New vaccine keeps Mycoplasma at bay

Mycoplasma can cause significant problems for poultry producers. Of the many species, Mycoplasma gallisepticum (M.g.) is the most important as far as chickens are concerned, and can cause respiratory disease, a drop in egg production and a reduction in feed conversion efficiency.

Like many poultry diseases, M.g. infection is usually part of a multiple challenge. Other diseases (for example Infectious Bronchitis or Colibacillosis) or stresses due to overcrowding can interact with M.g. to cause a respiratory/poor production syndrome. The overall effect can be anything from snicks, sneezing, conjunctivitis and egg production drops to bird mortality.

Diagnosis by serology generally shows a rising presence of antibodies against challenge. However, it can sometimes prove difficult to detect the rise in antibodies, since M.g. can do quite a lot of local respiratory harm without alerting the bird’s immune system. Vets often report that they suspect M.g. is involved but have difficulty confirming it.

This is clearly a disease the poultry industry does not want! Getting rid of it is not easy, particularly on extensive multi-age or free range sites. Control is best performed in breeding flocks by careful and continuous monitoring and blood testing. Unfortunately, M.g. can be passed from infected parents to pullets, after which the organism is passed from pullet to pullet. Bio-security and efficient disinfection between flocks is essential to minimise the spread of the disease. In the absence of any vaccine, control has been difficult.

However, vaccination is now possible with Intervet’s recently introduced Nobilis MG 6/85. This vaccine contains a live attenuated strain of Mycoplasma gallisepticum and is for immunisation against respiratory disease caused by M. gallisepticum.

Nobilis MG 6/85 is already available in many other EU countries and it is anticipated that it will be used in almost 40% of Italy’s layer flock this year. Extensive use has demonstrated that it can reduce pullet to pullet and parent to pullet transmission. When used on an annual basis it has been shown to substantially reduce the challenge of virulent M.g. on farms by replacing it with the non-virulent harmless vaccine strain.

Intervet recommends that Nobilis MG 6/85 is used in birds from six weeks of age. The vaccine has a zero withdrawal period and should be used at least four weeks before the onset of egg production, and not during lay. Administration should only be performed using a fine aerosol to ensure it reaches the bird’s respiratory system. A number of sprayers currently exist which will produce the required droplet size.

Further details on the new vaccine can be obtained from your veterinary surgeon or from Intervet’s poultry team on 01908 685249 or email poultry.uk@intervet.com