University of duhokUniversity of duhokcollege of veterinary college of veterinary

medicinemedicine

Mycoplasma gallisepticum (Mycoplasma gallisepticum (MG), MG), chronic respiratory disease (CRD), chronic respiratory disease (CRD), infectious sinusitis,mycoplasmosisinfectious sinusitis,mycoplasmosis

In poultryIn poultry

ByBy

Jivan Q. amadJivan Q. amad

Chronic respiratory diseaseChronic respiratory disease (CRD) is one of the (CRD) is one of the most common respiratory diseases of poultry most common respiratory diseases of poultry . The disease occurs when birds infected with . The disease occurs when birds infected with Mycoplasma gallisepticum Mycoplasma gallisepticum are stressed. The are stressed. The subsequent invasion by secondary bacteria subsequent invasion by secondary bacteria causes the major damage to the bird.causes the major damage to the bird.

The microorganisms of the class Mollicutes The microorganisms of the class Mollicutes (Mycoplasma) were first identified in 1898 as (Mycoplasma) were first identified in 1898 as the etiologic agent of the bovine contagious the etiologic agent of the bovine contagious pleuropneumonia (BCPP) and thereafter, all pleuropneumonia (BCPP) and thereafter, all similar agents were named similar agents were named pleuropneumonia-like (PPLO-like) organisms pleuropneumonia-like (PPLO-like) organisms

Avian mycoplasmosis can be caused by several Avian mycoplasmosis can be caused by several species of Mycoplasma (class Mollicutes, order species of Mycoplasma (class Mollicutes, order Mycoplasmatales, family Mycoplasmataceae) Mycoplasmatales, family Mycoplasmataceae) including Mycoplasma gallisepticum, M. synoviae, including Mycoplasma gallisepticum, M. synoviae, M. meleagridis and M. iowae. M. gallisepticum is M. meleagridis and M. iowae. M. gallisepticum is the most important pathogen in poultry. It also the most important pathogen in poultry. It also causes disease in other avian species. M. causes disease in other avian species. M. gallisepticum infections are also known aschronic gallisepticum infections are also known aschronic respiratory disease (CRD) of chickens, infectious respiratory disease (CRD) of chickens, infectious sinusitis of turkeys and house finch conjunctivitis. sinusitis of turkeys and house finch conjunctivitis. Several strains of M. gallisepticum have been Several strains of M. gallisepticum have been reported, including the R (poultry), P (psittacine) reported, including the R (poultry), P (psittacine) and house finch strains. Strains may vary greatly and house finch strains. Strains may vary greatly in their pathogenicity for different species of in their pathogenicity for different species of birds. In one study, budgerigars developed severe birds. In one study, budgerigars developed severe disease after experimental infection with the R disease after experimental infection with the R strain of M. gallisepticum but not the house finch strain of M. gallisepticum but not the house finch strain. strain.

ImportanceImportanceMycoplasma gallisepticum Mycoplasma gallisepticum is the most is the most

economically significant mycoplasmal economically significant mycoplasmal pathogen of poultry. pathogen of poultry. M. gallisepticum M. gallisepticum infections can cause significant economic infections can cause significant economic losses on poultry farms from chronic losses on poultry farms from chronic respiratory disease, reduced feed respiratory disease, reduced feed efficiency, decreased growth and decreased efficiency, decreased growth and decreased egg production. The carcasses of birds sent egg production. The carcasses of birds sent to slaughter may also be downgraded. to slaughter may also be downgraded. M. M. gallisepticum gallisepticum infections are notifiable to the infections are notifiable to the World Organization for Animal Health (OIE). World Organization for Animal Health (OIE). This organism has been eradicated from This organism has been eradicated from most commercial chicken and turkey most commercial chicken and turkey breeding flocks in the United States; breeding flocks in the United States; however, it remains endemic in many other however, it remains endemic in many other poultry operations.poultry operations.

EtiologyEtiology

Mycoplasma gallisepticum Mycoplasma gallisepticum + chronic + chronic stress factor + secondary coliform stress factor + secondary coliform organisms cause respiratory diseaseorganisms cause respiratory disease

Species susceptibleSpecies susceptible Chickens, Chickens, turkeys, pigeons, ducks,Peafowl and turkeys, pigeons, ducks,Peafowl and passerine birds.passerine birds.

IncidenceIncidence

Very widespread and present in most, if Very widespread and present in most, if not all commercial flocks. Each batch not all commercial flocks. Each batch of new pullets will become infected.of new pullets will become infected.

TransmissionTransmissionEgg TransmissionEgg Transmission - of major importance and - of major importance and

the means by which the disease perpetuates the means by which the disease perpetuates itself.itself.

AirborneAirborne (aerosol) (aerosol) - generally rapid, but does - generally rapid, but does not travel distances.not travel distances.

Indirect or mechanicalIndirect or mechanical - the major means of - the major means of entry of CRD is by the introduction of entry of CRD is by the introduction of infected carrier birds or transport by persons infected carrier birds or transport by persons such as service personnel, vaccinators and such as service personnel, vaccinators and blood testers. The risk is great when people blood testers. The risk is great when people handle CRD-free birds on the same day after handle CRD-free birds on the same day after handling CRD-infected birds. Transfer can handling CRD-infected birds. Transfer can also occur on equipment (crates, vehicles, also occur on equipment (crates, vehicles, and vaccinating equipment).and vaccinating equipment).

Incubation PeriodIncubation Period

Experimentally infected poultry Experimentally infected poultry develop symptoms after 6 to 21 develop symptoms after 6 to 21 days. In natural infections, the days. In natural infections, the incubation period is variable; incubation period is variable; infected birds may be asymptomatic infected birds may be asymptomatic for days or months until stressed. In for days or months until stressed. In finches, incubation periods from 4 to finches, incubation periods from 4 to 14 days have been reported.14 days have been reported.

Clinical signsClinical signs

In Layers / BreedersIn Layers / Breeders• Nasal and ocular discharge, (watery eyes) rattling in the • Nasal and ocular discharge, (watery eyes) rattling in the wind pipes, coughing, gasping (dyspnea), sneezing and wind pipes, coughing, gasping (dyspnea), sneezing and shaking of the hed.shaking of the hed.• Feed consumption drops off leading to decreased egg • Feed consumption drops off leading to decreased egg production and loss of weight.production and loss of weight.• Male birds frequently have the most prominent signs.• Male birds frequently have the most prominent signs.• Reduced hatchability and chick viability.• Reduced hatchability and chick viability.• Occassional encephalopathy and abnormal feathers• Occassional encephalopathy and abnormal feathersIn BroilersIn Broilers• Most outbreaks occur between 3rd and 6th weeks ofage.• Most outbreaks occur between 3rd and 6th weeks ofage.• Poor feed conversion, sharp decline in weight gain.• Poor feed conversion, sharp decline in weight gain.• Slow growth• Slow growth• Leg problems• Leg problems• Morbidity rate fairly high but not great mortality.• Morbidity rate fairly high but not great mortality.• Poor carcass quality, high contamination rate. Thin and • Poor carcass quality, high contamination rate. Thin and weak birds with razor-blade breasts.weak birds with razor-blade breasts.

In TurkeysIn TurkeysThere are two forms of this disease in the turkey. There are two forms of this disease in the turkey. With the With the

““upper formupper form” the birds have watery eyes and ” the birds have watery eyes and nostrils, the infraorbitals (just below the eye) nostrils, the infraorbitals (just below the eye) become swollen, and the exudate becomes become swollen, and the exudate becomes caseous and firm. The birds have respiratory rales caseous and firm. The birds have respiratory rales and show unthriftiness. With theand show unthriftiness. With the

““lower formlower form” infected turkeys develop airsacculitis. ” infected turkeys develop airsacculitis. As with chickens, birds can show no outward As with chickens, birds can show no outward signs if the infection is uncomplicated. Thus, the signs if the infection is uncomplicated. Thus, the condition may go unnoticed until the birds are condition may go unnoticed until the birds are slaughtered and the typical legions are seen. slaughtered and the typical legions are seen. Birds with airsacculitis are condemned, Birds with airsacculitis are condemned, Production is lower in infected flocks, decreased Production is lower in infected flocks, decreased weight gain, feed efficiency and egg production.weight gain, feed efficiency and egg production.

Post Mortem LesionsPost Mortem Lesions In uncomplicated cases in chickens, the lesions In uncomplicated cases in chickens, the lesions

typically include mild sinusitis, tracheitis and typically include mild sinusitis, tracheitis and airsacculitis. If the chicken is infected concurrently airsacculitis. If the chicken is infected concurrently with with E. coliE. coli, thickening and turbidity of the air sacs, , thickening and turbidity of the air sacs, exudative accumulations, fibrinopurulent exudative accumulations, fibrinopurulent pericarditis and perihepatitis may be seen. In pericarditis and perihepatitis may be seen. In turkeys, severe mucopurulent sinusitis may be turkeys, severe mucopurulent sinusitis may be found, with variably severe tracheitis and found, with variably severe tracheitis and airsacculitis. Lesions reported in naturally infected airsacculitis. Lesions reported in naturally infected chukar partridges and pheasants include chukar partridges and pheasants include conjunctivitis and sinusitis of one or both conjunctivitis and sinusitis of one or both infraorbital sinuses. Finches typically exhibit mild to infraorbital sinuses. Finches typically exhibit mild to severe inflammation in one or both eyes and the severe inflammation in one or both eyes and the periorbital region. The eyelids may be swollen and periorbital region. The eyelids may be swollen and inflamed, and a clear to cloudy, thickened ocular inflamed, and a clear to cloudy, thickened ocular discharge may be noted. There may also be discharge may be noted. There may also be drainage from the nares.drainage from the nares.

Chronic Respiratory Disease. Cloudy appearance ofChronic Respiratory Disease. Cloudy appearance ofthe abdominal air sacs in this 7 week old chickenthe abdominal air sacs in this 7 week old chicken..

Morbidity and MortalityMorbidity and MortalityIn chickens with uncomplicated infections, the In chickens with uncomplicated infections, the

morbidity rate is high and the mortality rate low; morbidity rate is high and the mortality rate low; however, more severe disease occurs if the birds however, more severe disease occurs if the birds are concurrently infected with other viruses or are concurrently infected with other viruses or bacteria. Mortality rates can be high in turkeys.bacteria. Mortality rates can be high in turkeys.

In wild songbirds, the impact of the disease is In wild songbirds, the impact of the disease is complicated by other factors. Under controlled complicated by other factors. Under controlled experimental conditions, house finches exhibited experimental conditions, house finches exhibited morbidity rates approaching 100%, but low morbidity rates approaching 100%, but low mortality rates of approximately 5% or less. mortality rates of approximately 5% or less.

DiagnosisDiagnosis Clinical signsClinical signsPm lesionsPm lesionsIsolationIsolation and and identificationidentification of the causative agent. of the causative agent. Laboratory tests Laboratory tests

• Isolation and identification of the causative agentIsolation and identification of the causative agent • indirect immunofluorescenceindirect immunofluorescence• immunoperoxidase stainingimmunoperoxidase staining• a growth inhibition testa growth inhibition test• metabolism inhibition or PCRmetabolism inhibition or PCR• Animal inoculation Animal inoculation • rapid serum agglutination (RSA) testrapid serum agglutination (RSA) test• enzyme-linked immunosorbent assays (ELISAs) enzyme-linked immunosorbent assays (ELISAs) • hemagglutination inhibition.hemagglutination inhibition.

TreatmentTreatment• Disinfect the farm and equipments with right • Disinfect the farm and equipments with right disinfectant.disinfectant.• • tetracyclinestetracyclines (oxytetracycline, chlortetracycline and (oxytetracycline, chlortetracycline and doxycycline), macrolides (erythromycin, tylosin, doxycycline), macrolides (erythromycin, tylosin, spiramycin, lincomycin, and kitasamycin), spiramycin, lincomycin, and kitasamycin), quinolonesquinolones (imequil, norfloxacin, enrofloxacin and danofloxacin) or (imequil, norfloxacin, enrofloxacin and danofloxacin) or tiamulintiamulin. Drugs that accumulate in high concentrations . Drugs that accumulate in high concentrations in the mucosal membranes of the respiratory and in the mucosal membranes of the respiratory and genitourinary tracts, such as genitourinary tracts, such as tiamulintiamulin and and enrofloxacinenrofloxacinFor CCRDFor CCRD• If the mycoplasmosis is clubbed with other bacterial • If the mycoplasmosis is clubbed with other bacterial infections like E.coli administer infections like E.coli administer NeomycinNeomycin and and DoxycyclineDoxycycline through drinking water in addition to the through drinking water in addition to the above treatment for 3 to 5 days.above treatment for 3 to 5 days.For ChicksFor Chicks• Chicks arrived from known infected parent flocks • Chicks arrived from known infected parent flocks should be treated with a suitable antibiotic during the should be treated with a suitable antibiotic during the first 48 hours after placement and then subsequently at first 48 hours after placement and then subsequently at 20 - 24 days for 24 to 48 hours period.20 - 24 days for 24 to 48 hours period.• Efforts should be made to reduce dust and secondary • Efforts should be made to reduce dust and secondary infections. Improve the ventiliation for having good infections. Improve the ventiliation for having good results of medicine. results of medicine.

PreventionPrevention• Establishment of Mycoplasma free breeding flocks.• Establishment of Mycoplasma free breeding flocks.• Treating infected hatching eggs with the antibiotic Tylosin • Treating infected hatching eggs with the antibiotic Tylosin to kill the organism contained in the eggs.to kill the organism contained in the eggs.• Before purchasing chicks from a hatchery, it should be • Before purchasing chicks from a hatchery, it should be confirmed that they are free from CRD.confirmed that they are free from CRD.• Chicks should be raised at the place where there is no • Chicks should be raised at the place where there is no approach of infected birds.approach of infected birds.• Complete fencing of the breeding farms and sufficient • Complete fencing of the breeding farms and sufficient isolation of prevent iarborne infections from infected flocks.isolation of prevent iarborne infections from infected flocks.• Disposing of dead birds by incineratin, deep burial or by • Disposing of dead birds by incineratin, deep burial or by means of special disposal pits.means of special disposal pits.• Using vaccines that are free from contamination of • Using vaccines that are free from contamination of Mycoplasma gallisepticum.Mycoplasma gallisepticum.• Construction of the houses must be done in such a way • Construction of the houses must be done in such a way that probibit the entrance of any type of wild birds and that probibit the entrance of any type of wild birds and wandering animals.wandering animals.• Prohibition of visitors in the farm.• Prohibition of visitors in the farm.• Before coming in contact with flocks, workmen should • Before coming in contact with flocks, workmen should take shower and put on special clothes.take shower and put on special clothes.

VaccinationVaccination - pullets reared in isolation can be - pullets reared in isolation can be vaccinated to prevent infection with vaccinated to prevent infection with Mycoplasma Mycoplasma gallisepticumgallisepticum. Suppliers of point of lay pullets can . Suppliers of point of lay pullets can provide vaccinated pullets.provide vaccinated pullets.

ManagementManagement -- house infected and uninfected flocks at house infected and uninfected flocks at least 50 to l00 m apart. Prevent the disease spreading least 50 to l00 m apart. Prevent the disease spreading by adopting basic principles of isolation and all-in, all-by adopting basic principles of isolation and all-in, all-out management and buy vaccinated pullets.out management and buy vaccinated pullets.

Differential diagnosisDifferential diagnosis

In poultry, the differential diagnosis includes respiratory In poultry, the differential diagnosis includes respiratory diseases such as infectious bronchitis, mild Newcastle diseases such as infectious bronchitis, mild Newcastle disease and avian influenza. disease and avian influenza. Hemophilus Hemophilus paragallinarumparagallinarum, , Pasteurella multocida Pasteurella multocida and and Mycoplasma Mycoplasma synoviae synoviae infections should also be ruled out. In turkeys, infections should also be ruled out. In turkeys, other pathogens to consider include avian other pathogens to consider include avian pneumovirus, pneumovirus, Pasteurella multocidaPasteurella multocida, , Chlamydia Chlamydia and and M. M. synoviaesynoviae. Mixed infections with . Mixed infections with M. gallisepticum M. gallisepticum and and other organisms can occur.other organisms can occur.

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