Bird flu virus mutates, more dangerous than COVID: How is it spreading?

A file picture of health department officials who were in Kottayam when bird flu was confirmed in the district in 2016. Photo: Manorama

Bird flu comes as an unexpected blow to farmers, who are perennially struggling to make ends meet. It sporadically hits various locations like a bolt of lightning. The situation is no different in April of 2024 with Alappuzha grappling with the disease. When bird flu is mentioned, it is often dismissed as inconsequential, with the belief that abstaining from chicken, duck meat, and eggs for a few days is sufficient to ride it out, given that only birds contract the disease. While this premise holds, recent research suggests that humans are on the brink of encountering deadly strains of bird flu (H5N1–H5N1).

'Treat with utmost seriousness'
Following the discovery in the US that bird flu is not only spreading among chickens and ducks but also transferring from birds to humans, the global health sector is grappling with this new challenge. Experts warn that if the virus infects humans, it could be 100 times more dangerous than COVID-19. The US Centre for Disease Control and Prevention has already cautioned doctors to treat cases occurring in individuals closely associated with birds and livestock with utmost seriousness, aiming to minimize further spread.

The US Center for Disease Control and Prevention has already cautioned doctors to treat cases occurring in individuals closely associated with birds and livestock with utmost seriousness, aiming to minimize further spread. Photo: IANS

Constant mutation
In Kerala, thousands of chickens and ducks have been culled in past years due to bird flu outbreaks in districts such as Alappuzha, Kottayam, and Kozhikode. But many farmers have yet to receive compensation for their losses, impacting other sectors as well. Amidst these ongoing crises, health experts are highlighting another pressing issue: the constant mutation of the H5N1 virus, increasing the likelihood of aggressive human infections. Individuals with influenza, pneumonia, or respiratory illnesses may be suspected of having bird flu if they have had direct or indirect contact with sick birds. Confirmation of bird flu can be obtained through laboratory tests.

How disease spreads
Bird flu viruses are relatively less contagious. However, under certain circumstances, viruses typically confined to birds can infect humans. The disease spreads through the excreta and bodily fluids of birds and is not airborne. If the virus transfers from birds to humans, viral pneumonia is likely to occur in 60% of cases. These viruses become pathogenic through specific genetic changes. Moreover, the virus can combine with human influenza viruses, creating new genomes that are highly pathogenic. Individuals working in bird breeding and poultry farms are particularly vulnerable to the disease. Research indicates that bird flu viruses can affect all parts of the human body.

In many countries, half of the number of infected people succumbed to the virus. The deadly H5N1 viruses are lethal to humans. Despite available drugs, viral pneumonia remains a severe condition with a mortality rate of around 70%. Infected patients require treatment in isolation wards of hospitals. Although a protective vaccine has been developed, its use in India is pending. Notably, the vaccine effective against common influenza (H1N1) does not offer protection against bird flu.

First in China; now in Kerala too
Bird flu initially spread to humans in Hong Kong, China, resulting in numerous deaths during that period. Subsequently, it spread to Asian countries, then to Europe and Africa. Although bird flu has not yet extensively affected humans in India, health researchers have consistently cautioned against dismissing the possibility of human transmission in the country. This concern has now materialized in the US.

The gravest aspect is the potential for bird flu to spread from humans to other humans if it first spreads from birds to humans. The World Health Organization advocates for the scientific culling of birds within a one-kilometre radius of the reported disease outbreak as an effective control measure. On November 24, 2014, residents of Kerala were alarmed by the first H5N1 infection report. Bird flu was initially confirmed in the districts of Kottayam and Alappuzha in Kerala. Emergency measures were promptly initiated to prevent human transmission.

The H5N1 influenza virus causes bird flu. In 2014, the bird flu threat primarily affected ducks in Kuttanad, Kerala. The Animal Husbandry Department conducted mass culling, eliminating thousands of ducks during that period. Thoughtful preventive measures and an awareness campaign successfully confined avian flu to the duck population of Kuttanad.

As fears escalate, many individuals remove chicken and duck from their menus. Photo: Chef Arun Vijayan

Is chicken also a villain?
When reports of bird flu surface, chickens often become the primary suspect. As fears escalate, many individuals remove chicken and duck from their menus. However, experts offer guidance on consuming chicken and duck safely. These poultry products can still be enjoyed without fear of contracting the disease. It is simply a matter of taking necessary precautions.

Avian flu symptoms in birds
Birds affected by bird flu exhibit various symptoms, including lethargy, sluggishness in movement, reluctance to eat, extreme fatigue, bluish beak and plumage, nosebleeds, diarrhoea, and respiratory distress. Additionally, the thickness of eggshells decreases and there is a significant reduction in the number of eggs laid. Ultimately, this can culminate in severe pneumonia. Without proper treatment, affected birds are prone to mass mortality.

Symptoms in humans
The typical symptoms of bird flu in humans encompass a range of common ailments, such as cold, headache, diarrhoea, vomiting, body aches, cough, unusual fatigue, and severe sore throat. Diagnosis of infected patients typically involves testing secretions obtained from the throat and nose. The definitive laboratory test is the Reverse Transcription Polymerase Chain Reaction (RT-PCR) test. Alternatively, diagnosis can be established by assessing the levels of H5N1 antibody in the patient's blood serum.

Bird flu a century ago
Avian flu, an infectious disease caused by a virus in birds, spreads from wild birds to domestic fowl. Italian scientist Eduardo Peroncito was the first to identify a virus as the cause of bird flu in 1878. In 1955, it was confirmed that this virus belongs to the type A influenza group. This disease can emerge globally irrespective of the season. Symptoms typically manifest in birds three to five days after exposure to the virus. This airborne disease can also be transmitted to humans through sewage, food, and clothing. However, in 1997, it was discovered to pose a significant threat to human life. Six fatalities occurred due to bird flu in Hong Kong at that time. Although highly contagious in birds, the virus does not spread as rapidly in humans.

Nonetheless, there is a risk of the virus entering humans and causing common cold or potentially fatal diseases. Bird flu was first confirmed in India on February 18, 2006, in a chicken farm in Navapur, Maharashtra. Subsequently, it was detected in States including Manipur, Bengal, Assam, Tripura, Odisha, Madhya Pradesh, Gujarat, Sikkim, and Meghalaya. The first instance of bird flu in South India occurred in October 2012 at a turkey farm belonging to the Central Poultry Development Organization in Bengaluru.

Avian flu, an infectious disease caused by a virus in birds, spreads from wild birds to domestic fowl. Photo: Shutterstock/Festa

Crows and cats are carriers
The disease stems from the type A influenza virus, primarily affecting chickens and turkeys. This virus belongs to the Orthomyxo family and is highly prone to mutation. The virus, which is highly susceptible to mutation, has three variants of influenza type A, type B and type C. All three variants are capable of infecting humans. Type A influenza predominantly affects birds and animals. The H5N1 subtype viruses identified in Kerala can afflict various avian species, including ducks, flamingos, quails, guinea fowl, wild birds, crows, cats, dogs, and even tigers. However, pet birds like pigeons and parrots are less susceptible to H5N1 virus infection.

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