METHODS: In this study we have designed new live-attenuated vaccine vectors based on recombinant vesicular stomatitis viruses (rVSV) expressing NiV glycoproteins (G or F) or nucleoprotein (N) and evaluated their protective efficacy in Syrian hamsters, an established NiV animal disease model. We further characterized the humoral immune response to vaccination in hamsters using ELISA and neutralization assays and performed serum transfer studies.
RESULTS: Vaccination of Syrian hamsters with a single dose of the rVSV vaccine vectors resulted in strong humoral immune responses with neutralizing activities found only in those animals vaccinated with rVSV expressing NiV G or F proteins. Vaccinated animals with neutralizing antibody responses were completely protected from lethal NiV disease, whereas animals vaccinated with rVSV expressing NiV N showed only partial protection. Protection of NiV G or F vaccinated animals was conferred by antibodies, most likely the neutralizing fraction, as demonstrated by serum transfer studies. Protection of N-vaccinated hamsters was not antibody-dependent indicating a role of adaptive cellular responses for protection.
CONCLUSIONS: The rVSV vectors expressing Nipah virus G or F are prime candidates for new 'emergency vaccines' to be utilized for NiV outbreak management.
Methods: Combination of throat and nasal swab specimens was subjected to viral RNA extraction. For screening, the extracted RNA was subjected to real-time RT-PCR targeting upstream of E gene, open reading frame 1b and open reading frame 1a. For confirmation, the RNA was subjected to RT-PCR targeting partial part of the RNA-dependent RNA polymerase and nucleocapsid, followed by amplification of complete N gene region. Nucleotide sequencing of the first Malaysian case of MERS-CoV was performed following the confirmation with real-time RT-PCR detection.
Results: Initial analysis of partial RNA-dependent RNA polymerase and N gene revealed that the nucleotides had high similarity to Jeddah_1_2013 strain. Analysis of complete N gene region (1 242 nucleotides) from the case showed high similarity and yet distinct to the nucleotide sequences of camel-derived MERS-CoV.
Conclusions: From the finding, there are possibilities that the patient acquired the infection from zoonotic transmission from dromedary camels.