最早在志愿者体内进行研究的三日疟原虫有 USPHS 株,VS 株,菲律宾株和尼日利亚株。USPHS 株原是在美国路易斯安娜州新奥尔良海军医院的一个病人中分离出来的。在分离后约30年,美国南卡罗利纳州哥伦比亚的卫生服务实验室主要用这株疟原虫治疗脑脊髓梅毒病人的研究。但是在1963年哥伦比亚实验室关闭后,不久,这株疟原虫即被丢失。这株疟 Plasmodium malariae, the first of the three studies in volunteers, were the USPHS strain, the VS strain, the Philippines strain and the Nigerian strain. The USPHS strain was isolated from a patient at the Naval Hospital in New Orleans, Louisiana. Approximately 30 years after isolation, the Health Services Laboratory in Columbia, SC, uses the malaria parasites to treat patients with cerebral spinal syphilis. However, shortly after the closure of the Colombian laboratory in 1963, the strain of Plasmodium was lost. This strain of malaria