Title : Etiology of acute meningitis and encephalitis in hospitalized patients, Kazakhstan, 2019 - 2020
Acute meningitis and encephalitis (AME) is a neurological inflammation associated with substantial morbidity and mortality caused by different pathogens. In Kazakhstan, comprehensive testing to identify viral causal pathogens is not routinely performed. Additionally, the national surveillance system does not capture all AME causes. We conducted syndromic surveillance of AME patients in the south region with high incidence.
We enrolled all patients hospitalized with AME in the Shymkent City Infectious Diseases Hospital from May 2019 to May 2020. We abstracted demographic, clinical, and laboratory data, and collected cerebrospinal fluid (CSF) and whole blood to test for causative pathogens. We performed serotyping or PCR to identify Neisseria meningitidis and Haemophilus influenzae strains and sequencing of Enterovirus VP1 gene.
Of 1344 patients (median age 10 years, range 0.5 months - 72 years, male – 55%) with AME, the causal pathogen was identified in 84.3% (81.6% viral and 2.7% bacterial). Viral pathogens included enteroviruses (79%), herpes simplex virus 1 or 2 (0.8%), varicella-zoster virus (0.8%), tick-borne encephalitis (0.9%), and herpes simplex virus 6 (0.2%). Of 28 enterovirus samples sequenced, 54% were Coxsackievirus A6, A10, and 46% were Echovirus E6. Among 36 patients with bacterial infections, 61% had N. meningitidis, 36% S. pneumoniae, 3% H. influenzae. N. meningitidis serogroups A and W138 were the most common strains. Of bacterial infections, 86% were confirmed only by CSF PCR, and 14% by culture.
Viral pathogens, specifically enteroviruses, were the most common cause of AME. We found tick-borne encephalitis (TBE) for the first time in a patient with AME in a region where TBE is not endemic. CSF PCR had a higher yield than bacteriology for identifying bacterial AME. Incorporating PCR into routine diagnostic testing of AME would improve pathogen identification for appropriate clinical care. Adding AME causes to the surveillance system can be useful for national disease prevention and control efforts.
Audience take away:
From our presentation, the audience will learn more about the etiological structure of bacterial and viral meningitis, which can help expand the spectrum of pathogens tested for adequate diagnosis and treatment, as well as assess the burden of encephalitis and meningitis in the population, and plan preventive measures. The results of this study substantiate the need for further comprehensive research on the epidemiology of Tick-Borne Encephalitis in the study region for the subsequent assessment of specific risk groups and territories and the development of targeted preventive and anti-epidemic measures.