A. R. Ribeiro

Epidemiologic study of environmental sources in a Prototheca zopfii outbreak of bovine mastitis

Bovine mastitis represents the main form of occurrence of protothecosis in animals. The detection of mastitis caused by Prototheca sp. indicates a serious problem which can affect an entire herd. The purpose of this study is to explain some aspects of the epidemiology of mastitis due to Prototheca zopfii with the evaluation of the presence of these microorganisms in samples collected from potential sources in the dairy herd. This study was performed during a Prototheca zopfii outbreak of clinical bovine mastitis in the State of São Paulo, Brazil. The following samples were aseptically collected for microbiological examination: milk (n = 211); rectal swabs (from 15 calves and 2 lactating cows); swabs from teat cup rubbers during milking (n = 2); water (n = 6); soil (n = 6). Prototheca zopfii was isolated from 77 (36.49%) of the 211 milk samples; 11 calves and 2 cows showed Prototheca zopfii in faecal samples; both swabs collected from the teat cup rubbers showed viable forms of Prototheca zopfii; this microorganism was also isolated from 2 water samples, and 1 soil sample collected from the dry cow pasture. Prototheca zopfii seemed to be widespread throughout the dairy herd environment where this outbreak of bovine mastitis occurred.

Bovine mastitis due to algae of the genus Prototheca

Protothecosis was described in many animals, with bovine mastitis being the main form. The increasing number of isolations of Prototheca spp. from bovine mastitis cases indicates the need of a detailed evaluation of this problem. Besides this, these algae do not respond to treatment with the antimicrobians most frequently applied, leading to elimination of the affected animals, as the best method to control the disease. In two dairy farms in the State of São Paulo, Brazil, a total of 155 lactating cows and 52 dry cows were examined. Milk samples were aseptically collected from lactating cows with clinical or subclinical mastitis. From dry cows, secretion samples from all quarters were collected. All samples were then taken to microbiological exams. At dairy farm 1, Prototheca spp. was isolated from 14.95% milk samples from lactating cows, (all of them cases of subclinical mastitis), and from 8.06% samples from dry cows. At dairy farm 2, Prototheca spp. was isolated from 5.1% milk samples and there were ten cases of clinical mastitis due to this agent. Although clinical mastitis has been considered the main form of occurrence of this pathology until now, it is important to consider Prototheca spp. as subclinical mastitis pathogen. Prototheca zopfii was the main specie isolated. In this study a high rate of intramammarian infections, as clinical or subclinical mastitis during lactation as well as in dry period, was observed, high lighting the importance of suitable diagnosis, so that control and preventive measures can be implemented to avoid dissemination of the agent.

Evaluation of the susceptibility of Prototheca zopfii to milk pasteurization

Protothecosis has been reported in humans (gastroenteritis, bursitis, etc.) and in many other animal species. Bovine mastitis represents the main form of occurrence of protothecosis in cattle. Milk as well as dairy products, when contaminated with Prototheca spp., represent a potential means of transmission of this zoonosis. The purpose of this study was to evaluate the susceptibility of forty Prototheca zopfii strains isolated from milk from intramammary infections in dairy cows and also from bulk milk tanks of dairy farms, to the different ratios of temperature/time employed in the thermal treatment of milk: 72–75 °C/1 5 seconds, 72–75 °C/20 seconds and 62–65 °C/30 minutes. The samples were subjected to these different temperature/time ratios. The evaluation of the thermal susceptibility of the P. zopfii strains showed that 34 strains were resistant in at least one of the tests. The results point out the need to consider the importance of mastitis caused by Prototheca spp. asrepresenting a public health risk.

An increased incidence of mastitis caused by Prototheca species and Nocardia species on a farm in São Paulo, Brazil

Mastitis caused by Prototheca spp or Nocardia spp is considered to be difficult to treat. Both microorganisms are contaminants commonly found in soil. The occurrence of mastitis caused by these agents was studied in a particular dairy farm. In this herd, the animals were kept at pasture overnight and during daytime were brought to a pen where they were fed. This pen accumulated mud and faeces, particularly in the rainy season. During milking, pre-dipping of the teats was performed with an iodide solution, but they were not washed, so a layer of soil and faeces remained which may have contaminated the milking equipment. The herd comprised 91 lactating animals and 47 dry cows. For microbiological examination, 107 milk samples were collected from lactating cows and 186 samples of mammary secretions from the dry cows. Prototheca spp were isolated from 14.55% of the milk samples and Nocardia spp from 4.55%. Prototheca spp were isolated from 8.06% of the secretion samples from dry cows and Nocardia spp were isolated from 2.15% samples. The high occurrence of mastitis due to these environmental agents reflects the problem of keeping animals in muddy pastures and pens, and the defective pre-milking hygiene for the teats.

Diagnosis of Clinical Bovine Mastitis by Fine Needle Aspiration Followed by Staining and Scanning Electron Microscopy in a Prototheca zopfii Outbreak

Biopsy by fine needle aspiration together with microbiological examination and scanning electron microscopy were evaluated in diagnosis of clinical bovine mastitis in a Prototheca zopfii outbreak. Fine needle aspiration was performed in 21 mammary quarters from ten Holstein cows presenting clinical mastitis caused by P. zopfii. The algae were previously identified in the microbiological examination of milk collected from these cows. Material aspirated from these 21 mammary glands was submitted to cytological staining (Gram, Giemsa and/or Shor staining). Fine needle aspiration enabled cytological identification of the algae in these 21 mammary glands, from which P. zopfii was isolated in the milk. Simultaneously, five mammary fragments collected by fine needle aspiration from these 21 mammary glands presenting clinical mastitis were also submitted to microbiological examination. P. zopfii was also isolated from these five fragments. Scanning electron microscopy technique also identified three of these five P. zopfii strains isolated from mammary fragments collected by cytological aspiration. These results suggest that fine needle aspiration may be an alternative method for the diagnosis of clinical mastitis.

Prevalence of intramammary infections in primigravid Brazilian dairy heifers

Abstract Mammary-gland secretions from 467 quarters of 120 primigravid purebred and crossbred Holstein heifers from six dairy herds were collected; 96 (80%) of the heifers had intramammary infections and 57% of the quarters were infected. Staphylococcus spp. were isolated from 230 (49%) quarters. Other microorganisms commonly isolated from secretion samples were: Corynebacterium sp. (33 quarters, 7%) and Streptococcus (21 quarters, 4%). Enterobacteriaceae ( Escherichia coli, Klebsiella spp.) were isolated from eight (2%) samples.