Martin Schutten

Newly discovered coronavirus as the primary cause of severe acute respiratory syndrome

Summary Background The worldwide outbreak of severe acute respiratory syndrome (SARS) is associated with a newly discovered coronavirus, SARS-associated coronavirus (SARSCoV). We did clinical and experimental studies to assess the role of this virus in the cause of SARS. Methods We tested clinical and postmortem samples from 436 SARS patients in six countries for infection with SARSCoV, human metapneumovirus, and other respiratory pathogens. We infected four cynomolgus macaques (Macaca fascicularis) with SARS-CoV in an attempt to replicate SARS and did necropsies on day 6 after infection. Findings SARS-CoV infection was diagnosed in 329 (75%) of 436 patients fitting the case definition of SARS; human metapneumovirus was diagnosed in 41 (12%) of 335, and other respiratory pathogens were diagnosed only sporadically. SARS-CoV was, therefore, the most likely causal agent of SARS. The four SARS-CoV-infected macaques excreted SARS-CoV from nose, mouth, and pharynx from 2 days after infection. Three of four macaques developed diffuse alveolar damage, similar to that in SARS patients, and characterised by epithelial necrosis, serosanguineous exudate, formation of hyaline membranes, type 2 pneumocyte hyperplasia, and the presence of syncytia. SARS-CoV was detected in pneumonic areas by virus isolation and RT-PCR, and was localised to alveolar epithelial cells and syncytia by immunohistochemistry and transmission electron microscopy. Interpretation Replication in SARS-CoV-infected macaques of pneumonia similar to that in human beings with SARS, combined with the high prevalence of SARS-CoV infection in SARS patients, fulfill the criteria required to prove that SARS-CoV is the primary cause of SARS. Published online July 22, 2003 http://image.thelancet.com/extras/03art6318web.pdf

Spatial, Temporal, and Species Variation in Prevalence of Influenza A Viruses in Wild Migratory Birds

Although extensive data exist on avian influenza in wild birds in North America, limited information is available from elsewhere, including Europe. Here, molecular diagnostic tools were employed for high-throughput surveillance of migratory birds, as an alternative to classical labor-intensive methods of virus isolation in eggs. This study included 36,809 samples from 323 bird species belonging to 18 orders, of which only 25 species of three orders were positive for influenza A virus. Information on species, locations, and timing is provided for all samples tested. Seven previously unknown host species for avian influenza virus were identified: barnacle goose, bean goose, brent goose, pink-footed goose, bewicks swan, common gull, and guillemot. Dabbling ducks were more frequently infected than other ducks and Anseriformes; this distinction was probably related to bird behavior rather than population sizes. Waders did not appear to play a role in the epidemiology of avian influenza in Europe, in contrast to the Americas. The high virus prevalence in ducks in Europe in spring as compared with North America could explain the differences in virus–host ecology between these continents. Most influenza A virus subtypes were detected in ducks, but H13 and H16 subtypes were detected primarily in gulls. Viruses of subtype H6 were more promiscuous in host range than other subtypes. Temporal and spatial variation in influenza virus prevalence in wild birds was observed, with influenza A virus prevalence varying by sampling location; this is probably related to migration patterns from northeast to southwest and a higher prevalence farther north along the flyways. We discuss the ecology and epidemiology of avian influenza A virus in wild birds in relation to host ecology and compare our results with published studies. These data are useful for designing new surveillance programs and are particularly relevant due to increased interest in avian influenza in wild birds.

Sustained HBeAg and HBsAg Loss After Long-term Follow-up of HBeAg-Positive Patients Treated With Peginterferon α-2b

BACKGROUND & AIMS The aim of this study was to evaluate the long-term sustainability of response in patients with hepatitis B e antigen (HBeAg)-positive chronic hepatitis B treated with pegylated interferon (PEG-IFN) alpha-2b alone or in combination with lamivudine. METHODS All 266 patients enrolled in the HBV99-01 study were offered participation in a long-term follow-up (LTFU) study. Patients were treated with PEG-IFN alpha-2b (100 mug/wk) alone or in combination with lamivudine (100 mg/day) for 52 weeks. Initial response was defined as HBeAg negativity at 26 weeks posttreatment. For the LTFU study, patients had one additional visit after the initial study (mean interval, 3.0 +/- 0.8 years). RESULTS Of 266 patients enrolled in the initial study, 172 (65%) participated in the LTFU study. At LTFU, HBeAg and hepatitis B surface antigen (HBsAg) negativity were observed in 37% and 11% of 172 patients, respectively. Sixty-four patients were classified as initial responders and 108 as nonresponders. Among the initial responders, sustained HBeAg negativity and HBsAg loss were observed in 81% and 30%, respectively. Significantly higher rates of HBeAg negativity were observed in genotype A-infected initial responders compared with those with genotype non-A (96% vs 76%; P = .06) as well as HBsAg loss (58% vs 11%; P < .001). CONCLUSIONS HBeAg loss after treatment with PEG-IFN alpha-2b alone or in combination with lamivudine is sustained in the majority of patients and is associated with a high likelihood of HBsAg loss, particularly in genotype A-infected patients. Therefore, PEG-IFN alpha-2b remains an important treatment option in this era of nucleos(t)ide analogue therapy.

Mallards and highly pathogenic avian influenza ancestral viruses, northern Europe

Surveillance studies in wild birds help generate prototypic vaccine candidates and diagnostic tests.

Practical Considerations for High-Throughput Influenza A Virus Surveillance Studies of Wild Birds by Use of Molecular Diagnostic Tests

Influenza A virus surveillance studies of wild bird populations are essential to improving our understanding of the role of wild birds in the ecology of low-pathogenic avian influenza viruses and their potential contribution to the spread of H5N1 highly pathogenic avian influenza viruses. Whereas the primary results of such surveillance programs have been communicated extensively, practical considerations and technical implementation options generally receive little attention. In the present study, the data obtained from 39,490 samples were used to compare the impacts of variables such as the sampling procedure, storage and transport conditions, and the choice of molecular and classical diagnostic tests on the outcome of the results. Molecular diagnostic tests allowed estimation of the virus load in samples, which has implications for the ability to isolate virus. Virus isolation in embryonated eggs was more sensitive than virus isolation in cell cultures. Storage and transport conditions had less of an impact on diagnostics by the use of molecular tests than by the use of classical approaches. These findings indicate that molecular diagnostic tests are more sensitive and more reliable than classical tests. In addition, molecular diagnostic tests facilitated analyses in real time and allowed the discrimination of H5 influenza viruses with low and high pathogenicities without the need for virus isolation. Critical assessment of the methods used in large surveillance studies like this will facilitate comparison of the results between studies. Moreover, the lessons learned from current large-scale influenza A virus surveillance activities could be valuable for other pathogen surveillance programs in the future.

Vaccination with Rev and tat against AIDS

Intro: More than 15 years after the discovery of HIV-1 as the causative agent of AIDS, and numerous attempts to develop a vaccine, it has become clear that the efficacy of the currently considered HIV-1 vaccine candidates will generally be limited. This is at least in part due to the relative resistance of so-called primary HIV strains to neutralization by HIV-1 envelope specific antibodies: even the most potent HIV-1 neutralizing antibodies failed to provide protection in in vivo models, at concentrations that can be maintained for longer periods in human vaccinees.

Low Nevirapine Plasma Concentrations Predict Virological Failure in an Unselected HIV-1-Infected Population

ObjectiveTo assess the relationship between plasma nevirapine concentrations and plasma HIV-1 RNA response in HIV-1-infected patients.DesignAn observational cohort analysis.MethodsPlasma samples were obtained on a routine basis from 189 patients receiving nevirapine 200mg twice daily, and plasma nevirapine concentrations were measured with reversed phase high performance liquid chromatography. Patients were divided into two groups based on plasma nevirapine concentrations below (and equal to) or above 3 mg/L. The association between steady-state nevirapine concentrations and plasma HIV-1 RNA was determined by multi-variate analysis.ResultsOut of 189 patients, 13 (7%) had low nevirapine plasma concentrations and 176 patients had concentrations above 3 mg/L. In total, 22 (12%) patients showed virological failure and 8 patients (4%) discontinued nevirapine because of adverse effects. The risk of failure in patients with nevirapine plasma concentrations ≤3mg/L was increased (relative risk 5.0, 95% CI 1.8–13.7). Rashes and liver enzyme elevations each occurred in 8% of patients.ConclusionLow nevirapine drug concentrations are predictive of virological failure.

Host cell membrane proteins on human immunodeficiency virus type 1 after in vitro infection of H9 cells and blood mononuclear cells. An immuno-electron microscopic study.

Human immunodeficiency virus type 1 (HIV-1)-infected H9 and blood mononuclear cells (MNCs) were studied by immunogold electron microscopy for the presence of HIV-1 gag p24 protein, env gp41 and gp120 proteins, and host cell molecules CD4, CD11a, CD25, CD54, CD63, HLA class I and HLA-DR. Uninfected H9 cells and MNC membranes labelled for CD4, HLA class I and class II, and, at low density, CD11a and CD54; lysosomal structures in the cytoplasm labelled for CD63. The infected cell surface showed immunolabelling for HIV-1 proteins, as did budding particle-like structures. Immunogold labelling of the cell membrane for CD4 was almost non-existent. The level of immunolabelling for CD11a and CD54 on infected cells was greater than that on uninfected cells; this is presumably related to a state of activation during virus synthesis. Budding particle-like structures and free virions in the intercellular space were immunogold-labelled for all host cell markers investigated. This was confirmed by double immunogold labelling using combinations of HIV-1 gag p24 labelling and labelling for the respective host cell molecule. We conclude that virions generated in HIV-1-infected cells concentrate host-derived molecules on their envelope. Also molecules with a prime function in cellular adhesion concentrate on the virion.

Long-Term Therapy With Tenofovir Is Effective for Patients Co-Infected With Human Immunodeficiency Virus and Hepatitis B Virus

BACKGROUND & AIMS We investigated the long-term efficacy and renal safety of tenofovir disoproxil fumarate (TDF), administered to patients co-infected with human immunodeficiency virus and hepatitis B virus (HBV) as part of an antiretroviral therapy. METHODS We performed a multicenter, prospective cohort study of 102 patients co-infected with human immunodeficiency virus and HBV who were treated with TDF. RESULTS At baseline, 80% of patients had a detectable viral load (HBV DNA >20 IU/mL). Among patients positive for hepatitis B e antigen (HBeAg) (n = 67), 92% had a virologic response (HBV DNA <20 IU/mL) after 5 years of treatment. There was no difference between patients with or without lamivudine resistance at baseline (P = .39). Loss rates of HBeAg and hepatitis B s antigen (HBsAg) were 46% and 12%, respectively. Among HBeAg-negative patients (n = 15), 100% had a virologic response after 4 years of treatment and 2 (13%) lost HBsAg. Twenty subjects (20%, all HBeAg-negative) had undetectable HBV DNA at baseline; during a median follow-up period of 52 months (interquartile range, 41-63 mo), 19 (95%) maintained a virologic response and 2 (10%) lost HBsAg. Overall, one patient acquired a combination of resistance mutations for anti-HBV drugs and experienced a virologic breakthrough. Three (3%) patients discontinued TDF because of increased serum creatinine levels. The estimated decrease in renal function after 5 years of TDF therapy was 9.8 mL/min/1.73 m(2), which was most pronounced shortly after TDF therapy was initiated. CONCLUSIONS TDF, administered as part of antiretroviral therapy, is a potent anti-HBV agent with a good resistance profile throughout 5 years of therapy. Only small nonprogressive decreases in renal function were observed.

Development of a real-time quantitative RT-PCR for the detection of HIV-2 RNA in plasma

An assay is described for the quantification of human immunodeficiency virus type 2 (HIV-2) RNA in EDTA plasma based on RT-PCR using the Taqman real-time PCR detection method. As standard, an electron microscopically counted virus stock of HIV-2 strain NIHZ was used. The lower detection limit is 5 # 102 HIV-2 RNA copies per ml of EDTA plasma. The assay is linear within the range required (5 # 102-106 HIV-2 RNA copies/ml of EDTA plasma) with an intra assay variability of 2.5% and an inter-assay variability ranging from 2% at 106 copies to 7.5% at the lower detection limit. Three primer/probe combinations were developed to circumvent false negative samples due to nucleotide variation in the target sequence. Using these primer/probe sets enabled the detection of HIV-2 DNA sequences from all HIV-2 seropositive individuals and two out of five dual human immunodeficiency virus type 1 (HIV-1) and HIV-2 seropositive individuals visiting the University Hospital Rotterdam.