Summer mastitis is currently considered to be a clinical infection of the non-lactating mammary gland of cattle (1). It is usually associated with heifers and dry cows just before or at the time of calving, but it can be seen in bulls and calves (2) (3). In beef cows, it can be seen in barren spring calving cows kept for later breeding (4). It is not deemed to specifically be one disease, but a non-specific term relating to a variety of infections (5). The exact means of infection are not fully understood and the disease has a complex aetiology. The peak of incidence is in the summer (6) (hence the name of the disease), and this is thought to be connected to the high number of cattle at risk and the occurrence of the potential vector Hydrotaea irritans, which is believed to increase spread of infection (5) (7). It has a complex bacterial background, often involving composite bacteria (8). The bacteria isolated predominantly include Arcanobacterium pyogenes (previously named Corynebacterium pyogenes and Actinomyces pyogenes, and recently renamed as Truepurella pyogenes, but due to the age of the literature, A. pyogenes shall be used as a denote this bacterium in this review), but other bacteria are thought to be involved synergistically to cause disease including Peptococcus indolicus and Streptococcus dysgalactiae (9) (8) (10).Bacteria including Staphylococcus aureus, Escherichia coli and Fusobacterium necrophorum have also been found, but these are generally thought of as secondary invaders rather than primary cause of infection (3). Clinical signs of summer mastitis include a leathery and swollen teat, which progresses to a hard, swollen and painful quarter, with thick yellow secretions and unpleasant smell (3) ...
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... Nansen P, editors. Summer Mastitis.: Springer Netherlands; 1987. p. 103-108.
24. Hansen J, Nielsen SA. Summer mastitis: a review. In Heifer Mastitis Seminar; 1983; Stockholm-Helsinki. As discussed in:
Thomas G. Cattle Flies and the Transmission of Summer Mastitis. In Thomas G, Over HJ, Vecht U, Nansen P, editors. Summer Mastitis.: Springer Netherlands; 1987. p. 103-108.
25. Hillerton JE, Bramley AJ, Thomas G. The role of Hydrotaea irritans in the transmission of summer mastitis. British Veterinary Journal. 1990; 146(2): p. 147-156.
26. Bramley AJ, Hillerton JE, Higgs TM, Hogben EM. The carriage of summer mastitis pathogens by muscid flies. British Veterinary Journal. 1985; 141(6): p. 618-627.
27. Bramley AJ. Aetiology and Pathogenesis of Summer Mastitis. In Thomas G, Over HJ, Vecht U, Nansen P, editors. Summer Mastitis.: Springer Netherlands; 1987. p. 81-85.