Could bird flu cause the next pandemic? And five other questions about this infectious disease

The Netherlands must continue to be vigilant against bird flu, a disease that regularly kills domestic and wild bird populations. that it Content of the message Which was sent to the House of Representatives by the Departments of Agriculture, Nature, Food Quality and Public Health on Monday. The letter discusses in detail the risks of bird flu to poultry, pigs, wild animals and humans.

Ministries write in a letter to Parliament about the status of implementation An intensified plan to prevent bird influenzaWhich dates back to last July. This plan was developed in response to 78 recommendations from the Zoonoses Expert Group From 2021. Zoonoses are diseases that can make animals and humans sick and can be transmitted between the two.

The ministries stated that the implementation of the procedures is going well. This is only partly the case, according to Thijs Kuijken, an avian influenza expert at the Erasmus MC Center in Rotterdam. “I am sure that things are not only happening in the poultry sector. On the other hand, I think that these recommendations are already 2.5 years old. Some things are moving unnecessarily slowly. Some measures were already agreed in 2008 and have not yet been implemented, such as Strict separation between pig farming and poultry farming.

What exactly is going on and should we be worried? Six questions about bird flu.

1 What is the current status of bird flu?

We are still witnessing a global outbreak of what is called a highly pathogenic strain of avian influenza: the strain that makes poultry seriously ill. This variant appeared in poultry in Asia in 1996 and has been increasingly spreading in Europe since 2005. Things have been moving very quickly since 2021, because the virus no longer disappears in the summer. In 2021 and 2022 alone, more than fifty million chickens and other types of poultry were culled in Europe. Including more than five million in the Netherlands. Wild birds also get sick from it. They have now spread the virus all over the world, as far as Antarctica. Many mammals die because of it. Like 30,000 sea lions in South America.

According to Kuiken, the Netherlands has been relatively quiet regarding the outbreak in 2023 – except for the cull of 110,000 chickens in Putten in December. The closing clause seems to help. “I think we have passed the peak in Europe, as well as among wild birds,” he says. “It is possible that some immunity has evolved.” The virus continues to spread among wild birds and continues to appear in new species populations.

2 Why is the government concerned about bird flu?

Avian influenza causes great suffering to animals and economic damage to the poultry sector. But the pig sector is also at risk: these animals can also become infected with bird flu. This is a problem, because influenza viruses can adapt quickly through mixing and genetic mutations. This allows them to adapt to their hosts, making them more transmissible or better able to evade the immune system.

Read also
How bird flu spread to Antarctica and threatens rare species there

3 What is the danger to people?

The Dutch swine sector is a large mixing bowl in which bird flu viruses can mix with swine flu and thus adapt to mammals. A bigger problem arises when a pig is infected with human influenza at the same time. A variant may then emerge that could cause the next pandemic in humans, as happened in 2009 with Mexican influenza, which originated in pigs. It is impossible to say how likely this is to happen. But what is certain is that the virus only needs a few genetic modifications to become a pandemic. This has already happened in the past with other bird flu viruses (including the 1918 Spanish flu, which killed millions). Three of the necessary mutations have already appeared in mammals in Europe.

4 The prevention plan talks about vaccinations. What about that?

RIVM, in cooperation with experts, has developed three scenarios of increasing risk. In the most severe scenario (spread between people), measures such as quarantine or maintaining distance may be necessary, the letter to Parliament said, “particularly to bridge the gap until vaccines can be deployed.” This relates to bird flu vaccines for humans, which do not yet exist. This development takes about six months.

The prevention plan already provides for vaccinating professionals in the pig and poultry sector against common seasonal influenza. This can help prevent the mixing of human and animal influenza. Meanwhile, the effectiveness of two avian influenza vaccines for poultry has been studied in Wageningen. These vaccines have proven their effectiveness in the laboratory and are now being tested in companies. This will continue until the end of 2025. If the vaccines continue to prove effective, a larger pilot trial will be initiated.

5 What other measures is the government taking to control bird flu?

The prevention plan also focuses on surveillance, prevention and preparedness. The RIVM, in collaboration with other parties, has established a pilot program for the detection of influenza viruses on pig farms. Ninety companies were followed. The pilot will continue. Ultimately, this should lead to structural monitoring. In terms of prevention, a mandatory biosecurity plan for commercial poultry farms will be implemented by mid-2024. “The government aims to impose a ban on the establishment of new poultry farms in poultry-intensive and water-rich areas, and is exploring options to prohibit expansion,” the ministries also wrote.

6 Overall, are things moving in the right direction?

“I found the observation pilot in particular very helpful,” answers Theis Kuijken. In this pilot project, several cases were found of people infected with swine flu (and recovered) and pigs infected with human influenza. “But this was only a short, small-scale pilot. Can you imagine how many cases there are in the entire pig sector year after year? It's incomprehensible that this hasn't been monitored on a larger scale for longer, if you know this poses a risk.”

He says extensive testing of vaccines to protect poultry from bird flu appears to be a postponement to Kuiken. “We know enough now that these vaccines are effective. Then immediately start mass vaccination of companies. I suspect there are commercial reasons behind this hesitation.

To participate




Email the editor