Avian Mycoplasma Myths

Published on: 01/30/2019
Author/s : Chris Morrow / Bioproperties.

1) Mycoplasma synoviae (MS) does nothing. 2) MS does not have airborne spread. 3) It is not MS because there is no joint involvement. 4) You must use F strain in the first stage of eradicating MG. That MS does nothing is an interesting view. There is great variation in the potential of MS strains to cause disease but avian Mycoplasma experts worldwide agree that MS is a pathogen, it has its ow...

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oumed gerjis oumed gerjis
Veterinary Doctor
January 30, 2019
Interesting paper
Hailu Mazengia Hailu Mazengia
DVM and MSc degree
January 31, 2019
Very nice article ??
January 31, 2019

Other myths are emerging.
1) ts-11 only works to 40 weeks (of age or after vaccination). This is a misunderstanding of the seroconversion that often takes place after the peak of lay in vaccinated flocks. Studies on these flocks don't find wild strains and there is no production problems or clinical signs. They only thing they seem to be suffering is antibiotic deficiency syndrome. See Barbour et al., 2000 Poult Sci 79:1730-1735 for a nice example of protection at 57 weeks.
2) There have been no reports of resistance to tylosin in MG etc. This is wrong. ts-11 was developed because tylosin stopped working in Australia in the 1980s and this and other examples are well reported in the literature. Same goes for nearly every other antibiotic for MG and MS.

Bouayad Bouayad
February 1, 2019

Good article, Dr. Morrow.
What do you think of vaccination in an infected environment? 
Thank you.

Ganesh Kumar Dahal Ganesh Kumar Dahal
Managing Director MDH Pharmaceuticals Pvt.Ltd.
February 3, 2019

Dr. Chris,

Good write up on myth of Avian Mycoplasmosis!
Since most of the antibiotics available in our region have become resistance to MG & MS, would vaccination become the only solution to MG & MS? What to do in case of peep/clutch of chicks are already under incubation with MG or MS?

Kathmandu, Nepal.

February 3, 2019

Ganesh Kumar Dahal I am just in Argentina and one vet is telling me how all antibiotics had stopped working on one client's farm and he was able to get control of mycoplasma again by vaccination. Remember not to forget MS as well as MG

February 3, 2019

Vaccination in an infected environment

All vaccines take a little while for the onset of useful immunity (save non specific protection from mechanisms like gamma interferon in viral infections). Mareks vaccination becomes more effective with the current vaccines if challenge can be delayed a couple of weeks.
Live Mycoplasma vaccines also take 3-5 weeks to generate immunity and challenge needs to be minimized before this time. Also, we don't think these vaccines can work below 21 days of age (something perhaps correlated with a specific T-cell subset appearing in the thymus).
So if you have a multiage farm then it is better to move the rearing to another farm (perhaps 2km from all other infected farms). The birds only have to be here till 8 weeks of age - it could be in an industrial park or apartment block. Biosecurity is also needed with staff movements. Have dedicated staff or visit these farms first thing in the day and have clean clothes and maybe shower in.
Vaccination of flocks that might have vertical contamination. Well in the long term tell the supplier to vaccinate the flocks when they are negative (on delivery from breeding programmes in the first world) but we have also had some success with antibiotics before vaccination. The aim is to keep the mycoplasma in the infected birds from spreading to the rest of the flock.

Replacement stock from positive parents

Antimycoplasmal antibiotics in first week, different antibiotic in second week in water and then stop 4 days before vaccination
No LaSota or stronger NDV vaccine within 14 days of live mycoplasma
Vaccinate with MG ts-11 and MS MSH at 21 days (as early as possible)
No antimycoplasmal antibiotics after vaccination.
For necrotic enteritis use amoxycillin or other penicillin.
If you have CRD after this time
Review antibiotics being used
Look at possible sources of potent early horizontal challenge (try to implement biosecurity till 5 weeks after vaccination.
Encourage supplier to use these vaccines

February 3, 2019
Really, very interesting article and advise further articles about MG myths.
Thank you very much Dr. Chris Morrow
February 19, 2019

In case of high titers (i.e > 12000 mean titer) for Ms with Elisa technique for a non vaccinated flock (Layer Breeder) at age 50 weeks, is it confirmative or do we have to proceed to another test?

February 26, 2019
Dr O S Alo Dr O S Alo
Veterinary Doctor
February 25, 2019

Could you comment on nasty production drop in layers after lasota vaccinations? Even despite preliminary antibiotic regimen can be embarrassing. Can you advise?

Badal Singh Badal Singh
veterinary science
February 25, 2019

Very useful information for me.

Thanks, Dr. Chris Morrow.

February 26, 2019

We have been examining vaccinated flocks by DIVA PCR and culture recently in Asia. Here we can not find the MG and MS live vaccines in flocks that have had anti-mycoplasmal antibiotics. We typically find field strains (we suspect they are resistant to antibiotics). The vaccine strains are sensitive to all anti-mycoplasmal antibiotics (even quinolones like enrofloxacin) even if local field strains are not (Enrofloxacin has a poor record in recent years in Asia for mycoplasma control and this is being confirmed by our MIC testing of asian strains). So if you are continuing to use antibiotics after vaccination you are probably wasting your money on the vaccine and if the challenge is by a resistant field strain you are probably wasting your money on the antibiotic but also putting pressure on antimicrobial resistance development with no benefit.

Muhammad Kashif Muhammad Kashif
Veterinary Doctor
February 27, 2019

Chris Morrow Dear Dr. Morrow, I fully agree with your comment. This is a real situation in Pakistan, also MIC levels of tylosin also increased. Both MG and MS are having poor response to antibiotics.

But I want your expert opinion about use of MG vaccine in PS stock as they will use vaccines the day old chicks may have antibodies if we will perform RSA/SPA it will be positive. In this situation, the farmer is confused, although is this due to vaccine?

Russ Cano Russ Cano
Doctor of Veterinary Medicine
March 6, 2019

Chris Morrow . Very True. I guess the best option after vaccination is to use Immunostimulant like 1,3/1,6 Beta-glucan to increase disease resistance after vaccination. Several published trials confirmed that BG increases Vaccination titers like AI, NCD & IB, so I guess it will also help improve the titer of MG after vaccination.

March 6, 2019

Good article to know more about MS. This Glass top/EAA should be looked at broad end or narrow end of the egg?

March 7, 2019

I want to know more sir, please. From India.

Wijaya Saputra Wijaya Saputra
Veterinary Doctor
March 20, 2019

Dear Dr. Chris Morrow.

I use ts11 vacine in the field to follow the procedure of properties. My birds are broiler breeder. We use ts11 vaccin at age 28 days. If result ELISA MG with mean titer range of 1000 to 2000 and % positive 50%, what is save to my birds of challange MG field infection. Please give me suggestions on what to do.

March 23, 2019
Wijaya Saputra Very strict bio-security measures should be implemented to control mycoplasmas
Ramzan Ali Ramzan Ali
Doctor Of Veterinary Medicine
March 18, 2021

Tylvalosin tartrate is a new third-generation macrolide with 16-membered lactone antibiotics in poultry and obtained from tylosin by the change of 3-acetyl-40-isovaleryl group to be acetyl isovaleryl tylosin tartrate which is the best effective on Avian mycoplasmosis and mildly necrotic enteritis in Poultry and chicken.

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