Virus In Human Population Research Articles

The role of RNA viruses in human cancers

Many RNA viruses have been reported to be oncogenic (or carcinogenic) in a variety of animal and human cancers. The increase in the incidence and prevalence of cancer-causing viruses in human populations can be known as a key precursor to the development of various cancers. The retrovirus family and Hepatitis C virus (HCV) are also reported to cause cancer. Viral oncoproteins such as Tax of HTLV 1 interacts with cellular ubiquitination complex such as cyclindromatosis tumor suppressor, ubiquitin-specific proteases 7, 11, 15 and 20, A-20 and signal-transducing adaptor molecule binding protein-like-1 in order to improve the cellular signaling pathways. The viral oncoproteins binding to DUB, leading to proliferation of virus-infected cells and cell transformation. Proto-oncogenes (c-onc genes) are the cellular form of v-onc genes. The activation of c-onc genes leads to cell growth. C-onc genes are transformed into an oncogenic form by viral infection. C-onc genes play some roles such as protein kinases, growth factors, growth factor receptors, and DNA binding proteins. The study of transforming retroviruses and their oncogenes and the multiple mechanisms deployed by other RNA viruses to use the growth-suppressive and proapoptotic function of tumor suppressor genes has been added to our current understanding of cancer biology. Oncogenic RNA viruses are important experimental models to study molecular investigation such as cellular networks, including the discovery of oncogenes and tumor suppressors. Understanding of different strategies of RNA viruses as well as the function of their proteins helps to make more extensive plans regarding the adoption of follow-up, prevention and treatment strategies in cancer patients caused by viral origin.

Deep mutational scanning reveals the functional constraints and evolutionary potential of the influenza A virus PB1 protein.

The influenza virus polymerase is important for adaptation to new hosts and, as a determinant of mutation rate, for the process of adaptation itself. We performed a deep mutational scan of the polymerase basic 1 (PB1) protein to gain insights into the structural and functional constraints on the influenza RNA-dependent RNA polymerase. We find that PB1 is highly constrained at specific sites that are only moderately predicted by the global structure or larger domain. We identified a number of beneficial mutations, many of which have been shown to be functionally important or observed in influenza virus' natural evolution. Overall, our atlas of PB1 mutations and their fitness impacts serves as an important resource for future studies of influenza replication and evolution.

Seroprevalence of Crimean-Congo Hemorrhagic Fever Virus and Rift Valley Fever Virus in human population in Senegal from October to November 2020

ObjectivesRift Valley Fever and Crimean-Congo Hemorrhagic Fever are two infections classified among the emerging diseases to be monitored with highest priority. Studies undertaken in human and animals have shown endemicity of these two arboviruses in several African countries. However, most of the investigations were carried out on domestic cattle and the studies conducted on human populations are either outdated or limited to a small number of well-known endemic areas. It is then critical to better evaluate the burden of these viruses in Senegal at a national scale. MethodsThis work relies on a previous seroprevalence survey undertaken in all regions of Senegal at the end of 2020. The existing biobank was used to determine the immunoglobulin G [IgG] Rift Valley Fever and Crimean-Congo Hemorrhagic Fever seroprevalences by indirect enzyme-linked immunosorbent assay. ResultsThe crude seroprevalences of Rift Valley Fever and Crimean-Congo Hemorrhagic Fever were 3.94% and 0.7% respectively, with the northern and central part of the countries as the main exposed areas. However, acute infections reported in both high and low exposed regions suggest sporadic introductions. ConclusionsThis study gives updated information and could be of interest to support the stakeholders in the management of these zoonoses.

Epidemiological survey and genetic characterization of type 3 vaccine-derived poliovirus isolated from a patient with four doses of inactivated polio vaccine in Henan Province, China

BackgroundVaccine-derived poliovirus (VDPV) is a potential threat to polio eradication because they can reintroduce into the general population and cause paralytic polio outbreaks, a phenomenon that has recently emerged as a prominent public health concern at the end of global polio eradication. This study aimed to describe the epidemiology and genetic characteristics of the first VDPV identified from a patient with acute flaccid paralysis (AFP), with four doses of inactivated polio vaccine immunization in Henan Province, China in 2017.MethodsThe patient was diagnosed with type 3 VDPV. Subsequently, a series of epidemiological approaches was implemented, including a retrospective search of AFP cases, rate of vaccination assessment, study of contacts, and supplementary immunization activities. Fecal samples were collected, viral isolation was performed, and the viral isolates were characterized using full-length genomic sequencing and bioinformatic analysis.ResultsPhylogenetic analysis showed that the viral isolates from the patient were different from other reported genetic clusters of type 3 VDPV worldwide. They were identified as a Sabin 3/Sabin 1 recombinant VDPV with a crossover site in the P2 region. Nucleotide substitutions, including U → C (472) and C → U (2493), have been identified, both of which are frequently observed as reversion mutations in neurovirulent type 3 poliovirus. A unique aspect of this case is that the patient had been vaccinated with four doses of inactive polio vaccine, and the serum neutralizing antibody for Sabin types 1 and 3 were 1∶16 and 1∶512, respectively. Thus, the patient was speculated to have been infected with type 3 VDPV, and the virus continued to replicate and be excreted for at least 41 d.ConclusionsThe existence of this kind of virus in human population is a serious risk and poses a severe challenge in maintaining a polio-free status in China. To the best of our knowledge, this is the first report of VDPV identified in the Henan province of China. Our results highlight the importance of maintaining a high-level vaccination rate and highly sensitive AFP case surveillance system in intercepting VDPV transmission.

Qualitative and quantitative analysis of wastewater viral contamination as a control element for the circulation of enteric viruses in the Republic of Belarus

Wastewater epidemiology is a new field of research that has great potential in the system of enteric virus surveillance. The purpose of the presented study was to analyze the results of wastewater monitoring of enteric viruses in 2020– 2021 in the Republic of Belarus. Detection and quantification of nucleic acids of rotaviruses A, noroviruses 1 and 2, enteroviruses and adenoviruses F were carried out using a quantitative real time RT-PCR followed by nucleic acid sequence genotyping. In 2020–2021, 487 (46.9 %) of 1038 wastewater samples contained nucleic acid of one or more viruses. The results indicated that there was a decrease in the circulating activity of the most enteric viruses in 2021 compared to 2020, likely due to stricter hygiene practices during the COVID-19 pandemic. Predominance of adenoviruses F in wastewater could be associated with their wide asymptomatic spread, on the one hand, and with greater resistance of pathogen DNA in the external environment, on the other. The quantitative analysis showed that the highest viral nucleic acid concentrations were found in hospital wastewater samples. According to the results of molecular typing, wastewater contained norovirus GII.4 [P16], adenovirus type 41, Coxsackievirus B3, B5 and Echovirus 13, the most common genotypes of enteric viruses in human population. Quantitative analysis and genotyping of nucleic acids of viruses from wastewater can be a source of valuable information for tracking their circulation in the human population to assess the current epidemiological situation and to predict its development in the short term.

Dengue virus circulation in West Africa: An emerging public health issue

Dengue is the most widespread arbovirosis in the world, with approximately 390 million cases per year, 96 millions of which have clinical manifestations and 25,000 deaths. In West Africa, the circulation of this virus in human populations was first reported in the 1960s in Nigeria. Clinical diagnosis of dengue in West Africa is made difficult by the existence of other diseases with similar clinical presentations. Biological diagnosis remains therefore the only alternative. This biological diagnosis requires high quality equipment and well-trained personnel, which are not always available in resource-limited countries. Thus, many cases of dengue fever are consistently reported as malaria, leading to mismanagement, which can have serious consequences on the health status of patients. It is therefore necessary to set up surveillance systems for febrile infections of unknown origin in Africa by strengthening the diagnostic capacities of national laboratories.

Detection of antibodies to duck tembusu virus in human population with or without the history of contact with ducks.

Duck tembusu virus (DTMUV) is an emerging duck pathogen in China and other Asian countries. It is unclear whether this emerging zoonotic infection poses a threat to humans. A previous study in 2012 showed surprisingly high rates of seropositivity and positive viral detection by RT-PCR in duck farm workers in China. To understand the nature of the threat of this emerging virus, we studied the neutralizing antibody response to a local isolate of DTMUV in an at-risk population, who were workers in duck farms and residents around farming areas in Central Thailand where DTMUV had been previously detected, and in a not-at-risk population, who were people living in the same or neighbouring province, but at a distance from the farms and who had no contact with ducks. The sera from the at-risk population showed higher anti-DTMUV neutralizing antibody titres as compared with those of the not-at-risk population. However, within the at-risk population, workers with direct contact with ducks did not show higher neutralizing titres than those without direct contact. Interestingly, some people in the not-at-risk group also displayed high neutralizing antibody titres to DTMUV. These sera were tested against other endemic Flaviviruses and showed no or low cross-reactivity suggesting the specificity of the neutralizing activity against DTMUV. These data raise a possibility of DTMUV as a potential zoonotic pathogen but the mode of transmission of the virus from ducks or other possible hosts to humans should be explored further.

Individual, household and environmental factors associated with arboviruses in rural human populations, Brazil.

Landscape change is one of the foremost drivers of the emergence of infectious diseases. Exploring demographic, household and environmental conditions under which infectious diseases occur may inform strategies to prevent disease emergence in human populations. We collected blood samples from 523 humans and explore factors for arbovirus emergence in Bahia, Brazil. The overall arbovirus seroprevalence was 65.2%, with the genus Flavivirus most prevalent (64.4%). Based on monotypic reactions, the population had contact with five arbovirus: Dengue 3, Ilheus, Oropouche, Caraparu and Eastern equine encephalitis virus. To our knowledge, this is the first study reporting exposure to Oropouche, Caraparu and Eastern equine encephalitis virus in human populations in Bahia, Northeast of Brazil. The best model fit demonstrated that household and environmental variables were more predictive of the risk of arbovirus exposure than demographic variables. The presence of forest and free-living monkeys in the areas close to the communities had a protective effect for the human population (i.e. lower seroprevalence). The dilution effect is considered as one explanation for this finding. These results highlight the important ecological role of wildlife-friendly agriculture.

Seroprevalence of hepatitis B virus in human population of district Buner Khyber Pakhtunkhwa Pakistan

Hepatitis B Virus is partially double standard DNA virus. It is a species of the genus Orthohepadnavirus and a member of the viral family Hepadnaviridae. This virus induces chronic liver infection known as hepatitis B which can finally leads to liver damage. Viral hepatitis is contagious infection it may transmit via blood transfusion, parental routes, and contaminated body fluids like saliva and semen. The current study was designed to determine the burden of HBV infection among people belongs to different areas of district Buner Khyber Pakhtunkhwa. A total of 6137 samples were collected from January 2017 to March 2018 in different Tehsils of district Buner. All the samples were tested for Anti-HBV antibodies using ICT and positive samples were then subjected to PCR to confirm active cases. About 139 (2.26%) individuals were found positive for antibodies in their sera and 107 (1.74%) were reconfirmed as active infection via PCR. On gender-based study, highest prevalence of HBV was found in male population 1.66%, while maximum incidence of infection was found in age group 1 month to 15 years 2.83%. According to the current study, the prevalence rate of HBV infection was low in Buner as compare to other districts of KP. The decreasing rate of HBV infection in Buner indicates awareness among the population about HBV infection.

Common European Origin of Hepatitis E Virus in Human Population From Eastern Romania.

The purpose of this research was to improve the epidemiological data on HEV infection in the human population in Romania. The analysis targeted hospitalized subjects with acute hepatitis (n = 94) of unknown etiology from the Infectious Diseases Regional Hospital in Iasi. Moreover, patients without liver disease (n = 40) from a different county hospital located in Eastern Romania were included. The presence of HEV infection and first characterization of human HEV strains was determined using serological and molecular assays. The apparent HEV seroprevalence varied between 29.16% (95% CI, 16.31–42.03) and 32.5% (95% CI, 17.98–47.02) according to patient grouping. Molecular analysis enhanced the detection of two HEV isolates, that clustered in subtype HEV-3c, the most commonly identified subtype in Europe. Identification of acute hepatitis E cases, together with the first detection and molecular characterization of human HEV in Romania represent the originality attributes of the present study.

Seroprevalence of Old World Hantaviruses and Crimean Congo Hemorrhagic Fever Viruses in Human Populations in Northwestern Ukraine.

In Ukraine, a retrospective review of clinical case reports by public health officials suggest that human cases of febrile illnesses associated with hemorrhage may be due to infections of Crimean-Congo hemorrhagic fever virus (CCHFV) and Old World hantaviruses. In a serosurvey of 966 healthy individuals in the Lviv Oblast, Ukraine, bordering Poland, we found that 1.6% showed cross-reactivity to hantaviral antigens by an immunofluorescence assay (IFA) and 1.7% of the study participants had antibodies cross-reactive to CCHFV by enzyme-linked immunosorbent assay (ELISA). Demographic variables and history of exposures obtained through questionnaires were assessed by logistic regression models for association with seroprevalence for both viruses with no significant risk factors found. Analysis of spatial distribution identified two clusters of samples positive for antibodies to both hantaviruses and CCHFV, which, however, were not statistically significant (p > 0.05). In general, the study results suggest that the population of the study area is exposed to hantaviruses and CCHFV. Further surveillance for respective pathogens in Ukraine is warranted and prospective surveillance of febrile patients with unidentified febrile illness.

A reliable and competitive mathematical analysis of Ebola epidemic model

The purpose of this article is to discuss the dynamics of the spread of Ebola virus disease (EVD), a kind of fever commonly known as Ebola hemorrhagic fever. It is rare but severe and is considered to be extremely dangerous. Ebola virus transmits to people through domestic and wild animals, called transmitting agents, and then spreads into the human population through close and direct contact among individuals. To study the dynamics and to illustrate the stability pattern of Ebola virus in human population, we have developed an SEIR type model consisting of coupled nonlinear differential equations. These equations provide a good tool to discuss the mode of impact of Ebola virus on the human population through domestic and wild animals. We first formulate the proposed model and obtain the value of threshold parameter mathcal{R}_{0} for the model. We then determine both the disease-free equilibrium (DFE) and endemic equilibrium (EE) and discuss the stability of the model. We show that both the equilibrium states are locally asymptotically stable. Employing Lyapunov functions theory, global stabilities at both the levels are carried out. We use the Runge–Kutta method of order 4 (RK4) and a non-standard finite difference (NSFD) scheme for the susceptible–exposed–infected–recovered (SEIR) model. In contrast to RK4, which fails for large time step size, it is found that the NSFD scheme preserves the dynamics of the proposed model for any step size used. Numerical results along with the comparison, using different values of step size h, are provided.

Current Views of Torque Teno Virus (TTV) in Liver Diseases

Aim of review . We review published evidence on the torque teno virus (TT virus, TTV), which was discovered in the late of the 20th century. Key points . TTV is frequently confirmed in patients with hepatitises of viral origin or no definite viral aetiology, as well as in healthy people. Particular biochemical and histological changes in hepatic tissue and bile duct epithelium are reported for TTV monoinfection, which suggest viral replication in hepatocytes. At the same time, no cytopathic effects inherent in pathogenic hepatotropic viruses were revealed in hybridisation assays with TTV-infected cells. Novel data incited novel opinions on the TTV interaction with human. Earlier views of hepatotropic TTV gradually changed with newer evidence on its dispersion and coinfection with other viruses, including known hepatitis agents. Polytropism of TTV disproves its exclusive attribution to hepatitis viruses. High prevalence of the virus in human population argues in favour of its non-pathogenic persistence in the human viriome. TTV DNA content in blood is proposed as an endogenous immune status marker to observe prior to organ transplantation. Conclusion . High TTV dispersion in human population suggests its persistence in the human viriome. Seldom observed damaging effect of TTV on hepatic cells and bile duct epitheliocytes may indirectly suggest its opportunistic pathogenic properties.

The effect of human mobility and control measures on the COVID-19 epidemic in China.

The ongoing COVID-19 outbreak expanded rapidly throughout China. Major behavioral, clinical, and state interventions have been undertaken to mitigate the epidemic and prevent the persistence of the virus in human populations in China and worldwide. It remains unclear how these unprecedented interventions, including travel restrictions, affected COVID-19 spread in China. We use real-time mobility data from Wuhan and detailed case data including travel history to elucidate the role of case importation on transmission in cities across China and ascertain the impact of control measures. Early on, the spatial distribution of COVID-19 cases in China was explained well by human mobility data. Following the implementation of control measures, this correlation dropped and growth rates became negative in most locations, although shifts in the demographics of reported cases were still indicative of local chains of transmission outside Wuhan. This study shows that the drastic control measures implemented in China substantially mitigated the spread of COVID-19.

COVID-19: what is next for public health?

COVID-19: what is next for public health?

Coronavirus disease-2019 pandemic: Tracing the source of viral infection and minimizing the possibility of reintroduction of virus in human population

The Corona Virus Disease-2019 (COVID-19) outbreak has overwhelmed the public health authorities and the health care delivery system of multiple nations. The ongoing pandemic is caused by one of the viruses - SARS-CoV-2, belonging to the coronaviruses family. The genetic sequence of the isolated virus was similar among all the initial patients from Wuhan, which clearly indicate that the outbreak began from a single point introduction among the humans. At present, it is critical to understand about the origin of the virus, as it is a novel viral infection. These findings will aid us in getting significant insights about the start of the outbreak or the origin of the virus and thus we will be able to mount a better public health emergency response. In conclusion, in order to contain the COVID-19 pandemic, it is vital to identify the source of the virus and then take appropriate prevention and control measures, otherwise there is always a potential risk of reintroduction of the virus in the future once again and then once again we might be facing the challenge of containing the outbreak.

Covid-19 pandemic: History, aetiology, epidemiology, vaccinology and societal impact

Covid-19 pandemic: History, aetiology, epidemiology, vaccinology and societal impact

The Ecology and Evolution of Influenza Viruses.

The patterns and processes of influenza virus evolution are of fundamental importance, underpinning such traits as the propensity to emerge in new host species and the ability to rapidly generate antigenic variation. Herein, we review key aspects of the ecology and evolution of influenza viruses. We begin with an exploration of the origins of influenza viruses within the orthomyxoviruses, showing how our perception of the evolutionary history of these viruses has been transformed with metagenomic sequencing. We then outline the diversity of virus subtypes in different species and the processes by which these viruses have emerged in new hosts, with a particular focus on the role played by segment reassortment. We then turn our attention to documenting the spread and phylodynamics of seasonal influenza A and B viruses in human populations, including the drivers of antigenic evolution, and finish with a discussion of virus diversity and evolution at the scale of individual hosts.

Japanese encephalitis virus: A multi-epitope loaded peptide vaccine formulation using reverse vaccinology approach

Japanese encephalitis (JE) is a serious leading health complication emerging expansively that has severely affected the survival rate of human beings. This fatal disease is caused by JE Virus (JEV). The current study was carried out for designing a multi-epitope loaded peptide vaccine to prevent JEV. Based on reverse vaccinology and in silico approaches, octapeptide B-cell and hexapeptide T-cell epitopes belonging to five proteins, viz. E, prM, NS1, NS3 and NS5 of JEV were determined. Hydrophilicity, antigenicity, immunogenicity and aliphatic amino acids of the epitopes were estimated. Further, the epitopes were analyzed for different physicochemical parameters, e.g. total net charges, amino acid composition and Boman index. Out of all the epitopes, a total of four T-cell epitopes namely KRADSS, KRSRRS, SKRSRR and KECPDE and one B-cell epitope i.e. PKPCSKGD were found to have potential for raising immunity in human against the pathogen. Taking into account the outcome of this study, the pharmaceutical industries could initiate efforts to combine the identified epitopes together with adjuvant or carrier protein to develop a multi-epitope-loaded peptide vaccine against JEV. The peptide vaccine, being cost effective, could be administered as a prophylactic measure and in JEV infected individuals to combat the spread of this virus in human population. However, prior to administration into human beings, the vaccine must pass through several clinical trials.

Mathematical approaches for optimization of dengue fever dynamics

Background and Objective: For dengue outbreak prevention and vectors reduction, fundamental role of control parameters like vaccination against dengue virus in human population and insecticide in mosquito population have been addressed theoretically and numerically. For this purpose, an existing model was modified to optimize dengue fever. Methodology: Using Pontryagin’s maximum principle, the dynamics of infection for the optimal control problem was addressed, further, defined cost functional, established existence of optimal control, stated Hamiltonian for characterization of optimization. Results: Numerical simulations for optimal state variables and control variables were performed. Conclusion: Our findings demonstrate that with low cost of control variables, state variable such as recovered population increases gradually and decrease other state variables for host and vector population.