Mycoplasma gallisepticum vaccine

Dear Sir,
Herewith I am mentioning all the advantages and disadvantages of the MG/MS vaccination in poultry and points to remembering before vaccination, please have a look-
Control by vaccines
1. Killed/Inactivated vaccines
- These are M. gallisepticum killed organisms with oil emulsion adjuvants to protect the birds from infection with virulent M. gallisepticum .
- Several adjuvant enhanced bacterin vaccines but they are expensive and administration is difficult because they need to be injected twice with a 4-6 week interval (Ley, 2003).
- Killed vaccines have been shown to reduce, but not eliminate the M. gallisepticum infection and are not effective in long term control of infection in multiple age farms.
- Killed vaccination did not reduce horizontal spread of M. gallisepticum (Levisohn et. al.,2000).
- These are more stable and safer than live vaccine.



2. Live/Attenuated vaccine
- There is three type of live vaccines is available for M. gallisepticum viz.
- Connecticut F-Strain
- MG 6/85 strain
- TS-11 strain (Temperature sensitive mutants)
A. Connecticut F-strain
- Live F-strain M. gallisepticum vaccine is a relatively mild strain that originate from the Connecticut F strain of United States. Despite the advantages of the f-strain vaccine, it has many of the disadvantages of the inactivated vaccines.
- MG free chickens tend to lay better than F-strain immunised ones.
- F-strain is too virulent for young chicks.
- F-strain is capable of lateral spread in the flock.
- F-strain does not completely block transovarial transmission when birds are challenged with virulent MG.
B. MG 6/85 strain
- The 6/85 strain of MG is in lyophilised form and originate from United States.
- It has low virulence in chicken.
- Vaccinates were protected against airsacculitis and colonisation of the trachea was detectable from 4 to 8 weeks after vaccination (Ley, et. al., 1997).
C. ts-11 strain
- ts-11 is a live chemically induced mutant strain of MG is in frozen form and developed from Australian MG field isolate (Whithear et. al.,1990a).



Point to be remembering prior to Vaccination of flock
- Vaccination must be done in only MG free breeder flocks by taking consideration vertical transmission MG from parent stock to offspring.
- Before vaccination flock should be tested by DNA based molecular diagnostic tool viz. PCR instead of antigen-antibody based assay for the accurate diagnosis.
- MG 6/85 strain and ts-11 strain are live vaccine so there is more concern of safety because they may have potential for infecting unvaccinated flocks.
- The circulating field strain and vaccine strain should be same for efficacy of vaccination because of antigenic shift and phenotypic switching of MG.
- Control of MG infection by vaccination is limited as onlya few vaccines are available.
- Secondary mutation can cause a reversion to virulence
Regards,
Dr Sachin Patil
M.V.Sc (Animal Biotechnology)
National Technical Manager
Huvepharma India

Great question, great answers. Thank you. Control of Mg and Ms day by day is getting harder. What do you think about the use of antimycoplasmic drugs every 4 or 6 weeks? And about the new releases like Tylvalosin and Sakamycin (please excuse me if they are not right written, in Spanish is "choques antimicoplásmicos", tilvalosina y sakamicina)?
Looking forward to hearing from you.

Thanks for this has come up, I have used the frozen strain and eye drop at the age of 6 weeks with a repeat at 9 weeks. However, mycoplasmosis has often times attached me. It's true it's not easy to control on a farm with multiples eggs of laying birds and that is what I have. The birds that I have not vaccinated also safer in the same way like those vaccinated however when I treat with tylosin 20% in water at a rate of 10mls per 20liters of water for 7 days. The birds get better I follow this up with biosecurity to prevent spread and this has worked out well to the extent that I can control my lock of 35,000 layers on the farm very clean without any cough.

MG infection is very common in many countries. Most of the PS & Com. flocks of Pakistan found positive in lab and also showing signs of infection in the field. Negative flocks are getting infection easily from contaminated field.
Keeping this in view, I personally feel that sue of vaccines either killed or live is useless. Tilmycosin, the latest antimycoplasma drug is giving better results to reduce the losses from Mycoplasmosis.
Dr. M. Akram, Consultant Microbiologist, Karachi, Pakistan.

Thank you for vaccine-related information.
I have few queries related to MG:
1) It is said that the broilers are not infected with MG, or the signs of MG infection are not seen, what do you say about it?
2) To prevent MG infection, preventive doses of Tylosin are used even in broilers, what do you comment upon this?
3) What about preventing MG in layers? Does only vaccination prevent?

Thank you.

MG is considered a serious economic threat in poultry.
All branches can become infected at any age and broilers are among the most affected as the commercial conditions and rapid growth promote the susceptibility of the birds to the MG infection and secondary E coli severe CRD complication.
Layers and breeders may suffer from a very light drop in egg production, but in breeders the MG is transmitted to the progeny.
Treatments based on Tylosin, Tilmicosin, doxacyllin etc can be of help only when the birds are treated at 1-3 days of age and then again at 14 -18 days. The program may be helpful for broilers to control severe losses due to CRD.

Treatment not successful whenever treat by the tylosin/timulian/doxcyclin .The problem exactly MG. Respiratory distress causing most serious in broilers during summer and winter then what will be the good treatment or correction for that? Respected dear Sir, please comment on this.

Mostly mycoplasma is vertical so initial doses with tylosin on 3d to 5th day follows tilmycosin with ctc and terra mycein la inj with cefoparazone on 20 days is useful as preventive measure.

Mycoplasma vaccine only works if disease is not endemic in flock, if it is followed by 5 days course of Tilmycosin it proves good.

Mostly the diagnosis is wrong, if right treatment for complications be done simultaneously, vaccine results are poor due to immune suppression, good ventilation, keep litter reasonably dry, check mycotoxins in feed and use more common sense than treatment-will give good results, thinking only to treat mycoplasma you will never succeed.

In field E coli is more fatal than mycoplasma, so giving previous treatment at regular intervals with antimycoplasmal drugs with E coli previous is best to my experience. Azithromycein with Amoxyllin combination is better to check secondary infections.

What are causes of this disease and how should we do to prevent and control when disease are recognised with a flock?

Use MG Live and killed vaccine in parent first for long term prevention.

Short term use drug of choice and good management plus good feed and DOC.

Use of tiamutin at the age of 10-15 days gives good results.

Do you believe is ok to combine ILT vaccine with Myco F as intranasal vaccination for pullet 12 weeks old?
I read that it will be better not to combine Myco F with any other respiratory diseases vaccine specially ILT and IB, ND.
Please advise. 
Dr. Abe Dessouki.