THe public has been urged to look out for swine flu symptoms after the first case in the UK has been detected.
A case of the H1N2 strain has been found, which is very similar to what has been circulating in pigs, the UK Health Security Agency (UKHSA) confirmed. Routine surveillance in GP surgeries picked up the case after the person suffered a mild illness.
The UKHSA said it was now carrying out contact tracing to prevent further spread of the virus. It is not known at this stage how transmissible the strain is, or if there could be other cases in the UK. The UKHSA has notified the World Health Organization of the latest case.
The WHO said that human infections were “usually due to direct or indirect exposure to pigs or contaminated environments”. Human infections with influenza variant viruses tend to result in mild clinical illness, although some cases have resulted in hospitalisation with more severe disease. Given the potential impact on public health, human infections with these viruses need to be monitored closely, it states.
People with swine flu can have symptoms that range from a mild fever and cough to acute pneumonia and death. However the WHO has said that nausea and sickness are not the most common in the H1N2 strain.
The WHO states: "Avian, swine and other zoonotic influenza infections in humans may cause disease ranging from mild upper respiratory infection (fever and cough) to rapid progression to severe pneumonia, acute respiratory distress syndrome, shock and even death.
"Gastrointestinal symptoms such as nausea, vomiting and diarrhea has been reported more frequently in A(H5N1) infection. Conjunctivitis has also been reported in influenza A(H7). Disease features such as the incubation period, severity of symptoms and clinical outcome varies by the virus causing infection but mainly manifests with respiratory symptoms."
To prevent the spread of swine flu, people are also advised to "avoid contact with animals that are sick or dead from unknown causes, including wild animals, and should report dead wild birds and mammals or request their removal by contacting local wildlife or veterinary authorities."
There have been about 50 reported human cases worldwide of the H1N2 virus since 2005; none of them related genetically to this strain. The person who has been detected with the H1N2 strain is not known to have worked with pigs and has fully recovered.
The case was detected as part of routine national flu surveillance undertaken by UKHSA and the Royal College of GPs, which was in place even before the Covid pandemic. The patient was tested by their GP in North Yorkshire after experiencing respiratory symptoms. The strain was identified via polymerase chain reaction (PCR) testing and genome sequencing.
UKHSA said people with respiratory symptoms should continue to follow the existing guidance - avoiding contact with other people while suffering symptoms and taking particular care around vulnerable people and the elderly. It said it was "monitoring the situation closely and is taking steps to increase surveillance within existing programmes involving GP surgeries and hospitals in parts of North Yorkshire.