“Experts warn of increasing risk of H5N1 bird flu worldwide but risk in Netherlands unchanged: Latest recommendations and measures for prevention”

The risk of spreading highly pathogenic bird flu (HPAI) among people in the Netherlands is unchanged. Due to the worldwide spread of bird flu variant H5N1, the uncertainty about the risk assessment is increasing, warn experts from the Center for Infectious Disease Control of the RIVM and the Expert Council on Zoonoses.

In a letter, the Ministers of Health, Welfare and Sport Ernst Kuipers and Piet Adema of Agriculture, Nature and Food Quality informed the members of the Lower House of the current bird flu situation and the risks to public health. In several parts of the world, H5N1 is regularly diagnosed in mammals, in more than thirty species. The spread of outbreaks around the world is still increasing. In some cases, mammal-to-mammal infection cannot be ruled out, such as an outbreak of bird flu on a mink farm in Spain and an outbreak among sea lions off the coast of Peru.

H5N1 has also been diagnosed in a few people, with two people also showing symptoms. For the third consecutive season, bird flu has increased among wild birds. As a result, there are also more outbreaks among poultry on farms. The estimate of infection for the general population remains low, as it was last year. The risk to people working professionally with poultry or infected animals is low to moderate. This risk is also unchanged compared to last year. According to the experts, the regularly reported infections in mammals in the Netherlands do force increased vigilance. ‘Especially because the Netherlands has one of the highest densities of animals in the world’, the ministers write.

Seasonal flu vaccination

The experts come up with a number of new recommendations in their report. For example, the ‘ordinary’ seasonal flu vaccination can reduce the risk of human seasonal flu strains mixing with avian flu strains, resulting in a variant of (bird) flu that is dangerous for humans. The ministers want to lower the threshold for obtaining a flu vaccination by making it available to people who may come into contact with bird flu professionally. These are poultry and pig farmers, employees of the Dutch Food and Consumer Product Safety Authority and people involved in clearing up dead or sick birds and mammals living in the wild.

The Zoonoses Expert Council also considers it a risk that bird shelters and animal ambulances have to pay for personal protective equipment themselves. Protective equipment that was available to protect against corona is now made available to animal aid organizations and other volunteers. Better information is also needed about picking up and cleaning up carcasses found in the wild.

Active monitoring among poultry farmers

The ministers also want to switch from ‘passive’ monitoring for bird flu among poultry farmers to ‘active’ monitoring. At the moment, poultry farmers can call the GGD for tests if they have complaints that could indicate flu. From now on, everyone who has been exposed to bird flu will be offered a test, even if they have no complaints. This applies to scrapers, veterinarians and poultry farmers themselves. The RIVM has been asked to extend this to pig farmers in the event that an HPAI infection is detected in pigs.

The latest advice devotes relatively much attention to pigs and pig farmers, now that the Zoonoses Expert Council has indicated that pigs are a ‘potential mixing vessel’ for HPAI and swine influenza viruses. The Zoonoses Experts’ Council recommends developing surveillance at pig farms for (bird) flu. This system could target companies with the highest risk. These are mixed farms that have both poultry and pigs, pig farms with a free range and pig farms in water and bird-rich areas. More attention should also be paid to biosecurity on pig farms in order to reduce the risk of the introduction of avian flu.

Pigs are already sampled if there is an outbreak of bird flu among poultry on mixed farms. HPAI has never been demonstrated in pigs in the Netherlands. Adema is looking at how a duty to report can be introduced for highly pathogenic bird flu in pigs.