WHO Raises Alarm: Bird Flu Threat to Humans an ‘Enormous Concern’

The WHO has raised concerns about the spread of H5N1 bird flu, noting its “extraordinarily high” mortality rate in humans. The United States is facing its most severe outbreak of highly pathogenic avian influenza (HPAI) to date, with cases spreading among dairy cow herds and increasing the risk of spillover to humans. Efforts are underway to develop vaccines and treatments for H5N1, while global preparedness for potential human-to-human transmission is being emphasized in light of the evolving situation.

Bird Flu a ‘Global Zoonotic Animal Pandemic’

The United States is facing its most severe outbreak of HPAI to date. An outbreak of bird flu among US dairy cows has expanded to impact over twenty-five herds across eight states, occurring shortly after the nation’s largest egg producer detected the virus in its chickens, affecting 8.61 million birds across 48 states. This widespread outbreak has led to significant culls of commercial poultry and incurred billions of dollars in losses, as reported by the US Department of Agriculture (USDA). Moreover, with the spread of the virus to more mammals, the increased concern for human transmission and viral mutation is becoming more pronounced.

Last month saw a surprising development as cows and goats, previously thought unsusceptible to this strain of influenza, joined the list of affected species. This event has resulted in researchers closely observing the spread of a troubling strain of avian influenza to cattle across farms in several US states. Federal agriculture officials confirmed infections in a Michigan dairy herd that had recently acquired cows from Texas. As of April 1st, the USDA had confirmed the detection of HPAI in dairy herds in Texas (7) Kansas (2), Michigan (1), and New Mexico (1). Accordingly, these infections mark the first significant outbreak of bird flu in cows. “This development is worrying because humans regularly interact with cattle on farms, providing ample opportunities for the virus to transmit to people”, explains Daniel Goldhill, an evolutionary virologist at the Royal Veterinary College in Hatfield, UK. 

At the start of April, sixteen herds across six states were infected, seemingly due to exposure to wild birds. As of April 18th, detections of HPAI have been reported in 29 livestock herds across 8 states, indicating an increasing trend. Jeremy Farrar, the chief scientist of the UN health agency, emphasized to reporters in Geneva that he still regards this as a significant concern. The A(H5N1) variant has become “a global zoonotic animal pandemic”, Farrar said.

Avian Flu and Human Transmission Risks

US authorities reported this month that a person in Texas contracted bird flu after exposure to dairy cattle. This development follows the detection of bird flu in cattle and the milk of dairy cows earlier this month. Accordingly, the WHO reported this to be the first case of human infection with A(H5N1) acquired from contact with an infected mammal, although human infections with other influenza virus strains from mammals have been reported previously. A recent WHO report conducted between February and March showed that cases of A(H5N1) and A(H9N2) have been documented in Asia. 

Currently, there’s no evidence of H5N1 spreading among humans. However, the virus’s high mortality rate in human cases contracted from animals, due to lack of natural immunity, is concerning. According to the WHO, there have been 887 reported cases worldwide of H5N1, resulting in 462 deaths over 23 countries since 2003 (as of February 2024). These numbers show a case fatality rate of 52%. 

The recent US case of human infection from contact with an infected mammal highlights increased risk. The virus that has infected the worker shares close genetic similarities with the strains identified in dairy cattle in Texas. However, a significant difference exists: the variant in the worker possesses a mutation associated with enhanced transmission in mammals. UN health agency’s chief scientist, Jeremy Farrar emphasized the need for enhanced monitoring, stating that understanding the extent of human infections is crucial as it is where the virus is most likely to adapt as well as where human transmission is more likely to occur.

US Slammed for Under-Reporting Severity

As H5N1 bird flu continues to spread to additional dairy cow herds, scientists and pandemic experts both domestically and internationally urge the US government to provide more information. This transparency is crucial for assessing the risk posed by the outbreaks to both cattle operations and human health. Until yesterday, US officials had not revealed whether the 29 affected herds across eight states constitute a single interconnected outbreak, potentially driven by the movement of cattle from the Texas panhandle, where the initial outbreak was detected. Despite the initial announcement three and a half weeks ago, crucial details such as the effectiveness of milk pasteurization against the virus and the origin of the outbreaks remain undisclosed. The lack of transparency has left experts worldwide operating in the dark and questioning whether the US response is adequate. Marion Koopmans from Erasmus Medical Center emphasizes the need for prompt and transparent updates, especially considering the global implications.

“A country with capacity like the United States should be able to generate this information within days,” Koopmans said. “I would expect very fast, very transparent updates and it’s somewhat amazing not to see that happening.”

The USDA defends its approach, stating its commitment to timely and transparent information release. However, concerns persist over the limited genetic data shared on the outbreak and the potential risks posed by the virus’s transmission among cattle.

Global Preparedness: Anticipating Bird Flu’s Next Move

Efforts are underway to develop vaccines and treatments for H5N1, and it’s crucial to ensure global readiness for potential human-to-human transmission. Ensuring that regional and national health authorities worldwide have the capacity to diagnose the virus is vital, whilst equitable access to vaccines, treatments, and diagnostics are paramount for an effective response. Drawing from the lessons learned during the COVID-19 pandemic, it’s anticipated that governments and health authorities worldwide will be better equipped to respond should Avian flu undergo a mutation enabling human-to-human transmission.

Avian Flu Awareness: What you Need to Know

Avian flu, caused by the influenza A virus, primarily impacts birds and poultry and spreads through various routes such as the digestive tract, respiratory secretions, wounds, and the eyes. Humans and animals can contract the virus by contact with infected bird excretions or inhaling viral particles. Avian influenza is categorized into highly pathogenic (HPAI) and low pathogenic (LPAI) strains based on their lethality. Scientists classify these viruses using surface proteins hemagglutinin (HA) and neuraminidase (NA), with prevalent subtypes like H5N1, H5N8, and H7N9 being highly pathogenic. H5N1 has caused widespread outbreaks since 2020, while H7N9 led to numerous human infections in China in 2013. The contagiousness and high fatality rate of avian flu pose significant concerns. As per reports from the World Organisation for Animal Health (OIE), different subtypes of influenza A(H5) are still being found in both wild and domestic birds across Africa, Asia, Europe, and the Americas. Additionally, infections in non-human mammals are also being documented. 

Tips for Staying Safe

To safeguard against bird flu, it’s essential to follow preventive measures recommended by the CDC. These include avoiding direct contact with wild birds, promptly reporting sick or dead birds to authorities, practicing safe poultry cooking methods, and receiving annual vaccinations. Individuals handling poultry, such as bird owners and farm workers, should wear protective gear like gloves and N95 masks, practice thorough handwashing, refrain from touching their face after contact, and change clothes before interacting with birds. In cases of infection, supportive care and antiviral medications like oseltamivir (Tamiflu), peramivir, and zanamivir are commonly used for treatment, with ventilators employed in severe cases to aid breathing.

Author

Bernice Lottering

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