Acute meningoencephalitis associated with echovirus 9 infection in Sri Lanka, 2009

Abstract

The aetiology of acute meningoencephalitis in Sri Lankan children and adults is poorly understood. This study was carried out to determine pathogens responsible for meningoencephalitis in Sri Lanka. A hospital-based cross-sectional study was performed using cerebrospinal fluid samples (22 adult and 17 pediatric) collected from August to December 2009 from patients clinically diagnosed with acute meningoencephalitis at two tertiary care hospitals in Sri Lanka. Routine microbiology for bacterial pathogens together with in-house RT-PCR and PCR assays for the detection of dengue viruses, Japanese encephalitis virus, West Nile virus, chikungunya virus, enteroviruses, mumps virus, measles virus, herpes simplex viruses types 1 and 2, and varicella zoster virus were performed. Bacterial pathogens were not isolated from any patient specimens. However, from nine of the paediatric patients aged 1 month to 10 years (mean age 5.2 years) echovirus 9 (E-9; family Picornaviridae, genus Enterovirus,species Enterovirus B ) was detected by RT-PCR. All nine patients presented with fever, six had headache, and seven had vomiting. Neck stiffness indicating meningitis was present in six of the patients. Phylogenetic analysis of partial VP1 and VP4-VP2 genes showed these E-9 strains to be most closely related to E-9 strains detected in CSF from Korea and France in 2005 and 2006. The remaining patients were negative for all other viruses tested. E-9 was the most common cause of acute meningoencephalitis in the tested paediatric population from Sri Lanka in 2009, which likely reflects circulation of this E-9 strain between Europe and Asia over several years.

Cerebrospinal fluid features in adults with enteroviral nervous system infection

“…All study patients with available sequence data from the enterovirus 5 0 -NTR had infections with human Enterovirus B. Members of the Enterovirus B species have been widely identified as the most common cause of aseptic meningitis worldwide (Danthanarayana et al, 2015;Dos Santos et al, 2006;Wieczorek et al, 2016), and cause aseptic meningitis significantly more often than other enterovirus species (Lo et al, 2010). Echovirus 30 predominated in this cohort, especially during the years 2013 and 2014.Thisisinagreementwiththedatareportedbyotherswhofound a peak of enteroviral meningitis due to echovirus 30 in 2013 and 2014 in Central Europe (Rudolph et al, 2017;Wieczorek et al, 2016).…”

The challenge of treating central nervous system infections in the developing world

“…However, it also carries the risks of overlooking many potentially treatable diagnoses, and a high cost of unnecessary treatment. Interestingly, no cases of microbiologically confirmed HSV encephalitis were found in our study and in the two subsequent Sri Lankan studies described 52,53 . Intravenous acyclovir is widely used on an empiric basis in patients with suspected meningo-encephalitis in Sri Lanka, as was seen in our studies, and these findings challenge the rationale for this practice.…”

“…Two Sri Lankan studies, conducted subsequent to our studies, have confirmed the difficulties in diagnosis in spite of access to good microbiological facilities. In a study by Danthanarayana et al (2015), Enterovirus (E-9) was detected in nine out of 39 CSF samples, and the samples were negative for all other viruses tested and bacterial culture 52 . Lohitharahjah et al (2017) identified a viral aetiology in 27.3% of 99 CSF samples from 108 patients with suspected encephalitis/ meningo-encephalitis; the aetiologies identified included dengue virus, JE virus, varicella zoster virus and West Nile virus.…”

“…Emerging infections such as Nipahvirus encephalitis is increasingly recognised from South East Asia [68][69][70][71] . Interestingly, the two subsequent Sri Lankan studies cited earlier detected only viral aetiologies and failed to isolate any bacterial causes 52,53 . Alternate diagnoses such as encephalopathy are common in unselected samples, e.g.…”

Molecular epidemiological study of enteroviruses associated with encephalitis in children from Hangzhou, China

“…In previous studies, many serotypes of EV were reported of causing encephalitis outbreak in children, such as Echovirus 30 in Belgium, 2000, [20] Echovirus 6 in Greece, 2006, [21] Echovirus 4 in Spain, 2008, [22] Echovirus 19 in Uttar Pradesh, India, 2008, [23] Echovirus 9 in Sri Lanka, 2009, [24] and Coxsackievirus B5 in Henan, China [25] ; Echovirus 30 is a mostly common serotype in meningitis outbreaks caused by EV around the world. [26] According to the sequence of VP1 or 5 0 UTR, Echovirus 30 was found to be the major serotype in Hangzhou, 2015.…”