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The U.S. Federal Public Health Agency announced on Thursday the first case of human infection with the H5 avian influenza virus in the United States. An announcement that may seem disturbing in the current context, but does not increase the risks to the general public.
The Centers for Disease Control and Prevention (CDC), the lead US federal public health agency, reported the first human infection with the H5 avian influenza virus in Colorado on Thursday, April 28.
Fatigue as the only symptom
Infected birds shed H5N1 viruses in saliva, mucus and feces. Human infection with the H5N1 virus is rare. However, human infection can occur when a sufficient amount of the virus comes into contact with a person’s eyes, nose, or mouth, or is inhaled. People who have close or prolonged unprotected contact (without respiratory or eye protection) with infected birds, or with areas touched by sick birds or their mucus, saliva or faeces, may be at increased risk of contracting the H5N1 virus. Illness in people infected with the avian influenza virus ranges from mild (eg, eye infection, upper respiratory symptoms) to severe (eg, pneumonia) that can lead to death.
The reported case occurred in a person under the age of 40 who was involved in the slaughter of a bird infected with suspected H5N1 avian influenza. The patient had only one symptom: he reported being tired for several days and has since recovered. He was isolated and treated with an antiviral drug against the flu.oseltamivir.
Second human case in the world
This is the second human case associated with this particular group of H5 viruses and the first in the United States. The first international case occurred in a man in December 2021 in the UK. His flock of poultry became infected with the virus and the man tested positive for the virus, although he appeared to be showing no symptoms of the disease.
Although this patient is believed to be the second person in the world, it is not completely certain that the Colorado man was actually infected. CDC says test could detect virus “surface pollution” – presumably a virus taken from a nasal swab – which was present due to human involvement in the slaughter of an infected bird. But the federal agency said the person in question met the criteria for a positive case and should be treated as such.
Low risk to the general public
“This H5-positive human case does not change the human risk assessment for the general public, which the CDC considers low. However, people who come into contact with infected birds at work or while playing are at higher risk of infection and should take appropriate precautions.” explained the CDC in its press release.
But what precautions are needed? The CDC has put forward various measures:
- Avoid contact with a bird that looks sick or dead;
- Avoid contact with surfaces that appear to be contaminated with droppings from wild or domestic birds;
- If you have to handle sick or dead wild birds or poultry, minimize direct contact by wearing gloves and washing your hands with soap and water after handling birds. If possible, use respiratory protection, such as a medical mask, and eye protection, such as goggles;
- Keep in mind that handling poultry and eggs properly and cooking them at an internal temperature of 74 degrees kills bacteria and viruses, including the H5N1 virus.
However, the United States federal agency continues to monitor H5N1 viruses for genetic changes associated with adaptation to mammals, which may indicate that the virus is adapting to spread more easily from birds to humans.
Thus, she announced that she was considering preventive measures against the H5N1 virus, in particular the development of a candidate virus that, if necessary, could be used to produce a vaccine for humans.