A comparative assessment of commonly employed staining procedures for the diagnosis of cryptosporidiosis

Following an increase in the number of reports of Cryptosporidium infections and the problems encountered in detecting these organisms in faecal smears, a comparative assessment of a modification of the Sheather's flotation technique and other commonly employed staining procedures proved the modified Sheather's technique to be most useful in identifying Cryptosporidium oocysts in diarrhoeal stools. This technique not only detected the parasite in the highest number of stools but also proved to be cost-effective and the least time-consuming. Other staining techniques assessed were the modified Ziehl-Neelsen, safranin-methylene blue and auramine-phenol fluorescence. Both the modified Ziehl-Neelsen and the auramine-phenol fluorescence procedures produced nonspecific staining, while the safranin-methylene blue method was found to be the least sensitive technique.