Dr.SHABIR AHMAD BHAT / Dr.PERVAIZ AHMAD DAR / Dr.TARIQ AHMAD WANI
Avian influenza (bird flu), an economically significant and highly contagious viral disease with a global presence as well as a major concern for public health, has devastating consequences for the poultry industry. The bird flu virus transmission is influenced by a number of factors, including globalisation and international trade, live bird markets, wild birds, and migration routes. Globalization, besides reducing the travel time of both humans and animals throughout the world, has encouraged the faster spread of various diseases, including bird flu. Furthermore, bird flu virus can also spread through the international poultry trade of infected birds before any bird flu case detection at the exporting country’s level.
With the involvement of a large number of birds, the poultry trade can facilitate the rapid transmission of viruses as was the case during the H7N2 virus outbreak in Pennsylvania in 1996-1998. The dynamics of bird flu virus transmission and evolution are highly influenced by the live bird markets, as they provide hotspots for viral evolution due to the intermingling of different animal species from different geographical areas, unsanitary conditions, and high bird densities. Although the above-mentioned ways of bird flu transmission are important while considering the control measures, migratory birds, especially wild aquatic birds, are mainly involved in the world-wide dissemination of the bird flu virus along the migratory routes.
As Jammu and Kashmir falls along the Central Asian Flyway Zone, we anticipate migratory birds visiting Kashmir in the present month. A large number of migratory flocks from different countries in the northern hemisphere can be spotted around mid-October, marking the beginning of migration. In Kashmir, the winged visitors land on various wetlands such as Dal Lake, Hokersar, Wular Lake, Haigam, Shalbugh, and other water bodies. These migratory birds visit the valley to avoid harsh climates, forage for feeding, breeding, and raising their young. Along with them, they also bring various avian pathogens, particularly the avian influenza virus. Wild aquatic birds are natural hosts and reservoirs for all types of avian influenza viruses and thus play a major role in the evolution, maintenance, and spread of these viruses. In recent decades, bird flu has become a major threat to both human and animal health worldwide. In particular, highly pathogenic avian influenza H5N1 and H5N8 have spread across Asia, Africa, and Europe, causing severe losses to the poultry industry. Furthermore, bird flu viruses rarely infect humans. However, sporadic human infections with these viruses have occurred.
Avian influenza (bird flu) is a highly contagious and deadly viral disease of poultry, with devastating consequences for the poultry industry. It is caused by influenza type A viruses divided into multiple subtypes (i.e., H5N1, H5N3, H5N8, etc.) whose genetic characteristics evolve rapidly and infect wild birds as well as domestic poultry. Although avian influenza occurs worldwide, its prevalence varies by region and is primarily classified into two categories: high or low pathogenic viruses (HPAI and LPAI, respectively), depending on their molecular characteristics and ability to cause disease and mortality in chickens. Poultry infected with the LPAI virus may show little or no signs of illness. However, infections with HPAI cause serious illness and death. Both types spread rapidly in poultry flocks. Furthermore, certain LPAI virus strains mutate into highly pathogenic strains, so prompt handling of bird flu outbreaks is critical. In particular, wild waterfowl are considered natural hosts for the low-pathogenic avian influenza (LPAI) virus and have been shown to spread the LPAI virus along migration routes in Asia, Africa, and the Americas.
Even though on-farm biosecurity measures protect poultry reared in intensive settings from coming in contact with disease-carrying wild birds or exposure to environmental pathogens, any breach in biosecurity protocol increases the risk of large-scale bird flu outbreaks. For backyard farming, sporadic cases of bird flu may occur due to higher chances of poultry being mixed with disease-carrying wild birds, environmental exposure, and intermingling with domestic ducks. An increase in poultry farming with poor hygiene has allowed the virus to persist. This is especially true when multiple susceptible species live in the same area. Healthy birds become infected through direct contact with sick birds or through contact with areas or objects contaminated by sick birds such as poultry equipment, manure, etc. Also, poultry workers may accidentally carry the virus on their hands, clothes, and shoes.
The poultry industry holds a unique position in the livestock economy of India. The industry has experienced tremendous growth over the past three decades and employs a significant portion of the population in both rural and urban areas. The structure and functioning of the national poultry industry have changed dramatically due to technological advances. Since the 2012 livestock census, the country’s poultry population has increased by 16.8% to 851.81 million in 2019. A total of 317.07 million birds are “backyard poultry” and 534.74 million are commercial birds. It has developed into one of the most specialised enterprises in many parts of the country. The poultry sector is highly developed in India, and the country’s poultry sector is worth Rs 125,000 crore. According to FAOSTAT production data (2020), India ranks 3rd in the world for egg production and 8th for meat production. National egg production increased from 78.48 billion in 2014-15 to 122.11 billion in 2020-21. National meat production increased from 6.69 million tonnes in 2014–15 to 8.8 million tonnes in 2020–21.
Being the 2nd most populous country in the world, India consumes about 30 crore eggs and 900 crore chickens every month and also exports hundreds of crores’ worth of poultry products, such as egg powder, egg yolk powder, and chicken, as well as pharmaceutical ingredients from the poultry sector annually. As a rich source of protein, fat, minerals, and vitamins, poultry products contribute to national food security. Avian influenza has captured the world’s attention over the years owing to its devastating impact on the poultry industry, farmers’ livelihoods, pandemic potential (H5N1), and international trade. The livelihoods of crores of people dependent on the poultry industry are set to suffer as the bird flu scare discourages more and more people from eating poultry and poultry products. Also, disease outbreaks cause high levels of illness and death in vulnerable species and can even threaten biodiversity. Additionally, due to the stamping-out policy, poultry farmers and traders suffer huge economic losses through the culling of all the poultry in the infected zone. Even though the government provides compensation in cases of culling poultry, however, that does not suffice for the expected profit.
Prevention is better than cure, as applicable to other diseases also applies to bird flu prevention. Practising bio-security “every day, always” in the poultry facilities is highly recommended. Also, discouraging the setting up of poultry farms near water bodies, in the vicinity of human habitation, and near forest areas, as already recommended by the animal husbandry department, should be fully followed to reduce the risk of any bird flu outbreaks. Furthermore, providing awareness among the general public concerning the hygienic handling and eating of well-cooked poultry and poultry products, besides removing any fake rumors, is highly needed. Personnel involved in live bird markets and other poultry outlets need to be educated about the hygienic handling of poultry and poultry products and also regarding the proper disposal of poultry waste. Additionally, promoting collaboration between public health and animal health groups. In the case of a bird flu outbreak, the World Organization for Animal Health recommends culling of both sick and healthy poultry in the infected zone along with active surveillance in the surveillance zone.
Bird flu is difficult to eradicate due to the persistence of the virus in vast aquatic bird reservoirs. On the ground, however, the spread of bird flu can be controlled through appropriate strategies, including targeted surveillance in high-risk areas such as popular flight routes and breeding grounds, regular monitoring of wild aquatic birds, and surveillance at the wild bird-poultry-wetland interface to get acquainted with the prevalent avian influenza viral strains. The surveillance data generated may be useful in promptly warning commercial poultry farms and the general public about the possibility of any upcoming bird flu outbreaks.
(Dr Shabir Ahmad Bhat is a Virologist and presently deployed at IAH & BP, Zakura, DAH-K, Dr Pervaiz Ahmad Dar is a Scientist at Krishi Vigyan Kendra, Ganderbal, SKUAST-K, Dr Tariq Ahmad wani is Veterinary Assistant surgeon, DAH-K)
