The pathogenesis of dengue virus infection is attributed to complex interplay between virus, host genes and host immune response. Host factors such as antibody-dependent enhancement (ADE), memory ...cross-reactive T cells, anti-DENV NS1 antibodies, autoimmunity as well as genetic factors are major determinants of disease susceptibility. NS1 protein and anti-DENV NS1 antibodies were believed to be responsible for pathogenesis of severe dengue. The cytokine response of cross-reactive CD4+ T cells might be altered by the sequential infection with different DENV serotypes, leading to further elevation of pro-inflammatory cytokines contributing a detrimental immune response. Fcγ receptor-mediated antibody-dependent enhancement (ADE) results in release of cytokines from immune cells leading to vascular endothelial cell dysfunction and increased vascular permeability. Genomic variation of dengue virus and subgenomic flavivirus RNA (sfRNA) suppressing host immune response are viral determinants of disease severity. Dengue infection can lead to the generation of autoantibodies against DENV NS1antigen, DENV prM, and E proteins, which can cross-react with several self-antigens such as plasminogen, integrin, and platelet cells. Apart from viral factors, several host genetic factors and gene polymorphisms also have a role to play in pathogenesis of DENV infection. This review article highlights the various factors responsible for the pathogenesis of dengue and also highlights the recent advances in the field related to biomarkers which can be used in future for predicting severe disease outcome.
There is strong evidence to suggest vertical and horizontal modes of transmission of human papilloma virus (HPV), an established etiologic agent of cervical cancer. Infants, children, and adults can ...acquire both high-risk and low-risk infections by birth or by close contact even though HPV is mainly transmitted sexually. A thorough review of the literature was performed to assess the possible non-sexual modes of transmission of HPV.
An electronic search of databases for review articles, cross-sectional studies, cohort studies, and case reports on non-sexual modes of transmission among sexually unexposed women and children was carried out using search terms such as "human papilloma virus, HPV, transmission, horizontal transmission, vertical transmission, and fomites". Articles published between 1983 and 2015 were retrieved.
Epidemiological and clinical data support various non-sexual modes of transmission especially at the time of birth and by close contact. Even though the role of fomites in the transmission of HPV is not well established, HPV-DNA positivity has been reported in transvaginal ultrasound probes and colposcopes after routine disinfection.
Awareness needs to be spread among the public about alternate modes of transmission. For a proper understanding of the exact natural history of HPV infection acquired via the non-sexual route, long-term prospective studies need to be undertaken.
Herbal plants, plant preparations and phytoconstituents have proved useful in attenuating infectious conditions and were the only remedies available, till the advent of antibiotics (many being of ...plant origin themselves). Among infectious diseases, viral diseases in particular, remain the leading cause of death in humans globally. A variety of phytoconstituents derived from medicinal herbs have been extensively studied for antiviral activity. Based on this rationale, an online search was performed, which helped to identify a large number of plant species harboring antiviral molecules. These herbal sources have been reported individually or in combinations across a large number of citations studied. Activities against rabies virus, Human immunodeficiency virus, Chandipura virus, Japanese Encephalitis Virus, Enterovirus, Influenza A/H1N1 and other influenza viruses were discovered during the literature search. This review includes all such plant species exhibiting antiviral properties. The review also encompasses composition and methodologies of preparing various antiviral formulations around the globe. An elaborate section on the formulations filed for patent registration, along with non-patented formulations, has also been included in this article. To conclude, herbal sources provide researchers enormous scope to explore and bring out viable alternatives against viral diseases, considering non-availability of suitable drug candidates and increasing resistance to existing drug molecules for many emerging and re-emerging viral diseases.
Respiratory syncytial virus (RSV) is a common cause of respiratory tract infections among children less than 5 years of age and the elderly. This study intended to determine the circulating genotypes ...of RSV among severe acute respiratory illness (SARI) cases during the period 2016–2018 in India, among hospitalized acute febrile illness cases of age ranging from 1 to 65 years. Throat/nasopharyngeal swab samples were subjected for testing RSV and subgroups by real-time reverse transcriptase polymerase chain reaction (RT-PCR), further sequencing and phylogenetic analysis were performed for the second hypervariable region of the G gene. RSV-A and B subtypes co-circulated during the years 2016, 2017, and 2018, with RSV-A as the dominant subtype in 2016, and RSV-B as the dominant subgroup in 2017 and 2018. Phylogenetic analysis revealed that the circulating genotypes of RSV were GA2 (16/16), of RSV-A, and GB5 (23/23) of RSV-B in the South, North, and Northeast region of India during the period between 2016 and 2018. Here we report the first study comprising the distribution of RSV-A and B genotypes in the different geographic regions of India among children and adults during the year 2016 to 2018. We also report GA2.3.7 lineage of GA2 genotype for the first time in India to the best of our knowledge.
Molecular surveillance of influenza viruses is essential for early detection of novel variants. The aim of the present study was to analyze the hemagglutinin gene of influenza A(H1N1)pdm09 and ...A(H3N2) viruses circulating during the 2017 season. To investigate the genetic diversity of hemagglutinin gene of influenza A(H1N1)pdm09 and A(H3N2) viruses from 2017 season, ten samples from each subtype were sequenced and analyzed. The season was predominated by influenza A(H1N1)pdm09 viruses. Ten samples were sequenced from each subtype and all sequenced influenza A(H1N1)pdm09 and A(H3N2) viruses belonged to clades 6B.1 and 3C.2a, respectively. Sequence analysis of H1 gene in comparison to 2010–2016 vaccine strain showed mutations K166Q and S188T (K180Q and S202T here) that most likely resulted in antigenic drift and emergence of variant viruses. H3 gene substitutions N137K, N187K, I422V, and G500E that define clade 3C.2a1 were detected during analysis of sequences in comparison to 2017–2018 vaccine strain of northern hemisphere. These substitutions contributed to the change of WHO’s recommendation of the 2018–2019 vaccine strain for northern hemisphere. The results of this study provide insights about the continuous genetic variability of the HA gene.
Chikungunya fever is a viral disease transmitted to humans by the bite of infected mosquitoes. The disease is characterized by fever, headache, rash, severe joint, and muscle pain. To evaluate the ...disease burden in the population and the effectiveness of public health measures, periodic seroprevalence surveys are essential. Chikungunya outbreaks were reported from many Asian countries since 2005, after more than three decades of disappearance. The study aimed to estimate the seroprevalence of the chikungunya virus in southern parts of Karnataka state, through demonstrating chikungunya virus‐specific neutralizing antibodies. A cross‐sectional study was carried out using 509 archived blood samples from a hospital‐based acute febrile illness surveillance project, representative of the period between June 2014 and 2018. The study reported a 3.7% seroprevalence of chikungunya virus‐neutralizing antibodies in Thirthahalli and Hosanagara taluks of South Karnataka. The low prevalence of chikungunya‐neutralizing antibodies indicates that a major population is unexposed and prone to future outbreaks.
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This study reports the low prevalence of chikungunya neutralising antibodies among the rural residents of Shimoga district of Karnataka, India indicating large number of susceptible individuals and hence possibility of outbreaks.
The causal association of human papillomavirus (HPV) in uterine cervical cancer was well established and this oncogenic virus was reported to be a biomarker for overall recurrence and central pelvic ...recurrence. The objective of the present systematic review and meta-analysis was to assess the role of HPV DNA testing in early detection of recurrence among cervical cancer survivors after radiotherapy.
We performed a systematic review and meta-analysis by means of searching electronic databases for published articles between January 1984 and June 2018, on the basis of standard systematic review guidelines prescribed by major agencies namely Cochrane Collaboration (https://www.cochrane.org) and Campbell Collaboration (https://www.campbellcollaboration.org). The meta-analysis component was further modified appropriately for the synthesis of sensitivity and specificity results.
A total of 1,055 cervical cancer cases who had received pelvic radiation with or without chemotherapy from ten cohort studies were evaluated. The overall pooled sensitivity and specificity of HPV DNA testing was 0.84 (95% confidence interval CI= 0.66-0.94) and 0.35 (95% CI=0.20-0.54) respectively. The positive likelihood ratio was 1.3 (95% CI=1.0-1.7) and the negative likelihood ratio was 0.45 (95% CI=0.18-1.10) with an estimated diagnostic odds ratio of 3 (95% CI=1-9).
The screening for HPV DNA testing during follow-up facilitates early detection of recurrence after radiotherapy.
There are inconsistent reports regarding the role of HPV in the origin and progression of oral squamous cell carcinoma (OSCC). The observed heterogeneity was mainly attributed to the social and ...cultural habits of the enrolled cases, discrepancies in the nature of samples procured and varying sensitivity of the assays employed for detection of HPV. The objective of this study was to assess the prevalence of HPV in OSCC in South West India. This was a cross sectional study conducted over a period extending from October 2015 to June 2017. This study involved Department of ENT-Head and Neck Surgery and Department of Virology, Manipal Academy of Higher Education. Fifty histologically confirmed oral squamous cell carcinoma patients undergoing wide local excision of the tumour were enrolled for the study. Intraoperatively 4–5 mm of tissue samples were transported in sterile normal saline at 4–80 °C. The primary screening of tissue samples was performed by nested PCR using PGMY09/11 consensus primers and GP5+/6+ consensus primers and TaqMan based real time multiplex PCR for HPV-16, HPV-18, HPV-31 and HPV-45. All samples tested negative for HPV DNA by conventional nested PCR and TaqMan based real-time Multiplex PCR ruling out four common HPV subtypes such as HPV-16, 18, 31, 45. We did not find presence of HPV DNA in the tissues of patients with OSCC from southwest India. However, studies with more geographic representation from other parts of India are required before generalising our findings.
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