Mycoplasma agalactiae: The Sole Cause of Classical Contagious Agalactia?

Contagious agalactia (CA) is suspected when small ruminants show all or several of the following clinical signs: mastitis, arthritis, keratoconjunctivitis and occasionally abortion. It is confirmed following mycoplasma isolation or detection. The historical and major cause is Mycoplasma agalactiae which was first isolated from sheep in 1923. Over the last thirty years, three other mycoplasmas (Mycoplasma mycoides subsp. capri, Mycoplasma capricolum subsp. capricolum and Mycoplasma putrefaciens) have been added to the etiology of CA because they can occasionally cause clinically similar outcomes though nearly always in goats. However, only M. agalactiae is subject to animal disease regulations nationally and internationally. Consequently, it makes little sense to list mycoplasmas other than M. agalactiae as causes of the OIE-listed CA when they are not officially reported by the veterinary authorities and unlikely to be so in the future. Indeed, encouraging countries just to report M. agalactiae may bring about a better understanding of the importance of CA. In conclusion, we recommend that CA should only be diagnosed and confirmed when M. agalactiae is detected either by isolation or molecular methods, and that the other three mycoplasmas be removed from the OIE Manual of Diagnostic Tests and Vaccines in Terrestrial Animals and associated sources.