Poultry Mycoplasma and Chronic Respiratory Disease

Chronic Respiratory Disease (CRD) is a respiratory condition in poultry characterized by inflammation of the air sacs, pericardium and peritoneum.

Mycoplasma gallisepticum (MG) is the primary cause of CRD in poultry. It weakens the respiratory system making it susceptible to secondary infections, especially E. coli.

CRD can also be a complication of other respiratory infections like Avian Influenza (AI), Newcastle disease (ND) or Infectious Bronchitis (IB). It can also develop due to poor management conditions.

Mycoplasma are the smallest free-living organisms that are bacteria-like. They belong to the class Mollicutes, order Mycoplasmatales and family Mycoplasmataceae. Mycoplasma gallisepticum is a member of this family.

Mycoplasma lack a cell wall, making them flexible and able to pass through filters. They exhibit pleomorphism (different shapes) and are difficult to stain with traditional bacterial stains. They are also resistant to certain antibiotics, like penicillins.

Atypical strains of Mycoplasma gallisepticum (MG) and Mycoplasma synoviae (MS) can emerge after treatment. These atypical strains are characterized by their ability to survive and cause disease despite treatment.

Mycoplasmosis is a serious problem for the poultry industry worldwide. It is typically complicated by other respiratory infections, such as E. coli and various viruses.

Mycoplasma gallisepticum (MG) infections are referred to as Chronic Respiratory Disease (CRD) in chickens and Infectious Sinusitis in turkeys.

The ability of a pathogen to cause disease. Reduced virulence means the pathogen is less likely to cause severe illness.

A slow rate of spreading from one individual to another. Low transmissibility means that the pathogen doesn't spread easily.

The pathogen's proteins are different from the typical strains, making it harder for the immune system to recognize and fight it.

The pathogen is difficult to grow in laboratory cultures, which makes it harder to study and diagnose.

Tests like SPA, HI, and ELISA may not reliably detect the pathogen, so additional tests like the in-vivo bioassay are needed.

At least 25 bird species are known to be affected by mycoplasma.

Mycoplasma can only reproduce and survive within a host or in specific laboratory conditions.

Poultry infected in a lab develop symptoms after 6-21 days. In natural settings, the incubation period can be longer and the infected bird might not show symptoms for days or months until stressed.

A condition that involves a swelling of the air sacs in chickens, often associated with poor growth and feathering problems. Can be caused by various factors, including Mycoplasma infection.

Infection caused by Mycoplasma, affecting young turkeys, leading to joint problems and poor growth.

A disease affecting chickens and game birds, characterized by inflammation of the eyes, leading to conjunctivitis and problems with vision.

Inflammation of the oviduct in chickens, significantly impacting egg production and leading to potential losses.

A condition where the bursa of Fabricius and thymus are affected, resulting in compromised immune function.

A skeletal deformity in chickens primarily affecting the legs and joints, leading to poor gait.

A condition where the abdominal cavity fills with fluid, often related to respiratory problems and heart issues.

A condition where the bursa of Fabricius, an important immune organ, is abnormally underdeveloped or missing.

A respiratory disease caused by Mycoplasma gallisepticum (MG), affecting poultry production.

Significant economic losses are caused by avian mycoplasmosis in poultry farms from direct and indirect losses.

Direct losses in poultry due to Avian Mycoplasmosis include reduced feed efficiency, decreased growth rate, carcasses downgrades, and decreased egg production.

Chronic respiratory disease (CRD) is a major direct economic loss caused by avian mycoplasmosis.

Indirect losses in poultry due to Avian Mycoplasmosis include immunosuppression and disease condition aggravation.

In the United States, Avian Mycoplasmosis is prevalent, infecting a significant portion of commercial layer farms.

Avian Mycoplasmosis infection can lead to a significant drop in hatchability due to late-period embryo death.

The Mycoplasma gallisepticum (MG) can cause various clinical signs in poultry, including conjunctivitis, sinusitis, depression, drop in egg production, corneal opacity, and trachea exudates.

The F strain of Mycoplasma is considered unsuitable for use in turkeys because it can cause severe respiratory issues and air sac inflammation.

Vaccination with F-strain Mycoplasma can lead to a decrease in egg production, although egg quality remains unaffected.

Bacterins are inactivated vaccines that protect against egg production decline in laying hens after exposure to Mycoplasma gallisepticum (MG).

Bacterins can reduce the rate of Mycoplasma gallisepticum (MG) transmission through eggs, delaying the spread of infection among breeder pullets.

While antibiotics can manage Mycoplasma infection, they are not a permanent solution. The birds remain infected, and continuous use can contribute to the development of antibiotic resistance.

Antibiotics are recommended in broiler chicks during the first 4 days of life and again at 19 days of age for two consecutive days. This helps control Mycoplasma infection.

Antibiotics are given to breeders following respiratory vaccination, particularly after Newcastle disease (ND) vaccination. This helps control Mycoplasma infection.

Mycoplasma develops resistance to antibiotics, making treatment less effective.

Egg transmission is the primary way Mycoplasma spreads, leading to infected chicks.

Eliminating an infected flock is the most effective way to prevent further spread, though it's not always practical.

Treating hatching eggs with antibiotics helps prevent Mycoplasma infection in chicks.

Biosecurity measures are essential for preventing Mycoplasma spread, such as sanitation and controlling bird movement.

Vaccination can help protect against Mycoplasma infection, but it's not a complete solution.

Surveillance involves testing birds to identify infected individuals early, preventing further spread.

Proper disposal of dead birds is essential to prevent the spread of Mycoplasma.