Mycoplasma gallisepticum is a chronic respiratory disease (infectious sinusitis) found in chickens, turkeys, pheasants, chukar partridges, peafowl, pigeons, quail, ducks, geese, and psittacine birds and can cause conjunctivitis in wild house finches and other similiar species found in North America. Most Songbirds are generally resistant to the disease possibly due to the fact that they are not exposed to the causes. Mycoplasma gallisepticum has been found in chickens and turkeys worldwide. Once the birds are infected they become carriers for life.
Symptoms of Mycoplasma Gallispticum Infection In Poultry
In Chickens:
Respiratory distress
Difficulty breathing
Slight to marked rales
Coughing and/or sneezing
Nasal discharge
Conjuctivitis (inflammation of the conjunctiva of the eye)
Frothiness about the eyes
Weight loss due to less effective feed processing (reduced feed efficiency)
Reduced expected weight gain
Lay less eggs
"Morbidity is high and mortality low in uncomplicated cases. The disease is generally more severe in turkeys than in chickens, and swelling of the infraorbital sinuses is common. Feed efficiency and weight gains are reduced. Commercial broiler chickens and market turkeys may suffer high condemnations at processing due to airsacculitis. In laying flocks, birds may fail to reach peak egg production, and the overall production rate is lower than normal" (Merck Veterinary Manual, 2018) .
Respiratory distress
Difficulty breathing
Slight to marked rales
Coughing and/or sneezing
Nasal discharge
Conjuctivitis (inflammation of the conjunctiva of the eye)
Frothiness about the eyes
Weight loss due to less effective feed processing (reduced feed efficiency)
Reduced expected weight gain
Lay less eggs
"Morbidity is high and mortality low in uncomplicated cases. The disease is generally more severe in turkeys than in chickens, and swelling of the infraorbital sinuses is common. Feed efficiency and weight gains are reduced. Commercial broiler chickens and market turkeys may suffer high condemnations at processing due to airsacculitis. In laying flocks, birds may fail to reach peak egg production, and the overall production rate is lower than normal" (Merck Veterinary Manual, 2018) .
How Do Chickens Get MYCOPLASMA GALLISPTICUM?
Transovarian-Can be transmitted within some eggs
From infected breeder birds to their offspring
Aerosol sprays-can cause respiratory infections which can spread the disease faster
Contaminated feed and water
Contaminated feed and water containers
From humans bringing it in on contaminated shoes and equipment
Flock to flock transfer-Movement of infected birds, people, objects or materials from an infected flock to an uninfected flock
Cold weather
Poor air quality
Over crowding
"Some potential reservoirs of M gallisepticum in the USA are noncommercial (backyard) flocks, multiple-age layer flocks, and some free-ranging songbird species. Good management and biosecurity practices are necessary to ensure that M gallisepticum infections are not introduced to commercial poultry from these and other sources. In many outbreaks, the source of infection is unknown. Cold weather, poor air quality or crowding, concurrent infections, and some live virus vaccinations may facilitate infection, disease, and transmission" (1).
From infected breeder birds to their offspring
Aerosol sprays-can cause respiratory infections which can spread the disease faster
Contaminated feed and water
Contaminated feed and water containers
From humans bringing it in on contaminated shoes and equipment
Flock to flock transfer-Movement of infected birds, people, objects or materials from an infected flock to an uninfected flock
Cold weather
Poor air quality
Over crowding
"Some potential reservoirs of M gallisepticum in the USA are noncommercial (backyard) flocks, multiple-age layer flocks, and some free-ranging songbird species. Good management and biosecurity practices are necessary to ensure that M gallisepticum infections are not introduced to commercial poultry from these and other sources. In many outbreaks, the source of infection is unknown. Cold weather, poor air quality or crowding, concurrent infections, and some live virus vaccinations may facilitate infection, disease, and transmission" (1).
Featured Video: Mycoplasma In Poultry Mode of Action Animation
Treatment, Control & Prevention
Broad spectrum antibiotics, includes tylosin, tetracyclines
Exeptions-No penicillins as they act on the cell wall.
Tylosin or tetracyclines have been commonly used to reduce egg transmission or as prophylactic treatment to prevent respiratory disease in broilers and turkeys. Antibiotics may alleviate the clinical signs and lesions but do not eliminate infection. Regulations on the use of antibiotics in food animals are rapidly evolving and you should be consult a veterinarian and your local authorities before use.
Denagard 12.5% is a common treatment for Mycroplasma Gallisepticum in chickens, turkeys, and swine. Prevention
"Prevention is based largely on obtaining chicks or poults from M gallisepticum–free breeder flocks. Eradication of M gallisepticum from chicken and turkey commercial breeding stock is well advanced in the USA because of control programs coordinated by the National Poultry Improvement Plan. The most effective control program is to establish M gallisepticum–free breeder flocks, managed and maintained under good biosecurity to prevent introductions, and monitored regularly with serology to continually confirm infection-free status. In valuable breeding stock, treatment of eggs with antibiotics or heat has been used to eliminate egg transmission to progeny. Medication is not a good longterm control method but has been of value in treating individual infected flocks".
Laying chickens free of M gallisepticum are desirable, but infection in commercial multiple-age egg farms where depopulation is not feasible is a problem. Inactivated, oil-emulsion bacterins are available and help prevent egg production losses but not infection. Three live vaccines (F-strain, ts-11, and 6/85) have been licensed in the USA for use during the growing phase to provide some protection during lay and may be used in some areas with permission of the State Veterinarian. F-strain is of low virulence in chickens but is fully virulent for turkeys. Vaccinated chickens remain carriers of F-strain, and immunity lasts through the laying season. Vaccine strains ts-11 and 6/85 are less virulent, offer the advantage of improved safety for nontarget birds, and are widely used in commercial layers. A commercial recombinant fowlpox–M gallisepticum vaccine has been marketed.
Exeptions-No penicillins as they act on the cell wall.
Tylosin or tetracyclines have been commonly used to reduce egg transmission or as prophylactic treatment to prevent respiratory disease in broilers and turkeys. Antibiotics may alleviate the clinical signs and lesions but do not eliminate infection. Regulations on the use of antibiotics in food animals are rapidly evolving and you should be consult a veterinarian and your local authorities before use.
Denagard 12.5% is a common treatment for Mycroplasma Gallisepticum in chickens, turkeys, and swine. Prevention
"Prevention is based largely on obtaining chicks or poults from M gallisepticum–free breeder flocks. Eradication of M gallisepticum from chicken and turkey commercial breeding stock is well advanced in the USA because of control programs coordinated by the National Poultry Improvement Plan. The most effective control program is to establish M gallisepticum–free breeder flocks, managed and maintained under good biosecurity to prevent introductions, and monitored regularly with serology to continually confirm infection-free status. In valuable breeding stock, treatment of eggs with antibiotics or heat has been used to eliminate egg transmission to progeny. Medication is not a good longterm control method but has been of value in treating individual infected flocks".
Laying chickens free of M gallisepticum are desirable, but infection in commercial multiple-age egg farms where depopulation is not feasible is a problem. Inactivated, oil-emulsion bacterins are available and help prevent egg production losses but not infection. Three live vaccines (F-strain, ts-11, and 6/85) have been licensed in the USA for use during the growing phase to provide some protection during lay and may be used in some areas with permission of the State Veterinarian. F-strain is of low virulence in chickens but is fully virulent for turkeys. Vaccinated chickens remain carriers of F-strain, and immunity lasts through the laying season. Vaccine strains ts-11 and 6/85 are less virulent, offer the advantage of improved safety for nontarget birds, and are widely used in commercial layers. A commercial recombinant fowlpox–M gallisepticum vaccine has been marketed.
"M gallisepticum is the most pathogenic avian mycoplasma; however, considerable strain variability is manifest in a range of host susceptibility, virulence, clinical presentation, and immunologic response. Integral membrane surface proteins (adhesins) that attach to receptors on host cells, allowing for colonization and infection, are important virulence factors involved in antigenic variation and immune evasion".
Mycoplasma gallisepticum, chicken
Courtesy of North Carolina State Poultry Health Management.
Uncomplicated M gallisepticum infections in chickens result in relatively mild catarrhal sinusitis, tracheitis, and airsacculitis. E coli infections are often concurrent and result in severe air sac thickening and turbidity, with exudative accumulations, adhesive pericarditis, and fibrinous perihepatitis. Turkeys develop severe mucopurulent sinusitis and varying degrees of tracheitis and airsacculitis. Microscopically, involved mucous membranes are thickened, hyperplastic, necrotic, and infiltrated with inflammatory cells. The mucosal lamina propria contains focal areas of lymphoid hypoplasia and germinal center formations.
Acute airsacculitis, chicken
Courtesy of American Association of Avian Pathologists.
Diagnosis:
History, clinical signs, and typical gross lesions may be suggestive of M gallisepticum infection. Serology by agglutination and ELISA methods are commonly used for surveillance. Hemagglutination-inhibition is used as a confirmatory test, because nonspecific false agglutination reactions may occur, especially after injection of inactivated oil-emulsion vaccines or infection with M synoviae. M gallisepticum should be confirmed by isolation from swab samples of infraorbital sinuses, nasal turbinates, choanal cleft, trachea, air sacs, lungs, or conjunctiva. Primary isolation is made in mycoplasma medium containing 10%–15% serum. Colonies on agar medium are used for species identification by immunofluorescence with species-specific antibodies. PCR can also be used for detection of M gallisepticum DNA using swabs taken directly from infected sites (choana, sinuses, trachea, air sacs) or after growth in culture.
Mycoplasma isolates must be identified by species, because birds may also be infected with nonpathogenic mycoplasmas. E coli infection, Newcastle disease, avian influenza, and other respiratory diseases (eg, infectious bronchitis in chickens) should be considered in the differential diagnosis and can act as inciting or contributing pathogens (1).
Mycoplasma gallisepticum, chicken
Courtesy of North Carolina State Poultry Health Management.
Uncomplicated M gallisepticum infections in chickens result in relatively mild catarrhal sinusitis, tracheitis, and airsacculitis. E coli infections are often concurrent and result in severe air sac thickening and turbidity, with exudative accumulations, adhesive pericarditis, and fibrinous perihepatitis. Turkeys develop severe mucopurulent sinusitis and varying degrees of tracheitis and airsacculitis. Microscopically, involved mucous membranes are thickened, hyperplastic, necrotic, and infiltrated with inflammatory cells. The mucosal lamina propria contains focal areas of lymphoid hypoplasia and germinal center formations.
Acute airsacculitis, chicken
Courtesy of American Association of Avian Pathologists.
Diagnosis:
History, clinical signs, and typical gross lesions may be suggestive of M gallisepticum infection. Serology by agglutination and ELISA methods are commonly used for surveillance. Hemagglutination-inhibition is used as a confirmatory test, because nonspecific false agglutination reactions may occur, especially after injection of inactivated oil-emulsion vaccines or infection with M synoviae. M gallisepticum should be confirmed by isolation from swab samples of infraorbital sinuses, nasal turbinates, choanal cleft, trachea, air sacs, lungs, or conjunctiva. Primary isolation is made in mycoplasma medium containing 10%–15% serum. Colonies on agar medium are used for species identification by immunofluorescence with species-specific antibodies. PCR can also be used for detection of M gallisepticum DNA using swabs taken directly from infected sites (choana, sinuses, trachea, air sacs) or after growth in culture.
Mycoplasma isolates must be identified by species, because birds may also be infected with nonpathogenic mycoplasmas. E coli infection, Newcastle disease, avian influenza, and other respiratory diseases (eg, infectious bronchitis in chickens) should be considered in the differential diagnosis and can act as inciting or contributing pathogens (1).
Related Topics
1. Mycoplasma gallisepticum Infection in Poultry - Poultry - Veterinary Manual. (2018). Veterinary Manual. Retrieved 18 March 2018, from https://www.merckvetmanual.com/poultry/mycoplasmosis/mycoplasma-gallisepticum-infection-in-poultry
2. Mycoplasma in Poultry Mode of Action Animation. (2018). YouTube. Retrieved 18 March 2018, from https://www.youtube.com/watch?v=mTEl3j9CYcI
2. Mycoplasma in Poultry Mode of Action Animation. (2018). YouTube. Retrieved 18 March 2018, from https://www.youtube.com/watch?v=mTEl3j9CYcI
