Detection of cryptosporidium parvum by recombinant antibodies

小隐孢子虫是引起肠道疾病隐孢子虫病的一种重要的、广泛分布的病原体。当有传染性的小孢子虫卵囊被吞下时，它们会分泌出孢子子，并附着在肠上皮细胞上。在这里，寄生虫在不同的有性和无性繁殖阶段繁殖，形成卵囊并随粪便排出。隐孢子虫病是一种急性但自限性疾病，发生于免疫能力强的患者，通常表现为腹泻、恶心、呕吐、腹部痉挛和发烧。免疫功能受损的人会遭受更严重的慢性感染，可能导致死亡。目前还没有已知的保护性疫苗或治疗隐孢子虫病的方法。水是隐孢子虫的常见传播媒介。人类隐孢子虫病的传播途径包括人畜共患、环境接触和通过粪口途径的人际接触。对于水工业来说，低水平的污染至少应该表明需要谨慎和加强控制措施。由于隐孢子虫本身的动态生命周期，评估水传播隐孢子虫的威胁变得复杂。即使在饮用水中发现卵囊，也很难确定其来源、生存能力和对人类的传染性。为了实现隐孢子虫的行动水平，必须研究饮用水中感染性卵囊的灵敏检测和定量方法，并将其推广应用。我们隐孢子虫研究计划的长期目标是开发有效检测隐孢子虫的改进方法。在短期内（5年资助期），我们计划专注于开发、评估和改进重组抗体（rAbs），用于检测隐孢子虫卵囊的存在、活力和感染性。我们将通过选择和改善rAbs对几种卵囊和孢子体表面蛋白的结合特性来实现这一目标。然后，我们将测试rAbs检测水样中存在的感染性和活的小孢子虫卵囊的能力。有效和早期发现小弧菌可最终保障饮用水供应。

The protozoan parasite Cryptosporidium parvum is an important and widely distributed pathogen causing the enteric illness cryptosporidiosis. When infective C. parvum oocysts are swallowed, they excyst into sporozoites which become attached to intestinal epithelial cells. Here, the parasites multiply by various sexual and asexual stages, and oocysts are formed and passed with feces. Cryptosporidiosis is an acute but self-limiting illness in immuno-competent patients who typically present with diarrhea, nausea, vomiting, abdominal cramps and fever. Immuno-compromised persons experience a more severe and chronic infection, which may lead to death. There is currently no known protective vaccine or treatment for cryptosporidiosis. Water is a common vehicle for transmission of Cryptosporidium spp. Routes of transmission for human cryptosporidiosis include zoonotic, environmental and person-to-person contact via the fecal-oral route. For the water industry, low-level contamination should at least indicate the need for caution and enhanced control measures. Assessing the threat of waterborne Cryptosporidium is complicated by the dynamic life cycle of the parasite itself. Even if oocysts are found in drinking water, it is difficult to determine their source, viability and infectivity towards humans. To implement an action level for Cryptosporidium, sensitive methods for detection and quantitation of infective oocysts in drinking water must be researched and brought into common use. The long term objective of our Cryptosporidium research program is to develop improved methods for the effective detection of Cryptosporidium. In the short term (5-year funding period of this grant), we plan to focus on the development, assessment and improvement of recombinant antibodies (rAbs) for detecting the presence as well as the viability and infectivity of Cryptosporidium oocysts. We will do this by selecting for, and improving the binding properties of, rAbs against several oocyst and sporozoite surface proteins. We will then test the ability of the rAbs to detect the presence of infective and viable C. parvum oocysts in water samples. Effective and early detection of C. parvum can ultimately lead to the safeguarding of drinking water supplies.