Avian Lymphoid Leukosis (ALL) is a neoplastic disease caused by the Avian Leukosis Virus (ALV), primarily affecting chickens. It is a retroviral infection that causes tumors and various systemic effects, significantly impacting commercial poultry production.
SYMPTOMS
CAUSES
PREVENTION
TREATMENT
Symptoms
- Primary Manifestations in Chickens:
- Tumors in various organs (especially liver and bursa)
- Depression and lethargy
- Weight loss
- Pale combs and wattles
- Reduced egg production
- Increased mortality after 16 weeks of age
- Enlarged abdomen
- Anemia
- Note:
- While primarily affecting chickens, other poultry species are generally resistant to the disease.
Causes and modes of transmission
- Viral Characteristics:
- Retrovirus (ALV)
- Multiple subgroups (A, B, C, D, E, J)
- Highly persistent in environment
- Transmission Routes:
- Vertical (through egg to offspring)
- Horizontal (direct contact)
- Contaminated equipment
- Mechanical vectors
- Congenital transmission
Prevention strategies
- Breeding Management:
- Testing and elimination of positive breeders
- Eradication programs
- Clean egg program
- Biosecurity Measures:
- Isolation of affected flocks
- Proper cleaning and disinfection
- Control of mechanical vectors
- Regular testing programs
- Management Practices:
- All-in-all-out production
- Proper disposal of affected birds
- Monitoring programs
- Record keeping
Treatment options
- Direct Treatment:
- No specific treatment available
- Affected birds should be culled
- Focus on prevention
- Control Measures:
- Regular surveillance
- Removal of affected birds
- Cleaning and disinfection
- Testing of breeding stock
Conclusion:
Prevention through breeding programs and biosecurity is the only effective approach to controlling ALL, as there is no effective treatment once birds are infected.
