Comparison of the Fluorescent Antibody Test and Direct Microscopic Examination for Rabies Diagnosis at the National Veterinary Research Institute, Vom, Nigeria.

Abstract

One hundred and eighty-nine (189) dog brain samples submitted to the National Veterinary Research Institute, Vom, Nigeria for rabies diagnosis were assayed by the Direct Microscopic Examination (DME) for Negri bodies, the Fluorescent Antibody Test (FAT) for rabies antigens, and the Mouse Inoculation Test (MIT). The MIT was used as a confirmatory test. There were 12(12.5%) false negative and 6(6.7%) false positive results with DME, while there was 2(1.7%) false negative and 2(1.7%) false positive with FAT. The FAT was more sensitive (98.26%) than the DME (87.5%), and also more specific, 97.29% and 93.55% respectively. The FAT predicted positive and negative results more accurately than the DME. Positive predictive value of FAT was 98.26% compared with 93.33% of DME, and the negative predictive value of FAT was 97.29% compared with DME’s 87.88%. The pre-test probability of rabies in Vom was 60.8%. This finding shows that FAT is a sensitive and reliable rabies diagnostic test than DME and its continued use is recommended in Nigeria whenever is feasible. The DME is still useful as a screening test, and the MIT must be used to confirm both FAT and DME

Keywords: Fluorescent antibody test, mouse inoculation, direct microscopic examination, rabies diagnosis, Nigeria.