What is bird flu?Approx Read Time: 6 min
- Recently, thousands of birds were found dead in various parts of the country.
- Himachal Pradesh, Kerala and Rajasthan have confirmed that bird flu (avian influenza) is the cause of death of these birds and several other states, including Punjab, Madhya Pradesh and Jharkhand, have given alerts on the disease.
Classification of Influenza:
- The influenza virus, which causes illness, is classified by WHO into four types: A, B, C, and D.
- According to the US Centers for Disease Control and Prevention (CDC), only the influenza A and B viruses are known to cause epidemics.
- The C type virus usually causes mild respiratory illness, while the D type virus typically affects cattle and is not known to infect humans.
- Only the influenza A virus is divided into subtypes and the subtype is based on two proteins on the surface of the virus, hemagglutinin (H) and neuraminidase (N).
- Hemagglutinin has 18 further subtypes, while neuraminidase has 11 and they are named from H1 to H18 and N1 to N11 in a sequential system that applies uniformly to influenza viruses from all sources.
What is Avian influenza or bird flu?
- Avian influenza is a highly contagious viral disease caused by Influenza Type A viruses which generally affects poultry birds such as chickens and turkeys.
- There are many strains of the virus – some of them are mild and may lead to low egg production or other mild symptoms among chickens, while others are severe and lethal.
- Wild aquatic birds such as ducks and geese are the natural reservoir (carriers) of Influenza A viruses. Many birds carry the flu without developing sickness, and shed it in their droppings (excreta).
- Many water birds that migrate and travel long distances, help to spread the virus to poultry and terrestrial birds. Sometimes, the virus jumps to mammals such as pigs, horses, cats and dogs.
Bird flu infection in humans:
- Bird flu outbreaks have been affecting poultry for decades, but it was in 1997 when humans first contracted bird flu after an outbreak in a live bird market of Hong Kong.
- It was the H5N1 strain of the virus, and 6 out of 18 infected humans died of the disease.
- The outbreak in Hong Kong was controlled, but re-emerged a few years in various other parts of the globe and caused hundreds of human deaths, particularly in Southeast Asia.
- Movement of infected poultry and migratory birds, and an illegal bird trade are believed to be the causes of the spread.
Mode of spread to humans:
- Generally, people coming in close contact with infected alive or dead birds have contracted the H5N1 bird flu. As per WHO, it does not spread from person to person.
- Further, as per WHO, there is no evidence that the disease can be spread to people through properly prepared and cooked poultry food. The virus is sensitive to heat, and dies in cooking temperatures.
- However, if the virus mutates and becomes easily transmissible from person to person, by altering its shape to catch human cells effectively, it can potentially cause a pandemic.
- Also, flu viruses are more prone to mutation. All known strains of flu – including the seasonal flu and the pandemic flu – have jumped from birds to humans in this way.
- When a virus replicates or makes copies of itself, it sometimes changes a little bit. These changes are called mutation.
- Unlike in birds, where it generally infects the gut (stomach), the avian influenza attacks the respiratory tract of humans and may cause severe respiratory illnesses such as pneumonia or Acute Respiratory Distress Syndrome (ARDS).
- Its early symptoms include fever, cough, sore throat, and sometimes abdominal pain and diarrhoea.
Treatment and prevention:
- Antiviral drugs help in the treatment and improve the chances of survival in humans. In the US, the Food and Drug Administration approved a vaccine for the H5N1 virus in 2007.
- Among poultry birds, vaccination strategies advised by the World Organisation for Animal Health can be used to prevent the flu.
- People working with poultry are advised to use Personal Protective Equipments (PPEs) and follow hand hygiene.
Bird flu in India:
- According to the Union health ministry, no case of bird flu in humans has been detected so far, in India.
- The department of animal husbandry has reported 25 episodes of H5N1 bird flu in poultry in 15 states from 2006 (when the first outbreak occurred in Maharashtra and Gujarat) till 2015. It has also been detected in crows.
Current measures taken in India:
- As the bird flu may transmit from birds to humans, the Centre has asked states to take all possible steps for containing the spread of the disease on an urgent basis.
- It has asked States to increase surveillance and monitoring of birds for any sign of disease.
- On monitoring of migratory birds, the Centre suggested setting up of state-level monitoring committee and preparing an action plan for dealing with any arising emergency.
- Several states have started culling (killing) birds and have banned sale and purchase of poultry products.
State disaster in Kerala:
- The Kerala government has declared bird flu as a state disaster. When a particular event is declared as a state disaster, it empowers the district collectors to deal with the issue under disaster management laws.
- It also helps in quickly getting funds from the State Disaster Response Fund.
About: State Disaster Response Fund (SDRF)
- The SDRF is constituted under the Disaster Management Act, 2005 and is the primary fund available with state governments for responses to notified disasters.
- The disasters covered under the SDRF include cyclones, droughts, tsunamis, hailstorms, landslides, avalanches and pest attacks among others.
- A state government may use up to 10% of funds available under SDRF for providing immediate relief to victims of an event considered to be a ‘disaster’ within local context in the state.
- The Central government contributes 75 per cent towards the SDRF allocation for general category states and UTs, and over 90% for special category states/UTs, which includes north-eastern states, Sikkim, Himachal Pradesh and Uttarakhand.