Antemortem Diagnosis Of Rabies Research Articles

Diagnosis of rabies using reverse-transcription polymerase chain reaction on post-mortem skin tissue specimens of the nasolabial plate in a rabies suspected cow: a case study.

In India, rabies in cattle is under-reported. Religious sentiments hamper its diagnosis, discouraging post-mortem examination, particularly opening the cranium. Specimens of peripheral tissue innervated by the cranial nerves could potentially be used as alternative diagnostic specimens to the brain. Herein, we present a case study of a novel approach for diagnosing rabies in a cow suspected of having rabies, using skin tissue specimens of the nasolabial plate obtained post-mortem. Brain and nasolabial tissue specimens tested positive for rabies using conventional reverse-transcription polymerase chain reaction. This approach has been previously shown to have a high diagnostic sensitivity in animals. We encourage further studies with more nasolabial plate skin specimens for both post- and antemortem diagnosis of rabies in cattle.

Antemortem diagnosis of rabies from skin by TaqMan real time PCR

Present study revealed application of TaqMan real time PCR technique for diagnosis of rabies viral RNA from 11/20 antemortem skin samples with a sensitivity of 92.85%. The successful use of TaqMan real time PCR concluded that it was a viable, alternative tool for the antemortem diagnosis of rabies. Results correlated well with those of the post-mortem fluorescent antibody test performed on brain specimens of same animals.

Detection of rabies viral RNA by TaqMan real-time RT-PCR using non-neural specimens from dogs infected with rabies virus

To determine the burden of rabies in developing countries, a reliable and accurate diagnostic test for the examination of the brains of animals is needed. Recently, the number of samples and carcasses submitted to rabies diagnostic units has been declining. Methods for obtaining tissues from different regions of the brain are even more difficult, and direct florescent antibody examination may fail if the samples decomposed. The spread of rabies virus to peripheral non-nervous tissues starts early during the pre-clinical phase. It has been shown that saliva and skin biopsies taken at the neck and containing hair follicles can be used in the ante-mortem diagnosis of rabies in humans. Obtaining oral swab samples, whisker or hair follicles from the heads of canines is easy and practical and can be performed without special equipment. The objective of this study was to determine whether these non-neural specimens can be used for the detection of rabies viral RNA. The RNAs extracted from these specimens were tested using a real-time reverse transcriptase polymerase chain reaction (RT-PCR). The sensitivity of the TaqMan real-time RT-PCR analysis using samples from dogs confirmed to be infected with rabies virus was 84.6% (55/65), 81.8% (54/66) and 66.7% (44/66) when using oral swab samples, extracted whisker follicles and extracted hair follicles; the specificity of all specimen types was 100%. The negative predictive values were 77.8%, 74.4% and 61.4%, respectively. Although the rate of positivity when combining the three non-neural specimen types was increased to 86.4%, this level of sensitivity was not sufficient to help physicians whether to administer post exposure prophylaxis. However, these oral swab and whisker specimens may serve to enhance epidemiological surveillance; such data will contribute in the planning of rabies control programs.

DEVELOPMENT AND EVALUATION OF AN IN VITRO ISOLATION OF STREET RABIES VIRUS IN MOUSE NEUROBLASTOMA CELLS AS COMPARED TO CONVENTIONAL TESTS USED FOR DIAGNOSIS OF RABIES

In vitro isolation of rabies virus using mouse neuroblastoma cells (MNA) was evaluated. The sensitivity and reliability of in vitro procedure was performed in comparison with mouse inoculation test (MIT), the in vivo method of virus isolation, direct fluorescent antibody test (FAT) and Sellers staining. Of the 33 animal brain samples tested, 24 (72.72%) were positive by MIT. Sensitivity of Sellers stain, FAT and rapid tissue culture infection test (RTCIT) was found to be 54.16, 100 and 91.6% respectively. Concordance of Sellers stain, FAT, RTCIT with MIT was found to be 66.6, 100 and 93.93% respectively. Two samples which were positive by FAT and MIT showed gross contamination in cell lines, which is one of the drawbacks of RTCIT. However, rabies virus could be isolated in MNA cells from two of the eight human cerebrospinal fluid (CSF) samples from clinico-epidemiologically suspected cases of rabies. Both MIT and FAT showed negative results in the two CSF samples. RTCIT appears to be a fast and reliable alternative to MIT and holds promise in antemortem diagnosis of rabies, which is otherwise, a challenging task for a reference laboratory.

Development and evaluation of an <i>In vitro</i> isolation of street rabies virus in mouse neuroblastoma cells as compared to conventional tests used for diagnosis of rabies

In vitro isolation of rabies virus using mouse neuroblastoma cells (MNA) was evaluated. The sensitivity and reliability of in vitro procedure was performed in comparison with mouse inoculation test (MIT), the in vivo method of virus isolation, direct fluorescent antibody test (FAT) and Sellers staining. Of the 33 animal brain samples tested, 24 (72.72%) were positive by MIT. Sensitivity of Sellers stain, FAT and rapid tissue culture infection test (RTCIT) was found to be 54.16, 100 and 91.6% respectively. Concordance of Sellers stain, FAT, RTCIT with MIT was found to be 66.6, 100 and 93.93% respectively. Two samples which were positive by FAT and MIT showed gross contamination in cell lines, which is one of the drawbacks of RTCIT. However, rabies virus could be isolated in MNA cells from two of the eight human cerebrospinal fluid (CSF) samples from clinico-epidemiologically suspected cases of rabies. Both MIT and FAT showed negative results in the two CSF samples. RTCIT appears to be a fast and reliable alternative to MIT and holds promise in antemortem diagnosis of rabies, which is otherwise, a challenging task for a reference laboratory.

Presence of rabies specific immune complexes in cerebro-spinal fluid can help in ante-mortem diagnosis of human paralytic rabies

Background Human rabies presents in two clinical forms, viz. furious or encephalitic and paralytic. Clinical diagnosis of paralytic form is difficult and requires laboratory confirmation. Presently available diagnostic techniques are not very sensitive for ante-mortem confirmation of rabies. Objective In the present study, we investigated whether presence of rabies specific immune complexes in cerebro-spinal fluid (CSF) of paralytic rabies patients could help in ante-mortem diagnosis of rabies. Study design A capture ELISA based on monoclonal antibodies to rabies nucleoprotein (N) and glycoprotein (G) was developed to detect immune complexes to rabies N and G proteins. We studied CSF samples collected ante-mortem from 30 suspected paralytic rabies patients in whom diagnosis was later confirmed by autopsy. We included 30 CSF samples from people undergoing spinal anesthesia as negative controls and 30 CSF samples from other viral encephalitis as disease controls. Results Twenty-three out of 30 CSF samples (76.6%) showed presence of immune complexes to both rabies N and G proteins. None of the negative controls and CSFs from other confirmed viral infections were positive. Thus, the results were 100% specific and the sensitivity of this test was 76.6%. Conclusions Detection of immune complexes to rabies antigens may be used as one of the techniques for rapid ante-mortem diagnosis of human rabies.