveillance of influenza viruses in pigs is a key measure for pre-warning the emergence of the next pandemic influenza... G4 viruses have all the essential hallmarks of a candidate pandemic virus. Of concern is that swine workers show elevated seroprevalence for G4 virus. Controlling the prevailing G4 EA H1N1 viruses in pigs and close monitoring in human populations, especially the workers in swine industry, should be urgently implemented.”
The researchers collected 338 blood samples from workers on 15 farms and 230 from people in nearby households. The results, as published, found that 10.4 % of the workers and 4.4 % of the others tested positive for antibodies to G4 EA H1N1. Over all, 20.5 % of the workers between the ages of 18 and 35 tested positive.
Is G4 a current pandemic?
No. The paper has merely forewarned of the possibility that the G4 virus might emerge into a pandemic in the future, and the authors have called for greater vigilance in monitoring people. It has not become potent in humans even though their blood contains antibodies for the virus.
Dr. Anthony S. Fauci, Director, National Institute of Allergy and Infectious Diseases, and also an adviser in the White House coronavirus taskforce, told the US Senate that U.S. health officials were watching the China developments with reference to G4, which has the characteristics of the 2009 H1N1 virus and the 1918 pandemic flu. The virus, which scientists are calling “G4 EA H1N1,” has not yet been shown to infect humans but it is exhibiting “reassortment capabilities”, the media cited him as saying.
At this point of time, the alert can be considered an early warning bell. It calls for vigil primarily because this is a new strain against which humans would have no inbuilt immunity from the virus, much like SARS-CoV-2, the virus that causes the disease, COVID-19.
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What is disease/pandemic risk surveillance?
Most countries have their own disease surveillance mechanisms in place to monitor and track emerging diseases. Public health teams evaluate the risk of a particular pathogen on the community, based on the cases occurring, and warn of potential risks from that pathogen. Early warning systems have been successful in predicting dengue and Ebola outbreaks, among other diseases, in the past, enabling health systems to be pre-warned and, thus, prepared to tackle the challenge. Local outbreaks of cholera or diarrhoeal disease have also been identified in cities, and have helped limit the damage in the community.
Closely studying a pathogen will yield valuable information on transmission, and behaviour of the organism, giving humans early lessons in its prevention and treatment. Alerts should also be sent out by global health mechanisms, including the World Health Organization (WHO), so that other nations at equal risk might be warned before the outbreak hits their shores.
Also read | Citing swine fever, China bans pork imports from India
What is the future?
Borrowing the urgency of a now famous phrase that WHO Director-General Tedros Adhanom Ghebreyesus used for the coronavirus (‘Test, Test, Test’), the world must seek ‘Vigilance, Vigilance, Vigilance’. All risk assessment systems across the world will have to be on active mode, besides forming a network globally to share information on emerging diseases and pathogens. WHO’s Global Outbreak Alert and Response Network (GOARN) is at the front of such initiatives to make scientific predictions based on certain models. While there is no doubt that disease and pathogen surveillance have a place in the modern world, it is also important to remember that scientists themselves regard it as an imprecise form, ergo, any undue alarm as a consequence of such studies would quite frustrate the target of preparedness.