Lindsay D S, Dubey J P, Blagburn B L
Department of Pathobiology, College of Veterinary Medicine, Auburn University, Alabama 36849-5519, USA.
Clin Microbiol Rev. 1997 Jan;10(1):19-34. doi: 10.1128/CMR.10.1.19.
Coccidial parasites of the genus Isospora cause intestinal disease in several mammalian host species. These protozoal parasites have asexual and sexual stages within intestinal cells of their hosts and produce an environmentally resistant cyst stage, the oocyst. Infections are acquired by the ingestion of infective (sporulated) oocysts in contaminated food or water. Some species of mammalian Isospora have evolved the ability to use paratenic (transport) hosts. In these cases, infections can be acquired by ingestion of an infected paratenic host. Human intestinal isosporiasis is caused by Isospora belli. Symptoms of I. belli infection in immunocompetent patients include diarrhea, steatorrhea, headache, fever, malaise, abdominal pain, vomiting, dehydration, and weight loss, blood is not usually present in the feces. The disease is often chronic, with parasites present in the feces or biopsy specimens for several months to years. Recurrences are common, Symptoms are more severe in AIDS patients, with the diarrhea being more watery. Extraintestinal stages of I. belli have been observed in AIDS patients but not immunocompetent patients. Treatment of I. belli infection with trimethoprim-sulfamethoxazole usually results in a rapid clinical response. Maintenance treatment with trimethoprim-sulfamethoxazole is needed because relapses often occur once treatment is stopped.
等孢球虫属的球虫寄生虫可在多种哺乳动物宿主中引发肠道疾病。这些原生动物寄生虫在其宿主的肠道细胞内经历无性和有性阶段，并产生具有环境抗性的囊蚴阶段，即卵囊。感染是通过摄入受污染食物或水中的感染性（孢子化）卵囊而获得的。一些哺乳动物等孢球虫物种已经进化出利用转续宿主的能力。在这些情况下，感染可通过摄入受感染的转续宿主而获得。人类肠道等孢球虫病由贝氏等孢球虫引起。免疫功能正常的患者感染贝氏等孢球虫的症状包括腹泻、脂肪泻、头痛、发热、不适、腹痛、呕吐、脱水和体重减轻，粪便中通常无血。该疾病通常为慢性，寄生虫可在粪便或活检标本中存在数月至数年。复发很常见，艾滋病患者的症状更严重，腹泻更稀。在艾滋病患者中观察到了贝氏等孢球虫的肠外阶段，但在免疫功能正常的患者中未观察到。用甲氧苄啶 - 磺胺甲恶唑治疗贝氏等孢球虫感染通常会导致快速的临床反应。由于停药后经常复发，因此需要用甲氧苄啶 - 磺胺甲恶唑进行维持治疗。
