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Transcript of Crd
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
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