Publications by authors named "Merav Weil"

Coxsackievirus B2 (CVB2) is a member of the enterovirus group known to induce a spectrum of illnesses, from mild to severe. In the summer of 2022, an unusual outbreak of enteroviral central nervous system (CNS) infections occurred that was attributed to CVB2. Cerebrospinal fluid (CSF) samples collected from patients in 2015-2022 were tested for enterovirus via RT-PCR, followed by Sanger sequencing for positive cases.

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Background: Similarly to wild poliovirus, vaccine-derived poliovirus (VDPV) strains can cause acute flaccid paralysis, posing a considerable challenge to public health and the eradication of poliovirus. VDPV outbreaks, particularly VDPV type 2 (VDPV2), are increasing worldwide, including in high-income countries with high vaccine coverage. We aimed to conduct a comprehensive analysis of the molecular epidemiology of a widespread VDPV2 outbreak in Israel in 2022-23 using conventional polio identification techniques and whole-genome sequencing.

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Background And Aims: An increase in the number of cases of acute hepatitis of unknown origin (HUO) in children was observed in 2021. Adenovirus and adeno-associated virus 2 (AAV2) infections have been suggested as possible triggers. However, the potential etiology is still unclear.

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Background: Enteroviruses (EV) comprise the single most common cause of aseptic meningitis with variable geographical and temporal epidemiology. While EV-PCR in CSF is considered a gold standard for diagnosis, it is not-uncommon to use stool EV as a surrogate. Our aim was to assess the clinical significance of EV-PCR-positive CSF and stool in the investigation of patients with neurological symptoms.

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Introduction: Inactivated polio virus (IPV) vaccinations are a mainstay of immunization schedules in developed countries, while oral polio vaccine (OPV) is administered in developing countries and is the main vaccine in outbreaks. Due to circulating wild poliovirus (WPV1) detection in Israel (2013), oral bivalent polio vaccination (bOPV) was administered to IPV primed children and incorporated into the vaccination regimen.

Objectives: We aimed to determine the extent and timeframe of fecal and salivary polio vaccine virus (Sabin strains) shedding following bOPV vaccination among IPV primed children.

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Background: Outbreaks of enteroviral meningitis occur periodically and may lead to hospitalization and severe disease.

Objective: To analyze and describe the meningitis outbreak in patients hospitalized in Israel in 2021-2022, during the COVID-19 pandemic.

Results: In December 2021, before the emergence of the SARS-CoV-2 omicron variant, an off-season increase in enterovirus (EV) infections was observed among patients hospitalized with meningitis.

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During July-September 2022, 14 children suffering from meningoencephalitis tested positive for Coxsackievirus B2 (8 cerebrospinal fluid, 9 stool samples). Mean age 22 months (range 0-60 months); 8 were males. Seven of the children presented with ataxia and 2 had imaging features of rhombencephalitis, not previously described in association with Coxsackievirus B2.

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Israel conducts routine environmental (15 sites) and acute flaccid paralysis (AFP) surveillance for poliovirus. During September 2021, increasing numbers of wastewater samples collected from more than one site in the Jerusalem region proved positive for ambiguous type 3 vaccine-derived poliovirus (aVDPV3), while environmental samples from remaining sampling sites were negative. In late February 2022, a VDPV3, genetically related to the Jerusalem environmental surveillance samples, was isolated from a stool sample collected from a non-immunodeficient, non-immunized child from Jerusalem who developed AFP, indicating that the aVDPV3s were circulating (cVDPV3s) rather than immunodeficiency-related VDPV3s (iVDPVs).

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Article Synopsis
  • The study focuses on the containment of wild-type 2 poliovirus (PV2) post-eradication, highlighting the need to destroy all materials that may contain it, while noting past cases of polio in Israel involved all three serotypes.
  • The researchers aimed to demonstrate that whole genome sequences (WGS) of wild-type 3 poliovirus (PV3) could be retrieved from archived samples without re-amplifying neurovirulent viruses, connecting these sequences to historical case data and their phylogenetic relationships.
  • They successfully generated WGS for 55 PV3 isolates, identifying seven distinct lineages, with one causing an outbreak over six years, and found recombinant vaccine-like PV3 strains in some cases, enhancing understanding
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Article Synopsis
  • Poliovirus type 2 was detected in wastewater samples from three different areas in Jerusalem between April and July 2022, indicating a rise in cases.
  • Genetic analysis revealed a connection among the viruses and the presence of mutations, with some identified as vaccine-derived polioviruses (VDPV).
  • This finding highlights the need for ongoing wastewater monitoring, even in countries with high vaccine coverage, to support polio eradication efforts.
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In this report, we describe a national-scale monitoring of the SARS-CoV-2 (SC-2) variant dynamics in Israel, using multiple-time sampling of 13 wastewater treatment plants. We used a combination of inclusive and selective quantitative PCR assays that specifically identify variants A19/A20 or B.1.

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Article Synopsis
  • Enterovirus D68 (EVD68) is linked to respiratory illnesses and acute flaccid myelitis in children, prompting a study of 472 pediatric patients for the virus between April and October 2021.
  • Out of the patients tested, 33 (7%) were positive for EVD68, while all tested wastewater samples showed the presence of the virus, highlighting an increase in viral loads from late May to July and a significant drop in early August.
  • This research is significant as it utilizes wastewater-based epidemiology to track EVD68 prevalence and demonstrates a strong correlation with clinically diagnosed cases, indicating the potential for ongoing surveillance of this and other enteroviruses.
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Objectives: To examine the association between seroprevalence and serum pepsinogens (PGs) as markers of gastric inflammation), with high neutralizing antibody titers to poliovirus type 1 and 3 vaccine strains among children age 3-4 years, subsequent to sub-clinical infection acquired during a wild-type poliovirus type 1 outbreak in Israel.

Methods: A serosurvey was conducted among 336 children aged 5-17 years who were vaccinated with both inactivated polio vaccine and oral polio vaccines. serum IgG antibodies and PG concentrations were measured using ELISA.

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Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an RNA virus, a member of the coronavirus family of respiratory viruses that includes severe acute respiratory syndrome coronavirus 1 (SARS-CoV-1) and the Middle East respiratory syndrome (MERS). It has had an acute and dramatic impact on health care systems, economies, and societies of affected countries during the past 8 months. Widespread testing and tracing efforts are being employed in many countries in attempts to contain and mitigate this pandemic.

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Article Synopsis
  • * Researchers found that SARS-CoV-2 RNA is present in urban wastewater, suggesting that monitoring wastewater can track virus activity and serve as an early warning system.
  • * In a study conducted in Ashkelon, Israel, changes in wastewater SARS-CoV-2 levels predicted increases in local COVID-19 cases about two weeks before they became clinically visible, using a new metric called Normalized Viral Load (NVL).
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Response to and monitoring of viral outbreaks can be efficiently focused when rapid, quantitative, kinetic information provides the location and the number of infected individuals. Environmental surveillance traditionally provides information on location of populations with contagious, infected individuals since infectious poliovirus is excreted whether infections are asymptomatic or symptomatic. Here, we describe development of rapid (1 week turnaround time, TAT), quantitative RT-PCR of poliovirus RNA extracted directly from concentrated environmental surveillance samples to infer the number of infected individuals excreting poliovirus.

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Article Synopsis
  • Scientists investigated how SARS-CoV-2 spreads and identified viral variants using wastewater samples in Israel, showing it can effectively track virus prevalence across larger populations compared to traditional clinical methods.
  • The study, conducted from August 2020 to February 2021, sequenced 58 samples, revealing the emergence and spread of the B.1.1.7 variant in December 2020, even in areas with limited clinical testing.
  • The research highlights wastewater analysis as a valuable tool for monitoring the diversity of SARS-CoV-2 strains and detecting important mutations, which can inform public health strategies.
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The routine detection, surveillance, and reporting of novel SARS-CoV-2 variants is crucial, as these threaten to hinder global vaccination efforts. Herein we report a novel local variant with a non-synonymous mutation in the spike (S) protein P681H. This local Israeli variant was not associated with a higher infection rate or higher prevalence.

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The COVID-19 pandemic and the fast global spread of the disease resulted in unprecedented decline in world trade and travel. A critical priority is, therefore, to quickly develop serological diagnostic capacity and identify individuals with past exposure to SARS-CoV-2. In this study serum samples obtained from 309 persons infected by SARS-CoV-2 and 324 of healthy, uninfected individuals as well as serum from 7 COVID-19 patients with 4-7 samples each ranging between 1-92 days post first positive PCR were tested by an "in house" ELISA which detects IgM, IgA and IgG antibodies against the receptor binding domain (RBD) of SARS-CoV-2.

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Background: Individuals with primary immune deficiencies (PIDs) may excrete poliovirus for extended periods and remain a major reservoir for polio after eradication. Poliovirus can spread by fecal-oral or oral-oral transmission. In middle- and high-income countries, oral-oral transmission may be more prevalent than fecal-oral transmission of polioviruses where PIDs patients survive longer.

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Article Synopsis
  • - This report highlights the first case of a persistent oropharyngeal infection with a type 2 poliovirus variant (iVDPV2) in a patient with primary immune deficiency, following the eradication of wild type 2 poliovirus.
  • - The iVDPV2 was found to persist not only in the throat but also in the gut, indicating its ability to survive in multiple locations within the body.
  • - The evolution of iVDPV2 in both the throat and gut occurred independently, raising concerns about the risk of oral and fecal transmission as the world aims for complete eradication of poliovirus type 2.
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Background: Human parainfluenza virus 3 (hPIV-3) causes respiratory tract infection.

Objectives: The objective of this study was to describe the epidemiology of hPIV-3 infection among hospitalized patients and characterize the circulating strains.

Study Design: A cross-sectional study was conducted using respiratory samples of 15,946 hospitalized patients with respiratory symptoms in 2012-2015 in Israel.

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Infants with severe combined immunodeficiency (SCID) are at risk of developing severe life-threatening infections if they are inadvertently given attenuated live vaccines. Concomitant appearance of two live vaccine-associated complications in one person is rarely reported. In this study, we present two SCID infants, who received BCG and oral polio vaccines according to their local immunization schedule early in life, before the diagnosis of immunodeficiency was made.

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Deep sequencing was used to determine complete nucleotide sequences of echovirus 11 (EV11) strains isolated from a chronically infected patient with CVID as well as from cases of acute enterovirus infection. Phylogenetic analysis showed that EV11 strains that circulated in Israel in 1980-90s could be divided into four clades. EV11 strains isolated from a chronically infected individual belonged to one of the four clades and over a period of 4 years accumulated mutations at a relatively constant rate.

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Background: In 1999, Israel became the first country to introduce an inactivated hepatitis A vaccine into its national childhood vaccination program. The objective of the present study was to evaluate the seroprevalence of hepatitis A virus antibodies in the Israeli population before and after the introduction of the program.

Methods: A cross-sectional serosurvey using the National Serum Bank was conducted on 1883 and 2027 serum samples collected before and after introduction of the vaccine, respectively.

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