‘Seven shades of Cryptosporidium’

Abstract

In this paper, we describe a case of clinically unsuspected cryptosporidiosis that was diagnosed through systematic screening of coccidia using the little known, but highly reliable, extemporaneous Heine technique. This is significant because this zoonosis is largely underestimated, probably since most of the laboratories may not look for Cryptosporidium unless specifically requested. Moreover, the performance of the modified Ziehl-Neelsen staining, still considered as "gold standard", remains variable owing to the increasing proportion of non-acid-fast oocysts "ghosts" in resolving infections. Contrastingly, the negative staining technique of Heine highlights oocysts irrespectively of the time since diarrhoea onset. In addition, we provide a rare panel of fluorescent images that would be useful for microscopists.