Comparative evaluation of Direct Rapid Immuno-Histochemical Test (DRIT) with Direct Fluorescent-Antibody Test (DFAT) for laboratory diagnosis of animal Rabies in Ethiopia

Summary Direct rapid immuno-histochemical test (DRIT) is used as a gold standard method for rabies virus detection. The present study aimed to compare and evaluate DRIT with direct fluorescent antibody test (DFAT) to use equivalently as one of rabies diagnosing methods in areas where DFAT is not accessible. The method is based on the capture of rabies nucleoprotein (N) antigen in brain smears using a cocktail of biotinylated monoclonal antibodies specific for the N protein and color development by streptavidin peroxidase-amino ethyl carbazole and counterstaining with hematoxylin. The test was performed in parallel with the standard DFAT and mice inoculation test (MIT) using ۱۰۰ brain specimens from various species of animals. The majority of them were dogs (n =۸۸), followed by cats (n =۸), cattle (n =۳), and donkey (n =۱), and also from those samples that were tested by DRIT and DFAT, we randomly selected and tested ۱۲ brain samples by MIT. The results indicated that ۶۳% of the tests were positive by DFAT and ۶۴% were positive by DRIT. A slight difference was observed in such a way that one sample was negative by DFAT but positive by DRIT and MIT. Although, further laboratory and field examinations are essential, our findings were providing and remark the potential value of the DRIT for countries with limited diagnostic resources.

Keywords:

DRIT , rabies , MIT , DFAT , Surveillance