In 1843, Swiss scientist Friedrich Miescher found “milky white threads” in the muscles of a mouse, which for years were known as “Miescher’s tubules”. In 1882, Lankester named the parasite Sarcocystis, from the Greek sarx (flesh) and kystis (bladder). Scientists were unsure whether to classify the organisms as protozoa or as fungi because only the sarcocyst stage had been identified. In 1967, crescent-shaped structures typical of some parasitic protozoa were seen in sarcocyst cultures, and the organism was determined to be a protozoan, a close relative of Toxoplasma. In the early 1970s, the two-host lifecycle of Sarcocystis was actually elucidated. In 1969, A. M. Mandour described a new species of Sarcocystis in rhesus macaques, which he named Sarcocystis nesbitti, after Mr. P. Nesbitt, who saw the trophozoites in stained smears. Snakes are now known to be the definitive hosts of S. nesbitti, and several primates, including humans, can be intermediate hosts.
