What is Bird Flu?
- Avian influenza (“bird flu”) is an infectious disease of birds caused by type A strains of the influenza virus.
- The infection can cause a wide spectrum of symptoms in birds, ranging from mild illness, which may pass unnoticed, to a rapidly fatal disease that can cause severe epidemics.
Are Humans affected by it?
- Avian influenza viruses normally do not infect humans.
- However, there have been instances of certain highly pathogenic strains causing severe respiratory disease in humans.
- In most cases, the people infected had been in close contact with infected poultry or with objects contaminated by their faeces.
- The H5N1 avian flu was first detected in geese in China in 1996.
- The first human cases of the contagion occurred in 1997 amid a poultry outbreak in Hong Kong.
- Whenever outbreaks happen, infected poultry and the birds in farms of surrounding area are culled to stop further spread.
What causes the Bird Flu?
- Bird flu is similar to swine flu, dog flu, horse flu and human flu as an illness caused by strains of influenza viruses that have adapted to a specific host.
- Out of the three types of influenza viruses (A, B, and C), influenza A virus is a zoonotic infection with a natural reservoir almost entirely in birds.
- Avian influenza, for most purposes, refers to the influenza A virus.
- epizootic = an epidemic in non-humans
- panzootic = a disease affecting animals especially over a wide area
What is H and N?
- Influenza type A viruses are classified into subtypes according to the combinations of different virus surface proteins hemagglutinin (H) and neuraminidase (N).
- There are 18 different known H antigens (H1 to H18) and 11 different known N antigens (N1 to N11)
- avian influenza “bird flu” virus subtypes A(H5N1) and A(H9N2) or swine influenza “swine flu” virus subtypes A(H1N1) and A(H3N2).
- All of these animal influenza type A viruses are distinct from human influenza viruses and do not easily transmit among humans.
- H17N10 was isolated from fruit bats in 2012.
- H18N11 was discovered in a Peruvian bat in 2013
Where do these viruses come from?
- Wild birds are the primary natural reservoir for most subtypes of influenza A viruses.
- Most cause asymptomatic or mild infection in birds, where the range of symptoms depends on the virus properties.
- Viruses that cause severe disease in poultry and result in high death rates are called highly pathogenic avian influenza (HPAI).
- Source of current outbreak?
- Normally, bird flu outbreaks are reported in February and March, due to widening differences in temperature between day and night.
- In this period, birds normally travel from cold regions in search of warm weather.
The Next Pandemic?
- H5N1 is a large threat in Asia with infected poultry due to low hygiene conditions and close quarters.
- Although it is easy for humans to contract the infection from birds, human-to-human transmission is more difficult without prolonged contact.
- H5N1 infection in humans can cause severe disease and has a high mortality rate.
- H5N1 caused the deaths of nearly 400 people and hundreds of millions of poultry after it spread from Asia into Europe and Africa in 2005-2006.
- However, public health officials are concerned that strains of avian flu may mutate to become easily transmissible between humans
Poultry farming in India
- The industry is valued at ₹1 trillion
- It employs over five million and indirectly supports over 25 million farmers.
- Nearly 80% of the eggs and chicken sold in India come from commercial farms.
- India is now the second largest producer of eggs and fourth largest producer of chicken. Chicken is its most widely consumed meat.
Rumours causing great harm to Industry
- The poultry business in India has taken a severe hit following the coronavirus cases in the country and a bird flu outbreak in parts of Kerala and Karnataka
- It has led to a scare on social media.
- The estimated loss to the industry is worth nearly Rs 700 crore in just the first two weeks of March.
Is it dangerous to eat chicken and eggs because of Bird Flu?
- The disease cannot be caught by eating cooked poultry or eggs.
- A few influenza A(H5N1) human cases have been linked to consumption of dishes made with raw, contaminated poultry blood