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By Cheryl Kahla

Content Strategist

Shift of bird flu to mammals raises fear of human infections

The World Health Organisation warns that the recent surge in bird flu among mammals could heighten the virus's ability to infect humans.

The World Health Organisation (WHO) on Wednesday sounded the alarm over the rising cases of bird flu among mammals, which is a worrying turn for humans.

If the virus can easily spread among mammals, it heightens the potential to spread more easily among humans as well.

Here’s what you need to know.

WHO’s bird flu alert

An unprecedented bird flu outbreak swept across Europe during 2021 while both South and North America grappled with several outbreaks.

The H5N1 – also known as Sporadic influenza A(H5N1) clade – virus strain was first detected in 1996, and to date, tens of millions of poultry had been culled.

These outbreaks inflicted “devastation” on poultry, affecting farmers’ livelihoods and the food trade, according to the WHO.

From animals to humans

The latest development, however, has seen an uptick in H5N1 cases in mammals – biologically closer to humans than birds.

This is stoking fear that the virus could adapt and infect humans more readily. The WHO cautions that some mammals could serve as ‘mixing vessels’ for flu viruses.

This could potentially lead to the emergence of even more harmful strains entering the populace.

For perspective, the current wave of outbreaks affects 26 different species, ranging from sealions in Chile to mink in Spain.

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An employee of the National Fisheries and Aquaculture Service (Sernapesca) attempts to capture a sick sea lion on a beach in La Serena, Chile on 31 May 2023. Photo: AFP/MARTIN BERNETTI

Just three days ago, the strain was also found in cats in Poland when at least 24 sick or dead cats have tested positive for H5N1.

READ: 500 000 chickens culled in latest WC bird flu outbreak

‘Paradigm shift’

Meanwhile, World Organization for Animal Health’s (WOAH) science chief, Gregorio Torres, said the avian flu ecology and epidemiology underwent a “paradigm shift”.

He said the disease’s spread to new regions, unusual wild bird deaths, and a worrying surge in mammalian cases have escalated global apprehensions.

When avian flu infections occur in humans – from direct or indirect exposure to infected animals – it can lead to severe illnesses and it has a high mortality rate.

WHO’s chief of pandemic preparedness Sylvie Briand said it doesn’t easily spread from person to person, but any evolution in the strain “could change this,” hence the need to stay vigilant and monitor the virus.

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An employee of the Agricultural and Livestock Service (SAG) removes a dead cormorant (Guanay Cormorant) from Changa Beach in Coquimbo, Chile on 29 May 2023. Photo: AFP/MARTIN BERNETTI

Briand said this can only be done if countries ramp up their monitoring capabilities, particularly those nations now grappling with avian flu for the first time.

READ: WHO declares end to Marburg virus outbreak in Equatorial Guinea

Bird flu outbreak timeline

The virus hit North America in 2021 before spreading to Central and South America in 2022.

Last year alone, 67 countries across five continents reported highly pathogenic H5N1 bird flu outbreaks, causing the loss of over 131 million domestic poultry.

For the current year, outbreaks have been reported in an additional 14 countries, mainly in Europe, North and South America, and Asia.

Back in June 2023, Gabon, Guinea, and Moldova were added to HPAI-at-risk (Highly pathogenic avian influenza) countries.

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