Suboptimal Serologic Immunity Against Poliomyelitis Among New Migrant Children in Greece Calls for Organized Action.

BACKGROUND: Migration-flows pose the risk of poliovirus reintroduction from endemic countries to Greece. This study aims to evaluate serologic-immunity/vaccination against poliomyelitis in newly-arriving migrant children. METHODS: Demographic-immunisation data and blood-serum were obtained from migrants 1-14years-old, referred to a hospital-clinic in Athens-Greece within three months from arrival. Immunity to polioviruses-1-3 was determined by serum-neutralizing-antibodies(WHO guidelines). Titers ≥ 1:8 were considered positive. RESULTS: From 9/2010 to 9/2013, 274 children(150 refugees/124 immigrants), mean age 7.1years-old, were enrolled. Only 57(20.8%) of them presented with vaccination-records. Children originated mainly from Asia(n = 198), Eastern Europe(n = 28), Middle East(n = 24) and Africa(n = 24) with 160(58.4%) from polio-endemic-countries(Afghanistan-112(40.8%), Pakistan-24(8.8%) and India-24(8.8%)). Seropositivity against polio-1-2&3 was 84.3%, 86.1% and 74.5%, respectively. Immigrants, had higher seroprotective rates against polioviruses-1-2&3 than refugees(polio-1:p = 0.002;polio-2:p = 0.004,polio-3:p < 0.001). Seronegativity to 1PVs-2PVs and all three polio serotypes was found in 37(13.5%),12 (4.4%), and 30 children(10.9%) respectively. Increasing number of vaccine-doses, and younger-age, were positively-associated with seropositivity. DISCUSSION: A remarkable fraction of newly-arrived migrant-children were seronegative to one or more polioviruses.

Tropheryma whipplei Intestinal Colonization in Migrant Children, Greece.

We obtained fecal samples from migrant children <12 years of age throughout hotspots in Greece and tested them for Tropheryma whipplei by using a quantitative PCR assay. We identified 6 genotypes of T. whipplei, 4 of which are newly described. Our findings suggest a high prevalence of T. whipplei in these regions.

Mesenchymal stem cells instruct a beneficial phenotype in reactive astrocytes.

Transplanted mesenchymal stromal/stem cells (MSC) ameliorate the clinical course of experimental autoimmune encephalomyelitis (EAE), a mouse model of multiple sclerosis (MS), reducing inflammation and demyelination. These effects are mediated by instructive cross-talk between MSC and immune and neural cells. Astroglial reaction to injury is a prominent feature of both EAE and MS. Astrocytes constitute a relevant target to control disease onset and progression and, based on their potential to acquire stem cell properties in situ, to foster recovery in the post-acute phase of pathology. We have assessed how MSC impact astrocytes in vitro and ex vivo in EAE. Expression of astroglial factors implicated in EAE pathogenesis was quantified by real-time PCR in astrocytes co-cultured with MSC or isolated from EAE cerebral cortex; astrocyte morphology and expression of activation markers were analyzed by confocal microscopy. The acquisition of neural stem cell properties by astrocytes was evaluated by neurosphere assay. Our study shows that MSC prevented astrogliosis, reduced mRNA expression of inflammatory cytokines that sustain immune cell infiltration in EAE, as well as protein expression of endothelin-1, an astrocyte-derived factor that inhibits remyelination and contributes to neurodegeneration and disease progression in MS. Moreover, our data reveal that MSC promoted the acquisition of progenitor traits by astrocytes. These data indicate that MSC attenuate detrimental features of reactive astroglia and, based on the reacquisition of stem cell properties, also suggest that astrocytes may be empowered in their protective and reparative actions by MSC.

Retrospective Analysis of Six Years of Acute Flaccid Paralysis Surveillance and Polio Vaccine Coverage Reported by Italy, Serbia, Bosnia and Herzegovina, Montenegro, Bulgaria, Kosovo, Albania, North Macedonia, Malta, and Greece.

Here we analyzed six years of acute flaccid paralysis (AFP) surveillance, from 2015 to 2020, of 10 countries linked to the WHO Regional Reference Laboratory, at the Istituto Superiore di Sanità, Italy. The analysis also comprises the polio vaccine coverage available (2015-2019) and enterovirus (EV) identification and typing data. Centralized Information System for Infectious Diseases and Laboratory Data Management System databases were used to obtain data on AFP indicators and laboratory performance and countries' vaccine coverage from 2015 to 2019. EV isolation, identification, and typing were performed by each country according to WHO protocols. Overall, a general AFP underreporting was observed. Non-Polio Enterovirus (NPEV) typing showed a high heterogeneity: over the years, several genotypes of coxsackievirus and echovirus have been identified. The polio vaccine coverage, for the data available, differs among countries. This evaluation allows for the collection, for the first time, of data from the countries of the Balkan area regarding AFP surveillance and polio vaccine coverage. The need, for some countries, to enhance the surveillance systems and to promote the polio vaccine uptake, in order to maintain the polio-free status, is evident.

Molecular characterization of enteroviruses among hospitalized patients in Greece, 2013-2015.

BACKGROUND: There are only sporadic data for the circulation of Enteroviruses (EVs) in Greece with previous studies reporting mainly the presence of Echoviruses (E) and Coxsackie viruses (CV) B. OBJECTIVES: We carried out a surveillance study for the molecular characterization of EVs detected in hospitalized patients throughout Greece as well as a phylogenetic analysis of the most frequently encountered serotypes. STUDY DESIGN: Stools, cerebrospinal fluids, throat swabs and blood samples were collected from hospitalized patients with suspicion of EV infection. All samples were tested for EVs by rRT-PCR targeting the 5' untranslated region of EV genome. For positive samples, PCR amplification and sequencing targeting a part of VP1 region was performed. RESULTS: We examined 831 samples and 209 were positive for EVs with Enterovirus B species being the most frequently amplified. E30, CVB5 and E9 were the most frequent serotypes of Enterovirus B species, whereas CVA6 and EV-A71 the most frequent serotypes of Enterovirus A species. Evs were significantly detected more frequently in stool samples compared to other types of specimens. Phylogenetic analysis revealed that most EV-A71 strains clustered in the subgenogroups C2 whereas all the CVA6 strains belonged to sub-genotype D3. Additionally, two different lineages of E30 and three different clusters of E9 viruses circulated simultaneously in Greece. Our data indicated that most EV strains from Greece were similar to strains circulating throughout Europe during the same period. CONCLUSIONS: We provide a comprehensive picture of EVs circulating in Greece which can be helpful to interpret trends in EV diseases by associating them with circulating serotypes.

Laboratory Surveillance of Polio and Other Enteroviruses in High-Risk Populations and Environmental Samples.

In the context of poliomyelitis eradication, a reinforced supplementary laboratory surveillance of enteroviruses was implemented in Greece. Between 2008 and 2014, the Hellenic Polioviruses/Enteroviruses Reference Laboratory performed detailed supplementary surveillance of circulating enteroviruses among healthy individuals in high-risk population groups, among immigrants from countries in which poliovirus is endemic, and in environmental samples. In total, 722 stool samples and 179 sewage water samples were included in the study. No wild-type polioviruses were isolated during these 7 years of surveillance, although two imported vaccine polioviruses were detected. Enterovirus presence was recorded in 25.3 and 25.1% of stool and sewage water samples, respectively. Nonpolio enteroviruses isolated from stool samples belonged to species A, B, or C; coxsackievirus A24 was the most frequently identified serotype. Only enteroviruses of species B were identified in sewage water samples, including four serotypes of echoviruses and four serotypes of coxsackie B viruses. Phylogenetic analysis revealed close genetic relationships among virus isolates from sewage water samples and stool samples, which in most cases fell into the same cluster. To the best of our knowledge, this is the first study to compare enterovirus serotypes circulating in fecal specimens of healthy individuals and environmental samples, emphasizing the burden of enterovirus circulation in asymptomatic individuals at high risk. Given that Greece continues to receive a large number of short-term arrivals, students, migrants, and refugees from countries in which poliovirus is endemic, it is important to guarantee high-quality surveillance in order to maintain its polio-free status until global eradication is achieved.IMPORTANCE This article summarizes the results of supplementary poliovirus surveillance in Greece and the subsequent characterization of enteroviral circulation in human feces and the environment. The examination of stool samples from healthy refugees and other individuals in "high-risk" groups for poliovirus enables the identification of enterovirus cases and forms the basis for further investigation of the community-level risk of viral transmission. In addition, the examination of composite human fecal samples through environmental surveillance links poliovirus and nonpoliovirus isolates from unknown individuals to populations served by the sewage or wastewater system. Supplementary surveillance is necessary to comply with the prerequisites imposed by the World Health Organization for monitoring the emergence of vaccine-derived polioviruses, reemergence of wild polioviruses, or disappearance of all vaccine-related strains in order for countries such as Greece to maintain their polio-free status and contribute to global poliovirus eradication.

Echovirus 30 outbreak associated with a high meningitis attack rate in Thrace, Greece.

Between late May and July 2012, 105 children (62 boys) originating from 2 cities of Thrace were examined because of fever, headache and abdominal pain. Thirty-three of them were hospitalized. They had normal hemograms, and mild to moderate cerebrospinal fluid pleocytosis. Echovirus 30 was isolated from fecal and cerebrospinal fluid samples. Among confirmed cases of echoviral illness, the meningitis attack rate was 51.9%.