Bird Flu Outbreaks In India: How Does Bird Flu Differ From Regular Flu?

Bird flu, also known as avian influenza, has been reported in parts of Kerala, including Alappuzha and Kottayam. Poultry farms in the neighbouring Tamil Nadu's Namakkal district, which is one of the one of the largest egg-producing hubs in the country, have stepped up biosecurity and surveillance measures to prevent the spread of the disease. Authorities in Tamil Nadu have intensified surveillance along the border to prevent the disease from spreading in the state. Dr Balakrishnan, the Joint Director in the Animal Husbandry Department has initiated special preventive measures.

Lakshmi Bhavya, Nilgiris District Collector, said that the transportation of live poultry, eggs, poultry waste and other related products from Kerala into the district has been temporarily banned as a precautionary measure. A poultry farm owner in Namakkal, Pathasarathy K, said that additional safety protocols have been implemented as a precautionary measure. He added, "After the avian flu outbreak in Kerala, we have strengthened biosecurity norms. Poultry here is raised in a controlled environment, and regular cleaning and disinfection are strictly followed. Formalin is used frequently to eliminate disease-causing organisms." Namakkal alone accounts for nearly 1,500 poultry farms and produces millions of eggs daily, supplying markets across several Indian states and overseas.

Understanding Bird Flu

Bird flu is caused by a type of influenza (flu) virus. It usually spreads in birds and animals. The condition not only impacts domestic poultry such as chickens, ducks and turkeys but can also spread through wild and migratory birds. In certain cases, there's also a risk of transmission to humans. The World Health Organization (WHO) reported 990 human cases of bird flu across 25 countries from 2003 to August 2025. This also includes 475 deaths which indicates a 48% fatality rate. With such a high fatality rate, it is important to stay cautious and prevent the spread. Cleveland Clinic says that it's extremely rare that the infection spreads from person to person.

Difference Between Bird Flu And Regular Flu

While both bird flu and regular seasonal flu occur due to influenza A viruses, they significantly differ in their origin, transmission, severity, and impact.

Bird flu infects birds and jumps to humans when they come in direct contact with infected poultry or contaminated environments. However, regular flu spreads from person-to-person through respiratory droplets.

Cause

Bird flu occurs from strains like H5N1. This binds to receptors in bird respiratory and digestive tracts, unlike seasonal flu viruses (H1N1, H3N2) which affect upper airways in humans. These avian strains evolve through genetic reassortment in birds, potentially causing pandemics via antigenic shift.

Transmission

Regular flu transmits between humans via airborne droplets, coughs, and surfaces, causing predictable annual epidemics. Bird flu rarely spreads from human-to-human due to its inefficient receptor binding in humans. Most of the cases of bird flu are linked to exposure to sick birds, their feces, or unpasteurised milk.

Incubation and Symptoms

Bird flu's incubation lasts 2-8 days, with symptoms of gastrointestinal problems like diarrhoea, vomiting, and abdominal pain. These signs are also accompanied by conjunctivitis and progression to severe pneumonia. Regular flu incubates faster, within 1 to 4 days. It starts with milder upper respiratory symptoms such as sore throat, runny nose, sneezing, and moderate fever that resolves in a week.

Severity and Mortality

Bird flu can lead to acute respiratory distress and multi-organ failure with mortality rates up to 48-50% in confirmed human cases. This exceeds seasonal flu's 0.1% fatality rate, which mostly impacts the elderly or immunocompromised.

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