Avian Mycoplasmosis ([FONT=Arial,Arial][FONT=Arial,Arial]Mycoplasma gallisepticum[/FONT][/FONT])
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]Pleuropneumonia–like Organism (PPLO) Infection, Chronic Respiratory Disease, Infectious Sinusitis, House Finch Conjunctivitis [/FONT][/FONT]
[FONT=Tahoma,Tahoma][FONT=Tahoma,Tahoma]Last Updated: [/FONT][/FONT][FONT=Tahoma,Tahoma]
[FONT=Tahoma,Tahoma]January 2007 [/FONT][/FONT]
Importance
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]Mycoplasma gallisepticum [/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]is the most economically significant mycoplasmal pathogen of poultry. [/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]M. gallisepticum [/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]infections can cause significant economic losses on poultry farms from chronic respiratory disease, reduced feed efficiency, decreased growth and decreased egg production. The carcasses of birds sent to slaughter may also be downgraded. [/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]M. gallisepticum [/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]infections are notifiable to the World Organization for Animal Health (OIE). This organism has been eradicated from most commercial chicken and turkey breeding flocks in the United States; however, it remains endemic in many other poultry operations.
Since 1994, [/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]M. gallisepticum [/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]conjunctivitis has become an emerging disease in finches. This disease has been responsible for major declines in house finch populations in the eastern U.S., and was recently reported in western house finch populations. [/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]M gallisepticum [/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]can also affect other finch species, although its impact has not been as severe. [/FONT][/FONT]
Etiology
[FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]Avian mycoplasmosis can be caused by several species of [/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]Mycoplasma [/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman](class Mollicutes, order Mycoplasmatales, family Mycoplasmataceae) including [/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]Mycoplasma gallisepticum[/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman], [/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]M. synoviae[/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman], [/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]M. meleagridis [/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]and [/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]M. iowae[/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]. [/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]M. gallisepticum [/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]is the most important pathogen in poultry. It also causes disease in other avian species. [/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]M. gallisepticum [/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]infections are also known as chronic respiratory disease (CRD) of chickens, infectious sinusitis of turkeys and house finch conjunctivitis. [/FONT][/FONT]
Several strains of [FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]M. gallisepticum [/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]have been reported, including the R (poultry), P (psittacine) and house finch strains. Strains may vary greatly in their pathogenicity for different species of birds. In one study, budgerigars developed severe disease after experimental infection with the R strain of [/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]M. gallisepticum [/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]but not the house finch strain. [/FONT][/FONT]
Species Affected
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]Mycoplasma gallisepticum [/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]causes disease in chickens, turkeys, and game birds including pheasants, chukar partridges, bobwhite quail, Japanese quail and peafowl. The organism has also been isolated from ducks and geese, as well as yellow-naped Amazon parrots, pigeons and greater flamingos. It has been found in wild peregrine falcons in Spain.
Since 1994, [/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]M. gallisepticum [/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]epidemics have been reported in house finches ([/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]Carpodacus mexicanus[/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]) in the U.S. This organism has also been confirmed by culture or polymerase chain reaction (PCR) in American goldfinches ([/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]Carduelis tristis[/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]), purple finches ([/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]Carpodacus purpureus[/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]), eastern tufted titmice ([/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]Baeolophus bicolor[/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]), pine grosbeaks ([/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]Pinicola enucleator[/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]), evening grosbeaks ([/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]Coccothraustes vespertinus[/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]) and a captive blue jay ([/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]Cyanocitta cristata[/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]). PCR-positive mourning doves (order Columbiformes) have also been reported, but these birds remained seronegative and culture negative, and may have been infected by a related species of [/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]Mycoplasma[/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]. Other passerine species have tested positive by serology. House sparrows ([/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]Passer domesticus[/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]) and budgerigars ([/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]Melopsittacus undualtus[/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]) have been infected experimentally with some strains. [/FONT][/FONT]
Geographic Distribution
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]M. gallisepticum [/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]can be found worldwide. In the United States, this organism has been eradicated from most commercial chicken and turkey breeding flocks, but remains present in other poultry operations. Beginning in 1994, [/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]M. gallisepticum [/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]epidemics associated with conjunctivitis were reported in house finches throughout the eastern U.S. Infected birds have recently been reported in house finch populations in the western U.S. [/FONT][/FONT]
Transmission
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]M. gallisepticum [/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]is transmitted during close contact between birds as well as on fomites. Aerosol spread occurs over short distances and can be responsible for transmission within a flock. [/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]M. gallisepticum [/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]is also transmitted vertically in eggs. [/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]Avian Mycoplasmosis ([/FONT][/FONT][FONT=Arial,Arial][FONT=Arial,Arial]Mycoplasma gallisepticum[/FONT][/FONT])
[FONT=Arial,Arial]
[FONT=Arial,Arial]Last Updated: January 2007 [/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]
2007 [/FONT][/FONT]
page 2 of 4
[FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]Shedding in the egg can vary; egg transmission is more frequent in birds infected during laying than in birds infected before they mature. Infected birds carry [/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]M. gallisepticum [/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]for life, and can remain asymptomatic until they are stressed. [/FONT][/FONT]
Incubation Period
[FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]Experimentally infected poultry develop symptoms after 6 to 21 days. In natural infections, the incubation period is variable; infected birds may be asymptomatic for days or months until stressed. In finches, incubation periods from 4 to 14 days have been reported. [/FONT][/FONT]
Clinical Signs
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]M. gallisepticum [/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]infections vary from asymptomatic to severe, depending on the infecting strain and other factors. More severe infections are seen when the birds are infected concurrently with Newcastle disease virus, infectious bronchitis virus, [/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]Escherichia coli [/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]or other pathogens.
Infected chickens usually develop respiratory symptoms that may include rales, coughing, sneezing, nasal discharges and dyspnea. Turkeys typically experience more severe disease, often accompanied by swelling of the paranasal (infraorbital) sinus. Conjunctivitis with a frothy ocular exudate is common in turkeys and occurs occasionally in chickens. Production is lower in infected flocks, with decreased weight gain, feed efficiency and egg production. The symptoms of avian mycoplasmosis are typically slow to develop, and the course of the disease can be prolonged. However, acute respiratory disease sometimes occurs in young birds, particularly turkeys.
Avian mycoplasmosis has also been reported from other species of birds. In game birds, avian mycoplasmosis is characterized by upper respiratory disease, conjunctivitis lethargy, weight loss, decreased egg production and deaths. Conjunctivitis, sometimes accompanied by infraorbital sinus swelling, rhinitis, and ocular and nasal discharges, occurs frequently in house finches infected with [/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]M. gallisepticum[/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]. Conjunctivitis has also been reported in experimentally infected American goldfinches, pine siskins, purple finches and tufted titmice. In one study, the clinical signs were severe in house finches and American goldfinches, and milder in pine siskins and purple finches. In experimentally infected house finches and other passerine species, [/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]M. gallisepticum [/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]infections may take weeks or months to resolve; in one study, conjunctivitis persisted for an average of 7 weeks. Clinical disease has also been reported in psittacine birds including experimentally infected budgerigars. [/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]M. gallisepticum[/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman], together with [/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]M. iowae [/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]and an unidentified mycoplasma, was isolated from a flock of yellow-naped Amazon parrots with upper respiratory disease. The condition appeared to be caused by concomitant infections with mycoplasmas and bacteria, and the precise role of [/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]M. gallisepticum [/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]was not established. [/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]M. gallisepticum [/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]infections seem to be subclinical in some species of birds. House sparrows infected with the R (poultry) strain shed the organism transiently, but remained asymptomatic. In another study, budgerigars developed severe disease after experimental infection with the R strain of [/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]M. gallisepticum [/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]but not the house finch strain. [/FONT][/FONT]
Post Mortem Lesions Click to view images
[FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]In uncomplicated cases in chickens, the lesions typically include mild sinusitis, tracheitis and airsacculitis. If the chicken is infected concurrently with [/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]E. coli[/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman], thickening and turbidity of the air sacs, exudative accumulations, fibrinopurulent pericarditis and perihepatitis may be seen. In turkeys, severe mucopurulent sinusitis may be found, with variably severe tracheitis and airsacculitis. Lesions reported in naturally infected chukar partridges and pheasants include conjunctivitis and sinusitis of one or both infraorbital sinuses. Finches typically exhibit mild to severe inflammation in one or both eyes and the periorbital region. The eyelids may be swollen and inflamed, and a clear to cloudy, thickened ocular discharge may be noted. There may also be drainage from the nares. [/FONT][/FONT]
Morbidity and Mortality
[FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]In the U.S., [/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]M. gallisepticum [/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]has been eradicated from most primary and multiplier poultry breeding flocks, but this organism can be endemic in large, multiple-age commercial egg laying flocks. Outbreaks also occur in meat flocks. Clinical cases tend to occur in large commercial operations during the winter. Stressors such as viral infections, vaccination with live viruses, cold weather or crowding can trigger disease outbreaks in infected flocks. In chickens with uncomplicated infections, the morbidity rate is high and the mortality rate low; however, more severe disease occurs if the birds are concurrently infected with other viruses or bacteria. Mortality rates can be high in turkeys.
In wild songbirds, the impact of the disease is complicated by other factors. Under controlled experimental conditions, house finches exhibited morbidity rates approaching 100%, but low mortality rates of approximately 5% or less. However, the mortality rate can be high in wild house finches, probably due to environmental factors such as cold, predation and difficulty locating food and water. American goldfinches are also highly susceptible to experimental infection; however, in the wild, the morbidity rate is reported to be 2-3% in this species, compared to a 20-27% morbidity rate in free-living house finches. The cause of this discrepancy is unknown. [/FONT][/FONT]
Diagnosis
[FONT=Arial,Arial][FONT=Arial,Arial]Clinical [/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]M. gallisepticum [/FONT][/FONT][FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]infections should be considered in poultry or game birds with upper respiratory disease and wild house finches with conjunctivitis. Avian mycoplasmosis may also be a possibility in other species of passerine and psittacine birds, as well as blue [/FONT][/FONT]
[FONT=Times New Roman,Times New Roman]
[FONT=Times New Roman,Times New Roman]Iowa State University[/FONT][/FONT]