What is H5N1 avian influenza, its symptoms, and how fatal can it be?

What is the News?

An 11-year-old boy in Delhi died of H5N1 avian influenza. This is the first recorded death due to the bird flu in India in 2021.

About Bird Flu:

• Bird flu or avian influenza is a disease caused by avian influenza Type A viruses found naturally in wild birds worldwide.
• The virus can infect domestic poultry including chickens, ducks, turkeys and there have been reports of H5N1 infection among pigs, cats, and even tigers in Thailand zoos.

Types:

• Avian Influenza type A viruses are classified based on two proteins on their surfaces – Hemagglutinin (HA) and Neuraminidase (NA).
• There are about 18 HA subtypes and 11 NA subtypes. Several combinations of these two proteins are possible e.g., H5N1, H7N2, H9N6, H17N10 among others.

Symptoms:

• Symptoms of avian influenza include – Fever, cough, sore throat, muscle aches, nausea, abdominal pain, diarrhea, vomiting, severe respiratory illness, and Neurologic changes.

Infection in Humans:

• There have been reports of avian and swine influenza infections in humans including A(H1N1), A(H1N2), A(H5N1), A(H7N9) among others.
• The first report of human H5N1 infection was in 1997. Moreover, the infection is deadly as it has a high mortality rate of about 60%.

Transmission to Humans:

• The most common route of transmission is direct contact — when a person comes in close contact with infected birds, either dead or alive.
• Humans can also be affected if they come in contact with contaminated surfaces or air near the infected poultry.
• There is no sufficient evidence suggesting the spread of the virus through properly cooked meat.
• Moreover, the cases of human-to-human transmission of the H5N1 virus are very rare.