Bovis ISSN 2398-2993

Mycoplasma bovis

Synonym(s): M. bovis

Contributor(s): Al Manning, Veronica Fowler

Introduction

Classification

Taxonomy

  • Phylum: Tenericutes.
  • Class: Mollicutes.
  • Order: Mycoplasmatales.
  • Family: Mycoplasmataceae.
  • Genus: Mycoplasma.

Etymology

  • From the Greek 'Myco', meaning 'fungus' and 'Plasma' meaning 'formed'.
  • 'bovis' - of the ox.

Morphology

  • Atypical bacteria: mollicutes do not have a rigid cell wall but a three-layered flexible cell membrane.
  • Mycoplasma are characterized by their small cell size (typically 0.3-0.8 µm).

Resting Forms

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Clinical Effects

Epidemiology

Lifecycle

  • Hematogenous spread within the animal. Intracellular pathogen.
  • Biofilm production contributes to bacterial survival in the environment and its persistence inside the host.
  • M. bovis is able to evade host defenses through variance in the cell surface proteins due to chromosomal recombination events during cell replication.

Transmission

  • M. bovis is typically associated with contagious mastitis Mastitis: approach to the herd mastitis problem, ie spread during the milking process.
  • It is shed in respiratory surface secretions and can be transmitted by aerosols through coughing.
  • Infected cows shed M. bovis in their milk and can pass the bacteria onto their calves. Due to the multimodal mechanism of spread and difficulties in diagnosis, M. bovis typically presents as an outbreak.
  • There is a large variation in shedding between infected animals. Intermittent shedding has been reported in cows with mastitis.
  • Asymptomatic carrier animals and/or those with only mild clinical symptoms, which have not been detected by stock keepers, are hypothesized to be an important source of infection, but the evidence base to support this theory is currently lacking.

Pathological effects

  • M. bovis is typically associated with respiratory disease Adult respiratory disease, otitis media, mastitis Mastitis: unusual forms overview, and arthritis:
    • Respiratory disease:
      • Coughing.
      • Chronic pneumonia which is non-responsive to treatment.
      • Not typically associated with pyrexia.
      • Can cause pneumonia in calves and adult cattle.
    • Otitis media: head tilt, circling.
    • Mastitis:
      • Clinical or subclinical.
      • Milk loss.
      • Purulent or serous udder exudate.
    • Polyarthritis:
      • Multiple swollen joints, with heat and non-weight bearing lameness.
      • Typically affected joints are in the distal limb, eg the carpus and tarsus are the most affected joints.
  • M. bovis has also been identified in cattle with ocular or reproductive disease or anemia.
  • Other Mycoplasma spp have been identified in cattle and can be isolated from bulk milk, although the clinical significance of all species is not clear. Some strains have been reported to cause similar symptoms to M. bovis, eg M. alkalescens, M. boviculi, M. dispar, M. mycoides subsp mycoides (contagious bovine pleuropneumonia), M. wenyonii Mycoplasma wenyonii.

Control

Control via animal

  • Most farms do not need to employ any specific control measures beyond surveillance.
  • On farms with a diagnosed history of M. bovis or in a suspected outbreak the following control measures should be employed:
    • M. bovis is typically spread through milking equipment, so known affected cattle should be milked separately using a different cluster and milking line. Clusters should be disinfected after milking cows known to be infected.
    • M. bovis can also be spread through aerosols, so affected cows and calves should be isolated from healthy stock in a separate airspace CowSignals: air.
    • Colostrum: avoid pooled colostrum or consider pasteurization Colostrum: overview.
    • Milk feeding: pasteurized whole milk or consider powdered milk feeding. Avoid feeding waste milk. Acidified milk feeding may also reduce the spread of Mycoplasma bovis Feeding milk and milk replacers to calves Milk acidification.
    • Historically culling has been recommended as a control strategy, however this is not supported by recent published evidence.
    • Avoid buying in animals with unknown disease status.

Control via chemotherapies

  • M. bovis isolates show resistance to many antimicrobials licensed in cattle.
  • Several antimicrobials are specifically licensed for treatment of Mycoplasma spp, including macrolides, tetracyclines and amphenicols.
  • For treating M. bovis calf pneumonia, the treatment of choice is a long acting macrolide, eg tulathromycin Tulathromycin, gamithromycin. This class of antimicrobials are classified as ‘high priority critically important antimicrobials’ by the (World Health Organization and their use should therefore be avoided as a first line One health.
  • There are no evidence-based treatments licensed for mastitis caused by M. bovis. Veterinary advice should focus on diagnostics, controlling spread and preventing new cases.
  • There is limited research to demonstrate efficacy against M. bovis causing lameness. Oxytetracycline Oxytetracycline is often used empirically, however the prognosis is guarded. Joint flushing can be attempted in a hospital setting Joint lavage.
  • Non-steroidal anti-inflammatory drugs are recommended for all M. bovis infections on welfare grounds Anti-inflammatory drugs: overview.

Control via environment

  • M. bovis has been reported to survive in the environment for many months.
  • When managing M. bovis respiratory disease on calf rearing units an ‘all-in-all-out’ system is recommended, with thorough disinfection between batches of calves.

Vaccination

  • There are no vaccines licensed for general use.
  • Several companies produce autogenous vaccines based on farm specific strains of M. bovis, although there is limited evidence to support their use.

Diagnosis

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Manning A (2020) Mycoplasma spp. mastitis - approach to diagnosis. Livestock 25 (4), 170-172 MAGOnline.
  • Gille L, Boyen F, Van Driessche L, Valgaeren B et al (2018) Short communication: Effect of freezer storage time and thawing method on the recovery of Mycoplasma bovis from bovine colostrum. J Dairy Sci 101 (1), 609-613 JDairySci.
  • Parker A M, Sheehy P A, Hazelton M S, Bosward K L & House J K (2018) A review of mycoplasma diagnostics in cattle. J Vet Int Med 32 (3), 1241-1252 WileyOnline.
  • Timonen A A E, Katholm J, Petersen A, Orro T et al (2018) Elimination of selected mastitis pathogens during the dry period. J Dairy Sci 101 (10), 9332-9338 JDairySci.
  • Parker A M, House J K, Hazelton M S, Bosward K L et al (2017) Bulk tank milk antibody ELISA as a biosecurity tool for detecting dairy herds with past exposure to Mycoplasma bovis. J Dairy Sci 100 (10), 8296-8309 JDairySci.
  • Barberio A, Flaminio B, De Vliegher S, Supr√© K et al (2016) Short communication: In vitro antimicrobial susceptibility of Mycoplasma bovis isolates identified in milk from dairy cattle in Belgium, Germany, and Italy. Journal of Dairy Science 99 (8), 6578-6584 JDairySci.
  • Nicholas R A J, Fox L K & Lysnyansky I (2016) Mycoplasma mastitis in cattle: To cull or not to cull. Vet J 216, 142-147 SciDirect.
  • Parker A M, House J K, Hazelton M S, Bosward K L et al (2016) Milk acidification to control the growth of Mycoplasma bovis and Salmonella dublin in contaminated milk. J Dairy Sci 99 (12), 9875-9884 JDairySci.
  • Nielsen P K, Petersen M B, Nielsen L R, Halasa T & Toft N (2015) Latent class analysis of bulk tank milk PCR and ELISA testing for herd level diagnosis of Mycoplasma bovis. Prevent Vet Med 121 (3-4), 338-342 SciDirect.
  • Piccinini R, Gosney F, Snel G G M, Luini M V & Nicholas R A J (2015) Environmental survival of Mycoplasma bovis on a white veal farm. Vet Rec Case Reports (1), e000207 BMJ.
  • Britten A M (2012) The role of diagnostic microbiology in mastitis control programs. Vet Clinf North Am Food Anim Pract 28 (2), 187-202 SciDirect.
  • Justice-Allen A, Trujillo J, Corbett R, Harding R et al (2010) Survival and replication of Mycoplasma species in recycled bedding sand and association with mastitis on dairy farms in Utah. J Dairy Sci 93, 192-202 JDairySci.
  • Caswell J L & Archambault M (2007) Mycoplasma bovis pneumonia in cattle. Anim Health Res Rev (2), 161-186 PubMed.
  • Godden S, Mcmartin S, Feirtag J, Stabel J et al (2006) Heat-Treatment of bovine colostrum. II: Effects of heating duration on pathogen viability and Immunoglobulin G. J Dairy Sci 89, 3476-3483 JDairySci.
  • Biddle M K, Fox L K & Hancock D D (2003) Patterns of mycoplasma shedding in the milk of dairy cows with intramammary mycoplasma infection. J Am Vet Med Assoc 223 (8), 1163-1166 JAVMA.
  • McAuliffe L, Ellis R J, Ayling R D & Nicholas R A J (2003) Differentiation of Mycoplasma species by 16S ribosomal DNA PCR and denaturing gradient gel electrophoresis fingerprinting. J Clin Microbiol 41 (10), 4844-4847 PMC.

Other sources of information

  • Animal & Plant Health Agency (2018) Mycoplasma bovis: current knowledge, industry challenges and knowledge gaps for othe UK cattle industry. UK Cattle Expert Group 2018. Website: apha.defra.gov.uk (pdf download).
  • Smith B P (2009) Large Animal Internal Medicine. 4th edn Mosby Elsevier, USA.
  • Guard C (2007) Musculoskeletal Disorders. In: Rebhun’s Diseases of Dairy Cattle. 2nd edn. Eds: Divers T J & Peek S F. Saunders Elsevier, USA. pp 467-503.
  • Hillman R & Gilbert R O (2007) Reproductive Diseases. In: Rebhun’s Diseases of Dairy Cattle. 2nd edn. Eds: Divers T J & Peek S F. Saunders Elsevier, USA. pp 395-446.

ADDED