Comparative evaluation of some techniques used for detection of rabies virus

Abstract

Background: Neurotropic viruses in the family Rhabdoviridae, genus Lyssavirus, are what cause rabies, an acute, progressive, and highly lethal encephalomyelitis. Aim: Evaluation of the used diagnostic techniques in order to determine the most simple; rapid and accurate test for rabies virus recognition in different specimens aiming to reach rapid diagnosis as a step aid in the disease control and to prevent or even minimize the suspected hazard. Method: The used techniques included infection trial of Swiss mice with the mice adapted rabies virus (CVS) followed by detection of the virus in infected mice brain. Virus detection was carried out through application BHK21 cell line infection; Fluorescent antibody technique FAT; Latex agglutination test LAT; direct ELISA; Rabies antigen detection kit ELISA; conventional PCR Results: It was found that virus inoculation in mice and BHK21 cell line need 5-7 days with positivity 90 and 100% respectively. Rapid antigen kit was able to detect rabies antigen in mice brains suspension and BHK21 infected fluid within 3-5 minutes with the percentage of 60 and 55.5 respectively. In 1-1.5 hours, the direct fluorescent antibody method (DFAT) detected 90% and 100% of the rabies antigen in BHK21 cell line infection and brain impressions, respectively. Latex agglutination showed clear results with 88.8% with BHK21 infected fluid within 3-5 minutes while it did not carry out on brain emulsions to prevent falsely positive results brought on by the presence of tissue fragments. Conventional one step polymerase chain reaction (PCR) revealed 100% positivity with either brain or cell culture preparations within 2 days. Direct enzyme immune linked sorbent assay (ELISA) showed 88.8% positivity with BHK21 infected fluid with one day work. Conclusion: Mice inoculation test, cell culture infection; DFAT and PCR are the most accurate techniques for detection of rabies virus with positivity 90-100% followed by LAT and ELISA with positivity 88.8% and lastly Rabies antigen ELISA kit (RAK) with positivity 55.5-60% taking in consideration the required time for each. In addition, the positivity % of the applied tests revealed their sensitivity and specificity.