Microbiological and Histopathological Investigations on Prototheca Mastitis in Dairy Animals

A total number of 100 and 300 milk samples from buffaloes and cows as well as 60 and 20 specimens from mammary parenchyma was collected for microbiological and histopathological examinations of Protothecosis in both species, respectively. Examined milk samples showed high scores with California Mastitis Test (CMT). Six buffaloʹs subclinical milk samples with percentage of 6% and seven cowʹs milk samples (Clinical and subclinical) with percentage of 2.33% were positive for Prototheca spp. Somatic cell count (SCC) and milk composition was investigated in this study. Prototheca spp. was detected in samples of 4 swabs took from 8 milking machine lines. Moreover, P. zopfii were detected in 8 (13.33%) and 2 (10%) of the collected buffalo and cowʹs mammary parenchyma specimens, respectively. After aerobic incubation for 24-72 h at 25-37°C, the visible Prototheca colonies were identified based on macro-microscopical morphology. Characteristic microscopic morula appearance of Prototheca spp. was observed by using light and phase-contrast microscopy. Prototheca spp. was stained by methyl-blue and Gram-stains. Biochemical characteristics of Prototheca were monitored using assimilation patterns of different types of sugars and Urease activity. P. zopfii was the most isolated species from the collected samples. Microscopical examination of mammary tissues revealed focal or diffuse, chronic and necrotizing interstitial mastitis associated with intralesional algal structures. Pronounced infiltrations of lymphocytes and macrophages with few neutrophils and multinucleated giant cells were observed. Prototheca was spheroid, ovoid, or elliptical with a prominent thick wall, contains several thick-walled autospores and was predominantly seen in macrophages which were markedly enlarged and both sporangiospores and sporangia were found. The algae were positively stained with PAS and Alcian blue as well as by GMS stains.