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.