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Biosecurity for MG Dr Syed Irfan Hussain, DVM Web Veterinary Services
Biosecurity for MG
Dr Syed Irfan Hussain, DVM
Web Veterinary Services
Disease
Prod.type
Cost ($)
Reference
Reovirus
Broiler
Breeders
6.89/bird
Dobson &Glisson
1992
LP AI
Egg layers
Breeders
turkeys
1.67/bird
2.94/bird
5.05/bird
Davison et al. 1999
HP AI Chickens
6.06/bird
(Feds)
19/bird
(industry)
Lasley 1986
Reynnells et al. 1987
MG
Egg layers
Breeders
1.72/bird
1.95/bird
Johnson 1983
UK Antec Inter’l
2004
THE COST OF DISEASE
Presumptive – History; signs; lesions
Definitive
Antibody detection-serology Serum plate agglutination (SPA)
Hemagglutination inhibition (HI)
Enzyme-linked immunosorbent assay (ELISA)
Diagnosis
Organism detection Culture, & id. by immunofluorescence
Polymerase Chain Reaction (PCR)
Random Amplified Polymorphic
DNA (RAPD)
PCR-based method of DNA
fingerprinting
Intraspecies (strain) identification of
avian mycoplasmas (e.g. MG)
MG RAPD
Fingerprints 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
1 & 15=standard, 2=nc, 3=F strain, 4=ts11, 5=6/85, 6=HF,
7-10=Strain B, 11-14=Strain A
Where Does Mycoplasma
Come From?
• Backyard poultry and some commercial layers
• Other birds carry the disease as well
• Turkeys, guineas, partridge, pheasants, quail, ducks,
pigeons, finches.
• Extremely easy to transmit
• BIOSECURITY FAILURE
– Objective
Remain as clean as posible
Peds, GGPs & GPs must be clean
– Monitoring and Control Programs National Poultry Improvement Plan
Company programs
– Erradication Difficult to achieve in multi-age facilities
– Biosecurity is key Feed trucks
Visitors
Live haul trucks
Vaccination crews
Contact with backyard and cockfighting chickens
Prevention and Control
BIOSECURITY…
is the key for
Mycoplasma Prevention
FEED
Skin: <4 hrs
Ear: 4 hrs
Nose: 1 day
Hair: 3 days
Feathers: 4 days
Feed: 4 hrs Rubber: 2 days Shavings: 8 hrs
Wood: 1 day
Straw: 2 days
Cotton: 4 days
Christensen et al, 1994
Survival
of MG
Testing and Monitoring
– Use the Plate Test as first test for seroconverstion, because
it can detect seroconversion in 2 weeks post exposure
(especially for Ms). It may take 4 weeks or more post
exposure for ELISA to detect seroconversion.
Ms tends to be more aggressive in producing seroconversion
and in spreading than Mg.
False positives occur if serum sample frozen, sample taken
after killed vaccines administered, Staph infection in birds.
– Use HI results to help determine the timing of infection.
If have high titers (I.e. 1:60’s and 1:80’s) then infection may
have occurred earlier than birds with lower titers (I.e. 1:20’s and
1:40’s).
Mycoplasma Control & Treatment
Sera Plate Agglutination Test
– Needs extensive quality control
Titration of antigens with a standard lyophilized positive (and
negative) serum
New batches of antigen should be tested for specificity
– Should only be done on sera less than 72 hr old
– Both MG and MS should be tested for
A recent MS infection will cause MG reactions
– If large number of reactors (>15% after heat treatment) the
flock is more likely to be truly infected
– Do not rely on day-old chick sera testing
False positive results are very common
– All samples should be heat treated before testing
(56C for 30 min)
Mycoplasma Control & Treatment
Testing and Monitoring
– Test pullet/breeder flocks every 3 weeks until
Don’t test a flock using PCR or isolation if birds treated
with antibiotics within the last 7 days.
Once a pullet/breeder flock is challenged, the recovered
birds will be OK because they will develop immunity to
mycoplasma, but the flock stays infected for life.
– Test sick broiler flocks at harvest. – The broilers may not be old enough if killed at an early
age/light wt. to produce antibodies to mycoplasma thus
Plate test may result in false negatives – may need to use
PCR or isolation.
Mycoplasma Control & Treatment
Mycoplasma Control &
Treatment
Treatment:
– Treatment does not eliminate carrier state, it
only suppresses the level of Mycoplasma.
– Positive Breeders should have a consistent
Mycoplasma reduction program
Continuous
Monthly treatments
– Good biosecurity practices in Positive Farms
are very critical
Tylosin: Water vs. Feed – Tylosin Tartrate is the water soluble form
– Absorbed well from gut = higher drug concentrations in tissues.
– Tylosin Phosphate is the feed grade form. Not absorbed well, thus need high dose to treat disease properly.
– Regulations may limit dose levels in feed
Consistency of drug level in the feed is dependent on the feedmill.
If Tylosin was a cure all for mycoplasma, it would be used all over the world in every breeder.
Mycoplasma Control &
Treatment
Tylosin Treatment Option in Broilers: – Treat broilers from mycoplasma positive breeder
flocks the first 5 days of life via the drinking water. 2gm/gallon drinking water (2.5 jars of Tylosin/gallon stock solution) (0.5gm/l of drinking water) or 50mg/lb (110mg/kg).
Tylosin Treatment Option in Breeders: – Every 4 weeks treat for 5 days at 1100ppm in the
feed.
– Treat continuously in between at 220ppm in the feed.
– Treat via water for 5 days at 0.5gm/l or 50mg/lb (110mg/kg) after move and/or vaccination.
Mycoplasma Control &
Treatment
Enrofloxacin Treatment Option in Breeders: – 10mg/kg/day (50ppm = 1gallon Baytril + 4 gallons
water for stock solution).
– Treat for 5 days and repeat treatment every 30 days.
Birds will culture and PCR negative following first treatment.
Birds will seroconvert negative 2-3 months after initial treatment.
– Monitor every 30 days to monitor seroconvertion status.
Tylosin may be the drug of choice for Ms, whereas either Tylosin or Enrofloxacin can be used for Mg.
Mycoplasma Control &
Treatment
Tiamulin Treatment
– 55 mg/kg for 7 days every month
– Synergistic activity with Chlortetracycline
450 ppm
– In broilers cannot be used with monensin
– Can be also given SQ
Mycoplasma Control &
Treatment
Tilmicosin Treatment
– 25 mg/kg for 7 days every month
– Residues
Mycoplasma Control &
Treatment
Mycoplasma Control & Treatment
Vaccination
– Inactivated bacterin:
Vaccinate before birds turn positive and before
move to hen house.
Generally administer at 5 and 15 weeks old.
– Some will use vaccine at 10 weeks and 15 weeks,
but the 10 week vaccine may be too late if they are
exposed earlier (test flock to see when turn positive).
Vaccinated flocks will produce positive plate
test results.
– May need to leave some sentinel birds in flock.
Vaccination
– Live vaccine:
6 and 10 week vaccination.
– Not younger than 6 weeks.
– Need to get vaccine in before field strain gets in to assure efficacy.
Advantage: less expensive than killed, better cross-protection
against MG strains, protects against tracheal colonization
(helps to eliminate field strain from farm).
Disadvantages: may spread among birds, houses, and farms,
may revert to virulence, may not vaccinate every bird.
Don’t treat birds with antibiotics (CTC, Oxytet, sulfas) 5 days
before or after vaccination.
– Tylan doesn’t seem to have an impact on protection provided by
live vaccines.
Don’t administer MG vaccine within 2 weeks of any live NCV,
IBV, or LT vaccinations.
– The MG vaccine will interfere with the other vaccines.
Mycoplasma Control & Treatment
Mycoplasma Control & Treatment
Vaccination
– Live vaccine: F-Strain
– Hot vaccine. Very immunogenic.
– Can be pathogenic for chickens and turkeys.
Can cause decline in body weights, egg production and egg quality.
– Can be found in trachea for life of bird.
– Will cause seroconverstion, so need PCR with proper probe to differentiate from field strain.
– Coarse spray application.
Mycoplasma Control & Treatment
Vaccination – Live vaccine:
Intervet’s 6/85 strain (Mycovac-L) – Mild and safe.
– Likes warmer temperatures, so it is administered via fine spray (<20 microns) to get into trachea and lungs.
– Minimal reaction, doesn’t spread horizontally, between houses or vertically. Thus, every bird needs to be vaccinated.
To get proper coverage: use 1 gallon of water with vaccine for every 1,000 birds,
Doesn’t cause birds to seroconvert using Serum Plate Agglutination test (ELISA titers may be erratic, but low). Thus can use Plate Test to help differentiate from field infection.
Mycoplasma Control & Treatment
Vaccination
– Live vaccine:
ts-11 (temperature sensitive)
– Mild vaccine
– Grows in cooler temperatures, thus needs
to be administered via eye drop (IO).
– Will get some seroconverstion, so need
PCR with proper probe to differentiate from
field strain.
Millions of breeders
become positive for
MG & MS worldwide
What do they do for MG ?
Sooner depletion if possible
Breeders will go clinical
Broilers: Higher plant condemnations
Immediate Mycoplasma Reduction Program 5 to 7 days/month for life of the flock
Enrofloxacin
Tylosin
Tiamulin
Others
BIOSECURITY becomes very critical
Future vaccination program (live, killed)
What do they do for MS ?
Usually no clinical signs
Progeny will do well unless:
Immunosuppresion: IBD, CAV, Mycotoxins, etc.
Co-infections
Poor ventilation
Immediate Mycoplasma Reduction Program 5 to 7 days/month for life of the flock
Enrofloxacin
Tylosin
Tiamulin
Others
BIOSECURITY becomes very critical
Some countries vaccinate: Australia, Mexico,etc
BIOSECURITY…
is the key for
Mycoplasma
Prevention & Control
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