Protothecosis and chlorellosis are sporadic algal diseases that can affect small ruminants. In goats, protothecosis is primarily associated with lesions in the nose and should be included in the differential diagnosis of causes of rhinitis. In sheep, chlorellosis causes typical green granulomatous lesions in various organs. Outbreaks of chlorellosis have been reported in sheep consuming stagnant water, grass from sewage-contaminated areas, and pastures watered by irrigation canals or by effluents from poultry-processing plants. Prototheca and Chlorella are widespread in the environment, and environmental and climatic changes promoted by anthropogenic activities may have increased the frequency of diseases produced by them. The diagnosis of these diseases must be based on gross, microscopic, and ultrastructural lesions, coupled with detection of the agent by immunohistochemical-, molecular-, and/or culture-based methods.

原藻病和小球藻病是可影响小型反刍动物的散发性藻类疾病。在山羊中，原虫病主要与鼻子病变有关，应包括在鼻炎病因的鉴别诊断中。在绵羊中，小球藻病会在各个器官中引起典型的绿色肉芽肿病变。据报道，食用死水的绵羊、来自污水污染地区的草，以及灌溉渠或家禽加工厂排放的水灌溉的牧场中都会爆发小球藻病。原藻和小球藻在环境中广泛存在，人为活动促进的环境和气候变化可能增加了由它们产生的疾病的频率。这些疾病的诊断必须基于大体、微观和超微结构病变，同时通过免疫组织化学、分子和/或基于培养的方法检测病原体。