Detection of non-polio and polio enteroviruses in Acute Flaccid Paralysis surveillance in Turkey

Poliomyelitis was a disease feared worldwide, striking suddenly and paralysing mainly children for life. Monitoring of suspected cases of poliomyelitis is carried out with Acute Flaccid Paralysis (AFP) surveillance in Turkey. This study examines national data of AFP surveillance and the epidemiology of enteroviruses (EV) in Turkey from 2000 to 2019 and gives an overview of the detected serotypes of EVs. A total of 13,640 samples collected from patients with 5216 AFP pre-diagnosed cases (2 samples from each patient) and 3,208 contacts, during a 20-year period (2000-2019) were investigated. All isolated polioviruses were tested for their wild or vaccine origin according to the WHO recommended protocol by PCR and sequencing analysis were performed. Enterovirus positivity was detected in a total of 915 cases, which were identified as 204 Sabin-like polio virus (SLPV) and 711 non-polio enterovirus (NPEV). Of the 204 SLPV, 141 (69.1%) AFP were detected in patients and 63 (30.9%) were detected in samples taken from their contacts. Of the 711 NPEVs, 516 (72.5%) were from AFP cases and 195 (27.5%) were detected in samples taken from their contacts. It is concluded that the reason for the higher detection rate of NPEV in samples from AFP pre-diagnosed cases is attributed to the polio vaccination rates reaching 97% between 2008 and 2019 in Turkey. The most frequently detected NPEV serotypes were Coxackie A24, B3, and Echo 30. This retrospective study is the first comprehensive study in Turkey to evaluate the results of the AFP surveillance in the last 20 years.

Role of Viral Agents in Childhood Central Nervous System Infections

Rapid laboratory diagnosis in acute viral infections in the central nervous system (CNS) is important for the direction of treatment. In this study, we aimed to evaluate viral agents detected by real-time polymerase chain reaction (PCR) in cerebrospinal fluid (CSF) samples sent to the national virology reference laboratory for the diagnosis of acute CNS viral infection in the 0 to 18 age group. The results of 5,255 CSF samples submitted to the laboratory between January 1, 2009, and February 14, 2018, were retrospectively reviewed. Test results of CSF samples tested with the multiplex real-time PCR panel (Fast Track Diagnostics/Viral Meningitis commercial kit, Luxembourg) kit were evaluated. PCR positivity was detected in 216 (4.11%) of the 5,255 CSF samples tested. The most common agents were enteroviruses 92 (42.6%) and herpes simplex virus-1 (HSV-1) 87 (40.2%) while varicella-zoster virus (VZV) 24 (11.1%), mumps virus 10 (4.62%), parechovirus 2 (0.92%), and herpes simplex virus-2 (HSV-2) 1 (0.46%) were less often identified. Considering the possibility that a wide variety of microorganisms may be agents of CNS infections, the performing of routine laboratory tests with multiple, fast, and reliable nucleic acid tests such as multiplex PCR provides a practical and effective approach. In addition to the identification of agents, retrospective studies of the incidence of agents will shed light on the clinical approaches in terms of the agents to be considered in the preliminary diagnosis. We consider that our results are valuable in terms of the high number of samples examined by the national virology reference laboratory over a 9-year period, and will contribute to clinicians' understanding of the epidemiology of meningitis in our country, and assist in identifying when and how to investigate patients for possible meningitis.