Mycoplasma bovis infection found in Finnish calves
M. bovis is one of the world’s most important and widespread causes of respiratory tract infections in cattle. In addition to respiratory tract infections, it causes arthritis, middle ear inflammation and conjunctivitis. It is also a common cause of bovine mastitis.
Mycoplasma infection exposes animals to other respiratory pathogens, which easily increases morbidity and the use of antibiotics. Unfortunately it is practically impossible to eradicate M. bovis infection from the animal population once it has spread there. M. bovis easily develops resistance to antibiotics when medicating animals. There are no vaccines available.
M. bovis spreads from farm to farm via animals that are symptomless carriers of the infection. It spreads from animal to animal through direct contact, as droplet infection and via items that have been in contact with animals. The bacteria survive in cool and damp conditions for months, but they are rapidly killed by dryness, heat and light.
When M. bovis is detected at a farm, the municipal veterinarian must be informed of the disease. The disease does not require legislative control and does not result in measures by the authorities, and it is possible to agree on the care of the animal with the local veterinarian. The disease is not transmitted to humans.
Efforts have been made to prevent the spread of M. bovis to Finland through early detection of the disease. Evira has studied respiratory tract disease samples from calves and also other samples from cattle since 2004 in case of any suspicion of M. bovis infection. This year, the microbial DNA test used by local laboratories in the diagnostics of bovine mastitis has included M. bovis, and therefore a large proportion of mastitic milk samples this year have been tested for M. bovis with negative results. Moreover, the Association for Animal Disease Prevention ETT has provided guidelines for testing imported animals for M. bovis.
When calves are presenting with respiratory tract symptoms, it is important to ask a veterinarian to take laboratory samples of the upper respiratory tract to establish the cause of disease. Using laboratory diagnostics, it will be possible to determine the cause of the disease and, if necessary, antimicrobial resistance of the bacteria.
Evira determines an M. bovis infection through culture, and the bacteria are identified on the basis of nucleotide sequence. Evira is testing the suitability of M. bovis antibody test in diagnostics and will probably start using the method in the near future.
Tarja Pohjanvirta, Senior Researcher, Head of Section,
Veterinary Bacteriology Research Unit, tel. +358 (0)44 720 1493
Paula Syrjälä, Senior Researcher,
Production Animal and Wildlife Health Research Unit,
studies into calf diseases, tel. +358 (0)44 720 1470