The first international conference on bovine mycoplasmosis, held in Saskatoon, Canada, in 2009, marked an official recognition of the importance of mycoplasmas in bovine respiratory disease, mastitis, arthritis and other disorders. Furthermore, bovine mycoplasmosis has been identified as a major emerging infectious disease by the European Community 7th Framework Programme under the EMIDA ERA-NET, which is funding a three-year study into the development of improved diagnosis and control of bovine mycoplasmosis involving the UK, Germany, Italy and Israel. These developments coincide with the publication of the complete sequence of the Mycoplasma bovis genome, which offers fresh insight into the properties of this tiny wall-less bacterium. With this in mind, it is an appropriate time to review our knowledge of cattle diseases caused by mycoplasmas.

Mycoplasma bovis is a major bovine pathogen associated with bovine respiratory disease complex and is responsible for substantial economic losses worldwide. M. bovis is also associated with other clinical presentations in cattle, including mastitis, otitis, arthritis, and reproductive disorders. To gain a better understanding of the genetic diversity of this pathogen, a multilocus sequence typing (MLST) scheme was developed and applied to the characterization of 137 M. bovis isolates from diverse geographical origins, obtained from healthy or clinically infected cattle. After in silico analysis, a final set of 7 housekeeping genes was selected (dnaA, metS, recA, tufA, atpA, rpoD, and tkt). MLST analysis demonstrated the presence of 35 different sequence types (STs) distributed in two main clonal complexes (CCs), defined at the double-locus variant level, namely, CC1, which included most of the British and German isolates, and CC2, which was a more heterogeneous and geographically distant group of isolates, including European, Asian, and Australian samples. Index of association analysis confirmed the clonal nature of the investigated M. bovis population, based on MLST data. This scheme has demonstrated high discriminatory power, with the analysis showing the presence of genetically distant and divergent clusters of isolates predominantly associated with geographical origins.M ycoplasma diseases cause substantial economic losses, particularly in intensively farmed cattle production systems worldwide, as a result of poor growth, morbidity, and deaths, as well as the costs associated with increased control and prophylactic measures. Mycoplasma bovis has increasingly been recognized as one of the main pathogens involved in the bovine respiratory disease complex, on its own or in association with other respiratory pathogens (1). M. bovis can also be found in association with mastitis, in which outbreaks can affect more than 20% of the cows in a herd, regardless of the stage of lactation, and infections are usually refractory to treatment. Arthritis and otitis have also been associated with M. bovis, usually appearing once pneumonia or mastitis is already established in the herd (1, 2). The control of M. bovis infections relies strongly on antimicrobial therapy, which has variable success rates in the field (3). Vaccination has been used in the early stages of cattle development and is mostly based on autogenous vaccines, which limits their use and the potential for widespread control of M. bovis infections (3).Taking into consideration the limited tools available for M. bovis disease management, the development of a dependable molecular typing scheme able to offer robust and reproducible epidemiological information would provide a valuable addition to control measures targeting this pathogen. M. bovis isolates have been characterized previously using multiple molecular typing methods, including amplified fragment length polymorphism (AFLP) analysis (4), random amplified polymorphic DNA (RAPD) analysis (5), pulsed-fiel...

The epidemiology, transmission, clinical signs, pathology, causative organisms, biochemistry, diagnosis, treatment and control, and other mycoplasma associated with respiratory diseases of sheep and goats are discussed.

Eggshell abnormalities were seen in the apex of eggs in two of three flocks of multi-age, Hy-Line layer chickens housed on a farm in Northern Italy. Approximately 1.3% to 1.8% of eggs in one flock were affected, amounting to 300-400 eggs per day; the abnormalities resulted in a great deal of breakage and spoilage of healthy eggs. The mean weight of eggs was also reduced. Egg abnormalities in a second flock were less severe. Mycoplasma synoviae was detected in birds from both of the affected flocks by serologic, cultural, and molecular techniques, but not in a third, adjacent flock where no eggshell abnormalities were seen. Treatment with tylosin, administered in the drinking water for 5 days, resulted in an immediate improvement of eggshell quality and egg weight. There was no evidence of infectious bronchitis virus in the flocks.

In this chapter, diseases caused by Mycoplasma bovis are discussed. The highlights of this chapter focused on the following topics: distribution, economic losses, host range, epidemiology, molecular epidemiology, causative organisms, disease course, diagnosis, prevention, control, and treatment of disease, and other bovine mycoplasmoses.