MEMBER IN INTERNATIONAL NETWORK FOR POULTRY DEVELOPMENTFAO

FAO IRAQ

Prevalence of Mycoplasma gallisepticum

Infection in Poultry Farms

Dr. Majed H. Mohammed Ph.D.

Virology and Moleculat Cell Biology

majed.mohammed@uod.ac

Background

• Mycoplasmas are highly versatile and successfulpathogen

• Chronic Respiratory Disease: Once infected,infection remains for life

• Mycoplasma lack a cell wall: resistant topenicillin group of antibiotics

• Antimicoplasmal drugs are bacteriostatic

• Antibodies can not eliminate infection

• Field infection (MG/MS) level is high due tovertical transmission and low level of biosecurity

• Raising mycoplasma clean flocks is notpracticable

Major pathogenic species

M. gallisepticum - Chickens, Turkeys

M. synoviae - Chickens, Turkeys

M. meliagridis - Turkeys

M. iowae - Turkeys

Smallest self replicating prokaryotes

Lack of cell wall, bounded by cell membrane

Fragile – easily killed out side its host by disinfectants

• Costliest Disease in Poultry

• Mortality

• Reduced feed conversion

• Loss of weight

• Complications with – IB, ND, E coli

• Drop in egg production

• Reduced hatchability & chick viability

• Cost of eradication and control programs

Economic significance

Transmission

• Horizontal

– Within a flock - contact or aerosols

– Between flocks - windborne

• Vertical

– Parent to the chick through egg

Some possible egg-borne infections

Target organs:

– Respiratory system

– Synovial membranes

– Reproductive system

Incubation period:

– Chronic slow spreading

– Varies from 6-21 days

Clinical Signs• Coughing, sneezing, Nasal discharge

• Foamy secretions in the eye

• Open mouthed breathing

• Tracheal rales

• Reduced feed consumption

• Loss of weight – more stunted chicks

• Drop in egg production – layer, breeder

• Reduced hatchability, chick viability

• Lameness

• Morbidity – up to 100%

• Mortality – up to 30%

Gross Lesions

• Sinusitis and conjunctivitis

• Tracheitis with excessive mucus

• Airsacculitis

• Pneumonia

• Synovitis

• Osteomyelitis

• Salpingitis

The most characteristic signs in adult flocks are tracheal rales, nasal discharge, coughing

Frothy exudate

in Air sac

Accumulation of

Cheesy mass in thoracic air sac

Foamy lesions

develop on air sacs

Within one weak later become 8-10 folds

thicker than normal

Secondary E.coli infection leads to severe

fibrinopurelent or Caseous exudates on

pericardium and liver capsule (fibrinous

pericarditis and fibrinous perihepatitis)

Complicated Chronic Respiratory Disease

Air-saculitis, Pericarditis, perihepatitis

Catarrhal inflammation of the nasal passages,

sinuses, trachea, and bronchi .

Diagnosis of maycoplasma

• Isolation: Laborious process (slow growth – complex

nutritional requirement) tubes should be incubated at 37 C

for at least 14 days before being discarded as negative.

• Identification: Biochemical & Serological (growth

inhibition test, agar gel precipitation test, ELISA, FAT, HI,

Agglutination test).

• Routine monitoring of flocks for MG and MS infection is usuallyby the RSA, (Rapid Sera Agglutination also known as the Platetest, SPA) or ELISA test. Testing is usually recommended to beevery 3 weeks in high risk areas

• Yolk samples from eggs can be tested in ELISA format tests andmay be useful, especially if access to the parent flock is notpossible or is a problem from a biosecurity point of view

Monitoring by serology

Serum separation for ELISA

Collection of choanal swab

• In the field, many cases of M. gallisepticum infection are complicated by other diseaseproducing bacteria. Therefore, effective treatment must also attack the secondary invaders.

• Most strains of mycoplasma M. gallisepticum are sensitive to a number ofantibiotics, but are resistant to penicillins or other antibiotics which act byinhibiting cell wall

• A combination of colistin and tylosin with other anti-bacterials generallyhelps and effect will be better if bronchodilators are also used in drinkingwater for 3-5

• tetracyclines, tylosin, tiamulin, quinolones (enrofloxacin) and tilmicosinbut most of these are bacteriostatic rather than bacteriosidal.tetracyclines, tylosin, tiamulin, quinolones (enrofloxacin) and tilmicosinbut most of these are bacteriostatic rather than bacteriosidal.

Treatment

The avian respiratory system is involved in the following functions:absorption of oxygen (O2)release of carbon dioxide (CO2)release of heat (temperature regulation)detoxification of certain chemicalsrapid adjustments of acid/base balance

Use of vaccines:

(a) Killed vaccines:

(b) Live vaccines: These are of three types: F strain vaccine, 6/85strain vaccine, and ts-11 vaccine

Management: Because M. gallisepticum can be transmitted byegg, maintaining chicken flocks free of M. gallisepticum ispossible only by starting with breeding stocks that are free of theinfection.

Prevention and Control

biosecurity is extremely important in the control of disease

Suggestions and Comments

Biosecurity – Preventing disease in poultry

The use of anolyte in poultry

The addition of neutral anolyte into the drinking water ...improves feed conversionpromote immunityincreases the resistance to diseasepermits an increase in the vitalityreduces mortality by 50 to 70%allows a higher life weight at lower feed consumptionreduced the use of antibioticseliminates E-coli, salmonella, coccidiosisimproving the quality of the feed of the animalsMinimizes the impact of mortality during epidemicsreduced the amount of small eggs increases the quality and the uniformity of the calibration of eggs