Health authorities are following new cases of bird flu “very carefully” after two Britons tested positive for the first time in over a year.
Routine checks on workers at a poultry farm in England found they had contracted the virus.
According to the British health authority UK Health Security Agency (UKSA), both suffered no symptoms of infection and there was no evidence of human-to-human transmission.
However, authorities are monitoring the situation and are running a program to test employees who work with birds infected with avian flu.
The UKSA’s senior medical adviser, Professor Susan Hopkins, told BBC Radio 4’s ‘Today’ programme: ‘This is clearly an ongoing risk that we need to monitor and monitor very carefully and understand how transmission can occur.’
She confirmed that the PCR swabs had now come back negative in both cases and that it remained uncertain whether it was a “real infection” that occurs when the virus sits in the nose.
Professor Hopkins added: “These are people who work in very close contact and close to infected birds on infected farms, so there will be a lot of dust and a lot of potential virus fragments in the air, but also on their clothes, when working in this environment.
“They wear a lot of PPE to protect themselves from contagion, but there is still a risk that this virus and environmental pollutants get under your nose and therefore we can detect avian flu if we swab it.”
“We test individuals’ contacts and offer testing.
“We will continue to do that as part of our monitoring.”
The first reported human case was detected with a swab inserted into the nose.
Experts believe it is likely that this worker inhaled the virus.
The second case is considered more complicated and it is unclear whether the person suffered a real infection or whether they inhaled the virus at work.
Further inquiries are ongoing but precautionary contact tracing has been carried out for this person, the UKHSA said.
Both people’s tests are now negative, the agency said, adding there was no evidence of human-to-human transmission.
The UKHSA said the cases had no impact on the level of risk to human health, which remained “very low” for the general population.
Professor Hopkins said: “Current evidence suggests that the avian influenza viruses that we see circulating in birds around the world are not readily transmissible to humans.”
“However, we already know that the virus can spread to people who have close contact with infected birds and so through screening programs like this we are monitoring people who have been exposed to the virus to learn more about this risk. “
“Globally, there is no evidence of human-to-human spread of this strain, but we know that viruses are constantly evolving and we remain vigilant for any indication of a change in risk to the population.”
“It remains important that people avoid touching sick or dead birds and that they follow Defra’s advice on reporting.”
Avian influenza is a known infectious disease in poultry and wild birds.
Other animals have also contracted the disease, such as seals, otters, wild dogs and foxes.
Animal cases have been reported in the UK and around the world.
The H5N1 virus is currently the most widespread virus strain.
According to the UKHSA, people at highest risk of being exposed to infected birds are being contacted daily to monitor the development of symptoms.
As part of the UKHSA’s asymptomatic surveillance programme, poultry workers are being asked to swab their nose and throat for 10 days after exposure to check for influenza.
In some cases, they may also be asked to have blood tests taken from the fingerprint sample to determine if antibodies to bird flu are present.
Anyone who has been in contact with a person who has bird flu can also be tested.
They may be offered antiviral medications to protect themselves from infection and reduce the risk of passing it on.
Everything you need to know about bird flu
What is bird flu?
Avian flu is a bird disease caused by influenza viruses.
What strain of bird flu is in circulation?
A Eurasian strain of the highly pathogenic H5N1 avian influenza is circulating in the UK and Europe.
This strain is a very potent and contagious virus for poultry and other birds, but the risk to human health is estimated to be very low.
What are the signs of bird flu?
Symptoms in birds infected with the most serious pathogen include a swollen head, closed and watering eyes, lethargy and depression, lying down and unresponsiveness, lack of coordination, eating less than usual, and a sudden increase or decrease in water consumption.
Some species such as ducks, geese and swans can carry and spread the bird flu virus without showing any signs of illness.
Birds infected with the less severe strain of avian influenza called low pathogenic avian influenza (LPAI) may not show clear signs of infection. They may have slight breathing problems. These signs can indicate bird flu, but only laboratory tests can confirm the bird flu virus.
Is bird flu a danger to humans?
The British health authority UK Health Security Agency (UKHSA) points out that the risk to public health from the virus is very low. People are advised not to touch or pick up dead or visibly sick birds they find.
The UKHSA said it had found no evidence of human-to-human transmission and the two newly announced findings did not change the level of risk to human health, which remains very low for the general population.
What measures have been taken?
A “mandatory containment order” for England and Wales was lifted on April 18, meaning poultry and captive birds can be kept outside again.
Bird keepers have been under a national containment order since 7 November to stem an unprecedented number of cases of bird flu – over 330 cases have been confirmed in the UK since October 2021.
The government said poultry and other captive birds could be kept outside again unless they were in a specific protection zone.
Is the virus still circulating in the environment?
In April said Dr. Christine Middlemiss, the UK’s chief veterinarian, said the risk of avian influenza had fallen following restrictive measures over the winter, although bird keepers were urged to adhere to “strict biosecurity standards”.
The Department for Environment, Food and Rural Affairs (Defra) said the strict rules put in place as part of the bird flu prevention zone would continue to apply as the virus could circulate in the environment for several more weeks.
Sites with poor biosecurity have been classified as medium risk of infection and sites with good biosecurity are considered low risk.