ABSTRACT
Chandipura virus (CHPV) is found to be associated with sporadic encephalitis outbreaks in humans in India since 1965. We report here, the investigation of CHPV activity during the period of June-August 2015 in the state of Gujarat, which revealed 24.44% positivity among 45 referred encephalitis cases. Phylogenetic study of the G gene sequences of strains from Gujarat 2015 along with available sequences of additional strains from different geographical locations and isolation years (1965-2015), indicated the relatedness of the 2015 strain to a group of the CHPV prototype strain of 1965 and the earliest outbreak strains of 2003. Analyses of selection pressure in the G gene revealed positively selected sites within the signal peptide region and a putative CHPV epitope. These results indicate a probable role of G protein-based immune selection and underline the need for continued surveillance to monitor genetic and antigenic variations in the CHPV.
Subject(s)
Disease Outbreaks , Vesicular Stomatitis/epidemiology , Vesicular Stomatitis/virology , Vesiculovirus/genetics , Viral Fusion Proteins/genetics , Amino Acid Sequence , Genetic Variation , Humans , India/epidemiology , Phylogeny , Sequence Analysis, DNA , Vesiculovirus/classificationABSTRACT
BACKGROUND: Chandipura virus (CHPV) is a leading cause of acute encephalitis with high mortality in paediatric population in India. A micro-neutralization ELISA (MN-ELISA) assay was developed for the detection of neutralizing antibodies (Nab) against CHPV. This novel method gives read-out in the form of ELISA optical density (OD) values and has a shorter turn-around time (TAT) as compared to the conventional cytopathic effect (CPE)-based neutralization assay (MN-CPE). The assay was developed using an Indian strain of CHPV. During the development of the assay different parameters such as cell count, dilution of primary and secondary antibodies and time point for the test termination were optimized. The new and conventional assays were run in parallel where known positive and negative human serum samples were used as test controls. The conventional MN-CPE was terminated at 48h post-infection (p.i.) and stained with Amido black, while in the new assay, MN-ELISA was terminated at pre-determined 18h p.i. and the infected cells were fixed with acetone, followed by in-situ ELISA. Results of both the assays were compared. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the new test was 100% when compared with the conventional MN-CPE method as a 'gold standard'. The MN-ELISA showed two-fold higher antibody titer in one sample and one sample was additionally positive than MN-CPE ELISA. CONCLUSION: The MN-ELISA is rapid, more sensitive and read-out of results is by measurement of OD, which could be more accurate than manual observation of reduction in CPE. This novel test could be used as an alternative to the conventional MN-CPE based assay in sero-surveillance and in future vaccine studies.
Subject(s)
Antibodies, Neutralizing/blood , Antibodies, Viral/blood , Enzyme-Linked Immunosorbent Assay/methods , Neutralization Tests/methods , Rhabdoviridae Infections/diagnosis , Vesiculovirus/immunology , Adolescent , Antibodies, Neutralizing/isolation & purification , Cell Line , Child , Cytopathogenic Effect, Viral , Female , Humans , India , Male , Predictive Value of Tests , Rhabdoviridae Infections/immunology , Sensitivity and Specificity , Vesiculovirus/isolation & purificationABSTRACT
BACKGROUND & OBJECTIVES: Rotavirus is the major cause of gastroenteritis in infants and young children all over the world. The objective of the study was to develop a rapid ELISA for the diagnosis of rotavirus infection in children hospitalised with diarrhoea. METHODS: Immune serum was raised in rabbits by inoculating semipurified rotavirus, SA-11 strain. Immunoglobulins were conjugated to horse radish peroxidase and a rapid ELISA for rotavirus diagnosis was developed. The rapid ELISA was compared with routine ELISA, developed earlier at NIV. RESULTS: Of the 155 faecal samples from patients with diarrhoea, 96 were positive by rapid ELISA and 95 in routine NIV ELISA. OD values were higher in rapid ELISA. The rapid ELISA takes only 4 h to complete. INTERPRETATION & CONCLUSION: Rotavirus diagnosis by rapid ELISA is simple and easy to perform. This may lead to a significant reduction in the unnecessary usage of antibiotics, which cannot control infection due to rotavirus. This technology is being commercialized.
Subject(s)
Diarrhea/diagnosis , Enzyme-Linked Immunosorbent Assay/methods , Rotavirus Infections/diagnosis , Rotavirus/isolation & purification , Child , HumansABSTRACT
We report on the isolation of enterovirus 70 (EV-70) in Pune, India in 1991. The isolate was identified by the neutralization and indirect immunofluorescent antibody tests. The isolate was found to be a prime type of the EV-70 (J670/71) which was isolated by Kono and collaborators in 1971 (Kono et al., 1974).
