Bird flu outbreaks have become frequent and common in recent years across the globe. India is currently facing bird flue outbreaks in states such as Himachal Pradesh, Haryana, Kerala and Madhya Pradesh, and a scare in some others such as Punjab, Rajasthan, Gujarat, Karnataka and Union Territory of Jammu and Kashmir.
Hundreds of birds have already died and authorities warn of possible transmission from birds to humans. Culling of birds is underway in the affected areas from Himachal Pradesh to Kerala. What is bird flu? It is influenza among birds, hence also called avian influenza. This viral disease is caused by Influenza Type-A virus that commonly affects both wild and poultry birds. This virus has several strains, most of them causing mild symptoms and affecting low egg production. But some variants are lethal causing loss of avian lives. The current outbreak has evidence of H5N1 and H8N1 strains of virus causing death of birds. How do flu outbreaks spread among birds? Some wild varieties of birds such as ducks and geese are considered to be the natural reservoirs of Influenza Type-A viruses. It is believed that certain birds carry the variants of flu viruses without becoming sick and spread the disease to other birds through their droppings.
Birds can relieve themselves while flying, the carrier birds spread the flu virus globally. And, usually, bird flu outbreaks coincide with the seasons when migratory birds are in large number in a region. This is the season when several states of India become home to many migratory birds. Himachal Pradesh, for example, has seen hundreds of migratory birds dying of avian influenza this season. What are the chances of bird flu transmitting to humans? The avian flu virus spreads from aquatic varieties to terrestrial birds including poultry and from them sometimes to animals such as dogs, cats, pigs and horses. Spread of bird flu from birds and animals is not a common occurrence. The first recorded occurrence of bird flu among humans came from its outbreak in 1997 in Hong Kong. The outbreak happened from a live bird market in Hong Kong. The strain was identified as H5N1 with a high mortality rate. Six of 18 confirmed cases among humans died. Since then more than 50 countries have detected avian influenza. According to the US Centers of Disease Control and Prevention (CDC), six countries are considered endemic for H5N1 virus in poultry. It includes India. Others are China, Bangladesh, Vietnam, Indonesia and Egypt. Bird flu re-emerged in 2003 on a bigger scale affecting many countries after that. How it may spread to humans? Spread of bird flu among humans is not easy. People-to-people spread of bird flu is not common.
Those who work in close contacts with infected birds, dead or alive, and eat uncooked or half-cooked poultry products including chicken meat are at risk. The World Health Organisation (WHO) clearly says that there is no evidence to suggest that the disease can spread through properly cooked food. Like all viruses, bird flu virus is also sensitive to heat and dies at cooking temperature or over 60 degree Celsius. However, due to constant mutation that viruses go through, the scientists have warned that a new variant poses a danger of turning a bird flu outbreak into a pandemic. The threat is considered more serious in the wake of Covid-19 pandemic that began from a Chinese city towards the end of 2019 and became a lethal pandemic in the first quarter of 2020. What if somebody catches bird flu? Bird flu usually affects the gut area among the birds but when the disease spreads to humans, it becomes a respiratory tract illness. It may cause ARDS or Acute Respiratory Distress Syndrome, similar to one caused by Covid-19. Early symptoms of bird flu among humans are fever, cough and sore throat. Sometimes, an infected person may complain of abdominal pain and suffer diarrhoea.
All these symptoms are seen in the case of Covid-19 as well. However, there is one key difference, that is, the H5N1 virus has its receptors deep inside the human lungs unlike H1N1 – which causes swine flu – or SARS-CoV-2 which causes Covid-19. These two viruses have their receptors in the upper respiratory system such as nasal cavities of humans. Though there is no specific medicine for bird flu among humans, some antiviral drugs such as oseltamivir helps speedier recovery and greater chances of survival. There is no vaccine for protection against bird flu yet. In India, the Union health ministry’s advisory says that those working or dealing with poultry should use PPE and strictly maintain hand hygiene. However, there has been no recorded case of bird flu among humans in India.
But if somebody shows symptoms and wants to be sure, a throat swab is taken from the patient to test for avian flu. And finally, can we eat eggs and chickens? Yes, if you normally do. A properly cooked egg or chicken meat or any poultry product for that matter is safe to consume.
