COMPARISON BETWEEN THE MODIFIED ZIEHL-NEELSEN AND FLUORESCENT ANTIBODY TESTS FOR THE DETECTION OF CRYPTOSPORIDIUM SPP. OOCYSTS IN FAECES
Jacqueline A. Marshalla, Anne Thomasb, *Ralph N. Marshalla
and Guy Robinsonb. aParasitology Section, Veterinary Laboratories Agency (Weybridge),
Woodham Lane, New Haw, Addlestone, Surrey, KT15 3NB, United Kingdom.
bCryptosporidium Reference Laboratory, Singleton Hospital, Swansea, SA2 8QA,
United Kingdom.
Corresponding Author: r.n.marshall@vla.defra.gsi.gov.uk
In both human and animal laboratories
Cryptosporidium oocysts have for many years been identified in faeces using the
modified Ziehl-Neelsen staining method (mZN). Collaborative work between the UK
Health Protection Agency (HPA) and the Veterinary Laboratories Agency (VLA) has
compared this traditional method with the Fluorescent Antibody Test (FAT), which
is now considered by the OIE as the “Gold Standard”. Faeces from
experimentally Cryptosporidium-infected lambs were examined daily using both
methods up to 21 days post infection (pi). Each sample was given a simple score
ranging from 0 to 5 depending on the number of oocysts observed and results
using both methods were compared. Results indicate that the FAT was more
sensitive than the mZN and was able to detect the presence of oocysts 1–2 days
pi earlier. Furthermore, it was also possible to detect Cryptosporidium oocysts
deep in intestinal tissues of infected animals by the FAT, but not the mZN.