College of Veterinary Medicine

AAHP Field Disease Investigation Unit (FDIU)

Mastitis


Mastitis is an inflammation of the mammary gland.  It is a disease that can affect production and its quality on dairies.  This research group focuses on the examination and development of new methods for controlling mastitis, especially mastitis caused by Staphylococcus aureus

DNA "fingerprinting" helps researchers trace this pathogen from reservoir to fomite to host.  Following one organism along this path will allow better understanding of the epidemiology of the disease, and will enable development of control strategies.

Other research includes a project designed to examine the role S. aureus exotoxins have as superantigens in mastitis, and their affects on milk quality.  Additionally, studies on the epidemiology of Mycoplasma and Streptococcal mastitis have been initiated.


Specific Research Areas

  • Control of S. aureus mastitis in heifers.
  • Control of S. aureus mastitis in cows through the maintenance of healthy teat skin condition.
  • Exotoxins in milk: affects on milk quality and mammary immunity.
  • Use of fingerprint technology to evaluate fomites and reservoirs of infection.
  • Epidemiology of Mycoplasma (see below) and Streptococcus mastitis pathogens.

(Adapted from DAIRY MANAGEMENT AND REDUCTION OF MASTITIS by Larry Fox)

Mycoplasma

Mycoplasma
is a contagious organism which causes mastitis in cattle.  It can cause complete cessation of milk production and the potential for no production during the next lactation.  The mastitis research group is searching for correlations between infection with Mycoplasma and with other contagious, opportunistic and environmental organisms.  Mycoplasma have been coined the "crabgrass" of organisms because their infections are persistent, difficult to cure, and frequently difficult to detect and diagnose. Top characteristics of Mycoplasma include:
  • Fastidious organism
  • No cell wall
  • Fried egg appearance
  • Unsuccessful treatment
  • Most cases appear to be in the US
  • Most cases appear to be sub-clinical (meaning no visible signs)
Symptoms:  In clinical cases we see abnormal, discolored (tannish or brownish) secretions and sandy or flaky sediments in watery or serous fluids. Particles usually sink to the bottom of the tube. Often the infections spread from one quarter to the other quarter on the same side and then to the opposite quarters.

Segregation or culling of infected animals is recommended. In contrast to other prokaryotes, Mycoplasma completely lacks a cell wall.  Penicillin and other antibacterial substances that interfere with cell walls of organisms do not work on Mycoplasma at all. In theory, drugs that work on the ribosomal complex should be effective (such as tetracycline and streptomycin, among others).  In practice, resistance and/or variable results have been reported (i.e. there really is no way to treat it). Current Concepts in Bovine Mastitis, put out by the National Mastitis Council, offers more information.
Last Edited: Nov 18, 2009 2:21 PM   

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