Quiz of the week #1: On June 2016, a 10-year-old male arrived at a Community Health Centre in Tripura to seek medical care. The child was presented with fever, sore throat and headache since 3 days. He had a tick bite and small bruises on his hand and subsequently came in contact with a rat. 2 days after, the boy showed symptoms of cough, coryza and arthralgia. This was followed by altered sensorium, lymphadenopathy, and pedal edema. A serum and a cerebrospinal fluid (CSF) sample was sent to the laboratory to conduct a series of medical tests. What will be the probable diagnosis for this case?
The patient was positive for IgM antibodies to Japanese Encephalitis virus in CSF, and confirmatory plaque reduction neutralization testing (PRNT) demonstrated the presence of neutralizing antibodies to the virus. Japanese Encephalitis Virus is one of the leading causes of acute encephalitis. It is a vector-borne disease transmitted by the bite of Culex mosquito. Pigs and ducks are the amplifying hosts while humans are the accidental dead-end host for this virus. These mosquitoes are commonly found in paddy rice fields. Most JEV cases are subclinical in areas with endemic transmission. The diagnosis on JEV is mostly based on IgM capture ELISA for JEV specific IgM antibody in CSF or blood and four-fold rise in IgG titer. JEV virus detection is very rare. Three licensed vaccines against JE are available. It is not recommended for routine use, but only for individuals living in endemic areas. There are no specific antivirals for JEV and treatment is supportive.