Etiology Of Mastitis Research Articles

Lamb mortality in an outbreak of Yersinia pseudotuberculosis mastitis, as a collateral effect of colostrum feeding for Lentivirus-control

Yersinia pseudotuberculosis infections have been reported in a wide range of wild and domestic hosts, as well as humans. There have been some reports on involvement of this pathogen in the aetiology of mastitis in cows and goats, but apparently not in sheep. We report here a case where subclinical mastitis in a Latxa dairy sheep flock appeared to cause an outbreak of perinatal mortality, as a consequence of unknowingly feeding infected colostrum for preventing vertical transmission of Small Ruminant Lentivirus. The flock was composed of 188 ewes that had lambed in late-January 2008. Deaths of 3–5-day-old lambs reached 50% mortality of lambs born on the 20th and the 21st day of the outbreak and then decreased, averaging 34% out of 105 lambs born during a 6-day period. Affected lambs appeared inactive and ceased eating and growing. Two lambs submitted for post mortem examination showed necrosuppurative enterocolitis, mesenteric lymphadenitis, necrotizing hepatitis, splenitis and pneumonia. Bacterial culture yielded Y. pseudotuberculosis. It was noticed that all sick lambs had been fed with colostrum from a single ewe that had three lambs on the 20th January. All that colostrum had been consumed, but the milk of all animals in the flock was immediately submitted to the California Mastitis Test (CMT). Several ewes resulted positive, but only two yielded any significant isolation, which was in both cases of Y. pseudotuberculosis. One was also a colostrum donor. Treatment with enrofloxacin was immediately given to the surviving lambs and these showed a quick recovery. All the contaminated bulk milk was destroyed after the first Y. pseudotuberculosis isolation from milk samples; the two infected ewes were separated and dried-off on a treatment with enrofloxacin immediately and at the end of lactation, respectively. On the 71st day, the donor ewe was killed after showing an acute mastitis, from which Y. pseudotuberculosis was recovered. The surviving ewe, that carried two foetuses, suffered pregnancy toxaemia 1 week after being transferred to new facilities nine months later. Stenotrophomonas maltophilia was isolated from placenta, right mammary gland and faeces and Escherichia coli from the intestine and lung, but no Y. pseudotuberculosis was recovered from any sample. Regarding use of colostrum, it was concluded that it is necessary to always check it with the CMT before using it for lambs on artificial lactation.

Survey of the incidence and aetiology of mastitis on dairy farms in England and Wales

A survey of clinical and subclinical mastitis was carried out on 97 dairy farms in England and Wales, selected at random from members of a national milk recording scheme. The farmers were asked to collect aseptic milk samples from five consecutive cases of clinical mastitis and from five quarters with high somatic cell counts using a defined protocol, and they completed a questionnaire that included information on the cows sampled, the herd and the history of mastitis in the herd. The samples were collected throughout the year. The mean incidence of clinical mastitis was 47 cases per 100 cows per year (estimated from historic farm records) and 71 cases per 100 cows per year (estimated from the samples collected). Streptococcus uberis and Escherichia coli were isolated in pure culture from 23.5 per cent and 19.8 per cent, respectively, of the clinical samples; 26.5 per cent of the clinical samples produced no growth. The most common isolates from the samples with high cell counts were coagulase-negative staphylococci (15 per cent), S uberis (14 per cent) and Corynebacterium species (10 per cent). Staphylococcus aureus and coagulase-positive staphylococci together accounted for 10 per cent of the samples with high somatic cell counts; 39 per cent produced no bacterial growth.

Occurrence of clinical and subclinical mastitis in buffaloes in the State of Haryana (India)

The purpose of present study was to determine the occurrence and etiology of mastitis in traditionally managed buffaloes. A total of 5707 quarter milk samples from 2057 buffaloes were examined. Of these, 2948 (51.65%) samples were found culturally positive. Among these, 1070 cases were from clinical mastitis and rest 1878 cases were positive for subclinical mastitis. As many as 3447 isolates were obtained from infected quarters. Out of these, 38.81% were Staphylococcus spp., 32.4% Streptococcus spp., 11.80% E. coli, 5.2% Corynebacterium spp., 1.36% Bacillus spp., 2.03% Klebsiella spp., 0.78% Pseudomonas aeruginosa, 0.14% Proteus , 0.14% yeast. Staphylococcus spp. was predominant mastitogenic organisms followed by Streptococcus spp. Of the staphylococcal organisms, Staphylococcus epidermidis was the most prevalent being present in the 63.15% of the isolates. Among streptococci, Streptococcus agalactiae were the predominant organisms followed by Streptococcus dysgalactiae and Streptococcus uberis. The mixed infections were detected in 7.33% quarters in different combinations. Most common combination was of Staphylococcus spp. and Streptococcus spp. followed by Streptococcus spp. and Corynebacterium spp. Results of Antibiotic sensitivity were variable.

The management and treatment of environmental streptococcal mastitis.

Environmental streptococci are responsible for at least one third of all cases of clinical mastitis, with the proportion varying widely between herds. Each dairy farmer should know the etiology of mastitis in the herd to allow for appropriate management. Control requires lowering the prevalence of infection, and includes shortening the duration of and preventing new infections. Prompt and aggressive treatment of clinical cases may achieve a high clinical and bactriologic rate of cure. Dry-cow treatment remains highly effective in eliminating infection. Prophylactic dry-cow treatment remains of substantial benefit in preventing new intramammary infections and clinical mastitis. An internal teat sealant has shown a comparable effect in uninfected cows in field studies. Management of exposure to environmental streptococci is essential and requires assessment of the risk of exposure (especially in bedding and other lying areas), reduction of teat-end contamination, and good hygienic milking practices. The key is in the quality of application of management.

New strategies to prevent mastitis.

Bovine mastitis remains as the disease causing the biggest economic losses to the dairy industry, despite the intensive research and prevention measures at herd level carried out for decades. Antibiotics are widely used to combat mastitis, but focus should be shifted from treatment to more economical and efficient prevention. The bacteriological aetiology of mastitis has changed from contagious to environmental pathogens, which has reduced the efficacy of the traditional mastitis control strategies. Considerable progress in the understanding of epidemiology, immunology, diagnostics and pathogenesis of mastitis has been made. The modern molecular biological methods offer good possibilities for the research of the epidemiological and virulence aspects of bacteria, which may help in building-up specific mastitis control strategies for dairy herds. Studies on the host response and relationship between somatic cell count and susceptibility to mastitis offer tools for genetic improvement of dairy cows. Biotechnological approaches for mastitis prevention are in the developmental stage, but many problems are associated, e.g. with vaccination of dairy cows against mastitis. Different methods of immunomodulation for the prevention of mastitis have shown promise in experimental trials, but the evidence is not yet enough to support commercial applications. Improving nutrition, housing and environment of dairy cattle are still crucial in the prevention of mastitis, especially during the most susceptible period after parturition. New milking techniques including robotic milking may provide better possibility for proper milking and improved udder health. Mastitis control should be part of the herd health programme in the dairy herds. In this paper, results from recent research and proposals for new prevention strategies in the field of mastitis are reviewed.

Prevalence and aetiology of mastitis in cows from two major Ethiopian dairies.

The study was undertaken to determine the aetiology and prevalence of mastitis in hand-milked cows (n = 186) in two major Ethiopian dairies. The California Mastitis Test and culturing for bacteria revealed that 21.5% of the cows were clinically infected and 38.2% had subclinical mastitis. Most mastitis pathogens isolated from milk samples testing positive by the California Mastitis Test were Gram-positive cocci. Staphylococci constituted 57% of the isolates, of which the predominant cause of bovine mastitis was Staphylococcus aureus (40.5%). Other mastitis pathogens isolated include streptococci (16.5%), coliforms (9%) and corynebacteria (5%). Retrospective analysis of farm records indicated that mastitis was the second most important cause of culling and accounted for 27% of the cows removed from these two dairies.

Characterization of Staphylococcal Bovine Mastitis Isolates Using the Polymerase Chain Reaction

A polymerase chain reaction (PCR) assay was adapted to detect toxin genes of staphylococcal isolates from cases of bovine mastitis. Samples were obtained from three geographical areas: Korea and Idaho and Washington in the northwest United States. Samples from Korea and Washington were randomly chosen. Idaho samples were from a prospective study of mastitis etiology. Forty-one milk samples from 25 commercial farms in south-central Idaho were collected from cows with symptoms of mastitis. Although Staphylococcus aureus constituted 37.5% of mastitis isolates, these isolates lacked genes for staphylococcal enterotoxins (SEs), toxic shock syndrome toxin, and exfoliative toxins. In contrast, 4 of 13 isolates from Washington and 6 of 20 isolates from South Korea expressed SEs. These results suggest that PCR may be an effective means of screening bovine isolates for toxins. They also emphasize the potential for significant geographic differences in mastitis etiology.

DO CHEMOKINES CAUSE MASTITIS? 60

Mastitis is a common problem causing cessation of breast feeding in modern nurseries. In an attempt to identify early markers for mastitis we measured the cell count and inflammatory chemokine content of breast milk longitudinally in 10 mothers following healthy term deliveries over 2-6 weeks(median 2.5 weeks). Two mothers gave milk samples separately from each breast. Milk samples were kept at 4°C, and processed within 8 hours of collection; centrifuged aliquots were frozen for batch ELISA assays (triplicates) for IL-8 and RANTES. Aliquots were cultured using routine microbiology. These methods were verified using spiked samples. We observed high levels of the chemokines in all samples (median IL-8 2.5 ± 0.5 ng/ml, range 0.5-12ng/ml, median RANTES 5.5 ± 0.8 ng/ml, range 0-20 ng/ml). Concentrations were higher in the first week of lactation, but particularly high levels were identified in one mother, and from one breast which subsequently over 4 days developed sterile mastitis (peak IL-8 12 ±0.9 ng/ml, peak RANTES 20 ± 1.1 ng/ml). Higher chemokine levels were associated with higher cell counts, this was not a linear association. There was no correlation with bacterial colony counts. Milk cytokines are useful preclinical indicators and as inflammatory mediators may play an important role in the aetiology of mastitis.