Mycoplasma agalactiae infection in Italy: past, present and future

Mycoplasma agalactiae is the major pathogen cause of contagious agalactia (CA), which still represents an unsolved problem for Mediterranean livestock particularly for those countries traditionally dedicated to dairy products with high productive milking breeds. The disease represents a real priority and it is included in the list of OIE notifible diseases because of its economic impact and widespread distribution. In Italy epidemiological data are actually underestimated and limited to those rare reports of Public Veterinary Services. This lack of information is mainly relate to the severe and often out of date/un-appropriate veterinary restrictions which must be applied once confirmed the outbreak. In the last twenty years there was a massive improvement of laboratory diagnosis but in spite of Molecular Biology and very advanced techniques, some issues are still unsolved: to recognize healthy carriers, to identify the pathogen during dry season, use of serology/immunology for individual test, choice of proper immune-prophylaxis in term of vaccination and associated antibiotic therapy. Antibiotic therapy may recover clinical symptoms but often the organism is not cleared and as a result can create sub-clinically infected animal (carrier state) for potentially years afterwards. Recently immunogenic proteins of Mycoplasma agalactiae have been identified as suitable for peptide vaccine against the disease but a practical development from the study to a real vaccine has been actually improbable. Many authors do not recommend single proteins as potential protective vaccine, also due to antigenic variation of the pathogen. In Italy, small ruminant livestock is an emerging sector especially with regard goat productions but the quality and health of these Mediterranean products, and this peculiar market often classifiable as biological or organic, has been always affected by severe losses caused by CA endemism. Future scenario would consider more sensitive serological tests (IgM) or sera should be consequently processed with joined methods (ELISA – Immunoblotting) discriminating antibodies from naturally infected or vaccinated animals. The use of live vaccines, whilst being the most antigenic, is banned in EU and the efficacy of inactivated vaccines is still debating. It appears that there is a need for so called marker vaccines and relate diagnostic tools in order to distinguish between vaccinated and infected animals.