Surveillance and Diagnosis of West Nile Virus in the Face of Flavivirus Cross-Reactivity

West Nile Virus (WNV) is an arthropod-borne flavivirus whose zoonotic cycle includes both mosquitoes and birds as amplifiers and humans and horses as dead-end hosts. In recent years WNV has been spreading globally and is currently endemic in Africa, The Middle East, India, Australia, central and southern Europe, and the Americas. Integrated surveillance schemes and environmental data aim to detect viral circulation and reduce the risk of infection for the human population emphasizing the critical role for One Health principles in public health. Approximately 20% of WNV infected patients develop West Nile Fever while in less than 1%, infection results in West Nile Neurological Disease. Currently, the diagnosis of WNV infection is primarily based on serology, since molecular identification of WNV RNA is unreliable due to the short viremia. The recent emergence of Zika virus epidemic in America and Asia has added another layer of complexity to WNV diagnosis due to significant cross-reactivity between several members of the Flaviviridae family such as Zika, dengue, Usutu, and West Nile viruses. Diagnosis is especially challenging in persons living in regions with flavivirus co-circulation as well as in travelers from WNV endemic countries traveling to Zika or dengue infected areas or vise-versa. Here, we review the recent studies implementing WNV surveillance of mosquitoes and birds within the One Health initiative. Furthermore, we discuss the utility of novel molecular methods, alongside traditional molecular and serological methods, in WNV diagnosis and epidemiological research

Neurovirulent Vaccine-Derived Polioviruses in Sewage from Highly Immune Populations

BACKGROUND: Vaccine-derived polioviruses (VDPVs) have caused poliomyelitis outbreaks in communities with sub-optimal vaccination. Israeli environmental surveillance of sewage from populations with high (>95%) documented vaccine coverage of confirmed efficacy identified two separate evolutionary clusters of VDPVs: Group 1 (1998–2005, one system, population 1.6×10(6)) and Group 2 (2006, 2 systems, populations 0.7×10(6) and 5×10(4)). PRINCIPAL FINDINGS: Molecular analyses support evolution of nine Group 1 VDPVs along five different lineages, starting from a common ancestral type 2 vaccine-derived Sabin-2/Sabin-1 recombinant strain, and independent evolution of three Group 2 VDPVs along one lineage starting from a different recombinant strain. The primary evidence for two independent origins was based on comparison of unique recombination fingerprints, the number and distribution of identical substitutions, and evolutionary rates. Geometric mean titers of neutralizing antibodies against Group 1 VDPVs were significantly lower than against vaccine strains in all age-group cohorts tested. All individuals had neutralizing titers >1∶8 against these VDPVs except 7% of the 20–50 year cohort. Group 1 VDPVs were highly neurovirulent in a transgenic mouse model. Intermediate levels of protective immunity against Group 2 VDPVs correlated with fewer (5.0+1.0) amino acid substitutions in neutralizing antigenic sites than in Group 1 VDPV's (12.1±1.5). SIGNIFICANCE: VDPVs that revert from live oral attenuated vaccines and reacquire characteristics of wild-type polioviruses not only threaten populations with poor immune coverage, but are also a potential source for re-introduction of poliomyelitis into highly immune populations through older individuals with waning immunity. The presence of two independently evolved groups of VDPVs in Israel and the growing number of reports of environmental VDPV elsewhere make it imperative to determine the global frequency of environmental VDPV. Our study underscores the importance of the environmental surveillance and the need to reconsider the global strategies for polio eradication and the proposed cessation of vaccination

Onset of a pandemic: characterizing the initial phase of the swine flu (H1N1) epidemic in Israel

<p>Abstract</p> <p>Background</p> <p>The swine influenza H1N1 first identified in Mexico, spread rapidly across the globe and is considered the fastest moving pandemic in history. The early phase of an outbreak, in which data is relatively scarce, presents scientific challenges on key issues such as: scale, severity and immunity which are fundamental for establishing sound and rapid policy schemes. Our analysis of an Israeli dataset aims at understanding the spatio-temporal dynamics of H1N1 in its initial phase.</p> <p>Methods</p> <p>We constructed and analyzed a unique dataset from Israel on all confirmed cases (between April 26 to July 7, 2009), representing most swine flu cases in this period. We estimated and characterized fundamental epidemiological features of the pandemic in Israel (e.g. effective reproductive number, age-class distribution, at-risk social groups, infections between sexes, and spatial dynamics). Contact data collected during this stage was used to estimate the generation time distribution of the pandemic.</p> <p>Results</p> <p>We found a low effective reproductive number (<it>R</it>_{<it>e </it>}= 1.06), an age-class distribution of infected individuals (skewed towards ages 18-25), at-risk social groups (soldiers and ultra Orthodox Jews), and significant differences in infections between sexes (skewed towards males). In terms of spatial dynamics, the pandemic spread from the central coastal plain of Israel to other regions, with higher infection rates in more densely populated sub-districts with higher income households.</p> <p>Conclusions</p> <p>Analysis of high quality data holds much promise in reducing uncertainty regarding fundamental aspects of the initial phase of an outbreak (e.g. the effective reproductive number R_e, age-class distribution, at-risk social groups). The formulation for determining the effective reproductive number <it>R</it>_{<it>e </it>}used here has many advantages for studying the initial phase of the outbreak since it neither assumes exponential growth of infectives and is independent of the reporting rate. The finding of a low <it>R</it>_{<it>e </it>}(close to unity threshold), combined with identification of social groups with high transmission rates would have enabled the containment of swine flu during the summer in Israel. Our unique use of contact data provided new insights into the differential dynamics of influenza in different ages and sexes, and should be promoted in future epidemiological studies. Thus our work highlights the importance of conducting a comprehensive study of the initial stage of a pandemic in real time.</p

Possible Transmission of Pandemic (HIN1) 2009 Virus with Oseltamivir Resistance

To the Editor: In March 2009, a new strain of influenza A (H1N1) virus of swine origin emerged; the virus had crossed the species barrier to humans and acquired the capability of human-to-human transmission. Soon after, the World Health Organization raised the worldwide pandemic alert to level 6 (www.who.int/en), declaring the first influenza pandemic in the past 42 years. The virus was named influenza A pandemic (H1N1) 2009 virus. The illness caused by this virus is particularly dangerous for pregnant women and for patients with chronic diseases (1). The preferred treatment is a neuraminidase inhibitor, zanamivir or oseltamivir (2). Around the world, several dozen cases of resistance to oseltamivir in persons with or without exposure to the drug have been reported (3). However, only limited information is available with regard to initial infections with oseltamivir-resistant viruses (4). We report a case of possible human-to-human transmission of pandemic (H1N1) 2009 virus in Israel. After the recent discovery of oseltamivir-resistant strains, we conducted a retrospective study of oseltamivir-resistance mutations in viral RNA amplified from specimens from patients hospitalized&gt;1 week with pandemic (H1N1) 2009. All samples were first tested for the H275Y mutation by using an in-house real-time reverse transcription–PCR (RT-PCR) assay developed a

Antiviral Activity of 3(2H)- and 6-Chloro-3(2H)-Isoflavenes against Highly Diverged, Neurovirulent Vaccine-Derived, Type2 Poliovirus Sewage Isolates

BACKGROUND: Substituted flavanoids interfere with uncoating of Enteroviruses including Sabin-2 polio vaccine strains. However flavanoid resistant and dependent, type-2 polio vaccine strains (minimally-diverged), emerged during in vitro infections. Between 1998-2009, highly-diverged (8 to >15%) type-2, aVDPV(2)s, from two unrelated persistent infections were periodically isolated from Israeli sewage. AIM: To determine whether highly evolved aVDPV(2)s derived from persistent infections retained sensitivity to isoflavenes. METHODS: Sabin-2 and ten aVDPV(2) isolates from two independent Israeli sources were titered on HEp2C cells in the presence and absence of 3(2H)- Isoflavene and 6-chloro-3(2H)-Isoflavene. Neurovirulence of nine aVDPV(2)s was measured in PVR-Tg-21 transgenic mice. Differences were related to unique amino acid substitutions within capsid proteins. PRINCIPAL FINDINGS: The presence of either flavanoid inhibited viral titers of Sabin-2 and nine of ten aVDPV(2)s by one to two log(10). The tenth aVDPV(2), which had unique amino acid substitution distant from the isoflavene-binding pocket but clustered at the three- and five-fold axies of symmetry between capsomeres, was unaffected by both flavanoids. Genotypic neurovirulence attenuation sites in the 5'UTR and VP1 reverted in all aVDPV(2)s and all reacquired a full neurovirulent phenotype except one with amino acid substitutions flanking the VP1 site. CONCLUSION: Both isoflavenes worked equally well against Sabin 2 and most of the highly-diverged, Israeli, aVDPV(2)s isolates. Thus, functionality of the hydrophobic pocket may be unaffected by selective pressures exerted during persistent poliovirus infections. Amino acid substitutions at sites remote from the drug-binding pocket and adjacent to a neurovirulence attenuation site may influence flavanoid antiviral activity, and neurovirulence, respectively

Forty Five Percent of the Israeli Population were Infected with the Influenza B Victoria virus During the Winter season 2015-16

While infection with influenza A viruses has been extensively investigated, infections with influenza B viruses which are commonly categorized into the highly homologous Victoria and Yamagata lineages, are less studied, despite their considerable virulence. Here we used RT-PCR assays, hemagglutination inhibition assays and antibody titers to determine the levels of influenza B infection. We report of high influenza B Victoria virus prevalence in the 2015-16 winter season in Israel, affecting approximately half of the Israeli population. We further show that the Victoria B virus infected individuals of all ages and that it was present in the country throughout the entire winter season. The vaccine however included the inappropriate Yamagata virus. We propose that a quadrivalent vaccine, that includes both Yamagata and Victoria lineages, should be considered for future influenza vaccination

Neutralising capacity against Delta and other variants of concern following Comirnaty vaccination in health care workers, Israel

Since its emergence, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has been responsible for more than 170 million cases and 3.5 million deaths. During December 2020 the Comirnaty (BNT162b2 mRNA, BioNTech-Pfizer, Mainz, Germany/New York, United States (US)) vaccine was approved by the US Food and Drug Administration and shown to be 95% efficacious in preventing symptomatic coronavirus disease 2019 (COVID-19). Clinical and real-world data demonstrated 95% effectiveness of the mRNA- based vaccine against the original SARS-CoV-2 and the Alpha variant. Since December 2020, several SARS-CoV-2 variants have emerged and were classified by the World Health Organization (WHO) as variants of concern (VOC): Alpha (Phylogenetic Assignment of Named Global Outbreak (Pango) lineage designation B.1.1.7), first detected in the United Kingdom (UK), Beta (B.1.351) first documented in South Africa [5] and Gamma (P.1) initially detected in Brazil. Most recently, in April 2021, the Delta (B.1.617.2) variant was identified in India and classified on May 11 as VOC due to its fast spread and potential immune escape. Here, we describe the neutralising response of sera from healthcare workers without prior SARS-CoV-2 infection following a second vaccine dose against viral isolates of the Delta VOC, and compared it to the response against isolates of the original, the Alpha, Beta and Gamma VOCs

Genetic Divergence of Influenza A(H3N2) Amino Acid Substitutions Mark the Beginning of the 2016-2017 Winter Season in Israel

BACKGROUND: Influenza vaccine composition is reevaluated each year due to the frequency and accumulation of genetic changes that influenza viruses undergo. The beginning of the 2016-2017 influenza surveillance period in Israel has been marked by the dominance of influenza A(H3N2). OBJECTIVES: To evaluate the type, subtype, genetic evolution and amino acid substitutions of influenza A(H3N2) viruses detected among community patients with influenza-like illness (ILI) and hospitalized patients with respiratory illness in the first weeks of the 2016-2017 influenza season. STUDY DESIGN: Respiratory samples from community patients with influenza-like illness and from hospitalized patients underwent identification, subtyping and molecular characterization. Hemagglutinin sequences were compared to the vaccine strain, phylogenetic tree was created, and amino acid substitutions were determined. RESULTS: Influenza A(H3N2) predominated during the early stages of the 2016-2017 influenza season. Noticeably, approximately 20% of community patients and 36% of hospitalized patients, positive for influenza CONCLUSIONS: Characterization of the 2016-2017 A(H3N2) influenza viruses is imperative for determining the future influenza vaccine composition