Viability of periodontal ligament cells in selected transport media for avulsed teeth: an in vitro study

To compare the viability of periodontal ligament (PDL) cells stored in Hanks Balanced Salt Solution (HBSS) with those in readily available transport media over a variable period of time. Methods: Periodontal ligament cells harvested from premolars freshly extracted for orthodontic reasons were cultured for exponential growth. The cells were exposed to egg white, evaporated milk, water and Hanks Balanced Salt Solution (HBSS) at room temperature. Their viability was evaluated after 30 minutes, 1 hour and 3 hours with the tetrazolium salt-based colorimetric assay (MTT assay). Statistical analysis was done using the IBM® SPSS version 23.0 software. Comparison between the Mean Optical Densities (MODs) of the cells stored in HBSS and other media at each time interval was done using the independent t test. Repeated measure ANOVA and Tukey post-hoc test were also carried out to compare the MOD of cells within each medium over time. The level of significance was set at p <0.05. Result: The PDL cells stored in egg white had higher MODs than those in HBSS at 30 minutes and 1 hour. Conversely, the MODs of the cells stored in milk and water were lower than those in HBSS at all the studied points. There was a significant difference in the viability of the cells stored in HBSS and water at all the time points (p<0.05). Conclusion: For up to an hour, egg white was found to perform better than HBSS in supporting the viability of PDL cell

Circulation of hepatitis B virus genotype-E among outpatients in tertiary hospitals in the Niger-Delta region of Nigeria.

Introduction: Hepatitis B virus (HBV) infection continues to be a significant public health challenge globally, with higher disease burden in developing countries. HBV genotypes are associated with different geographical regions and clinical outcomes. Limited information exists on epidemiology of HBV in the Niger-Delta region (South-South) of Nigeria. Consequently, this study was designed to characterise hepatitis B virus infection among outpatients in selected tertiary hospitals in the region. Methodology: Between June and August 2017, consenting nine hundred asymptomatic out-patients were enrolled and initially screened for HBV infection using one step Hepatitis B surface antigen (HBsAg) strip and subsequently re-tested using HBsAg and Hepatitis B core total antibody (anti-HBc) specific Enzyme-Linked Immunosorbent Assay (ELISA). Blood serum with detectable HBsAg were subsequently subjected to DNA extraction, S-gene amplification using a nested polymerase chain reaction (PCR) protocol, gel electrophoresis, sequencing and phylogenetic analysis. Results: Seroprevalence of HBsAg was 4.6% (95% CI 2.5-7.1) and anti-HBc was 10.1% (95% confidence interval (CI) 6.1-15.3). Of the 41 HBsAg positive samples subjected to DNA extraction and HBV S-gene specific PCR, only 6 (14.6%) yielded the expected ∼408bp band. Phylogenetic analysis based on HBV pre-S/S sequences identified all six typable samples as genotype E, subtype ayw4 of the West African clade. Conclusion: Results of the study confirm the presence and circulation of HBV genotype-E in the Niger-Delta region of Nigeria, thus corroborating the inclusion of the country in the Genotype E crescent. The authors advocate value-added HBV intervention in the region and the country at large.

VP7, VP4, and NSP4 genes of species a rotaviruses isolated from sewage in Nigeria, 2014/2015: partial sequence characterization and biophysical analysis of NSP4 (enterotoxin).

Species A rotavirus are an important cause of childhood gastroenteritis, and the main contributor to its pathogenicity is the enterotoxin (NSP4) protein. Some biophysical properties of partial NSP4 genes of RVAs isolated from sewage in Nigeria during 2014/2015 were investigated. Samples were typed by RT-PCR and Sanger sequencing of partial VP4, VP7 and NSP4 genes. Phylogeny identified lineages within genotypes, predicted glycosylation sites; hydrophobicity profiles and amino acid alignments were employed to determine some biophysical properties of the NSP4 protein. The VP7 sequences of our isolates were the most diversified, the majority of the isolates carried NSP4 genes of the E1 genotype. Genotype specific variations both in hydrophobicity and potential glycosylation were identified, mutations were highest within the H3 hydrophobic domain and VP4 binding domain. The study of RVA NSP4 genes from non-clinical samples revealed that there were structural consistencies with those of reference genes.

Multiple expansions of globally uncommon SARS-CoV-2 lineages in Nigeria.

Disparities in SARS-CoV-2 genomic surveillance have limited our understanding of the viral population dynamics and may delay identification of globally important variants. Despite being the most populated country in Africa, Nigeria has remained critically under sampled. Here, we report sequences from 378 SARS-CoV-2 isolates collected in Oyo State, Nigeria between July 2020 and August 2021. In early 2021, most isolates belonged to the Alpha "variant of concern" (VOC) or the Eta lineage. Eta outcompeted Alpha in Nigeria and across West Africa, persisting in the region even after expansion of an otherwise rare Delta sub-lineage. Spike protein from the Eta variant conferred increased infectivity and decreased neutralization by convalescent sera in vitro. Phylodynamic reconstructions suggest that Eta originated in West Africa before spreading globally and represented a VOC in early 2021. These results demonstrate a distinct distribution of SARS-CoV-2 lineages in Nigeria, and emphasize the need for improved genomic surveillance worldwide.

Coincident rapid expansion of two SARS-CoV-2 lineages with enhanced infectivity in Nigeria.

The emergence of new SARS-CoV-2 variants with enhanced transmissibility or decreased susceptibility to immune responses is a major threat to global efforts to end the coronavirus disease 2019 (COVID-19) pandemic. Disparities in viral genomic surveillance capabilities and efforts have resulted in gaps in our understanding of the viral population dynamics across the globe. Nigeria, despite having the largest population of any nation in Africa, has had relatively little SARS-CoV-2 sequence data made publicly available. Here we report the whole-genome sequences of 74 SARS-CoV-2 isolates collected from individuals in Oyo State, Nigeria in January 2021. Most isolates belonged to either the B.1.1.7 Alpha "variant of concern" or the B.1.525 Eta lineage, which is currently considered a "variant of interest" containing multiple spike protein mutations previously associated with enhanced transmissibility and possible immune escape. Nigeria has the highest reported frequency of the B.1.525 lineage globally with phylogenetic characteristics consistent with a recent monophyletic origin and rapid expansion. Spike protein from the B.1.525 lineage displayed both increased infectivity and decreased neutralization by convalescent sera compared to Spike proteins from other clades. These results, along with indications that the virus is outpacing the B.1.1.7 lineage in Nigeria, suggest that the B.1.525 lineage represents another "variant of concern" and further underline the importance of genomic surveillance in undersampled regions across the globe.

Characterization of hepatitis delta virus strains spreading in Abuja, Nigeria.

Hepatitis delta virus (HDV) is responsible for the most severe form of liver disease in humans. So far, eight genotypes (HDV-1 to -8) have been individualized worldwide. Little is known about HDV strains that spread in Nigeria. HDV genotyping was performed in 15 anti-HDV positive samples from a cohort of 306 hepatitis B virus (HBV)-infected patients in Abuja (Nigeria). Phylogenetic analyses revealed 90% were HDV-1, two among them clustering with European/Asian HDV-1, the remaining one being HDV-6. It was also found that two members of a couple superinfected with the same HDV strain, were enveloped by two different HBV strains of genotype E.

Antiviral potentials of Lactobacillus plantarum, Lactobacillus amylovorus, and Enterococcus hirae against selected Enterovirus.

Enteroviruses have been associated with a host of clinical presentations including acute flaccid paralysis (AFP). The site of primary replication for most enteroviruses is the gastrointestinal tract (GIT) and lactic acid bacteria (LAB) may confer protection in the GIT against them. This study therefore investigates the antiviral potential of some selected lactic acid bacteria against enterovirus isolates recovered from AFP cases. The antiviral activities of Lactobacillus plantarum, Lactobacillus amylovorus, and Enterococcus hirae in broth culture, their cell-free supernatant (CFS), and bacterial cell pellets were assayed against Echovirus 7 (E7), E13, and E19 in a pre- and post-treatment approach using cytopathic effect (CPE) and cell viability (MTT) assay. The tested Lactobacillus plantarum, Lactobacillus amylovorus, and Enterococcus hirae strains have good antiviral properties against E7 and E19 but not against E13. Lactobacillus amylovorus AA099 shows the highest activity against E19. The pre-treatment approach displays better antiviral activities compared to post-treatment approach. The LAB in broth suspension have better antiviral activities than their corresponding CFS and bacterial pellet. Lactic acid bacteria used in this study have the potential as antiviral agents.

High-Throughput Next-Generation Sequencing of Polioviruses.

The poliovirus (PV) is currently targeted for worldwide eradication and containment. Sanger-based sequencing of the viral protein 1 (VP1) capsid region is currently the standard method for PV surveillance. However, the whole-genome sequence is sometimes needed for higher resolution global surveillance. In this study, we optimized whole-genome sequencing protocols for poliovirus isolates and FTA cards using next-generation sequencing (NGS), aiming for high sequence coverage, efficiency, and throughput. We found that DNase treatment of poliovirus RNA followed by random reverse transcription (RT), amplification, and the use of the Nextera XT DNA library preparation kit produced significantly better results than other preparations. The average viral reads per total reads, a measurement of efficiency, was as high as 84.2% ± 15.6%. PV genomes covering >99 to 100% of the reference length were obtained and validated with Sanger sequencing. A total of 52 PV genomes were generated, multiplexing as many as 64 samples in a single Illumina MiSeq run. This high-throughput, sequence-independent NGS approach facilitated the detection of a diverse range of PVs, especially for those in vaccine-derived polioviruses (VDPV), circulating VDPV, or immunodeficiency-related VDPV. In contrast to results from previous studies on other viruses, our results showed that filtration and nuclease treatment did not discernibly increase the sequencing efficiency of PV isolates. However, DNase treatment after nucleic acid extraction to remove host DNA significantly improved the sequencing results. This NGS method has been successfully implemented to generate PV genomes for molecular epidemiology of the most recent PV isolates. Additionally, the ability to obtain full PV genomes from FTA cards will aid in facilitating global poliovirus surveillance.

Sabin Vaccine Reversion in the Field: a Comprehensive Analysis of Sabin-Like Poliovirus Isolates in Nigeria.

UNLABELLED: To assess the dynamics of genetic reversion of live poliovirus vaccine in humans, we studied molecular evolution in Sabin-like poliovirus isolates from Nigerian acute flaccid paralysis cases obtained from routine surveillance. We employed a novel modeling approach to infer substitution and recombination rates from whole-genome sequences and information about poliovirus infection dynamics and the individual vaccination history. We confirmed observations from a recent vaccine trial that VP1 substitution rates are increased for Sabin-like isolates relative to the rate for the wild type due to increased nonsynonymous substitution rates. We also inferred substitution rates for attenuating nucleotides and confirmed that reversion can occur in days to weeks after vaccination. We combine our observations for Sabin-like virus evolution with the molecular clock for VP1 of circulating wild-type strains to infer that the mean time from the initiating vaccine dose to the earliest detection of circulating vaccine-derived poliovirus (cVDPV) is 300 days for Sabin-like virus type 1, 210 days for Sabin-like virus type 2, and 390 days for Sabin-like virus type 3. Phylogenetic relationships indicated transient local transmission of Sabin-like virus type 3 and, possibly, Sabin-like virus type 1 during periods of low wild polio incidence. Comparison of Sabin-like virus recombinants with known Nigerian vaccine-derived poliovirus recombinants shows that while recombination with non-Sabin enteroviruses is associated with cVDPV, the recombination rates are similar for Sabin isolate-Sabin isolate and Sabin isolate-non-Sabin enterovirus recombination after accounting for the time from dosing to the time of detection. Our study provides a comprehensive picture of the evolutionary dynamics of the oral polio vaccine in the field. IMPORTANCE: The global polio eradication effort has completed its 26th year. Despite success in eliminating wild poliovirus from most of the world, polio persists in populations where logistical, social, and political factors have not allowed vaccination programs of sustained high quality. One issue of critical importance is eliminating circulating vaccine-derived polioviruses (cVDPVs) that have properties indistinguishable from those of wild poliovirus and can cause paralytic disease. cVDPV emerges due to the genetic instability of the Sabin viruses used in the oral polio vaccine (OPV) in populations that have low levels of immunity to poliovirus. However, the dynamics responsible are incompletely understood because it has historically been difficult to gather and interpret data about evolution of the Sabin viruses used in OPV in regions where cVDPV has occurred. This study is the first to combine whole-genome sequencing of poliovirus isolates collected during routine surveillance with knowledge about the intrahost dynamics of poliovirus to provide quantitative insight into polio vaccine evolution in the field.

Incidence of dengue virus infections in febrile episodes in Ile-Ife, Nigeria

Background: Dengue viruses have been identified as the most important arboviral pathogen in the world. They are transmitted by mosquitoes of Aedes species. While dengue infection is accompanied by little or no subclinical signs in many; about 1-2% may produce clinically severe Dengue Haemorrhagic Fever/Dengue Shock Syndrome. Early recognition; appropriate treatment and elimination of mosquito vectors will help control it. The study is aimed at determining the incidence of dengue infections in Ile-Ife. Materials and Methods: Three millilitres venous blood was collected from each of one hundred and seventy nine patients presenting with fever in the last two weeks; and analyzed for the presence of anti-dengue IgM antibodies using Dengue Virus IgM ELISA kit (DIA.PRO; Italy) according to the manufacturer's instructions while the results and demographic data were analyzed using SPSS version 16. Results: It was observed that 46 (25.7%) of the 179 had detectable IgM antibodies to dengue virus with 9 of them having no detectable malaria parasite. The incidence was 26.5% and 25% in male and female respectively. Further studies will be necessary to confirm the relatedness of blood transfusion as an important risk factor to the transmission of dengue virus.Conclusion: The study established the presence of fresh dengue infections for the first time in Ile-Ife among different groups of people. Clinicians are advised to prioritize laboratory diagnosis; especially of fever

Poliovirus and other enteroviruses in children infected with intestinal parasites in Nigeria.

INTRODUCTION: Poliovirus, an enterovirus, still persists in Nigeria despite the global efforts tailored towards its eradication. This study aimed to assess the impacts of poliovirus and other enteroviruses on the susceptibility of individuals to intestinal parasite infections. METHODOLOGY: A cross-sectional study on the prevalence of intestinal parasites was conducted on two-sample stool specimens of 717 Nigerian children (between 1 and 19 years of age) whose poliovirus/other enteroviruses infection status had been determined. RESULTS: The overall prevalence of Sabin poliovirus and other related enteroviruses infections were 6.6% and 13.8%, respectively. The prevalence of Ascaris lumbricoides was significantly higher than that of other intestinal parasites (p < 0.05), with children in the 0-4 year age group being the most predisposed age group to intestinal parasitic infection (OR = 11.7, CI = 9.2-15.0). While the prevalence of all species of parasites except S. mansoni showed no significant variations in children with Sabin poliovirus (p > 0.05), the prevalence of hookworms and Taenia spp. was significantly higher in children with other enteroviral infections (p < 0.05). CONCLUSIONS: The high risk of children of acquiring enteroviral infection through some intestinal parasites is an indication of possible association of the parasites in a more poliovirus-endemic population. A combined intervention approach for the two infections is advocated.

Measles Virus Infection Among Vaccinated and Unvaccinated Children in Nigeria.

This study investigated measles infection in vaccinated and unvaccinated children presenting with fever and maculopapular rash during measles outbreaks in the southern and western states of Nigeria. Measles, an acute viral illness caused by a virus in the family Paramyxoviridae, is a vaccine-preventable disease. Measles outbreak is common in Nigeria, despite the national immunization program. Children presenting with symptoms of measles infection in general hospitals and health centers in the states of southern and western Nigeria were recruited for this study. Vaccination history, clinical details, and 5 mL of blood were obtained from the children. Their sera samples were screened for specific immunoglobulin M antibodies to measles virus. Of 234 children tested (124 [53.2%] female), 133 (56.8%) had previously been vaccinated against measles virus, while 93 (39.7%) had not been vaccinated. Vaccination information for eight children could not be retrieved. One hundred and forty-three (62.4%) had measles IgM antibodies. Of these, 79 (55.3%) had been vaccinated for measles, while 65 (44.7%) had not. Despite the ongoing vaccination program in Nigeria, a high number of children are still being infected with measles, despite their vaccination status. Therefore, there is need to identify the reason for the low level of vaccine protection.

Effect of temperature and distance on the viral outcome of clinical specimens from acute flaccid paralysis cases in Nigeria.

AIM: The effect of cold box temperature and distance on virus titers, poliovirus isolation rate, and appearance of orphan polioviruses was investigated. METHODS: Cold boxes with stools were randomly selected and examined for internal temperature over a 7-month period. After virus isolation in Rhabdomyosarcoma (RD) cell line RDand L20B, titer calculations and intratypic differentiation were done on isolates. Sequencing and molecular studies were done on the isolates periodically in the order of arrival in the laboratory for a period of 30 months. RESULTS: Seventy-one (51.1%) boxes had the temperature range of 1 -4°C, 53 (38.1%) had 4.5 -8°C,. while 15 (10.8%) had temperature between 8.5°C and 17.0°C. Poliovirus was isolated from 24 (8.6%) specimens made up of 13 wild 1 and 2 and 11 Sabins 1, 2, 3 with titers between 10(1.8) and 10(5.4) TCID(50) /100 µl. Temperature and titer were inversely proportional and statistically significant. (r = -0.83, P < 0.05). Distance to laboratory was not significantly related (r = -0.025) to temperature when appropriate cold box temperature was maintained. Of the 18,188 acute flaccid paralysis (AFP) specimens received in the laboratory between June 2008 and December 2010, 1,752 poliovirus isolates (9.6%) consisting of 480 wild and 82 orphans were found. A positive correlation between the distance and orphan viruses (r = 0.425; P = 0.027) was observed. CONCLUSION: While poliovirus titer depends on the inside temperature of the cold box, distance to the laboratory was found to be a predisposing factor to the appearance of orphan viruses.

Prevalence of antibodies to influenza viruses among handlers of live pigs at three locations in Ibadan, Nigeria.

The authors investigated the prevalence of haemagglutination inhibition (HI) antibodies to four strains of influenza viruses among handlers of live pigs in Ibadan, Nigeria. Venous blood specimens were collected from thirty pig handlers (out of a total of forty-eight) at three locations in Ibadan in April and May 2008. The overall prevalence of antibodies to influenza viruses was 100%, while those of influenza A and B viruses were 68.3% and 58.3%, respectively. The prevalence of influenza A/Brisbane/59/2007 (H1N1), A/Brisbane/10/2007 (H3N2), B/Shanghai/361/2002-like and B/Malaysia/2506/2004-like was 46.7%, 90.0%, 76.7% and 40.0%, respectively. A total of 96.7% (n = 30) of pig handlers tested had polytypic influenza antibody reactions. This is the first report to document the prevalence of influenza antibodies among pig handlers in Nigeria and shows that humans who have regular and direct contact with live pigs in Ibadan are exposed to different strains of influenza viruses.

Isolation of influenza A viruses from pigs in Ibadan, Nigeria.

The authors investigated influenza virus types in pigs in Ibadan, a city in Oyo State, south-western Nigeria. From April to June 2008, nasal swabs were collected from pigs at three locations in Ibadan. Influenza A viruses (four A [H1N1], two A [H3N2] and one A [H1N1]-A [H3N2] double reactant) were isolated from 7 of the 50 apparently healthy Landrace pigs tested. This study is the first documented isolation of swine influenza viruses in Nigeria and it reveals that different strains of influenza viruses co-circulate in pigs in Ibadan. These pigs serve as reservoirs of different subtypes of influenza viruses and potential 'mixing vessels' in which genetic reassortment and the generation of future human pandemic strains could occur. These findings support the need for adequate and periodic surveillance among swine populations and pig handlers in Nigeria to detect circulating strains of influenza viruses. This would serve as an effective early warning system.