Kochi: Bird flu has reared its head again in Kerala. Last week, authorities ordered the culling of at least 8,000 birds, including poultry and ducks, in the district of Kottayam.
Worldwide too, cases of bird flu have surged over the past few months. The US and UK witnessed their worst-ever outbreaks of bird flu in October-November this year. The zoonotic disease is spreading rapidly in France too. Poultry exports, including India’s, are beginning to take a hit.
Bird flu, or avian influenza, is a zoonotic disease that affects wild and domestic birds and can spill over to humans as well.
Bird flu in Kerala
Almost a week ago, two panchayats in Kerala’s Kottayam district – Arpookara and Thalayazham – reported a bird flu outbreak. Authorities have ordered the culling of around 8,000 ducks, hens and other domestic birds within a kilometre radius of the affected areas, reported India Today. The district administration also ordered a ban on the sale and import of chicken, duck, quail, and other poultry eggs and meat for three days from December 13 within 10 km of the epicentre of bird flu. The ban has now been lifted.
As per district authorities, tests conducted at the National Institute of High-Security Animal Diseases (NIHSAD) in Bhopal confirmed it to be the H5N1 strain of the virus, reported Livemint. The H5N1 strain is the most prevalent one now across the world.
Kerala had already reported cases of bird flu in October this year and around 1,500 birds died, reported The Hindu. Authorities had prepared to cull around 20,000 birds then. The Nilgiris district administration in Tamil Nadu also temporarily suspended the transport of poultry products from Kerala in November.
The impacts of bird flu are beginning to tell on poultry exports too. There is a reduction in poultry exports due to the bird flu, which has resulted in reduced demand from major importing countries, the Indian government said recently.
Bird flu cases surge worldwide
Worldwide, the cases of bird flu have surged over the past months. As of November 2022, 97 million birds have died globally, as per one estimate, and experts have warned that infections could rise even higher over the winter.
The US witnessed around 47 million birds dying either due to infections or culling – almost a record – as a result of bird flu. As per reports, this was caused by a different form of the virus (a subtype of the H5N1 strain) than usually seen in the area. This in turn infected more wild birds that then transmit the disease, officials said.
Bird flu is rife across Europe as well. Fifty million birds have been culled in Europe alone, reported Down to Earth. The United Kingdom witnessed its worst-ever outbreak of avian influenza last month. Authorities closed down the renowned Berlin Zoo temporarily last month due to an outbreak.
Bird flu has also spread quickly over the past weeks in France, the country’s farm ministry said on Wednesday. According to the ministry, 217 bird flu outbreaks were detected on French farms by December 20, up from 100 on December 2, and the number of cases has also risen sharply in wildlife, reported Reuters. France is the European Union’s second-largest poultry producer, and the sudden spike in bird flu cases raises concerns about shortages.
What is bird flu?
Bird flu, or avian influenza, refers to a variety of influenza type A viruses and is a zoonotic disease that affects wild and domestic bird populations. The disease makes its presence felt particularly during winter in most of India and other parts of the globe, as wintering migratory birds arrive and bring pathogens with them. Temperature is also a factor: the virus thrives better in cooler climes, thus enabling its spread during winter.
Bird flu is a concern because the virus can spread quickly among domestic birds, causing drastic economic losses. It can also spill over to people, and poses a significant public health risk. Strains of avian influenza differ in their impacts and some such as the H5N1 strain have caused human deaths worldwide too. Globally, from January 2003 to November 11 this year, there have been 868 cases of human infection with the H5N1 strain of the virus, across 21 countries according to a report by the World Health Organisation. Of these, 457 were fatal.
Bird flu affects wild bird populations drastically as well. The highly contagious H5N1 strain of the virus killed around 13,000 pelicans, blue-footed boobies and other seabirds in Peru last month, according to biologists. This year’s outbreaks have been particularly hard on wild bird populations: it has killed more wild birds than ever before and sea birds have been especially affected, reported the BBC.
Culling infected domestic bird populations is one of the measures that can be taken to tackle such outbreaks. Some countries, such as China, also vaccinate their birds; others such as the Netherlands have begun vaccine trials to control outbreaks. Surveillance of domestic and wild birds is another measure that is used to detect an outbreak early so that control measures can be taken immediately to minimise spread.