Rabies Virus Antigen Research Articles

An epidemiological investigation of the rabies between 1999 - 2008 in Yancheng city, Jiangsu province.

To better understand the epidemiology of rabies during the past ten years in Yancheng city, Jiangsu province. Data was collected and analyzed on rabies cases in Yancheng. Density and vaccination rate on Canine, Rate of injured people bit by dogs, and the information of post-exposure prophylaxis were studied. Rabies virus in the dog brains, collected around the epidemic areas of Yancheng, were detected and analyzed. A total of 135 human rabies cases occurred from 1999 through 2008, and formed the second epidemic peak since 1958. Of these victims, 84% (114) were farmers. In general, the rate of people having dogs were 3% - 6% per 100 people, and the injured person-times of 100 dogs were 6.37 per year. Notably, the vaccination rate of dogs was only 20%. Of those people injured by dogs and other animals, 77% had received post-exposure treatment, and only 5% - 10% had been administered anti-rabies serum. Rabies virus antigen was found in 4 (3.6%) of 111 brain specimens among dogs collected from epidemic areas. Genetic analysis of N and G genes, which were amplified from brain specimens, indicated that these viruses belong to genotype I rabies and expressing a close relationship with the Chinese vaccine strain CTN. The large number of dogs with low vaccination rate among them, together with the incorrect and low post-exposure treatment in rural areas seemed to be responsible for the outbreak of rabies in Yancheng city.

Role of Oxidative Stress in Rabies Virus Infection of Adult Mouse Dorsal Root Ganglion Neurons

Rabies virus infection of dorsal root ganglia (DRG) was studied in vitro with cultured adult mouse DRG neurons. Recent in vivo studies of transgenic mice that express the yellow fluorescent protein indicate that neuronal process degeneration, involving both dendrites and axons, occurs in mice infected with the challenge virus standard (CVS) strain of rabies virus by footpad inoculation. Because of the similarities of the morphological changes in experimental rabies and in diabetic neuropathy and other diseases, we hypothesize that neuronal process degeneration occurs as a result of oxidative stress. DRG neurons were cultured from adult ICR mice. Two days after plating, they were infected with CVS. Immunostaining was evaluated with CVS- and mock-infected cultures for neuron specific beta-tubulin, rabies virus antigen, and amino acid adducts of 4-hydroxy-2-nonenal (4-HNE) (marker of lipid peroxidation and hence oxidative stress). Neuronal viability (by trypan blue exclusion), terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) staining, and axonal growth were also assessed with the cultures. CVS infected 33 to 54% of cultured DRG neurons. Levels of neuronal viability and TUNEL staining were similar in CVS- and mock-infected DRG neurons. There were significantly more 4-HNE-labeled puncta at 2 and 3 days postinfection in CVS-infected cultures than in mock-infected cultures, and axonal outgrowth was reduced at these time points in CVS infection. Axonal swellings with 4-HNE-labeled puncta were also associated with aggregations of actively respiring mitochondria. We have found evidence that rabies virus infection in vitro causes axonal injury of DRG neurons through oxidative stress. Oxidative stress may be important in vivo in rabies and may explain previous observations of the degeneration of neuronal processes.

Evidence of Lagos Bat Virus Circulation among Nigerian Fruit Bats

During lyssavirus surveillance, 350 brains from four species of fruit bats and one species of insectivorous bat were collected from seven locations in Northern Nigeria during May to October, 2006. Lyssavirus antigen was not detected in the brains, and isolation attempts in mice were unsuccessful. However, serologic tests demonstrated the presence of lyssavirus-neutralizing antibodies in bat sera. Of 140 sera tested, 27 (19%) neutralized Lagos bat virus, and two of these additionally neutralized Mokola virus. The positive samples originated from the straw-colored fruit bat (Eidolon helvum) and the Gambian epaulet bat (Epomophorus gambianus). No neutralizing activity was detected against other lyssaviruses including rabies, Duvenhage, and West Caucasian bat viruses.

Correlation of cytokine expression with rabies virus distribution in rabies encephalitis

Rabies encephalitis is a significant health hazard, particularly in Asia. To understand the role of immune mechanisms and cytokines in rabies encephalitis, we performed a retrospective and prospective study on the autopsy material. Representative histopathological sections were studied and subjected to immunostaining for rabies virus antigen, TNF-α and IL-1β. Immunohistochemistry for IL-1β and TNF-α revealed expression of these cytokines in 96% of cases in microglial cells, macrophages and lymphocytes with a strong positive correlation between IL-1β and TNF-α immunopositivity and degree of perivascular and parenchymal inflammation. In addition, expression of IL-1β and TNF-α also correlated positively with each other. However there was no direct correlation of viral antigen load with grading of cytokine expression. These findings indicate that IL-1β and TNF-α together may play an important role to coordinate the dramatic inflammatory response associated with the rabies-encephalopathy. They may serve as important targets for future therapy.

A retrospective longitudinal study of animal and human rabies in Botswana 1989-2006

A longitudinal study of animal and human rabies covering 18 years from 1989 to 2006 was retrospectively conducted in order to highlight the epidemiological features and trends of the disease in Botswana. Over the 18-year period, a total of 4 306 brain specimens collected from various species of animals including human beings with clinical signs consistent with rabies were submitted to the National Veterinary Laboratory in Gaborone for confirmatory diagnosis. Of the samples submitted, 2419 cases were found to be positive for lyssavirus antigen; this presents an overall prevalence rate of 56.18 +/- 1.48%. About 85.7% (2 074/2 419) of the cases were from domestic animals, 14.2% (343/2 419) cases were from wild animals and two cases (0.1%) were from human beings. During the first half of the study (1989-1997) the prevalence rate of the disease was estimated at 62.79 +/- 1.85% (1645/2620 positive) whereas during the second half (1998-2006) it was estimated at 45.91 +/- 2.38% (774/1686 positive) and the difference between the two estimates was statistically, highly significant (delta % = 16.88, SE(95) diff % = 3.015, SD = 5.599; P < 0.001). Ruminant rabies accounted for 79.99% (50.92% bovine, 928.40% caprine and 0.67% ovine) whereas canine (domestic dog) and feline (domestic cat) accounted for 16.01 and 0.87%, respectively. Equine rabies accounted for 3.13% with 1.35 and 1.78%, respectively, for horses and donkeys. Jackal rabies accounted for more than 60% of the total cases in wild animals. These findings are discussed in relation to the previous epidemiological situation of the disease (1979-1988), its socio-economic impact, monitoring and control in Botswana.

Update on rabies diagnosis and treatment

The diagnosis of rabies depends on recognizing the clinical picture, because a history of an animal bite may be present or absent. Laboratory tests, particularly when based on detection of rabies virus antigen or RNA in tissues or fluids, often confirm the diagnosis. Negative laboratory tests do not exclude the diagnosis unless they are performed on brain tissues. Preventive therapy, including wound cleansing and active and passive immunization after a recognized exposure, is well established and highly efficacious. No established therapy exists that is effective for patients with rabies encephalomyelitis. The Milwaukee protocol involves induction of therapeutic coma; however, there is no clear rationale for a neuroprotective role of this therapy, many reports exist of its failures, and its use should be abandoned. Basic research is needed on the mechanisms of rabies pathogenesis. This may allow the development of new therapeutic approaches for this ancient disease.

Neuroanatomical mapping of rabies nucleocapsid viral antigen distribution and apoptosis in pathogenesis in street dog rabies – an immunohistochemical study

To date, there is no study from Asian countries describing the pathology and topographic distribution of virulent, "street" rabies viral infection in the canine brain. In the present study, neuroanatomical distribution of rabies viral antigen in the brains of rabid street dogs, by immunohistochemical techniques is documented and the role of apoptosis in pathogenesis of rabies in natural hosts especially canines infected with street virus is studied. 10 brains of adult street dogs from urban areas of Bangalore, South Central India, infected with rabies were collected. The diagnosis was confirmed by immunofluorescent study. The pathomorphological features and the neuroanatomic distribution of the viral antigen by immunohistochemistry were studied. The ability of the virus to activate apoptosis in nerve cells if any, was studied by determining the DNA fragmentation and TUNEL technique in infected canine brains. The viral antigen was mostly localized to the neuronal perikaryon extending along the dendrites, while occasional astrocytes were also labeled. In the brain, the limbic areas, thalamus and the reticular formation of the brain stem, the trigeminal and the vagal nuclei were involved, corresponding to areas of cholinergic innervation. It is proposed that the preferential involvement of these cholinergic zones could explain some of the clinical features of rabies in canines. The extensive involvement of thalamus and immunolocalization of the rabies viral antigen in the axons are the unusual features noted in a dog's brain in contrast to murine experimental studies with "fixed virus". Characteristic DNA fragmentation forming 180-200 bp, leading to laddering was not seen, indicating apoptosis is not involved in the evolution of lesions in rabies in adult dogs infected by street virus.

Post-exposure prophylaxis (PEP) of rabies-infected Indian street dogs

A rabies post-exposure prophylaxis study was carried out to examine the efficacy of two commercially available rabies vaccines and the efficacy of a 5- or 3-dose vaccination regime. Healthy, native breed dogs ( N = 40), seronegative for rabies antibody, were challenged intramuscularly with virulent rabies virus brain suspension (10 4.4 MLD 50) by direct inoculation into the masseter muscle. The dogs were divided into four equal groups and injected intramuscularly with either Nobivac ® Rabies (Intervet), Rabisin ® (Merial) or placebo on multiple occasions (3 or 5-times) over the next 28 days. All dogs were confined in their respective groups for 90 days post-challenge and observed for the development of any clinical signs. Serum samples were assayed for rabies antibody using both the Rapid Fluorescent Focus Inhibition Test (RFFIT) and the Enzyme Linked Immunosorbent Assay (ELISA). None of the vaccinated dogs showed any clinical signs of rabies at any stage of the study. All of their brain tissue samples taken at the end of the study were found negative for rabies viral antigen. Six of the dogs in the control group showed signs of either furious or dumb rabies and died before the end of the study. In all these dogs the diagnosis of rabies was confirmed by means of a specific fluorescent antibody test (FAT) and by the presence of Negri-bodies in brain smears. Four control dogs survived after mild and transient clinical signs showing protective titers at the end of the trial (day 90). Their brain samples were negative for Negri-bodies and in the FAT. Both vaccines were found to be safe and effective in preventing rabies when inoculated intramuscularly applying the 5-dose regime (0, 3, 7, 14 and 28 days). Limited by space only one vaccine could also be tested in a 3-dose schedule. Using this 3-dose regime (0, 5 and 28 days) Nobivac Rabies was also found to be safe and effective in preventing rabies. All vaccinated dogs responded with antibody titers >0.5 IU by 7 days.

Immunohistochemical evaluation of calbindin expression in mouse brain at different times after rabies virus inoculation.

Introduction: The calcium-binding protein calbindin (CB) plays a critical role in intracellular calcium metabolism. In a previous study we demonstrated that the infection with fixed rabies virus caused loss of CB expression in mouse brain during terminal state of the disease, 7-8 days after intramuscular inoculation. Objectives: To determine loss of CB expression also appears in early stages of the infection and if it is a consequence immediate to the appearance of viral antigens in the brain. Materials and methods: Mice were inoculated with fixed rabies virus, by intramuscular route, in the left hind limbs. Daily, to sixth day, 4-6 animals and their respective controls were killed and fixed by intracardiac perfusion with paraformaldehyde and their brains were extracted to obtain coronal sections using a vibratome. Free-floating sections were treated by immunohistochemical procedures to evaluate the presence of rabies viral antigens and the expression of CB. The last one was quantified by optical densitometry in a microscope with a system of image analysis. Results: Rabies immunoreactivity was observed in the brain three days after virus inoculation, beginning in pyramidal neurons of the frontal cortex whereas the immunostaining for CB did not undergo any qualitative nor quantitative changes neither in the cerebral cortex or striatum during the six days post-inoculation. Conclusions: These results agree with other studies in which it has been settled down that the rabies molecular or metabolic effects on the nervous system are well-known only in the final stage of the disease.

Immune modulating effect by a phosphoprotein-deleted rabies virus vaccine vector expressing two copies of the rabies virus glycoprotein gene

The type of immune response induced by a vaccine is a critical factor that determines its effectiveness in preventing infection or disease. Inactivated and live rabies virus (RV) vaccine strains elicit an IgG1-biased and IgG1/IgG2a-balanced antibody response, respectively. However, IgG2a antibodies are potent inducers of anti-viral effector functions, and therefore, a viral vaccine vector that can elicit an IgG2a-biased antibody response may be more effective against RV infection. Here we describe the humoral immune response of a live replication-deficient phosphoprotein (P)-deleted RV vector (SPBN-ΔP), or a recombinant P-deleted virus that expresses two copies of the RV glycoprotein (G) gene (SPBN-ΔP-RVG), and compare it to a UV-inactivated RV. Mice inoculated with UV-inactivated RV induced predominantly an IgG1-specific antibody response, while live recombinant SPBN-ΔP exhibited a mixed IgG1/IgG2a antibody response, which is consistent with the isotype profiles from the replication-competent parental viruses. Survivorship in mice after pathogenic RV challenge indicates a 10-fold higher efficiency of live SPBN-ΔP compared to UV-inactivated SPBN-ΔP. In addition, SPBN-ΔP-RVG induced a more rapid and robust IgG2a response that protected mice more effectively than SPBN-ΔP. Of note, 10 3 ffu of SPBN-ΔP-RVG-induced anti-RV antibodies that were 100% protective in mice against pathogenic RV challenge. The increased immune response was directed not only against RV G but also against the ribonucleoprotein (RNP), indicating that the expression of two RV G genes from SPBN-ΔP-RVG enhances the immune response to other RV antigens as well. In addition, Rag2 mice inoculated intramuscularly with 10 5 ffu/mouse of SPBN-ΔP showed no clinical signs of rabies, and no viral RNA was detected in the spinal cord or brain of inoculated mice. Therefore, the safety of the P-deleted vectors along with the onset and magnitude of the IgG2a-induced immune response by SPBN-ΔP-RVG indicate that this vector holds great promise as either a therapeutic or preventative vaccine against RV or other infectious diseases.

Impaired cellular immune response in harbour seals (Phoca vitulina) feeding on environmentally contaminated herring.

In a 2.5-year immunotoxicological study, two groups of captive harbour seals (Phoca vitulina) were fed herring from the heavily polluted Baltic Sea or from the relatively uncontaminated Atlantic Ocean. Blood samples were collected at regular intervals, and functional immunological parameters were monitored. T cell mitogen and mixed lymphocyte-induced proliferative responses of peripheral blood mononuclear cells (PBMC) obtained from seals fed Baltic herring were significantly reduced over the course of experiment. Upon immunization with rabies virus antigen (RV) and tetanus toxoid (TT), specific proliferative responses of PBMC from the seals fed Baltic herring were also significantly reduced. Impairment of T cell-mediated immune responses became especially apparent during the second year on the respective diets, and correlated significantly to 2,3,7,8-tetrachloro-dibenzo-p-dioxin toxic equivalent levels in blubber biopsies taken from the seals after 2 years on the respective diets. Humoral immune responses, including lipopolysaccharide (LPS)-induced lymphoproliferative responses, in vitro immunoglobulin production by PBMC, as well as RV-, TT-and poliovirus-specific serum antibody responses following immunization, remained largely unaffected. We conclude that suppression of the cellular immune response in the seals fed Baltic herring was induced by the chronic exposure to immunotoxic environmental contaminants accumulated through the food chain. Since cellular immune responses are known to be of crucial importance in the clearance of morbillivirus infections, these results suggest that environmental pollution-related immunosuppression may have contributed to the severity and extent of recent morbillivirus-related mass mortalities among marine mammals.

Investigation of the Role of Healthy Dogs as Potential Carriers of Rabies Virus

To investigate whether healthy animals are potential carriers of rabies virus in China, 153 domestic dogs were collected from a rabies enzootic area, Anlong county in Guizhou Province, and monitored for 6 months. Initially, findings of rabies virus antigen in the saliva of 15 dogs by an enzyme-linked immunosorbent assay (ELISA) test suggested they might be carriers. These 15 dogs were kept under observation for 6 months. None of the dogs showed any clinical signs of rabies during the observation period. Moreover, using the ELISA test alone, detection of rabies virus antigen in saliva of some animals was not consistent during the observation period. However, none of the saliva samples collected either at the time of acquisition or during the observation period was found to be positive for rabies virus RNA by reverse transcriptase-polymerase chain reaction (RT-PCR). Furthermore, neither viral antigen nor viral RNA was detected in the brain samples collected at the time of euthanasia. These results do not provide support for the contention that healthy dogs act as carriers in rabies. Caution is urged when preliminary and nondefinitive tests, such as ELISA, are used to infer clinical status related to rabies.

Caracterização de amostras do vírus da raiva, isoladas nas regiões Norte e Centro-Oeste do Brasil, com anticorpos monoclonais antilissavírus

The occurrence of rabies virus antigenic variants in North and Central West regions of Brazil was studied using 61 rabies viruses isolated from different species: 30 from domestic dogs, 20 from cattle, four from horses, two from cats, one from a human and four from unidentified species. The isolates were submitted to antigenic analyses by indirect immunofluorescence with a panel of 12 monoclonal antibodies (Mabs) to lyssavirus antigens. Antigenic analyses revealed consistent differences between isolates whose natural hosts were dogs and those of haematophagous bats, often isolated from cattle. Three out of four isolates from horses and one from a domestic dog showed patterns of reactivity found only in viruses of insectivorous bats, indicating that non-haematophagous bats do play a unique role in the transmission of the virus to other species.

Protection of Mice from Rabies by Intranasal Immunization with Inactivated Rabies Virus

The mucosal immunization method is a needle-free alternative way of vaccination. This study evaluated the efficacy of mucosal immunization for rabies. Mice were intranasally administered five times with inactivated and concentrated rabies virus antigen (CRV) supplemented with or without cholera toxin (CT). The anti-rabies virus antibody titer of mice intranasally immunized with CRV plus CT (CRV/CT) was comparable to that of mice intraperitoneally immunized twice with the same amount of CRV. Virus neutralizing (VNA) titers of mice immunized intranasally with CRV/CT were slightly lower than those of intraperitoneally immunized mice. Both anti-rabies virus ELISA antibody and VNA titers of mice immunized with CRV without CT were significantly lower than those of mice immunized with CRV/CT. In mice intranasally immunized with CRV/CT, and intraperitoneally immunized mice, high levels of IgG(2a) antibody were detected, suggesting the activation of Th1-driven cellular immunity by the two ways of immunization. All immunized mice were challenged intracerebrally with a lethal dose of virulent rabies virus CVS strain. The survival rates of mice immunized with CRV/CT and CRV without CT were 67% and 17%, respectively, while the rate of intraperitoneally immunized mice was 100%. Antigen-specific whole IgG and IgG(2a), and VNA titers of survived mice were significantly higher than those of dead mice at the challenge day. These data suggest the possibility of intranasal immunization with inactivated antigen as a rabies vaccination strategy and the importance of a mucosal adjuvant such as CT.

Recombinant single-chain Fv antibody fragment–alkaline phosphatase conjugate: A novel in vitro tool to estimate rabies viral glycoprotein antigen in vaccine manufacture

The purpose of this study was to design a novel in vitro tool by using recombinant protein technology to qualify the whole reagent preparation procedure, to be used to quantify rabies viral antigen preparation in a simple and rapid format for potency control of rabies vaccines. 50AD1 is a neutralizing monoclonal antibody directed against the rabies virus glycoprotein that binds to native conformational antigenic site III. In the present study, the DNA fragments encoding the variable domains of 50AD1 were inserted into a prokaryotic expression vector so as to produce a single-chain Fv antibody fragment (scFv) genetically fused to the bacterial alkaline phosphatase (AP). The recombinant fusion protein preserved both the AP enzymatic activity and the antigen-binding activity against the rabies virus glycoprotein nearly identical to the parental antibody, and was used successfully in different assays including ELISA, dot-blot and cell culture tests. The present study shows that the genetic fusion protein provides a new tool for one-step rabies virus immunodetection, which can be produced in homogeneous bifunctional reagent, easily, quickly and reproducibly. In addition, this recombinant immunoconjugate is a promising alternative reagent for applications involving immunodetection, it presents a similar sensitivity and specificity to that obtained with classical reagents.

Therapy with Minocycline Aggravates Experimental Rabies in Mice

Minocycline is a tetracycline derivative with antiapoptotic and anti-inflammatory properties, and the drug has been shown to have beneficial effects in a variety of models of neurological disorders. The potentially neuroprotective role of minocycline was assessed in experimental in vitro and in vivo models of rabies virus infection. In this study, 5 nM minocycline did not improve the viability of embryonic mouse cortical and hippocampal neurons infected in vitro with the attenuated SAD-D29 strain of rabies virus, based on assessments using trypan blue exclusion. Two-day-old ICR mice were inoculated in the right hind limb thigh muscle with SAD-D29, and they received daily subcutaneous injections of either 50 mg/kg minocycline or vehicle (phosphate-buffered saline). Infected minocycline-treated mice experienced an earlier onset of neurologic signs and greater mortality (83% versus 50%) than those receiving vehicle (log rank test, P=0.002 and P=0.003, respectively). Immunohistochemical analysis of rabies virus antigen distribution was performed at early time points and in moribund mice. There were greater numbers of infected neurons in the regional brain areas of minocycline-treated mice than in vehicle-treated mice, which was significant in the CA1 region of the hippocampus. There was less apoptosis (P=0.01) and caspase 3 immunostaining (P=0.0008) in the midbrains of mice treated with minocycline than in mice treated with vehicle, consistent with a neuroprotective role of neuronal apoptosis that may have had a mild effect of inhibiting viral spread. Reduced infiltration of CD3+ T cells was observed in the pons/medulla of moribund mice that received minocycline therapy (P=0.008), suggesting that the anti-inflammatory actions of minocycline may intensify the neurologic disease. These findings indicate that minocycline has important detrimental effects in the therapy of experimental rabies. Empirical therapy with minocycline should therefore be approached with caution in cases of human rabies and possibly other viral encephalitides until more experimental data become available.

Response of feral cats to vaccination at the time of neutering

To determine whether administration of inactivated virus or modified-live virus (MLV) vaccines to feral cats at the time of neutering induces protective serum antiviral antibody titers. Prospective study. 61 feral cats included in a trap-neuter-return program in Florida. Each cat received vaccines against feline panleukopenia virus (FPV), feline herpes virus (FHV), feline calicivirus (FCV), FeLV, and rabies virus (RV). Immediately on completion of surgery, vaccines that contained inactivated RV and FeLV antigens and either MLV or inactivated FPV, FHV, and FCV antigens were administered. Titers of antiviral antibodies (except those against FeLV) were assessed in serum samples obtained immediately prior to surgery and approximately 10 weeks later. Prior to vaccination, some of the cats had protective serum antibody titers against FPV (33%), FHV (21%), FCV (64%), and RV (3%). Following vaccination, the overall proportion of cats with protective serum antiviral antibody titers increased (FPV [90%], FHV [56%], FCV [93%], and RV [98%]). With the exception of the FHV vaccine, there were no differences in the proportions of cats protected with inactivated virus versus MLV vaccines. Results suggest that exposure to FPV, FHV, and FCV is common among feral cats and that a high proportion of cats are susceptible to RV infection. Feral cats appeared to have an excellent immune response following vaccination at the time of neutering. Incorporation of vaccination into trap-neuter-return programs is likely to protect the health of individual cats and possibly reduce the disease burden in the community.

Detection of rabies virus antigen or antibody using flow cytometry

Rabies is invariably a fatal encephalomyelitis that is considered to be a serious public health problem. Rabies diagnosis must be rapid and conclusive. Detection and quantification of antirabies antibodies is used for assessment of the effectiveness of rabies vaccines. Hence, computer-automated detection of fluorescence using flow cytometry was attempted to reduce the work time required to undertake the conventional rapid fluorescent focus inhibition test (RFFIT). Pasteur virus (PV)-infected mouse neuroblastoma (MNA) cells were stained with rabies virus antinucleocapsid antibody, fluorescein isothiocyanate (FITC) conjugate, and the percentage of infected cells at 24, 48, and 72 h postinfection (PI) was determined using flow cytometry. Serum samples containing known antibody titres estimated by RFFIT in terms of IU/ml were used to neutralize 50 FFD50 dose of PV. The percentage of MNA cells infected by the un-neutralized virus was estimated by flow cytometry. Using the value of the percentage of cells infected in the presence of known negative serum as 100%, the infection inhibition caused by antibodies at each dilution of positive reference serum was calculated and a regression equation generated for the prediction of rabies virus antibody titres in test sera samples as equivalent units per ml (EU/ml). There was a significant increase in the percentage of infected cells between 24 and 48 h PI from 26.45 to 75.28%. The percentage of cells having high side scatter was also highest at 72 h PI (11.11%). Antibody titres predicted by flow cytometry and those estimated by RFFIT as IU/ml showed a correlation coefficient of 0.74. Thus, flow cytometry could be used to detect rabies virus antigen in infected cells and to predict serum antibody titres from a single dilution of serum tested with the potential advantages of automation, rapidity, and lack of subjectivity. It has the potential to replace the time-tested RFFIT in rabies serology in the years to come.

Postmortem Confirmation of Human Rabies Source

Postmortem Confirmation of Human Rabies Source

Evaluation of a Direct, Rapid Immunohistochemical Test for Rabies Diagnosis

A direct rapid immunohistochemical test (dRIT) was evaluated under field and laboratory conditions to detect rabies virus antigen in frozen and glycerol-preserved field brain samples from northwestern Tanzania. Compared to the direct fluorescent antibody test, the traditional standard in rabies diagnosis, the dRIT was 100% sensitive and specific.