# Chikungunya viral load in cerebrospinal fluid and blood is not associated with severity of neurological manifestations in children

## TL;DR

The study found that high levels of chikungunya virus in blood and spinal fluid of children did not correlate with the severity of neurological symptoms or long-term cognitive issues.

## Contribution

This study is the first to show that chikungunya viral load in cerebrospinal fluid and blood does not predict neurological severity or long-term outcomes in children.

## Key findings

- High viral load in cerebrospinal fluid and blood was observed in children with chikungunya.
- No significant association was found between viral load and severity of neurological manifestations.
- Some children showed neurodevelopmental impairment four years after infection.

## Abstract

Chikungunya virus (CHIKV) can induce severe neurological manifestations in children. Investigating the role of the viral load (VL) in the blood and cerebrospinal fluid (CSF) could be of interest in understanding the mechanisms that mediate severity. This study aimed to analyze the characteristics of neurological manifestations of CHIKV in young patients at diagnosis and follow-up, with a particular focus on the potential relation between the severity of neurological involvement and the VL in the CSF and blood.

We conducted an observational longitudinal retrospective single-center study during the Chikungunya outbreak of 2014 on the French Caribbean Island of Martinique. We included children (excluding newborns) requiring lumbar puncture and who had positive CHIKV RT-PCR in the blood. Blood and CSF VL were assessed, and sociodemographic, clinical and biological characteristics were recorded.

Among 651 children with a positive CHIKV RT-PCR in the blood; 86 were included, of whom 84 had positive RT-PCR in the CSF. Seven children developed probable encephalitis. Neurological manifestations were deemed severe in eight patients (9.3%), intermediate in 11 (12.8%) and non-severe in 67 (77.9%). Mean VL was 9.8 log in blood and 4.9 log in CSF. While mean blood and CSF VL were significantly higher in children aged <1 year, there was no significant association between blood and CSF VL and neurological severity. An initial follow-up carried out on 20 children one to six months after infection, showed good recovery. Additionally, 45 children underwent a neurology consultation 4 years later, of whom 8 (17.8%) presented with neurodevelopmental impairment.

Our results suggest that the CHIKV can invade the CNS at a high level during the acute phase of infection, but does not seem to be associated with the severity of neurological manifestations in children at the acute phase or with long-term cognitive development.

Neurological manifestations including encephalitis may complicate chikungunya infection among children. Hypothesizing that the viral load (VL) in blood and cerebrospinal fluid (CSF) could be of interest in understanding the mechanisms that mediate severity, we conducted a study on children infected by chikungunya virus and who required lumbar puncture during the 2014 Chikungunya outbreak on the Caribbean Island of Martinique. Among 651 children who had a positive RT-PCR in blood, we included 86 who required lumbar puncture, after exclusion of newborns and patients with bacterial meningitis. Neurological manifestations ranged from severe in eight patients (9.3%), intermediate in 11 (12.8%), to non severe in 67 (77.9%). Mean VL was 9.8 log in the blood and 4.9 log in the CSF. An initial follow-up carried out on 20 children one to six months after infection, showed good recovery. Additionally, 45 children underwent a neurology consultation 4 years later, of whom 8 presented with neurodevelopmental impairment. Our results suggest that chikungunya virus can invade the CNS at a high level during the acute phase of infection, without significant association between the viral load in the CSF or blood and the neurological severity of disease and the long-term cognitive development of infected children.