6 questions & answers "There are bird flu infections that we are not aware of"

The largest documented wave of bird flu is currently spreading across several parts of the world. The pathogen mainly affects birds, but has also been found in many mammals.

On March 25th a year ago, terrible news came from the USA: a form of H5N1 bird flu was detected in dairy cows for the first time, initially in the states of Texas, Kansas and New Mexico. What has happened since then - and what happens next?

There is no sign of the wave being contained. According to the Centers for Disease Control and Prevention (CDC), there are now more than 12,500 registered cases in wild birds in the USA, and more than 166 million farmed birds such as chickens and ducks have been culled.

In addition, outbreaks have been detected in almost 1000 cattle herds in 17 states. 70 human cases have been detected. The cattle often have less appetite and give less milk. According to the authorities, the infection was probably mostly spread by wild birds and then passed on via milking machines and udders.

At the beginning of the year, a person died for the first time in the USA after being infected with the H5N1 bird flu virus. According to the authorities, the Louisiana resident was over 65 years old and also had other health problems.

However, these are just the published figures. In a small CDC study in September, 3 out of 150 veterinarians carried antibodies to the virus. Two of them had had no contact with infected animals or suspected cases.

Experts concluded that the virus must therefore be much more widespread among both animals and humans than officially known. "We don't know the extent of this outbreak in the US," virologist Seema Lakdawala from Emory University in Atlanta told the New York Times. "There are obviously infections that we are not aware of."

According to the CDC, human-to-human transmission has not yet been proven. The risk for the general population is low, and those infected are almost exclusively people with a lot of direct contact with cattle or poultry, such as farm workers. The authorities generally advise people to avoid contact with sick and dead animals.

Commercially available milk, meat and egg products are safe, as heat and pasteurization eliminate the virus, the CDC emphasizes. However, the consumption of raw milk is not recommended. The supply of sufficient beef and milk is not at risk. Cattle can survive an infection and do not have to be killed.

However, more than 160 million farm birds have been culled in the USA since the outbreak began. This has caused the price of chicken meat, and especially eggs, to skyrocket. Eggs are in short supply in many places, with supermarkets often only selling one pack per customer. The issue is also politically explosive.

During the election campaign, US President Donald Trump repeatedly blamed his predecessor Joe Biden for the high inflation and promised that everything would become cheaper with him as president - so far without success. This earned him ridicule from the Democrats. Trump repeatedly emphasized - without providing any evidence - that Biden was to blame for the fact that egg prices in the USA were "out of control".

The outbreak has hit the USA at a turbulent time. Following the change of government, some of the relevant authorities are still without leadership and are being battered by funding cuts and reductions. A unified strategy has not yet been presented, and Trump is ignoring the issue as far as possible.

One of the key issues concerns vaccinations: While the previous government had commissioned relevant studies and there was even already a conditional approval for a vaccine, the new Secretary of Health Robert F. Kennedy Jr. is much more critical of this option.

Kennedy recently told the TV channel "Fox News" that all his authorities would advise him against it. It is possible that vaccinations could turn chicken coops into "mutation factories".

Many are very concerned - both for the USA and worldwide. Sharp criticism has come from Germany: unfortunately, there is no sign that measures are being taken to quickly stop what is happening, says Martin Beer, Vice President of the Friedrich Loeffler Institute (FLI) on the island of Riems near Greifswald.

Berlin virologist Christian Drosten confirms the impression that in the USA more emphasis is placed on avoiding economic damage in the short term than on preventing a possible further zoonosis: "It is striking how little targeted infection monitoring and data insight takes place, both in animals and in humans."

That is completely unclear, says the World Health Organization (WHO). However, it is clear that these infectious diseases transmitted from animal to human have the potential to do so - and therefore need to be well monitored and contained as far as possible.

In addition, mutations could occur with each transmission, which could change the properties of the virus - and thus possibly also increase the potential risk to humans.

For example, a new variant recently appeared in cows for the first time in the USA. D1.1 was detected in cow's milk in Nevada. Previously, infections with the virus had been attributed to the B3.13 variant.