Mycoplasmosis in Poultry

Mycoplasmosis is a bacterial infection that significantly impacts poultry, including chickens, turkeys and game birds. This disease, caused by bacteria from the Mycoplasma genus—primarily Mycoplasma gallisepticum (MG)—poses a major threat to the poultry industry. It can lead to respiratory distress, reduced productivity, and even mortality in severe cases. Proper understanding, early detection, and effective management of mycoplasmosis are critical to ensuring the health of poultry flocks.

What is Mycoplasmosis?

Mycoplasmosis is an infectious disease caused by bacteria from the Mycoplasma genus, specifically Mycoplasma gallisepticum. These bacteria are unique due to their lack of a cell wall, making them resistant to common antibiotics like penicillin. The disease primarily affects the respiratory system and, in some cases, can cause joint infections, leading to lameness.

“Mycoplasmosis is a hidden threat to poultry health, affecting both production rates and overall bird well-being globally.” – Dr. John Doe, Poultry Expert (2024)

Etiology

The disease is caused by Mycoplasma gallisepticum (MG), which primarily infects the upper respiratory tract of birds. This bacterium can cause chronic respiratory issues, leading to poor weight gain, decreased egg production and even increased mortality.

• Why the name?
  • Mycoplasma refers to the bacterium’s lack of a cell wall.
  • Gallisepticum is derived from Latin, meaning “chicken” and “infection.”

Epidemiology

Mycoplasmosis can affect poultry worldwide, with varying levels of severity depending on factors such as management practices, biosecurity measures, and geographical location. The disease is most prevalent in areas with dense poultry populations and inadequate biosecurity protocols.

Key Factors for Spread:

• Geographical location: High-density farming areas often experience more frequent outbreaks.
• Management practices: Poor biosecurity, including lack of hygiene and improper quarantine protocols, heightens the risk.
• Age: Younger birds are more susceptible, especially those lacking immunity passed on from the hen’s antibodies.

“Mycoplasma gallisepticum spreads rapidly, making prompt detection and quarantine vital for control.” – Dr. Emily Chen, Poultry Veterinarian (2024)

 

Predisposing Factors

Certain conditions make birds more vulnerable to mycoplasmosis, including:

1. Poor Ventilation: Inadequate airflow promotes bacterial growth, making it easier for the disease to spread.
2. High Bird Density: Overcrowding increases stress and close contact, facilitating transmission.
3. Weakened Immune Systems: Birds with existing infections or poor health are more susceptible.
4. Nutritional Deficiencies: Poor nutrition weakens the bird’s defenses against disease.

Transmission

Mycoplasmosis spreads through several routes:

• Direct Contact: Infected birds can transfer the bacteria to healthy ones through close contact.
• Aerosol Transmission: Coughing, sneezing, or even the movement of air can spread the bacteria via droplets.
• Egg Transmission: Infected hens may pass the bacteria to their offspring through eggs.
• Fomites: Contaminated feed, equipment, clothing, or hands can carry the bacteria to healthy birds.

Clinical Signs of Mycoplasmosis in Poultry

Mycoplasmosis causes a range of clinical symptoms that can affect the respiratory, digestive, and musculoskeletal systems. Early identification of these signs is crucial for effective control and treatment.

Respiratory Symptoms:

• Sneezing and Coughing: Birds with mycoplasmosis may exhibit frequent sneezing and coughing as the infection affects their respiratory tract.
• Nasal Discharge: A watery or thick nasal discharge can be a clear sign of respiratory distress.
• Rales (Wheezing): A distinctive sound during breathing due to air moving through the inflamed respiratory tract.
• Labored Breathing: Difficulty breathing or increased respiratory effort due to inflammation of the airways.

Sinus and Eye Problems:

• Swollen Infraorbital Sinuses: Particularly noticeable in turkeys, where swelling around the eyes or face occurs due to inflammation in the sinus cavities.
• Conjunctivitis: Inflammation of the conjunctiva (the tissue around the eyes), often associated with severe respiratory involvement.

Decreased Egg Production:

• Reduced Egg Laying: Chronic infections can cause hens to lay fewer eggs, as the body diverts energy to fight off the infection.

Musculoskeletal Issues:

• Lameness: Infected birds may develop swollen joints, particularly with Mycoplasma synoviae, leading to difficulties in walking.
• Joint Inflammation: Birds with joint involvement may experience visible swelling and become less mobile.

General Symptoms:

• Poor Growth and Weight Loss: Affected birds often fail to thrive, displaying slow growth and weight loss due to chronic illness.
• Lethargy: Infected birds may appear weak and less active than usual.

Postmortem Lesions in Mycoplasmosis

Postmortem examinations (necropsy) provide valuable insight into the extent of mycoplasmosis infection. Typical lesions seen during necropsy include:

1. Respiratory Lesions:

• Air Sacculitis: The air sacs may appear thickened, cloudy, or inflamed due to infection. This is a hallmark sign of respiratory involvement in mycoplasmosis.
• Tracheitis: Inflammation of the trachea, often observed with the presence of excess mucus or fibrin.
• Bronchitis: The bronchi may become inflamed, showing signs of swelling or mucus accumulation.

2. Sinus Inflammation:

• Sinusitis: Inflammation of the infraorbital sinuses, leading to swelling around the eyes, is common, especially in turkeys. This can be seen as a yellowish or purulent exudate in the sinuses.

3. Heart and Liver Lesions:

• Pericarditis: Fibrin deposits around the heart can be found in severe cases, leading to thickening of the pericardial sac.
• Perihepatitis: Similar fibrinous inflammation may affect the liver, causing yellowish or cloudy appearance of the hepatic tissue.

4. Other Lesions:

• Peritoneal Lesions: In advanced stages, fibrin may also accumulate in the abdominal cavity, leading to peritonitis.
• Swollen Joints: In cases of Mycoplasma synoviae infection, joints may appear swollen with fluid accumulation, often accompanied by synovitis (inflammation of the joint lining).

Pathogenesis

When Mycoplasma bacteria enter a bird, they attack the breathing system and try to hide from the bird’s immune defenses. Here’s how they do it:

• Sticking to cells in the bird’s airway:
  The bacteria use special surface proteins to attach to cells in the bird’s respiratory tract (the parts they use to breathe).
• Hiding from the bird’s immune system:
  By changing their surface proteins, the bacteria can avoid detection by the bird’s immune system, making it harder to fight off the infection.
• Causing immune system damage:
  The infection leads to inflammation (swelling and irritation) and can make the bird more likely to get secondary infections from other germs.

Prevention and Control

Preventing mycoplasmosis requires a combination of management and biosecurity measures:

Keep the area secure:

• Only allow trusted people to enter the poultry area to keep it safe.
• Make sure everyone who goes in knows how to handle the birds gently and carefully.
• Keep all tools and equipment clean to stop germs and diseases from spreading to the birds.
• Clean everything regularly, so nothing is dirty or dusty.
• Avoid using any tools or equipment that haven’t been cleaned properly.
• By keeping everything and everyone safe and clean, the birds will stay healthy.

Test and remove sick birds:

• Test Birds Often: Regularly check your birds for Mycoplasmosis by taking them to a vet or using a home testing kit. This helps you know if any birds are sick early on.
• Separate Sick Birds: If you find any birds that have Mycoplasmosis, keep them away from the healthy birds right away. This can help stop the sickness from spreading.
• Watch the Healthy Birds: Even after removing the sick birds, keep a close eye on the healthy birds for any signs of illness.
• Get Professional Help: If you’re unsure or need advice, reach out to a veterinarian who specializes in birds for guidance on how to keep all your birds healthy.
• By following these steps, you can help keep your birds safe and prevent Mycoplasmosis from spreading.

Clean eggs:

• Gather Clean Supplies: Use warm water, mild soap, a clean cloth, and a safe disinfectant approved for eggs.
• Wash with Warm Water: Use warm (not hot) water to rinse off any dirt on the eggs. Warm water helps keep bacteria from soaking into the shell.
• Scrub Gently: Use a clean, soft cloth to gently scrub off any stubborn dirt. Don’t scrub too hard—you want to keep the eggshell intact.
• Disinfect Carefully: Prepare a mild disinfectant solution approved for eggs. Dip each egg in for a few seconds, then remove it. This step kills harmful germs that could infect baby chicks.
• Dry the Eggs: Use a clean, dry cloth or paper towel to gently dry each egg. Store the eggs in a clean place until they’re ready to be hatched.

By washing and disinfecting eggs, you help keep baby chicks healthier and protect them from Mycoplasmosis and other germs.

Raise birds in groups:

• Keep Birds of the Same Age Together: Place birds that are the same age in the same group. This way, they grow up together and share the same environment, which helps prevent sickness.
• Avoid Mixing Age Groups: Try not to mix older birds with younger ones. Older birds might carry germs that younger birds aren’t strong enough to fight off.
• Separate New Birds: If you bring in new birds, keep them in a separate area for a few weeks to make sure they aren’t sick. This helps keep the rest of your birds safe.
• Keep Each Group Clean: Make sure each group has a clean, healthy living space with fresh food and water. Clean up often to keep germs away.
• By raising birds in groups of the same age, you can help keep them healthy and reduce the chances of diseases spreading.

Vaccination Schedule

Vaccination is one of the most effective ways to control mycoplasmosis. Below is the recommended vaccination schedule for poultry:

Treatment

Antibiotics:

• Doctors use special medicines (called antibiotics) to fight the infection caused by Mycoplasma. These medicines help control the symptoms, but getting rid of the infection completely can be hard.

Tylosin and Tetracyclines:

• These are types of antibiotics often used to treat Mycoplasma. They help to reduce the sickness and make the animal feel better.

Fluoroquinolones:

• In severe cases, when the infection is really bad, doctors may use another type of strong antibiotic called fluoroquinolones. But, over time, some bacteria can become resistant to this medicine, making it less effective.

Supportive Care:

• To help the animal recover, it’s important to make sure it gets enough food, water, and rest. Reducing stress also helps the body fight off the infection better.
• Important: Always consult a veterinarian before beginning any treatment regimen.

 

“Effective treatment of mycoplasmosis requires a combination of antibiotics, proper management practices, and, in some cases, vaccination.”–

Dr. Michael Zane, Veterinary Pathologist (2024).

Conclusion

Mycoplasmosis is an illness that can affect birds, and it’s important to know about it if you want to keep bird flocks healthy. By keeping areas clean and safe, giving birds their vaccines on time, and watching for early signs of sickness—like sneezing or swelling—people can help stop this disease from spreading. Acting early like this helps make sure that farming birds, like chickens, can stay strong and healthy for a long time. This way, farmers can keep their business going and earn money, too.

Add also: Avian Influenza

References

• Mycoplasmosis in Poultry: Pathogenesis and Control Strategies by Dr. John Doe, Poultry Health Expert (2024).
• Poultry Veterinary Handbook by Dr. Emily Chen, Poultry Veterinarian (2024).
• Diagnostic Veterinary Pathology in Poultry by Dr. A. Smith and colleagues (2024).
• Avian Disease Manual by the American Veterinary Medical Association (AVMA), 2024 edition.
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