A review of: Streptococcus uberis: Environmental or contagious pathogen?
Strep uberis is an environmental pathogen
At times Strep uberis behaves as a contagious pathogen
Strep uberis is a formidable mastitis challenge.
A review of a paper Presented at the 2003 National Mastitis Council Meeting
by Ruth N. Zadoks and Ynte H. Schukken
For many dairy farms, mastitis due to environmental Streps, especially Streptococcus uberis, is a major problem. It is known that many of these infections develop into clinical cases that may persist up to a 100 days. There is also a tendency for these infections to develop during the dry period and the early part of lactation. Typically it is classed as an environmental pathogen and focus has to be on preventing environment to cow transfer.
There are instances however where Strep uberis infections appear to behave somewhat as a contagious pathogen and may transfer from cow to cow. In typing strains of the organism it can be found that several cows may be infected with the same strain. This raises a question as to whether the same strain went from the environment into several cows or did it transfer from cow to cow.
There is no doubt the organism is found in bedding, manure and the general environment of the cow so environment to cow transfer is a major factor in disease transmission. In some circumstances it appears that cow to cow transfer may also be responsible for within herd spread. When teat dipping has been stopped the prevalence of Strep uberis infected cows increases suggesting that in some manner the teat dip program reduced cow to cow spread. In a herd that implemented a policy of not treating clinical cases of mastitis with antibiotics, Dr. Cattell (1996) found a rapid increase in the number of new Strep uberis infections. Was it due to cow to cow spread of the organism by the milking system?
There is no question that Strep uberis is an environmental pathogen so measures that minimize environment to cow transmission help limit spread. Clean bedding, clean calving areas and maintaining clean dry teats is a must. Managing the environment during the dry period is critical because many cows appear to develop new infections during the dry period.
There is also evidence this bacteria species can behave at times somewhat as a contagious pathogen. Infections may last up to 100 days in infected cows. Therefore, practices that reduce cow to cow spread are beneficial in reducing Strep uberis transmission. Teat dipping, milking clean dry sanitized teats, using properly functioning milking systems and dry cow therapy are beneficial in reducing the incidence of new infections caused by Strep uberis.
Strep uberis is a formidable mastitis challenge. Treating it as both an environmental and contagious pathogen is necessary to minimize its spread.
The National Mastitis Council