Will the H10N3 Avian Flu Strain, Now in Humans, Become the Next Pandemic?

Virus

The first human case of a new strain of avian flu was diagnosed in China in late May. Chinese health authorities say there is a low risk of contagion. After China notoriously underreported COVID-19 mortality, can this new assurance be trusted?

Dubbed H10N3, this strain of bird flu is a subtype of the Influenza A virus. It was diagnosed May in a 41-year-old man in Jiangsu province. The man developed symptoms April 23, was admitted to a hospital April 28, and diagnosed a month later. A few days ago, China’s National Health Authority announced he was ready to be discharged, according to coverage by The Wall Street Journal.

There was no information about how the man contracted the H10N3 virus, but the public was advised to avoid contact with sick poultry.

That advice was based on previous outbreaks of other strains of avian flu – notably Asian lineage H7N9 and HPAI Asian lineage H5N1. Those incidents occurred after close contacts with infected poultry, according to the Centers for Disease Control & Prevention (CDC). So far, however, there is no evidence of human-to-human transmission for the H10N3 strain, and the Chinese government says contact tracing efforts have not identified any other cases.

So far, so good.

Of course, China has a history of downplaying outbreaks. The SARS-CoV-2 virus that caused COVID-19 was responsible for illnesses as early as October 2019 that weren’t reported until late December 2019. Even then, the risk was minimized until other nations realized the severity of the situation.

Estimates of mortality figures in Wuhan, based on crematorium activity in January and February of 2020, for example, suggested 10-fold more deaths than normal. Early in the COVID-19 outbreak, China cracked down on scientists by requiring extra scrutiny on academic research papers relating to the cause of the pandemic before determining whether they could be published, CNN reported in April 2020. This spring, leaked documents revealed the underreporting of serious adverse conditions by China’s health authorities.

Since the beginning of the pandemic, Johns Hopkins University’s COVID-19 tracker reports that nearly 172 million people have been infected and nearly 3.7 million have died, globally, from COVID-19. It reports 103,094 cases of COVID-19 in China and 4,846 deaths from a population of 1.4 billion people, versus the 33.3 million U.S. cases and 6,723 deaths from a population of nearly 327 million.

The severe acute respiratory syndrome (SARS) outbreak that began in November 2002 in Guangdong province is another example. At the time, SARS was an unknown virus and physicians didn’t understand what was going on. Reporting was slow and the Chinese government admitted underreporting the numbers. Eventually, 8,096 people died in 26 nations.

Sometimes, of course, it’s right to merely keep an eye on things. Although the 2009 outbreak of a strain of H1N1 killed between nearly 152,700 and 575,400 worldwide, according to CDC estimates, the G4 strain of the H1N1 virus that emerged in 2020 still seems to be relatively benign despite having potentially pandemic-causing characteristics.

Hopefully, the H10N3 virus that just jumped to human will be a similarly uneventful infectious disease. After both SARS and COVID-19, however, the world is wary.

Avian influenza strains often originate in Asia and rarely spread to human populations. The H10N3 strain of the influenza virus is likely to follow that pattern. Even among birds it is rare, Filip Claes, regional laboratory coordinator for the United Nation's Emergency Center for Transboundary Animal Diseases, told Reuters.

Rarity doesn’t affect lethality, though.

A prior strain of H5N1 first was detected in geese in 1996 before jumping to humans in 1997. Only about 700 human cases have been reported since that jump. Those cases, however, had a 60% mortality rate. Mortality was highest among people between the ages of 10 and 19, the CDC reported, most likely because older adults still had immunity from a related virus that swept the U.S. decades earlier.

Unless the H10N3 virus becomes easily transmissible among humans, it doesn’t pose a significant health threat to the world’s human population. As Adolfo Garcia-Sastre, a professor at the department of microbiology at Icahn School of Medicine at Mount Sinai in New York told the Wall Street Journal, “It is highly likely that this infection just represents one of the rare incidents of human infection with an avian influenza virus, without any more consequences.”

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