Chikungunya virus is a cause of encephalitis in children in bellary, India

Abstract

Introduction: Chikungunya virus, a single stranded RNA Alphavirus of the family Togaviridae, is transmitted to humans by the bite of Aedes aegypti, Aedes albopictus and other mosquitoes. An epidemic starting in Reunion Islands in March 2005 spread to Southern India, affecting 1.3 million people between Oct 2005 and Oct 2006. The epidemic reached Bellary, Karnataka in southern India by Dec 2005. Methods: From Oct 2005 to Dec 2007, children admitted to the paediatric department of the Vijayanagar Institute of Medical Sciences with an acute encephalitis syndrome were prospectively studied. All children presenting to the paediatric ward were recruited if they had suspected CNS infection or acute flaccid paralysis [and] fever or history of fever in the previous 2 weeks, together with one or more of the following: meningism (neck stiffness), photophobia, severe headache meriting lumbar puncture, altered mental state, reduced consciousness, convulsions, focal neurological signs or acute flaccid paralysis. Results: 243 patients have been recruited to date. Between April and Oct 2006, 8 children had positive plasma PCR tests for Chikungunya RNA and are described in more detail. Viral RNA was also detected by PCR in the CSF of 3 of these 8. Mean age was 6 years, range 8 months to 11 years, 5 were girls. 3 children had a rash at some stage in their illness and one had conjunctivitis. Altered mental state was reported in 7, and 6 had a GCS of less than 15 at admission. One had deafness, 3 had nausea and vomiting, and 3 had meningism. 7 had seizures, amongst whom 4 had an episode of status epilepticus (seizure lasting more than 30 minutes). 3 were aphasic during their illness and 4 had extensor plantar reflexes. There were no fatalities. At discharge, 2 patients had ongoing aphasia. The remaining 4 with a reduced GCS at admission had recovered to full coma score. Sequencing information obtained from the E1 envelope gene from plasma and CSF samples confirmed that the chikungunya genomes are of the East African lineage, which appears to have caused the more severe epidemic form of illness, compared to the Asian genotype which previously circulated in India. Conclusions: Chikungunya virus causes encephalitis in children and may be found in the CSF. It can cause severe neurological disease sequelae although the extent to which these sequelae will persist is uncertain. Given frequent travel between Asia and Europe and the potential for autochtonous transmission, as has occurred in Italy, we need to be increasingly aware of global disease outbreaks. A CASE OF HYPERCALCAEMIA IN THE RETURNING