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Prototheca microalgae, although still considered uncommon etiologic agents, represent an insidious intruder, threatening cattle herd health and determining productive losses. Increasing numbers of clinical cases globally identified would indicate these microalgae as emerging pathogens. They can be isolated from a wide variety of environmental and non-environmental sources, due also to their ability to produce biofilm. This ability to spread and contaminate a huge variety of substrates, as well as the high resistance to elevated temperatures, renders Prototheca prevention a very hard task. In addition, early infection signs are subtle and difficult to detect. The poor response to conventional antimycotic drugs represents an additional challenge when facing this infection. Although it would seem unrealistic to completely eradicate the exposure risk of cows to these microalgae, the adoption of proper on-farm protocols and management, with the highest attention to hygiene measures, would be beneficial in reducing the magnitude of this problem. Keeping the attention focused on early diagnosis, together with the development of new, alternative, and effective agents and formulations, would be strongly advised to prevent, treat, and control Prototheca infections.

Definition: Prototheca microalgae, although still considered uncommon etiologic agents, represent an insidious intruder, threatening cattle herd health and determining productive losses. Increasing numbers of clinical cases globally identified would indicate these microalgae as emerging pathogens. They can be isolated from a wide variety of environmental and non-environmental sources, due also to their ability to produce biofilm. This ability to spread and contaminate a huge variety of substrates, as well as the high resistance to elevated temperatures, renders Prototheca prevention a very hard task. In addition, early infection signs are subtle and difficult to detect. The poor response to conventional antimycotic drugs represents an additional challenge when facing this infection. Although it would seem unrealistic to completely eradicate the exposure risk of cows to these microalgae, the adoption of proper on-farm protocols and management, with the highest attention to hygiene measures, would be beneficial in reducing the magnitude of this problem. Keeping the attention focused on early diagnosis, together with the development of new, alternative, and effective agents and formulations, would be strongly advised to prevent, treat, and control Prototheca infections. [ABSTRACT FROM AUTHOR]

• Prototheca spp. are pathogenic algae with zoonotic potential. • Algicidal effect of blue light was investigated by first time in Prototheca species. • P. zopfii genotype 1 and 2 are more sensitive to blue light than P. blaschkeae. • Blue light irradiation is a promising candidate as an antialgal agent for protothecosis. Prototheca spp. are pathogenic algae with important zoonotic potential. Most importantly, these algae often infect dairy cattle. Since there is no effective therapy against the algae, the standard recommendation is the disposal or culling of infected cows to avoid outbreaks. This study investigated the ability of blue light to inactivate pathogenic Prototheca species. Blue LED light (λ = 410 nm) was used to inactivate in vitro suspensions of P. zopfii genotypes 1 and 2, and P. blaschkeae. Our results showed that blue light irradiation induced a strain-specific dose-dependent algicidal effect against all tested strains. P. zopfii genotype 1, was more sensitive than genotype 2 and P. blaschkeae was the most tolerant. Even though we observed different inactivation kinetics, all strains presented significant photoinactivation levels within feasible procedure periods. Therefore, we conclude that blue light irradiation offers promising potential for the development of novel technologies that control contaminations and infections caused by Prototheca spp. [ABSTRACT FROM AUTHOR]

Protothecal mastitis poses an emergent animal health problem in dairy herds, with a high impact on dairy industries, causing heavy economic losses. Current methods of treating protothecal infections are ineffective, and no drug is licensed for use in cattle. The aim of the present study was to check the antialgal activity of 30 chemically defined essential oils (EOs) against Prototheca zopfii and Prototheca blaschkeae isolated from the milk of dairy cows with mastitis. A microdilution test was carried out to estimate the antialgal effectiveness of the selected chemically defined EOs. The microdilution test showed different degrees of inhibition among the examined Prototheca species. The activity of some of the examined EOs seem interesting. In particular, Citrus paradisi yielded the lowest minimal inhibitory concentration values (0.75%) for both algal species. P. zopfii appeared to be more sensitive to EOs in comparison to P. blaschkeae. The present study investigated the in vitro susceptibility of P. zopfii and P. blaschkeae to a wide range of EOs, obtained from different botanical families. Further investigations are necessary to evaluate the efficacy of EO-based formulations intended for the disinfection of both udder and milking products. [ABSTRACT FROM AUTHOR]

Protothecal mastitis poses an emergent animal health problem in dairy herds, with a high impact on dairy industries, causing heavy economic losses. Current methods of treating protothecal infections are ineffective, and no drug is licensed for use in cattle. The aim of the present study was to check the antialgal activity of 30 chemically defined essential oils (EOs) against Prototheca zopfii and Prototheca blaschkeae isolated from the milk of dairy cows with mastitis. A microdilution test was carried out to estimate the antialgal effectiveness of the selected chemically defined EOs. The microdilution test showed different degrees of inhibition among the examined Prototheca species. The activity of some of the examined EOs seem interesting. In particular, Citrus paradisi yielded the lowest minimal inhibitory concentration values (0.75%) for both algal species. P. zopfii appeared to be more sensitive to EOs in comparison to P. blaschkeae. The present study investigated the in vitro susceptibility of P. zopfii and P. blaschkeae to a wide range of EOs, obtained from different botanical families. Further investigations are necessary to evaluate the efficacy of EO-based formulations intended for the disinfection of both udder and milking products.

The article discusses the study which aims to assess the applicability of partial 26S ribosomal DNA (rDNA) sequence for the phylogenic analysis of Prototheca zopfii and to determine the relation between the genotype of P. zopfii and clinical mastitis in Japan. In the process, the phylogenetic analysis identified that all genotype 2 isolates were grouped into the cluster of strain of P. zopfii while all mastitis isolates were independent of the cluster of the genotype 1 isolates. In addition, the 18S rDNA analysis were sufficient sequencing of 560-bp fragment of 26s rDNA to identify genotypes and Prototheca blaschkeae for bovine mastitis based on polymerase chain reaction (PCR).

We describe the first known case of an algaemia by Prototheca blaschkeae in a dairy cow, which occurred after a chronic episode of mastitis caused by this pathogen. The organism was isolated from milk, joint fluid and blood samples, and microbiologic and molecular methods were performed to obtain a definitive identification of the algae. The affected cow was culled only after confirmation of a systemic infection by Prototheca. [ABSTRACT FROM AUTHOR]

Abstract: The most important animal disease caused by yeast-like algae belonging to the genus Prototheca is bovine mastitis. Although the infection can be caused by both Prototheca zopfii genotype 2 and Prototheca blaschkeae, the bulk of prevalence of bovine protothecal mastitis has been so far attributed to the former, being P. blaschkeae only sporadically isolated. However, we report here the first outbreak of bovine mastitis caused by P. blaschkeae in an Italian dairy herd. One hundred and four individual milk samples, three bulk tank milk and 16 environmental samples within the herd were screened for the presence of Prototheca: five, one and four positive samples, were respectively observed. Molecular analysis revealed that, with the sole exception of one environmental isolate belonging to P. zopfii genotype 2, all Prototheca strains were identified as P. blaschkeae. Our results might suggest that even P. blaschkeae can induce mastitis outbreaks, while it is not clear if the higher incidence of P. zopfii genotype 2 as causative agent of protothecal mastitis could reflect an intrinsic higher pathogenicity or it could be simply the consequence of its, so far observed, higher diffusion in worldwide dairy herd ecosystems. [Copyright &y& Elsevier]