A hundred-year retrospective on cryptosporidiosis

Abstract

Tyzzer discovered the genus Cryptosporidium a century ago, and for almost 70 years cryptosporidiosis was regarded as an infrequent and insignificant infection that occurred in the intestines of vertebrates and caused little or no disease. Its association with gastrointestinal illness in humans and animals was recognized only in the early 1980s. Over the next 25 years, information was generated on the disease's epidemiology, biology, cultivation, taxonomy and development of molecular tools. Milestones include: (i) recognition in 1980 of cryptosporidiosis as an acute enteric disease; (ii) its emergence as a chronic opportunistic infection that complicates AIDS; (iii) acknowledgement of impact on the water industry once it was shown to be waterborne; and (iv) study of Cryptosporidium genomics.

Figure 1

Micrographs of Tyzzer's histological sections of the stomach of an experimentally infected mouse. The information pertaining to this slide is copied from a handwritten catalogue card (# 1897), dated Jan 16, 1908, and entitled ‘Cryptosporidium feeding experiment’. The above micrographs were taken by Xiaochuan Feng, Tufts Cummings School of Veterinary Medicine, from an archive slide containing the gastric section of a mouse experimentally fed infected stomach contents and gastric mucus and sacrificed 14 days later. Note the small forms outpouring from an open pit onto the gastric surface (left) and a pit filled with parasite forms (right). There was no reference to fixative or stain used. Scale bar = 20 μm.