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Page No. : 24-27

ABSTRACT

Japanese encephalitis (JE) is a mosquito-borne flaviviral disease endemic in most parts of Asia, including India where it is the most common cause of encephalitis and a major cause of morbidity and mortality in children. Swine, being the amplifier host for JE virus play important role in its epidemiology and also considered as suitable sentinel for predicting outbreaks in humans. However, fi eld blood sample collection from swine is a tedious task. Further, transportation and storage in cold condition becomes imperative to avoid RNAse activity. We hypothesize that collecting approximately 2 ml of blood in serum collection tube should be sufficient for both serology and molecular based assays, instead of collecting whole blood separately in EDTA vial for molecular assays alone. Therefore, we conducted the present study with the objective to determine the most sensitive sample amongst swine blood, serum or plasma for the detection of Japanese encephalitis virus. The confirmed negative samples of blood, serum and plasma were spiked with 104 copy number of positive JE virus. The RNA was extracted from spiked samples and TaqMan probe based real time RT-PCR assay was performed to detect JE virus. We observed that there was no significant difference amongst the Ct values of JE virus spiked blood, plasma and serum samples. Further, we screened 46 field samples of swine blood, serum and plasma for JEV and found no significant difference in the positivity rate of different samples (p>0.05). Hence, it can be concluded from the present study that use of serum sample instead of whole blood or plasma does not aff ect the detection rate of JE virus by real time RT-PCR.

Keywords: Japanese encephalitis, spiking, real time RT- PCR