Transmission of Zika virus (ZIKV) in the Americas was first confirmed in May 2015 in northeast Brazil. Brazil has had the highest number of reported ZIKV cases worldwide (more than 200,000 by 24 ...December 2016) and the most cases associated with microcephaly and other birth defects (2,366 confirmed by 31 December 2016). Since the initial detection of ZIKV in Brazil, more than 45 countries in the Americas have reported local ZIKV transmission, with 24 of these reporting severe ZIKV-associated disease. However, the origin and epidemic history of ZIKV in Brazil and the Americas remain poorly understood, despite the value of this information for interpreting observed trends in reported microcephaly. Here we address this issue by generating 54 complete or partial ZIKV genomes, mostly from Brazil, and reporting data generated by a mobile genomics laboratory that travelled across northeast Brazil in 2016. One sequence represents the earliest confirmed ZIKV infection in Brazil. Analyses of viral genomes with ecological and epidemiological data yield an estimate that ZIKV was present in northeast Brazil by February 2014 and is likely to have disseminated from there, nationally and internationally, before the first detection of ZIKV in the Americas. Estimated dates for the international spread of ZIKV from Brazil indicate the duration of pre-detection cryptic transmission in recipient regions. The role of northeast Brazil in the establishment of ZIKV in the Americas is further supported by geographic analysis of ZIKV transmission potential and by estimates of the basic reproduction number of the virus.
Background
This study aims to compare the efficiency of four oral fluid collection methods (Salivette, FTA Card, spitting and DNA‐Sal) to detect HBV DNA by qualitative PCR.
Materials and Methods
...Seventy‐four individuals (32 HBV reactive and 42 with no HBV markers) donated serum and oral fluid. In‐house qualitative PCR to detect HBV was used for both samples and commercial quantitative PCR for serum.
Results
HBV DNA was detected in all serum samples from HBV‐infected individuals, and it was not detected in control group. HBV DNA from HBV group was detected in 17 samples collected with Salivette device, 16 samples collected by FTA Card device, 16 samples collected from spitting and 13 samples collected by DNA‐Sal device. Samples that corresponded to a higher viral load in their paired serum sample could be detected using all oral fluid collection methods, but Salivette collection device yielded the largest numbers of positive samples and had a wide range of viral load that was detected.
Conclusion
It was possible to detect HBV DNA using all devices tested, but higher number of positive samples was observed when samples were collected using Salivette device, which shows high concordance to viral load observed in the paired serum samples.
In Brazil, the Amazon Basin is endemic for hepatitis D virus (HDV) infection; however, studies in other regions of the country are scarce. This study aims to map the seroepidemiological situation of ...anti‐Delta antibodies in chronic hepatitis B carriers in all five Brazilian geographic regions. Serum samples from 1240 HBsAg positive individuals (55.4% men; mean age 43.1 ± 13.4 years) from 24 of 26 Brazilian states were tested for the presence of anti‐Delta antibodies using a commercial immunoassay. Anti‐Delta antibodies were detected in 40 samples (3.2%; 52.5% female; mean age of 38.1 ± 13.8 years). Age less than 20 years was significantly associated with anti‐HDV positivity (P < 0.001). The distribution of anti‐Delta differed markedly in the diverse regions of the country. The highest prevalence of anti‐HDV was found in the North (8.5%; P < 0.001), followed by Central West (2.5%), Southeast (1.7%), Northeast (0.8%), and South (0.0%). Anti‐Delta antibodies were detected in 12 states, but more than 60% of the positive cases were observed in two states, Amazonas and Acre, located in the western portion of the Amazon region. The overall HDV prevalence of 3.2% emphasizes that HDV is far from being a disease under control in Brazil. Despite the low HDV prevalence in non‐endemic regions, this infection persists as a major concern in two states (Acre and Amazonas) in the north of the country, indicating that a continuous epidemiological surveillance program should be implemented in all Brazilian regions.
With or without antiviral treatment, few individuals achieve sustained functional cure of chronic hepatitis B virus (HBV) infection. A better definition of what mediates functional cure is essential ...for improving immunotherapeutic strategies. We aimed to compare HBV-specific T cell responses in patients with different degrees of viral control.
We obtained blood from 124 HBV-infected individuals, including those with acute self-limiting HBV infection, chronic infection, and chronic infection with functional cure. We screened for HBV-specific T cell specificities by ELISpot, assessed the function of HBV-specific T cells using intracellular cytokine staining, and characterized HBV-specific CD4 T cells using human leukocyte antigen (HLA) class II tetramer staining, all directly ex vivo.
ELISpot screening readily identified HBV-specific CD4 and CD8 T cell responses in acute resolving infection compared with more limited reactivity in chronic infection. Applying more sensitive assays revealed higher frequencies of functional HBV-specific CD4 T cells, but not CD8 T cells, in functional cure compared to chronic infection. Function independent analysis using HLA multimers also identified more HBV-specific CD4 T cell responses in functional cure compared to chronic infection, with the emergence of CD4 T cell memory both after acute and chronic infection.
Functional cure is associated with higher frequencies of functional HBV-specific CD4 memory T cell responses. Thus, immunotherapeutic approaches designed to induce HBV functional cure should also aim to improve CD4 T cell responses.
Immunotherapy is a form of treatment that relies on harnessing the power of an individual’s immune system to target a specific disease or pathogen. Such approaches are being developed for patients with chronic HBV infection, in an attempt to mimic the immune response in patients who control HBV infection spontaneously, achieving a so-called functional cure. However, what exactly defines protective immune responses remains unclear. Herein, we show that functional cure is associated with robust responses by HBV-specific CD4 T cells (a type of immune cell).
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•HBV-specific CD4 T cells can be analysed directly ex vivo, without the need for in vitro expansion.•Functional HBV-specific CD4 T cell responses are stronger in functional cure vs. chronic infection.•MHC-class II multimers identify HBV-specific CD4 T cells reliably in HBsAg- patients, but rarely when HBsAg is present.•CD4 T cell immunity should be considered as a target for HBV immunotherapies.
Distinct molecular pathways govern the differentiation of CD8+ effector T cells into memory or exhausted T cells during acute and chronic viral infection, but these are not well studied in humans. ...Here, we employed an integrative systems immunology approach to identify transcriptional commonalities and differences between virus-specific CD8+ T cells from patients with persistent and spontaneously resolving hepatitis C virus (HCV) infection during the acute phase. We observed dysregulation of metabolic processes during early persistent infection that was linked to changes in expression of genes related to nucleosomal regulation of transcription, T cell differentiation, and the inflammatory response and correlated with subject age, sex, and the presence of HCV-specific CD4+ T cell populations. These early changes in HCV-specific CD8+ T cell transcription preceded the overt establishment of T cell exhaustion, making this signature a prime target in the search for the regulatory origins of T cell dysfunction in chronic viral infection.
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•Disease outcome and viral escape are linked to transcriptional differences in T cells•T cells from different outcomes share a core of co-regulated T cell identity genes•Metabolic, nucleosome, and immune genes are dysregulated early in chronic infection•Dysregulation correlates with sex, age, and presence of HCV-specific CD4 T cells
Wolski et. al show that transcriptional dysregulation of metabolic, nucleosomal, and immune processes in virus-specific CD8+ T cells during early persistent HCV infection is both under tight transcriptional control and associated with differences in predictors of disease outcome, like patient sex, age, and the presence of HCV-specific CD4+ T cells.
T cell exhaustion is associated with failure to clear chronic infections and malignant cells. Defining the molecular mechanisms of T cell exhaustion and reinvigoration is essential to improving ...immunotherapeutic modalities. Here we confirmed pervasive phenotypic, functional and transcriptional differences between memory and exhausted antigen-specific CD8
T cells in human hepatitis C virus (HCV) infection before and after treatment. After viral cure, phenotypic changes in clonally stable exhausted T cell populations suggested differentiation toward a memory-like profile. However, functionally, the cells showed little improvement, and critical transcriptional regulators remained in the exhaustion state. Notably, T cells from chronic HCV infection that were exposed to antigen for less time because of viral escape mutations were functionally and transcriptionally more similar to memory T cells from spontaneously resolved HCV infection. Thus, the duration of T cell stimulation impacts exhaustion recovery, with antigen removal after long-term exhaustion being insufficient for the development of functional T cell memory.
Serological evidence of hepatitis E virus infection (HEV) has been
observed in both humans and different animal species living in
non-endemic areas, suggesting that animals could be important ...reservoir
for virus transmission to man. Antibodies to HEV have been detected in
some Brazilian population groups. Nevertheless, sporadic cases of acute
HEV infection have never been reported. We collected 271 serum samples
from several domestic animals and also from pig handlers from Southeast
of Brazil in order to investigate the seroprevalence of HEV infection.
Anti-HEV IgG was detected in cows (1.42%), dogs (6.97%), chickens
(20%), swines (24.3%), and rodents (50%), as well as in pig handlers
(6.3%). The recognition of swine HEV infections in pigs in many
countries of the world led us to investigate a larger sample of pigs (n
= 357) from the same Brazilian region with ages ranging from 1 to >
25 weeks. IgG anti-HEV was detected in 100% of 7-day old pigs.
Following a gradual decline between weeks 2 and 8 (probably due to loss
of maternal IgG), the prevalence then steady increased until it reached
97.3% of animals older than 25 weeks. Besides the detection of anti-HEV
antibodies in different animal species, the results showed that swine
HEV infection seems to be almost universal within this Brazilian pig
population. This is the first report that shows evidences of HEV
circulation in Brazilian animal species and pig handlers.
Abstract Background Enzyme immunoassays (EIA) designed to detect hepatitis C virus (HCV) core antigen and anti-HCV antibodies (HCV AgAb) simultaneously can improve the early detection of HCV ...infection when molecular diagnostic methods are not widely available. Objectives To evaluate the suitability of dried blood spot (DBS) samples for detecting HCV AgAb using commercial EIAs. Study design Paired serum and DBS samples were assayed using two commercial EIAs for HCV AgAb (Monolisa™ HCV AgAb ULTRA and Murex HCV AgAb). Manufacturer's recommendations were followed for sera while sample volume, incubation time and cut-off (CO) determination were evaluated for the DBS samples. The values of sensitivity, specificity, inter-rater agreement, detection limit, assay precision and stability of DBS samples at different conditions (22–26 °C, 2–8 °C and −20 °C) were determined. Results It was necessary to increase the DBS sample volume fourfold compared to the sera samples to approximate the DBS Optical Density (OD) values to the sera OD values. Using ROC curve to recalculate CO values for the DBS samples, sensitivity was 97.5% for both EIAs, while the specificity was 99.71% for Monolisa™ HCV AgAb ULTRA and 95.95% for Murex HCV AgAb. Accurate testing results were obtained with DBS samples for 60 days at all conditions evaluated; storage at −20 °C resulted in low OD variation. Both EIAs demonstrated the same limit of detection among DBS samples estimated viral load of 3.1 International Units per millilitre (IU/mL) and low OD value variability in repetitivity and reproducibility studies. Conclusion DBS samples can be used for the detection of HCV AgAb by EIA as they present comparable performance characteristics and excellent stability among various storage conditions.
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