Genotype D1.1

Why in the News?

The US Department of Agriculture has confirmed a new spillover of H5N1 avian flu genotype D1.1 into dairy cattle in the United States.

What is Genotype D1.1?

• Genotype D1.1 is a strain of the H5N1 highly pathogenic avian influenza (HPAI) virus, primarily found in poultry and wild birds.
• It is part of the H5 clade 2.3.4.4b, which has been responsible for multiple outbreaks worldwide.
• It was recently confirmed in dairy herds in Churchill County, Nevada, USA.
• Symptoms in Cattle: Includes fever, reduced milk production, coughing, sneezing, and nasal discharge.
• Differences from B3.13: Genotype B3.13, the previous dominant H5N1 strain in cattle, caused milder infections in humans, whereas D1.1 has led to more severe cases.

Bird Flu (Avian Influenza) Spillover of H5N1 Virus

• A spillover event occurs when a virus jumps from its natural host species (wild birds) to other animals or humans.
• It spreads through wild bird migration routes, carrying the virus across continents.
• The virus has been detected in unpasteurized milk from infected cows, raising concerns about worker exposure.

Impacts on India

• Although genotype D1.1 has not been detected in India, the growing spread of H5N1 in cattle and humans abroad raises concerns for public health and livestock industries in India.
• India is part of major bird migration routes (Central Asian Flyway & East Asian-Australasian Flyway), making it vulnerable to H5N1 spread from infected wild birds.
• With India being the world’s largest milk producer, a spillover of H5N1 into dairy cattle could severely impact milk production and exports.
• While human cases remain rare, a mutation allowing human-to-human transmission could lead to a pandemic-like scenario.
•  India poultry products exports to Middle Eastern and Asian markets; an H5N1 outbreak could lead to bans and economic losses.