Bovine mastitis due to algae of the genus Prototheca

Abstract

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.

Pathophysiology: Review of the microbiological, pathological, and clinical aspects of bovine mastitis caused by the algaPrototheca zopfii

“…from climatic conditions which are known to be advantageous for the rapid multiplication of this pathogen in the environment (3,14,16,20,25,35,36). Although available international references report numerous cases of mastitis caused by P. zopfii, the real incidence of this disease is probably much higher, because of the possible misidentification of P. zoplii as a yeast or its failure to grow under routine microbiological conditions (22,51).…”

Antimicrobial susceptibility of Prototheca zopfii isolated from bovine mastitis

“…does not respond to the routine therapy of mastitis (9,15,16,21). The studies concerning in vitro and in vivo susceptibility of algae indicate their high resistance to antibacterial and antifungal antibiotics (4)(5)(6)11).…”

“…The algae in natural environment occur in places characterised by high humidity and high organic matter content (bedding, wastes, and animal faeces) (6,16,28). Therefore, the development of bovine udder infections induced by Prototheca pathogens is considered to be highly dependent on predisposing factors, i.e.…”

Fatores de risco associados à mastite bovina causada por Prototheca zopfii

“…é de difícil tratamento pela resistência à maioria dos antimicrobianos tanto in vitro quanto in vivo, sendo recomendada a segregação e/ou o descarte de animais acometidos como medida de controle eficaz (KIRK, 1991). Além disso, como o diagnóstico pode apresentar dificuldades na identificação das algas do gênero Prototheca, freqüentemente, vacas acometidas por infecções intramamárias subclínicas com resultado microbiológico negativo não são medicadas e podem disseminar o agente para outros animais do rebanho, principalmente durante a ordenha (COSTA et al, 1996b). COSTA et al (1993) observaram que animais com mastite crônica, submetidos à terapia antibacteriana excessiva e repetida, são mais suscetíveis às infecções fúngicas ou mistas.…”

“…foram relatados em propriedades leiteiras dos Estados de Minas Gerais e São Paulo, sendo que os estudos subseqüentes mostraram que a mastite causada por Prototheca spp. em rebanhos pode se manifestar sob forma de surtos e casos isolados (COSTA et al, 1995;1996a;1996b;1998). A doença é considerada emergente, pois a sua ocorrência tem aumentado consideravelmente (COSTA et al, 1996a).…”