Check pigs for bird flu! Those are a great mixing bowl

The Netherlands must do more to prevent and detect bird flu in pigs. that A team of experts advised (Expert Council on Zoonotic Diseases) to the Minister of Agriculture last week. Such infections pose a public health risk, veterinarians, virologists and epidemiologists wrote in their advice, because avian influenza is a zoonosis: one that can affect both animals and humans and can jump between the two. When avian influenza viruses infect pigs, they can mix with swine and human influenza viruses. This could lead to a variant that could make people sick, spread easily between people and thus cause another pandemic.

“This chance is very small, but not zero,” says Professor Ron Foucher, a virologist at Erasmus MC Rotterdam and a member of the Expert Council – Zoonoses. Therefore, according to experts, pigs and poultry should not be kept on mixed farms, and there should be mandatory surveillance for influenza viruses in pigs – especially on high-risk farms.

Since 2020, a highly contagious – very sickening – type of bird flu has been circulating among wild birds, which previously originated in Chinese poultry. Since then, this variant has regularly caused outbreaks of the disease in poultry farms and has spread to almost all parts of the world, bringing much suffering and economic harm to animals. In the Netherlands alone, more than 6.6 million birds have been culled since 2020.

This mammalian infection is a concern because the virus can adapt to its host through admixture and mutation

Ron Faucher Mr

But the damage is also massive among wild birds. In 2020, the main victims in the Netherlands were barnacle geese; In the past two years so have other species, including white-tailed eagles, black-headed gulls, and terns. In addition, wild mammals around the world are increasingly infected with the virus. Modern Dutch research showed that one in five dead wild mammals carried the virus, or was recently infected with it. “This infection of mammals is of concern because the virus can adapt to its host through admixture and mutation, which could become dangerous to humans, possibly even epidemic,” says Foucher. This happened, for example, in 2009 with swine flu, which originated in pigs. This pandemic was relatively mild, but the Spanish (1918), Asian (1956), and Hong Kong (1968) flu, which also originated in pigs, killed millions.

widespread permits

There have been recent outbreaks of avian influenza among mink in Spain and sea lions in Peru Perhaps the virus has already been transmitted among mammals. One of the mutations necessary for easy transmission between humans has already been seen in a polecat in the Netherlands.

Pigs are susceptible to swine, human and avian influenza viruses. Thus, the Dutch hog strip is a mixing bowl to be reckoned with, according to the experts in their latest tip. This is precisely why rules and procedures must be put in place to reduce risk – including systematic and mandatory monitoring. “In the poultry sector, this is already a possibility,” says Foucher. “It may seem strange, given the culling on such a large scale. But it is precisely because of this that outbreaks are nipped in the bud. There is very strict control.”

The situation is different in the swine sector, because the ministry considers swine influenza viruses less dangerous than avian influenza. The Ministry of Agriculture, Nature and Food Quality therefore leaves the monitoring process to the sector itself – and there is also no obligation to report influenza on pig farms. This is not regulated in Europe either. “While in my opinion there are sufficient reasons to set up proper surveillance in Pigsty Europe. And also to put in place a good plan for what should happen in the event of an outbreak of avian influenza. There is no such plan in the swine sector. I find that very strange.”

Manon Houben of the Royal GD, formerly the Animal Health Service, is also a member of the zoonotic disease expert board. She supports the last advice of the Ministry, but wishes to make little difference to the situation in the swine sector. “It’s definitely not that there’s no oversight there and so we don’t have much insight into anything,” she says. Explain that GD is a government-owned company Responsible for animal health control in the Netherlands. GD is paid by the government and animal husbandry, including pig breeders.

mesh network

“We have a close collaboration in Holland between GD, livestock farms and veterinarians,” says Houben. “It’s a finely meshed network that exchanges information quickly and easily. For example, we receive dead animals that vets send in when they see something suspicious, and we perform an autopsy on them. And we run.” Veekijker, which is my phone helpline Veterinarians and ranchers can contact them to request information or to discuss the outcome. We record every call and analyze statistics. Finally, all veterinarians working on pig farms are required to send us a monthly report on those farms. The latter is part of the mandatory IKB quality system, Integrated Chain Control.

No hog farm goes under the radar, Hobbin stresses, because every farm uses the services of a veterinarian. She knows that no veterinarian will report a suspected case of illness. According to her, the system in which the central inspection service comes to take viral samples without warning has no added value.

We do not yet know enough what a good monitoring system is

Manon Hoppen Royal J

Due to the seriousness of the current avian influenza epidemic, various parties, including RIVM and GD, have started small-scale voluntary surveillance this year. This trial, funded by the Department of Health, Welfare and Sport, identifies which swine flu viruses circulate in pigs. Veterinarians take random samples from pigs that sniff or cough on farms owned by farmers who want to take part. “Not all pigs have a cold, and not all businesses,” Houben explains. “And not with asymptomatic pigs. But we think we get a representative picture this way — and that we can quickly detect any avian influenza viruses that are present.”

The first results are expected at the end of this year. The trial has been underway for a year, but Hobbin expects a follow-up. The Zoonoses Expert Council recommends that the findings be used to set up large-scale detection of avian influenza among pigs. But according to Houben, other steps are needed first. “We don’t know yet enough what a good monitoring system is,” she says. “Exactly what information is needed, how many samples do you need to take, what question do you actually want answered? You can only design a good system after you have a clear picture of it.”

And the system should be good, according to her, because the sector should also benefit from it. “The surveillance we already have is really good. The infrastructure is in place, the people are there, and we can quickly scale it up and down.”

Vaccination of employees

Arjan Stegmann is Professor of Farm Animal Health at Utrecht University and Vice-Chair of the Expert Council for Zoonoses. He asserts: “I think mandatory monitoring is particularly important for high-risk farms, such as mixed farms, farms where pigs work outside and farms near wetlands. If you read the advice carefully, you’ll take it out.”

Like Manon Houben, he does not see much added value in mandatory monitoring in all companies. “I see more in other actions, such as urgent advice for people who work in this sector to get a seasonal flu vaccine,” he says. This is to reduce the risk of human and swine influenza viruses mixing with each other. The Board of Health is now considering such a measure.

Normal respiratory problems in pigs are very common

Arjan Stegman Mr

But Stegeman is somewhat more critical of current surveillance. “Hitting things are already being reported,” he says. But normal respiratory problems in pigs are very common. Only a small minority end up in GD.” In other words, an influenza virus that causes few complaints can lie dormant among pigs for a long time without being caught.

So why don’t we randomly monitor all companies? Stegemann replies: “I don’t think that’s a good idea, as long as we don’t know how to interpret the results and how to act afterwards. Moreover, such monitoring provides a false sense of security.”

He explains that although there are 12 million pigs in the Netherlands, there are more than 2 billion pigs living elsewhere. “The likelihood of a new pandemic virus emerging in pigs is many times greater outside our borders than at home. There, these problems are on the same scale, but biosecurity in general is less well regulated.”

What can we, Plummer, do about this? “Ensuring better hygiene in companies where the virus is constantly circulating,” Stegemann replies. and vaccination of pigs. We in the Netherlands cannot do that to other countries. But we can do research into influencing the dynamics of infection. How do viruses spread and how do we intervene? This knowledge is also a product that we can export. This now seems like a reasonable priority to me.”