High temperatures and reduced salinity in Sambhar lake may have created conditions conducive to avian botulism, resulting in the mass deaths of migratory birds in Rajasthan.

• At least 600 migratory bird deaths were reported by the Centre for Avian Research Institute earlier this month.

About Avian Botulism

• Avian botulism is a neuro-muscular disease caused by Botulinum, a natural toxin produced by the bacterium Clostridium botulinum. 
• Habitat of Bacteria: Clostridium botulinum is commonly found in soil, rivers, and seawater, and affects both humans and animals.
• Growth Conditions: The bacteria thrive in anaerobic (oxygen-free) environments and do not grow in acidic conditions.
• Impact on Birds: It affects the nervous system, causing paralysis in the legs and wings of birds.
• Prevalence in Wetlands: Bacterial spores are prevalent in wetland sediments and are found in wetland-dwelling invertebrates like insects, mollusks, and crustaceans, as well as healthy vertebrates, including birds.
• Trigger Conditions: Outbreaks often occur when temperatures exceed 21°C and during drought conditions.
• Management and Challenges
  • Treatment Limitations: Avian botulism cannot be treated; prompt removal and proper disposal of affected birds are essential to prevent the spread.
  • Past Incidents: A similar outbreak in Sambhar Lake in 2019 caused the deaths of nearly 18,000 birds.
  • Predictability: Outbreaks are difficult to forecast as they depend on specific environmental conditions, such as shifts in salinity coinciding with the arrival of migratory birds.
• Vulnerability of Migratory Birds
  • Susceptibility: Migratory birds arriving after long flights are often weakened, making them more prone to diseases like botulism.
  • Role of Carcasses: Decaying bird carcasses attract maggots, which can contaminate water sources and infect other birds and animals.

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About Sambhar Lake

• Location: Situated about 80 km southwest of Jaipur, Rajasthan.
• Geographical Significance: It is India’s largest inland salt lake and represents a depression in the Aravalli Range.
• Fauna: Flamingoes, pelicans and the waterfowls are commonly sighted at the Sambhar Lake.
• Environmental Importance 
  • Ramsar Site: Declared a wetland of international importance under the Ramsar Convention in 1990.
  • Water Sources: Receives water from six rivers: Samaod, Khari, Mantha, Khandela, Medtha, and Roopangarh.
  • Vegetation: Features xerophytic vegetation, which is adapted to dry conditions.

Central Avian Research Institute (CARI)

• Location: Based in Izzatnagar, near Bareilly, Uttar Pradesh.
• Establishment: Founded in 1979 under the Indian Council of Agricultural Research (ICAR).
• Functions
  • Conducts research in poultry science, focusing on areas like avian genetics, breeding, nutrition, feed technology, physiology, and reproduction.
  • Aims to enhance the Indian poultry industry through scientific advancements.