First human death from H5N2 Bird Flu: Reasons and Diagnosis

H5N2 bird flu, also known as avian influenza A(H5N2) virus, is a subtype of influenza. Check here Reasons, Effect and Diagnosis of H5N2 Bird Flu in this article.

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Context: In Mexico, a 59-year-old man died recently from H5N2, which is a type of bird flu.

The recent human case in Mexico is under investigation, as the man had no reported contact with poultry. This raises the possibility that the virus might be acquiring the ability to spread between humans, although health officials currently assess the risk to the general public as low.

H5N2 Bird Flu

H5N2 is one of several types of avian influenza viruses.
It is characterised by specific proteins on its surface: hemaglutinin (H) and neuraminidase (N), with H5N2 belonging to the H5 family.
Transmission to Human: The H5 family includes nine known subtypes, primarily infecting wild birds.
- Unlike H1 and H3 strains, H5 viruses infrequently infect humans.
- Infections in humans have primarily been acquired through direct contact with infected animals or contaminated environments.

Avian Influenza

Bird flu or avian influenza primarily infects poultry and wild birds, with strains like H5N1 becoming highly pathogenic when they jump from wild birds to farmed birds.

Reasons Behind Spread of H5N2 Bird Flu

The spread of H5N2 bird flu is primarily driven by two factors:

Migratory bird patterns: Wild birds, especially waterfowl, can carry the virus over long distances as they migrate. When they come into contact with domestic poultry, the virus can spread easily in crowded conditions.
Interaction with domestic birds: Poultry farms with poor biosecurity measures are at higher risk. If the virus infects domestic birds, it can spread quickly through the flock and potentially to other farms through contaminated equipment or vehicles.

There’s also some concern that environmental changes might influence the spread of H5N2 by altering bird migration patterns or behavior, but this requires further investigation.

Effect of H5N2 Bird Flu

It can infect a wide variety of birds, including chickens, ducks, turkeys, falcons, and ostriches. The severity of the disease in birds can vary depending on the specific strain of H5N2. Some strains are highly pathogenic and can cause death in birds within hours or days. Other strains are low pathogenic and may cause only mild illness or no symptoms at all.

Diagnosis of H5N2

Diagnosing H5N2 bird flu in humans and birds requires different approaches.

In Birds

Veterinarians typically diagnose H5N2 bird flu in birds based on a combination of factors, including:

Signs and symptoms: Birds infected with H5N2 bird flu may exhibit a variety of signs and symptoms, including sudden death, respiratory distress, lack of energy, decreased appetite, swelling around the head and eyes, purple discoloration of the legs and wattles, diarrhea, and abnormal droppings.
Laboratory testing: Veterinarians will collect samples from sick or dead birds and send them to a laboratory for testing. The most common test used to diagnose H5N2 bird flu is a real-time reverse transcriptase polymerase chain reaction (rRT-PCR) test. This test can identify the specific strain of influenza virus present in the sample.

In Humans

H5N2 bird flu infection in humans cannot be diagnosed by clinical signs and symptoms alone because these symptoms can be similar to those of other respiratory illnesses. Doctors will rely on a combination of factors for diagnosis, including:

Signs and symptoms: People infected with H5N2 bird flu may experience a range of symptoms, including fever, cough, sore throat, runny or stuffy nose, muscle or body aches, headaches, fatigue, shortness of breath, diarrhoea, nausea, vomiting, and eye infections (conjunctivitis).
Exposure history: Doctors will ask about a person’s recent travel history and contact with birds or poultry. People who have travelled to areas with known outbreaks of H5N2 bird flu or who have had contact with sick or dead birds are at higher risk of infection.
Laboratory testing: Similar to testing in birds, real-time RT-PCR testing is the primary method to diagnose H5N2 bird flu infection in humans. Doctors will collect a nasal swab or sputum sample to test for the presence of the virus.

H5N1 Virus

H5N1 Virus is another subtype within the H5 family.
H5N1 belongs to the highly pathogenic “Goose Guangdong lineage” and has caused numerous outbreaks in poultry.
Spreading Beyond Birds:
- Worryingly, the virus is jumping to mammals, including:
  - Seals and sea lions (tens of thousands dead worldwide)
  - Foxes, pumas, skunks, bears (North America)
  - Farmed minks (Spain and Finland)