Poliovirus Type Research Articles

ОЦЕНКА УРОВНЯ КОЛЛЕКТИВНОГО ИММУНИТЕТА У ДЕТЕЙ г. ЕКАТЕРИНБУРГА К ВАКЦИНОУПРАВЛЯЕМЫМ ИНФЕКЦИЯМ НА ФОНЕ РАСПРОСТРАНЕНИЯ ПАНДЕМИИ COVID-19

The vaccination is recognized as one of the most effective and cost-effective measures to prevent the emergence and spread of infectious diseases. There is a possibility that the COVID-19 pandemic may lead to disruption of the vaccination campaign against vaccine-preventable infections and the formation of herd immunity. The aim of the study is to assess the level of collective immunity to vaccine-preventable infections in children living in the city of Yekaterinburg, Russia, against the backdrop of the COVID-19 pandemic. Research materials and methods: an observational cohort retrospective study was conducted, which included the results of a survey of 520 children aged 1 to 18 years old in 2021 for the presence of antibodies (AB) to the pathogens of measles, whooping cough, mumps, diphtheria and poliomyelitis. As a comparison the study used materials from a survey of children conducted in 2007 - 2013 for the assessment of herd immunity to vaccine-preventable infections (n=298). So the total number of children examined was 818. Results: the proportion of seronegative individuals examined for the presence of IgG to the causative agent of diphtheria among children aged 1 to 6 years old was 6.3%, 7 to 14 years old - 4.0%, 15 to 17 years old - 0.7 % (p<0.001). The proportion of children with no antibodies to the measles virus is 11.9%, 7.6%, and 12.4%, respectively, in the age groups of 1 to 6/7 to 14/15 to 17 years old (p=0.02). The proportion of seronegative to the mumps virus among children of different ages lays within 12% to 23.8%. The share of children with the absence of protective antibody titers to the whooping cough pathogen was 51.1% in children aged 15 to 17 years old, 69.5% for 7 to 14 years old, and 62.5% for 1 to 6 years old (p<0.001). With a cut-off of 10%, the proportion of children unprotected from type I poliovirus was 9.1% in the 3 to 5 years old age group and 6.8% in the 11 to 17 years old age group. The proportion of seronegative to poliovirus type III was 11.2% and 23.9%, respectively, in the younger and older groups of children. Discussion: the most favorable state of herd immunity was found in relation to diphtheria. Alertness is caused by immunity to measles and mumps. The most alarming is the state of herd immunity to whooping cough. Conclusion: for the period 2012-2021 there was an increase in the number of children with protective antibodies to the pathogens of diphtheria, measles, mumps, and whooping cough. However, with the exception of diphtheria, in all of these infectious diseases, the level of seronegative individuals exceeds the recommended thresholds. A high proportion of seronegative individuals increases the risk of the emergence and spread of infectious diseases.

Emergence of vaccine-derived poliovirus in high-income settings in the absence of oral polio vaccine use

On June 22, 2022, the UK Health Security Agency announced that vaccine-derived poliovirus type 2 (VDPV2) had been repeatedly detected in sewage in London, UK.1 Several weeks later, the New York State Department of Health reported a case of acute flaccid paralysis caused by VDPV2 in an unvaccinated individual; the first case of poliomyelitis in almost a decade in the USA.2 A similar virus has also been detected in sewage from Jerusalem, Israel.3

Emergence of vaccine-derived poliovirus type 2 after using monovalent type 2 oral poliovirus vaccine in an outbreak response, Philippines.

ObjectiveIn response to an outbreak of circulating vaccine-derived poliovirus (cVDPV) type 2 in the Philippines in 2019–2020, several rounds of supplementary immunization activities using the monovalent type 2 oral poliovirus vaccine (OPV) were conducted for the first time in the Western Pacific Region. After use of the monovalent vaccine, the emergence of vaccine-derived poliovirus unrelated to the outbreak virus was detected in healthy children and environmental samples. This report describes the detection of this poliovirus in the Philippines after use of the monovalent type 2 OPV for outbreak response.MethodsWe describe the emergence of vaccine-derived poliovirus unrelated to the outbreak detected after supplementary immunization activities using the monovalent type 2 OPV. This analysis included virus characterization, phylogenetic analyses and epidemiological investigations.ResultsThree environmental samples and samples from six healthy children tested positive for the emergent vaccine-derived poliovirus. All isolates differed from the Sabin type 2 reference strain by 6–13 nucleotide changes, and all were detected in the National Capital Region and Region 4, which had conducted supplementary immunization activities.DiscussionSince the 2016 removal of type 2 strains from the OPV, vaccine-derived poliovirus outbreaks have occurred in communities that are immunologically naive to poliovirus type 2 and in areas with recent use of monovalent OPV. To prevent the emergence and further spread of cVDPV type 2, several interventions could be implemented including optimizing outbreak responses by using the monovalent type 2 OPV, accelerating the availability of the novel type 2 OPV, strengthening routine immunization using inactivated polio vaccine and eventually replacing OPV with inactivated poliovirus vaccine for routine immunization.

Recovery of enteroviruses and poliovirus in Harare sewage using the bag-mediated filtration system at the introduction of the inactivated polio vaccine in Zimbabwe

Environmental surveillance is a sensitive method for detecting circulating virus in the absence of clinical cases and is important for monitoring progress for poliovirus (PV) eradication. This study used the bag-mediated filtration system (BMFS) to determine PV and enterovirus (EV) prevalence in sewage at the transition from oral polio vaccine type 2 (OPV2) use to inactivated polio vaccine (IPV) use in Zimbabwe, and examined the correlation between environmental surveillance results and vaccination coverage of OPV. A total of 18 BMFS samples from 6 sampling sites were analysed for the presence of EV and PV via direct RT-qPCR, direct ITD (intratypic differentiation), and the WHO algorithm. EV prevalence in Harare wastewater was 88.9% (16/18) using direct RT-PCR, 61.1% (11/18) using direct ITD, and 77.8% (14/18) using the WHO algorithm. Of the 18 samples analysed using the WHO algorithm, 10 samples (55.6%) were positive for Sabin-like PV type 3 (SL3). Of these 10 samples, 2 were also positive for non-polio enteroviruses (NPEV), resulting in a total of 6 (33.3%) samples positive for NPEV and 4 negative. The sensitivity of isolation in detecting EVs in sewage was 92.9% when comparing direct RT-qPCR results to the WHO algorithm. Using direct ITD, two high-density, low-income sampling sites were negative for SL3 and one low-density, high-income sampling point was negative for SL3 using the WHO algorithm. There was a strong association between relative EV concentration and the number of OPV3 vaccine recipients (r = 0.8590; p = 0.0284) in sampled areas. This study demonstrated the ability of BMFS to detect PVs circulating in Harare wastewater at the beginning of the OPV–IPV switch and can be used to monitor potential reintroduction of wild PV or vaccine-derived PVs from endemic areas.

Antiviral Activity and Wound Healing Potential of a Traditionally Used Herbal Oil Blend

Objective: Complementary and alternative medicine (CAM) has an increasing usage in the last decades throughout the world. Herbal medicine, the most preferred CAM, is used in the treatment of various disorders by approximately eighty percent of the world's population. In this study, it was aimed to determine the antiviral activity and wound healing potential of a special herbal oil blend prepared from Olea europaea, Nigella sativa and Rosmarinus officinalis that has been used for centuries in Middle and East Anatolia. Materials and Methods: The nontoxic concentration of herbal blend was determined by MTS assay. This concentration was investigated for its wound healing potential using in vitro scratch assay. A scratch was made on cultured keratinocyte cell layer and the herbal blend was added to medium. Pictures of cells were taken at different time points. The antiviral activity was determined using Adenovirus type 5 and Poliovirus type 1. Virus titer was calculated by Spearman-Karber method. Results: The nontoxic concentration of the blend was found to show statistically higher wound healing rate in compare to control group at the end of 12, 24 and 36 hours. According to antiviral efficacy test, four log of reduction in virus titer was seen, which meant that the mixture was quite effective against the viruses used in the study. Conclusion: The study shows that the special herbal blend speed up wound healing rate and it also has antiviral activity.

Update on Pakistan Polio Eradication Initiative

The global polio eradication initiative (GPEI) was established in 1988 as a result of the declaration of commitment by the World Health Assembly. In Pakistan, National Emergency Action Plan [NEAP] coined the strategies under government directives to play a pivotal role in line with international requirements to make poliomyelitis extinct. At the program’s initiation, there were around 350,000 cases of polio reported annually. The incidence has fallen by 99% due to the immunization of more than 2.5 billion children worldwide. Poliovirus has three serotypes; two have already been eradicated (the last case of poliovirus type 2 was reported in 1999 and of poliovirus type 3 in 2012). Poliovirus transmission has ceased with the exception of Pakistan and Afghanistan. In April 2022, two cases of acute flaccid paralysis due to poliovirus type 1 have been reported in KPK province. In this communication, insight is provided regarding the issues that have contributed to this wild poliovirus resurgence after a 15-month gap and the way forward.

Modeling scenarios for ending poliovirus transmission in Pakistan and Afghanistan.

Pakistan and Afghanistan pose risks for international transmission of polioviruses as the last global reservoir for wild poliovirus type 1 (WPV1) and a reservoir for type 2 circulating vaccine-derived polioviruses (cVDPV2s). Widespread transmission of WPV1 and cVDPV2 in 2019-2020 and resumption of intensive supplemental immunization activities (SIAs) in 2020-2021 using oral poliovirus vaccine (OPV) led to decreased transmission of WPV1 and cVDPV2 as of the end of 2021. Using an established dynamic disease transmission model, we explore multiple bounding scenarios with varying intensities of SIAs using bivalent OPV (bOPV) and/or trivalent tOPV (tOPV) to characterize potential die out of transmission. This analysis demonstrates potential sets of actions that may lead to elimination of poliovirus transmission in Pakistan and/or Afghanistan. Some modeled scenarios suggest that Pakistan and Afghanistan could increase population immunity to levels high enough to eliminate transmission, and if maintained, achieve WPV1 and cVDPV2 elimination as early as 2022. This requires intensive and proactive OPV SIAs to prevent transmission, instead of surveillance followed by reactive outbreak response. The reduction of cases observed in 2021 may lead to a false sense of security that polio has already or soon will die out on its own, but relaxation of immunization activities runs the risk of lowering population immunity to, or below, the minimum die-out threshold such that transmission continues. Transmission modeling may play a key role in managing expectations and supporting future modeling about the confidence of no virus circulation in anticipation of global certification decisions.

Addressing vaccine inequities among Ukrainian refugees

Addressing vaccine inequities among Ukrainian refugees

Investigation of airport sewage to detect importation of poliovirus, Poland, 2017 to 2020

BackgroundPolioviruses are human pathogens which may easily be imported via travellers from endemic areas and countries where oral polio vaccine (OPV) is still routinely used to polio-free countries. Risk of reintroduction strictly depends on polio immunisation coverage. Sustaining a polio-free status requires strategies that allow rapid detection and control of potential poliovirus reintroductions.AimThe aim of this study was to apply environmental surveillance at an international airport in Poland to estimate the probability of poliovirus importation via air transport.MethodsBetween 2017 and 2020, we collected 142 sewage samples at Warsaw Airport. After sewage concentration, virus was isolated in susceptible cell cultures. Poliovirus isolates were characterised by intratypic differentiation and sequencing.ResultsSeven samples were positive for polioviruses. All isolates were characterised as Sabin-like polioviruses type 3 (SL-3). No wild or vaccine-derived polioviruses were found. The number of mutations accumulated in most isolates suggested a limited circulation in humans. Only one SL-3 isolate contained seven mutations, which is compatible with more than half a year of circulation.ConclusionSince OPV was withdrawn from the immunisation schedule in Poland in 2016, detection of SL-3 in airport sewage may indicate the events of importation from a region where OPV is still in use. Our study shows that environmental surveillance, including airport sewage investigation, has the capacity to detect emerging polioviruses and monitor potential exposure to poliovirus importation. Poliovirus detection in sewage samples indicates the need for sustaining a high level of polio immunisation coverage in the population.

Spatial analysis of genetic clusters and epidemiologic factors related to wild poliovirus type 1 persistence in Afghanistan and Pakistan.

Following the certification of the World Health Organization Region of Africa as free of serotype 1 wild poliovirus (WPV1) in 2020, Afghanistan and Pakistan represent the last remaining WPV1 reservoirs. As efforts continue in these countries to progress to eradication, there is an opportunity for a deeper understanding of the spatiotemporal characteristics and epidemiological risk factors associated with continual WPV1 circulation in the region. Using poliovirus surveillance data from 2017-2019, we used pairwise comparisons of VP1 nucleotide sequences to illustrate the spatiotemporal WPV1 dispersal to identify key sources and destinations of potentially infected, highly mobile populations. We then predicted the odds of WPV1 detection at the district level using a generalized linear model with structural indicators of health, security, environment, and population demographics. We identified evidence of widespread population mobility based on WPV1 dispersal within and between the countries, and evidence indicating five districts in Afghanistan (Arghandab, Batikot, Bermel, Muhamandara and Nawzad) and four districts in Pakistan (Charsada, Dera Ismail Khan, Killa Abdullah and Khyber) act as cross-border WPV1 circulation reservoirs. We found that the probability of detecting WPV1 in a district increases with each armed conflict event (OR = 1·024, +- 0·008), level of food insecurity (OR = 1·531, +-0·179), and mean degrees Celsius during the months of greatest precipitation (OR = 1·079, +- 0·019). Our results highlight the multidisciplinary complexities contributing to the continued transmission of WPV1 in Afghanistan and Pakistan. We discuss the implications of our results, stressing the value of coordination during this final chapter of the wild polio virus eradication initiative.

The sensitivity of acute flaccid paralysis surveillance - the case of South Sudan: retrospective secondary analysis of AFP surveillance data 2014-2019.

IntroductionSouth Sudan has made quite impressive progress in interrupting wild poliovirus and maintaining a polio-free status since the last case was reported in 2009. South Sudan introduced different complementary strategies to enhance acute flaccid paralysis (AFP) surveillance. Hence, the objective of this study is to evaluate the sensitivity of the surveillance system using the WHO recommended surveillance standard and highlight the progress and challenges over the years.Methodswe conducted a retrospective, descriptive, quantitative study design and used the available secondary AFP surveillance database.Resultsthe overall non-polio AFP rate was 6.2/100,000 children under 15 years old in the study period. The stool adequacy was maintained well above the certification level of surveillance. The two main surveillance performance indicators were met at the national level throughout the study period. In contrast, only five out of ten states persistently attained and maintained the two main surveillance performance indicators throughout the study period, while in 2019 all states achieved except for Jonglei state. During the analysis period, no wild poliovirus was isolated except two circulating Vaccine Derived Poliovirus Type 2 (cVDPV2) cases in 2014 and one Immunodeficiency Vaccine Derived Poliovirus Type 2 (iVDPV2) case in 2015. However, on average, three cases were classified as polio compatible with each year of the study.ConclusionSouth Sudan met the two key surveillance performance indicators and had a sensitive AFP surveillance system during the period studied. We recommend intensifying surveillance activities in the former conflict-affected states and counties to maintain polio-free status.

Acute flaccid paralysis surveillance performance from 2011 to 2020 in Jonglei State, South Sudan: progress and challenges encountered.

IntroductionSouth Sudan reported the last indigenous wild poliovirus (WPV) in 2001 in Unity State, while the country was part of Sudan. In addition, the country reported an imported case of WPV in 2004-2005 and 2008-2009. The WPV circulation in the state was interrupted in 2009 and the last case was reported in Ayod county. The country continues to be at risk of importation of circulating vaccine-derived poliovirus type 2 (cVDPV2). In 2014 and 2020 the country experienced an outbreak of cVDPV2, in which Jonglei state was one of the affected states. Four out of 50 (8%) cVDPV2 cases in 2020 were reported from Jonglei State. The purpose of this study is to review surveillance performance indicators of Jonglei and compare them with the WHO surveillance performance standard and other country´s surveillance performances.Methodsretrospective secondary data analysis was conducted using the Jonglei state Acute Flaccid Paralysis (AFP) surveillance case-based database from 2011 to 2020. The reason for selecting Jonglei is because it is one of the poor performing states and is chronically hit by flood and internal conflicts. Data analyses were carried out using the Microsoft Excel (2016) program, where descriptive analysis frequencies, tables, and graphs were generated.Resultsthe study revealed that 346 AFP cases were reported in the counties of Jonglei state from 2011 through 2020. Out of 11 counties, 11 (100%) of them have reported suspected AFP cases. Children under five years accounted for 275 (79%) of all cases. The male gender accounted for 175 (51%) of all cases. A total of 249 (72%) had received three or more doses of Oral Polio Vaccine (OPV). Non-Polio Acute Flaccid Paralysis (NPAFP) rate varies from 1.2 in 2014 to 4.4 cases per 100,000 children under 15 years in 2018. The stool adequacy ranges from 58% in 2020 to 100% in 2011.Conclusionthe performance of Jonglei´s AFP surveillance system did not meet the WHO recommended target for both major AFP surveillance indicators (non-polio AFP rate and stool adequacy) during the study period.

Notes from the Field: Initial Outbreak Response Activity Following Wild Poliovirus Type 1 Detection - Malawi, February 2022.

Notes from the Field: Initial Outbreak Response Activity Following Wild Poliovirus Type 1 Detection - Malawi, February 2022.

Re-emergence of poliomyelitis in the Ukraine, caused by circulating vaccine-derived poliovirus type 2 (cVDPV2)

On October 2nd, 2021, a case of circulating vaccine-derived poliovirus type 2 (cVDPV2) was notified to the World Health Organisation from the Rivne Oblast of Ukraine. The index case was a seventeen-month-old unvaccinated girl who had an onset of acute flaccid paralysis (AFP) on September 1st, 2021. A second cVDPV2 case of an unvaccinated 2-year-old boy was reported from Transcarpathia Oblast on December 13th, 2021, who subsequently developed AFP on December 24th, 2021. A further 19 close contacts were identified with cVDPV2 that did not develop AFP that were all linked to the index case. Poliomyelitis outbreaks have occurred infrequently in the Ukraine since 2015, after being certified polio-free in 2002. The current outbreak has occurred against the backdrop of suboptimal vaccination coverage across the Ukraine since the previous outbreak saw a serious vaccine push across the country. However, the latest vaccine push in February 2022 has stalled due to the Russia-Ukraine war, leaving citizens displaced in shelters and border crossings, unable to access healthcare or routine immunisations.

One Full or Two Fractional Doses of Inactivated Poliovirus Vaccine for Catch-up Vaccination in Older Infants: A Randomized Clinical Trial in Bangladesh.

BackgroundThe polio eradication endgame called for the removal of trivalent oral poliovirus vaccine (OPV) and introduction of bivalent (types 1 and 3) OPV and inactivated poliovirus vaccine (IPV). However, supply shortages have delayed IPV administration to tens of millions of infants, and immunogenicity data are currently lacking to guide catch-up vaccination policies.MethodsWe conducted an open-label randomized clinical trial assessing 2 interventions, full or fractional-dose IPV (fIPV, one-fifth of IPV), administered at age 9–13 months with a second dose given 2 months later. Serum was collected at days 0, 60, 67, and 90 to assess seroconversion, priming, and antibody titer. None received IPV or poliovirus type 2-containing vaccines before enrolment.ResultsA single fIPV dose at age 9–13 months yielded 75% (95% confidence interval [CI], 6%–82%) seroconversion against type 2, whereas 2 fIPV doses resulted in 100% seroconversion compared with 94% (95% CI, 89%–97%) after a single full dose (P < .001). Two doses of IPV resulted in 100% seroconversion.ConclusionsOur study confirmed increased IPV immunogenicity when administered at an older age, likely due to reduced interference from maternally derived antibodies. Either 1 full dose of IPV or 2 doses of fIPV could be used to vaccinate missed cohorts, 2 fIPV doses being antigen sparing and more immunogenic.Clinical Trial RegistrationNCT03890497.

Phytochemical study and evaluation of the antiviral activity of aqueous extracts of three medicinal plants; Xylopia aethiopica, Gliricidia sepium and Ocimum gratissimum used in Cote d'Ivoire

Background: The present work is part of the exploration of new antiviral molecules to combat antimicrobial resistance. In purpose, this study determined the phytochemical analysis, cytotoxicity and antiviral activity of extracts from three Ivorian medicinal plants; Gliricidia sepium, Ocimum gratissimum and Xylopia aethiopica against poliovirus 1, a non-enveloped RNA virus.&#x0D; Methodology: Aqueous extract of the three plants, which were identified at the herbarium of National Floristic Center Abidjan, was done using a previously described method. The precipitation or staining technique was used to highlight the chemical groups in the three extracts while the polyphenol content of each extract was assessed by the colorimetric method. Cytotoxicity and antiviral activity tests were performed in 96-well plates. Cytotoxicity of each extract on L20B (a genetically engineered mouse cell line) was determined by observation of the cell line carpet. Antiviral activity of three extracts against poliovirus type I was determined after 72 hours using an assay that measures inhibition of the cytopathic effect on cell culture.&#x0D; Results: The three plant extracts contain polyterpenes, sterols and polyphenols, flavonoids, catechetical tannins, saponosides and quinones but none of the extract contains gallic tannins. With the exception of O. gratissimum, alkaloids were found in extracts from the two other plants, and extract of G. sepium was richer in polyphenol than the other two extracts. The cell carpet of L20B after 72 hours contact period with three extracts remained intact at concentrations ranging from 2 to 1000 μg/ml. The aqueous extract of G. sepium showed higher antiviral activity on poliovirus 1 (74.569%) at 2µg/ml than the extracts of O. gratissimum (45.6112%) and X. aethiopica (44.5247%) after 72 hours of incubation.&#x0D; Conclusion: The extract of G. sepium showed potent antiviral activity against poliovirus 1 than that of O. gratissimum and X. aethiopica. This was justified by its higher polyphenol content than the two extracts.

Проблема поліомієліту: загроза чи реальність?

The relevance of infectious pathology in children in modern conditions has acquired new significant features. We are talking about the measles epidemic (2017–2019), then the incidence and mortality caused by the Covid-19 virus (since 2020), and now (autumn 2021–January 2022) – an outbreak of polio in Ukraine. Already in January 2022, the second case of polio in a child from Ukraine was confirmed, so we have two outbreaks (Rivne and Zakarpattia regions), where the level of vaccination is the lowest in the country. And it is one of the lowest in the Zakarpattia region, and the tendency to further decrease has been observed for the last 2 years. It was found that the children were infected with the second type of poliovirus. This has greatly alarmed ukrainian and foreign experts, as the previous active campaign on global vaccination has reduced the number of polio cases in the world by 99% (for the period 1988-2021). The risk of polio in Ukraine is still high. These circumstances motivate to update the knowledge of doctors on diagnostic issues, differential diagnosis, to improve the quality of diagnosis. In the context of a decrease in the activity of the vaccine company, a high percentage of asymptomatic course and carriers of the polio virus, difficulties in differential diagnosis, and the absence of etiopathogenetic therapy, the threat of the spread of this dangerous infection among the child population with serious long-term consequences is obvious. The only step that can make a real difference is the introduction of active action to close the gap in routine immunization coverage for children. No conflict of interests was declared by the author. Key words: children, polio, diagnosis, differential diagnosis.

Circulating vaccine derived polio virus type 1 outbreak, Saadah governorate, Yemen, 2020

BackgroundYemen has faced one of the worst humanitarian crises in the world since the start of the war in 2015. In 2020; 30 Vaccine Derived Polio Virus type 1 (VDPV1) isolates were detected in Saadah governorate. The aims are to characterize the outbreak and address the gaps predisposing the emergence and circulation of VDPV1 in Saadah governorate, Yemen.MethodA retrospective descriptive study of confirmed cases of VDPV1 between January and December 2020 was performed. Surveillance staff collected data from patient cases, contacts, as well as stool specimens that shipped to WHO accredited polio labs. Data of population immunity was also reviewed. The difference in days between the date of sample collection, shipment, and receiving lab result was used to calculate the average of delayed days for lab confirmation.ResultsFrom January to December 2020, a total of 114 cases of acute flaccid paralysis (AFP) were reported from 87% (13/15) districts, and cVDPV1 was confirmed among 26% (30) AFP cases. 75% (21) were < 5 years, 73% (20) had zero doses of Oral Polio Vaccine (OPV). The first confirmed case (3%) was from Saadah city, with paralysis onset at the end of January 2020 followed by 5 cases (17%) in March from another four districts, 8 cases (27%) in April, and 13 (43%) up to December 2020 were from the same five districts in addition to 3 (10%) form three new districts. The lab confirmation was received after an average of 126 days (71–196) from sample collection. The isolates differ from the Sabin 1 type by 17- 30 VP1 nucleotides (nt) and were linked to VDPV1 with 13 (nt) divergence that isolated in July 2020 from stool specimens collected before one year from contacts of an inadequate AFP case reported from Sahar district.ConclusionThe new emerging VDPV1 was retrospectively confirmed after one year of sample collection from Sahar district. Delayed lab confirmation, as well as the response and low immunization profile of children against polio, were the main predisposing factors for cVDPV1 outbreak. This outbreak highlights the need to maintain regular biweekly shipments to referral polio labs in the short-term, and the exploration of other options in the longer-term to enable the Yemen National Lab to fully process national samples itself.

Environmental Monitoring for Enteroviruses in Maputo, Mozambique-2018.

Due to the possibility of wild poliovirus importation from endemic regions and the high circulation of vaccine-derived poliovirus type 2 in the African region, Mozambique implemented a surveillance program to monitor the circulation of enteroviruses in the environment. From January to November 2018, a period that immediately preceded the cVDPV outbreak in Africa, 63 wastewater samples were collected from different areas in Maputo city. A total of 25 samples (39.7%) were positive based on cell culture isolation. Non-polio enteroviruses were found in 24 samples (24/25; 96%), whereas 1 Sabin-related poliovirus was isolated. Neither wild nor vaccine-derived poliovirus was detected. High circulation of EVB species was detected. Environmental surveillance in the One Health approach, if effectively applied as support to acute flaccid paralysis, can be a powerful aid to the public health system to monitor poliovirus besides non-polio enteroviruses in polio-free areas.

Разработка рекомбинантного онколитического штамма полиовируса 3-го типа с измененным клеточным тропизмом

Diffuse gliomas are incurable, prevalent, and aggressive central nervous system tumors. Therefore, the development of selective oncolytic viral strains for malignant neoplasms is highly relevant. This study aimed to create an oncolytic virus based on a vaccine strain of poliovirus type 3 with natural antitumor activity. To achieve this goal, we replaced the internal ribosome entry site (IRES) of poliovirus with the corresponding fragment of human rhinovirus 30. The resulting recombinant oncolytic strain RVP3 retained the serotype of poliovirus type 3, as confirmed by virus neutralization micro-test with specific antiserum. In addition, the oncolytic efficacy of RVP3 was assessed in vitro on a broad panel of cell cultures. According to the results, RVP3 has changed its tropism, losing the ability to replicate in conditionally normal cell lines of embryonic astrocytes and embryonic fibroblasts while retaining the ability to replicate in tumor cells.