Poultry farming plays a critical role in the global food supply, but diseases like Infectious Tenosynovitis pose a severe threat to productivity. This viral disease, caused by a reovirus, primarily affects the joints, tendons, and synovial membranes of chickens and turkeys. It leads to lameness, joint swelling, and reduced mobility, ultimately impacting growth rates and meat production.
Due to its contagious nature, Infectious Tenosynovitis can spread rapidly in poultry farms, causing economic losses due to increased mortality, poor weight gain, and treatment expenses. Understanding how it spreads, recognizing symptoms early, and implementing preventive measures are essential for effective disease management.
This guide will provide an in-depth discussion of:
✔️ Causes & Risk Factors
✔️ Symptoms & Diagnosis
✔️ Prevention Strategies
✔️ Treatment & Management
How Infectious Tenosynovitis Spreads (Modes of Transmission)
Understanding how Avian Reovirus spreads is crucial to controlling the disease. The virus is highly contagious and spreads through both horizontal and vertical transmission.
1. Direct Contact Transmission
- The virus spreads when healthy birds come into contact with infected birds.
- Infected birds shed the virus in their droppings, nasal discharge, and saliva.
- Pecking at contaminated surfaces increases the risk of exposure.
2. Indirect Transmission through Contaminated Objects
- The virus can survive on farm equipment, feed trays, water containers, and worker clothing.
- Rodents, insects, and wild birds can act as mechanical carriers.
- Contaminated litter, bedding, and soil can harbor the virus for long periods.
3. Vertical Transmission from Parent Birds
- Infected breeding hens can transmit the virus through eggs to offspring.
- Chicks born from infected eggs already carry the virus, leading to rapid spread in hatcheries.
Causes of Infectious Tenosynovitis in Poultry
1. Reovirus Infection – The Primary Cause
Infectious Tenosynovitis is caused by avian reovirus, which specifically targets tendons and synovial membranes (the lining of joints). The virus damages these tissues, causing swelling, pain, and lameness.
2. Modes of Transmission
- Direct Transmission: Infected birds shed the virus through feces, saliva, and nasal secretions, contaminating feed, water, and litter.
- Indirect Transmission: The virus can survive on farm equipment, shoes, hands, and rodents, making contaminated environments a major risk factor.
- Vertical Transmission (Egg-Borne Infection): Some reovirus strains pass from infected breeder hens to chicks via the egg, leading to early-onset lameness in young birds.
3. Environmental & Managemental Factors
- Overcrowding increases the spread of the virus due to close contact between birds.
- Poor sanitation allows the virus to persist in water, litter, and surfaces, increasing infection risk.
- Nutritional deficiencies, especially lack of Vitamin D, Calcium, and Phosphorus, can weaken bones and tendons, making birds more susceptible.
- Immunosuppression from other diseases (e.g., Marek’s Disease, Newcastle Disease) weakens the bird’s ability to fight the virus.
Symptoms of Infectious Tenosynovitis in Poultry
Recognizing symptoms early helps in reducing disease spread and preventing severe complications.
1. Early-Stage Symptoms (Mild Infection)
✅ Swelling around the hock joints (initial sign of tendon inflammation).
✅ Birds sit down more often and avoid walking.
✅ Slight stiffness in leg movements.
✅ Decreased activity and reluctance to move.
2. Progressive Symptoms (Moderate Infection)
🔸 Severe lameness – Birds struggle to walk, hop, or stand.
🔸 Thickened tendons – The gastrocnemius and digital flexor tendons become enlarged and inflamed.
🔸 Stiff joints – Birds find it painful to bend their legs.
🔸 Weight loss – Due to reduced mobility, birds fail to compete for food.
3. Severe & Advanced Symptoms (Severe Infection)
⚠️ Tendon rupture – The Achilles tendon or hock tendons rupture, leading to permanent disability.
⚠️ Secondary bacterial infections worsen swelling, turning it into pus-filled abscesses.
⚠️ Birds collapse on their legs and stop moving completely.
⚠️ High mortality rates in flocks with weak immune systems.
Diagnosis of Infectious Tenosynovitis
A veterinarian can confirm the disease through:
🔬 Clinical Examination – Checking for joint swelling, limping, and thickened tendons.
🧪 Serology Tests (ELISA & Virus Neutralization Test) – Detects antibodies against reovirus.
🧫 PCR Test – Identifies viral RNA from joint fluid samples.
🦴 Postmortem Findings – Examining ruptured tendons, inflamed synovial membranes, and joint abscesses.
Prevention of Infectious Tenosynovitis in Poultry
Since there is no direct treatment, prevention is the most effective control method.
1. Vaccination – The First Line of Defense
💉 Breeder hens should receive reovirus vaccines to pass immunity to chicks.
💉 Chicks can be vaccinated at 7-14 days of age to develop resistance.
2. Biosecurity Measures
🚧 Limit farm access – Only allow trained workers to handle birds.
🧼 Daily cleaning & disinfection of poultry houses, drinkers, and feeders.
🐀 Rodent & insect control – Prevent them from spreading the virus.
3. Proper Nutrition
🥚 Adequate Vitamin D, Calcium, and Phosphorus – Supports bone and tendon health.
🍗 High-protein feed – Strengthens muscles and immune response.
4. Avoiding Stress & Overcrowding
🏠 Provide sufficient space to prevent unnecessary pressure on joints.
🌡️ Maintain proper temperature & ventilation to reduce stress.
5. Maintain a Clean and Dry Environment
- Replace wet and soiled bedding to prevent infection buildup.
- Disinfect water and feeding systems regularly.
- Improve ventilation to minimize moisture and ammonia levels.
6. Implement Strong Biosecurity Measures
- Restrict farm access to essential personnel only.
- Place disinfection stations at entry points.
- Use separate footwear and clothing for poultry houses.
Management & Treatment of Infectious Tenosynovitis
Since there is no antiviral cure, treatment focuses on supportive care and secondary infection control.
1. Use Anti-Inflammatory Drugs & Antibiotics for Secondary Infections
- NSAIDs (Non-Steroidal Anti-Inflammatory Drugs) can reduce pain.
- Antibiotics like tetracyclines or sulfonamides can treat secondary infections.
2. Isolate and Treat Infected Birds
- Immediately separate sick birds from healthy ones.
- Keep them in a warm, dry, and stress-free environment.
- Use soft bedding to reduce joint pressure.
3. Supportive Treatment
💊 Electrolytes & Vitamin Therapy – Boosts immunity and recovery.
🥦 High-quality feed – Ensures birds receive proper nutrition for joint repair.
4. Antibiotic Therapy (For Secondary Bacterial Infections)
- Tetracyclines, Amoxicillin, and Enrofloxacin prevent bacterial complications.
- Administer antibiotics only under veterinary supervision.
5. Pain Management & Physical Support
- Anti-inflammatory drugs (under veterinary guidance) reduce swelling & pain.
- Providing soft bedding helps relieve stress on swollen joints.
6. Culling of Severely Affected Birds
- Birds with ruptured tendons or permanent lameness should be culled.
- Proper disposal of carcasses prevents disease spread.
Economic Impact of Infectious Tenosynovitis
This disease significantly affects commercial and backyard poultry farms, causing:
💰 Decreased feed conversion efficiency – Affected birds eat but fail to gain weight.
💰 Reduced egg production – Laying hens become weaker.
💰 High veterinary costs – Continuous treatment and care increase expenses.
💰 Financial losses from culling – Severely infected birds must be removed.
Conclusion
Infectious Tenosynovitis is a serious reovirus infection that damages joints and tendons, leading to lameness, weight loss, and decreased productivity. Since there is no cure, preventative strategies such as vaccination, biosecurity, and proper nutrition are the best ways to protect flocks.
Farmers must prioritize early detection and supportive management to reduce economic losses and improve flock health. By following these preventive and management strategies, poultry farms can significantly lower the risk of Infectious Tenosynovitis outbreaks.