Pediatric Enteroviral Central Nervous System Infections in Bialystok, Poland: Epidemiology, Viral Types, and Drivers of Seasonal Variation

Figures

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  Figure 1. The flowchart representing the process of selecting children for the study. A total of 345 children with signs of meningitis of encephalitis were tested for enteroviruses. Of those, 224 were diagnosed with central nervous system (CNS) infection caused by enteroviruses. Abbreviations: EV PCR, diagnostic pan-enterovirus RT-PCR; virus isolation, virus isolation in cell cultures; CSF, cerebrospinal fluid; LNB, Lyme neuroborreliosis; TBE, tick-borne encephalitis; NA, not available for EV PCR.

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  Figure 2. Enterovirus types detected in children with infection of the CNS attributed to enteroviruses. Abbreviations: EV-A, enterovirus A species; EV-B, enterovirus B species; CV, coxsackievirus; E, echovirus.

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  Figure 3. Age distribution by enterovirus types isolated from children with infection of the CNS attributed to enteroviruses in Bialystok, Poland from 2015 to 2019. Abbreviations: EVs, enteroviruses; EV-A, enterovirus A species; CVB5, coxsackievirus B5; E30, echovirus 30; E6, echovirus 6.

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  Figure 4. Phylogenetic trees depicting the relationships between a complete VP1 coding region of Polish E30 (a), CVB5 (b), and E6 strains (c) isolated from 2015 to 2019 and sequences from the GenBank. Each strain is referenced by its geographical origin and its accession number. The tree was constructed by the neighbor-joining method and evaluated with 1000 bootstrap pseudoreplicates. Only bootstrap values ≥80% are indicated. In the analyses, genetic distances were calculated with Kimura 2-parameter algorithm. Analyses were conducted in MEGA 10.0.5.

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  Figure 5. The heatmap showing the temporal distribution of different EV types isolated from samples collected from children, who were hospitalized with aseptic meningitis and encephalitis in Bialystok, Poland from 2015 to 2019. Abbreviations: CV, coxsackievirus; E, echovirus.

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  Figure 6. The scatterplots illustrating the associations between mean air temperatures (a), relative humidity (b), wind speed (c), precipitation rates (d), sunshine duration (e), precipitation duration (f), and monthly number of cases of pediatric EV central nervous system infections with the linear regression curves; r-Person’s correlation coefficient.

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  Figure 7. The comparison of hospitalizations for CNS infections caused by enteroviruses in Bialystok, Poland with the number of cases predicted by the generalized linear mixed effects model (GLMM) including the temperature and the precipitation as covariates.