| 1. |
- Elfving, Kristina, et al.
(författare)
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Acute Uncomplicated Febrile Illness in Children Aged 2-59 months in Zanzibar : Aetiologies, Antibiotic Treatment and Outcome
- 2016
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Despite the fact that a large proportion of children with fever in Africa present at primary health care facilities, few studies have been designed to specifically study the causes of uncomplicated childhood febrile illness at this level of care, especially in areas like Zanzibar that has recently undergone a dramatic change from high to low malaria transmission.METHODS: We prospectively studied the aetiology of febrile illness in 677 children aged 2-59 months with acute uncomplicated fever managed by IMCI (Integrated Management of Childhood Illness) guidelines in Zanzibar, using point-of-care tests, urine culture, blood-PCR, chest X-ray (CXR) of IMCI-pneumonia classified patients, and multiple quantitative (q)PCR investigations of nasopharyngeal (NPH) (all patients) and rectal (GE) swabs (diarrhoea patients). For comparison, we also performed NPH and GE qPCR analyses in 167 healthy community controls. Final fever diagnoses were retrospectively established based on all clinical and laboratory data. Clinical outcome was assessed during a 14-day follow-up. The utility of IMCI for identifying infections presumed to require antibiotics was evaluated.FINDINGS: NPH-qPCR and GE-qPCR detected ≥1 pathogen in 657/672 (98%) and 153/164 (93%) of patients and 158/166 (95%) and 144/165 (87%) of controls, respectively. Overall, 57% (387/677) had IMCI-pneumonia, but only 12% (42/342) had CXR-confirmed pneumonia. Two patients were positive for Plasmodium falciparum. Respiratory syncytial virus (24.5%), influenza A/B (22.3%), rhinovirus (10.5%) and group-A streptococci (6.4%), CXR-confirmed pneumonia (6.2%), Shigella (4.3%) were the most common viral and bacterial fever diagnoses, respectively. Blood-PCR conducted in a sub-group of patients (n = 83) without defined fever diagnosis was negative for rickettsiae, chikungunya, dengue, Rift Valley fever and West Nile viruses. Antibiotics were prescribed to 500 (74%) patients, but only 152 (22%) had an infection retrospectively considered to require antibiotics. Clinical outcome was generally good. However, two children died. Only 68 (11%) patients remained febrile on day 3 and three of them had verified fever on day 14. An additional 29 (4.5%) children had fever relapse on day 14. Regression analysis determined C-reactive Protein (CRP) as the only independent variable significantly associated with CXR-confirmed pneumonia.CONCLUSIONS: This is the first study on uncomplicated febrile illness in African children that both applied a comprehensive laboratory panel and a healthy control group. A majority of patients had viral respiratory tract infection. Pathogens were frequently detected by qPCR also in asymptomatic children, demonstrating the importance of incorporating controls in fever aetiology studies. The precision of IMCI for identifying infections requiring antibiotics was low.
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| 2. |
- Alm, Erik, et al.
(författare)
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Universal Single-Probe RT-PCR Assay for Diagnosis of Dengue Virus Infections
- 2014
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Ingår i: PLoS Neglected Tropical Diseases. - : Public Library of Science (PLoS). - 1935-2727 .- 1935-2735. ; 8:12, s. e3416-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Dengue is a mosquito-borne viral disease that has become more prevalent in the last few decades. Most patients are viremic when they present with symptoms, and early diagnosis of dengue is important in preventing severe clinical complications associated with this disease and also represents a key factor in differential diagnosis. Here, we designed and validated a hydrolysis-probe-based one-step real-time RT-PCR assay that targets the genomes of dengue virus serotypes 1-4. Methodology/Principal Findings: The primers and probe used in our RT-PCR assay were designed to target the 39 untranslated region of all complete genome sequences of dengue virus available in GenBank (n=3,305). Performance of the assay was evaluated using in vitro transcribed RNA, laboratory-adapted virus strains, external control panels, and clinical specimens. The linear dynamic range was found to be 10(4)-10(11) GCE/mL, and the detection limit was between 6.0x10(2) and 1.1x10(3) GCE/mL depending on target sequence. The assay did not cross-react with human RNA, nor did it produce false-positive results for other human pathogenic flaviviruses or clinically important etiological agents of febrile illnesses. We used clinical serum samples obtained from returning travelers with dengue-compatible symptomatology (n = 163) to evaluate the diagnostic relevance of our assay, and laboratory diagnosis performed by the RT-PCR assay had 100% positive agreement with diagnosis performed by NS1 antigen detection. In a retrospective evaluation including 60 archived serum samples collected from confirmed dengue cases 1-9 days after disease onset, the RT-PCR assay detected viral RNA up to 9 days after appearance of symptoms. Conclusions/Significance: The validation of the RT-PCR assay presented here indicates that this technique can be a reliable diagnostic tool, and hence we suggest that it be introduced as the method of choice during the first 5 days of dengue symptoms.
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| 3. |
- Bergqvist, Cecilia, et al.
(författare)
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Multiplex Nucleic Acid Suspension Bead Arrays for Detection and Subtyping of Filoviruses
- 2015
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 53:4, s. 1368-1370
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Tidskriftsartikel (refereegranskat)abstract
- Here we describe multiplex suspension bead array systems that allow fast and reliable detection of reverse transcriptase (RT) PCR amplified filovirus genomes and also enable subtyping of Ebola virus species and Marburg virus strains. These systems have an analytical sensitivity equivalent to that of RT-PCR.
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| 4. |
- Clark, Andrew G., et al.
(författare)
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Evolution of genes and genomes on the Drosophila phylogeny
- 2007
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 450:7167, s. 203-218
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Tidskriftsartikel (refereegranskat)abstract
- Comparative analysis of multiple genomes in a phylogenetic framework dramatically improves the precision and sensitivity of evolutionary inference, producing more robust results than single-genome analyses can provide. The genomes of 12 Drosophila species, ten of which are presented here for the first time (sechellia, simulans, yakuba, erecta, ananassae, persimilis, willistoni, mojavensis, virilis and grimshawi), illustrate how rates and patterns of sequence divergence across taxa can illuminate evolutionary processes on a genomic scale. These genome sequences augment the formidable genetic tools that have made Drosophila melanogaster a pre-eminent model for animal genetics, and will further catalyse fundamental research on mechanisms of development, cell biology, genetics, disease, neurobiology, behaviour, physiology and evolution. Despite remarkable similarities among these Drosophila species, we identified many putatively non-neutral changes in protein-coding genes, non-coding RNA genes, and cis-regulatory regions. These may prove to underlie differences in the ecology and behaviour of these diverse species.
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| 5. |
- Enbom, Malin, et al.
(författare)
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Detection of Epstein-Barr virus, but not human herpesvirus 8, DNA in cervical secretions from Swedish women by real-time polymerase chain reaction
- 2001
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Ingår i: Sexually Transmitted Diseases. - : Ovid Technologies (Wolters Kluwer Health). - 0148-5717 .- 1537-4521. ; 28:5, s. 300-306
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Epstein-Barr virus (EBV) and human herpesvirus 8 (HHV-8) are two related herpesviruses that may be sexually transmitted. GOAL: To examine the presence of HHV-8 and EBV DNA in the female genital tract. STUDY DESIGN: Real-time polymerase chain reaction systems for quantification of DNA from HHV-8, EBV, and herpes simplex virus type 2 were developed and used for examination of cervical secretions from 112 Swedish women. HHV-8, EBV, and herpes simplex virus type 2 serology was also performed on samples from all subjects. RESULTS: EBV DNA was found in 10 cervical secretion samples, sometimes in high amounts. No cervical secretion or leukocyte sample contained detectable HHV-8 DNA. Antibodies to HHV-8-latent and -lytic antigens were found in 2.7 % and 24% of serum samples, respectively. CONCLUSION: This study supports a possible sexual route of transmission for EBV but not for HHV-8. The new real-time polymerase chain reaction systems could be valuable in future studies of relations between virus load and disease
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| 6. |
- Falk, Kerstin I
(författare)
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Epstein-Barr virus gene methylation and variation in latency
- 1997
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Epstein-Barr virus is a human herpesvirus and approximately 95 % of the adults carry the virus in a latent form. EBV has been implicated in the pathogenesis of human malignancies such as Burkitt's lymphoma and nasopharyngeal carcinoma. DNA methylation is one of the mechanisms that is involved in control of gene expression in viruses. We therefore investigated the methylation status of the EBV genome and determined the possible role of methylation in latent gene expression and activation. We have used two methods for analysing the methylation status of the EBV genome in cells with different forms of latency. One sequence-specific method based on restriction enzyme digestion was applied. The second method used involved chemical alteration of cytosines followed by sequencing. We examined two control regions of EBV for methylation: the origin of latent replication (ori P) and the LMP 1 regulatory sequence (LRS). In all cell lines and EBV-carrying tumours tested ori P was always found to be unmethylated, whereas the LRS was unmethylated in LMP1-expressing cells and methylated in LMP1-negative cells. Furthermore, we demonstrated that demethylation of the viral genome is independent of DNA replication. We can conclude from these studies that methylation is likely to play a role in the control of EBV-gene expression. A second aim of the thesis was to explore reliable and simple methods for detection of virus strain variation. We found a correlation between restriction fragment length polymorphisms (RFLPs) within exons coding for Epstein Barr virus nuclear antigen (EBNA) 1, EBNA 3, EBNA 6 and the size of the respective proteins. Based on the strong correlation between an n x 39 bp repeat in the EBNA 6-coding region and the size of the protein, we developed a polymerase chain reaction (PCR) assay over this repetitive sequence. We have shown that it is possible with our PCR-based method, to differentiate between types A and B and variants thereof in clinical samples. We have also shown by ELISA that a peptide derived from the n x 39 bp repeat is a major epitope for antibody reactivity.
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| 7. |
- Hammarin, Anna-Lena, et al.
(författare)
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Systematic Screening of BK Virus by Real-Time PCR Prevents BK Virus Associated Nephropathy in Renal Transplant Recipients
- 2011
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Ingår i: Journal of Medical Virology. - : Wiley. - 1096-9071 .- 0146-6615. ; 83:11, s. 1959-1965
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Tidskriftsartikel (refereegranskat)abstract
- BK virus associated nephropathy occurs in approximately 5% of renal transplant recipients. Quantitation of BKV DNA in serum/plasma early in the course of disease has been suggested to be an important diagnostic tool for polymavirus-associated nephropathy (PVAN). The aim of this study was to develop a BKV real-time PCR (qPCR), which could be included in a diagnostic qPCR platform. Additionally, the significance of the assay as a surrogate marker for PVAN was investigated. Quantitation of BKV DNA by qPCR was carried out on 234 serum samples from a retrospective study including 31 renal transplant recipients monitored for at least 6 months post-transplantation. BKV viremia was detected in 9 out of 31 patients. Four patients had a viral load of >10,000 copies/ml at least on one occasion. In two of these patients, PVAN was diagnosed clinically during the study period. In retrospect, these patients were shown to be BKV positive before the clinical diagnosis of PVAN was made. Another two patients had a permanent graft dysfunction, but were never clinically diagnosed with PVAN. None of the remaining five patients with BKV DNA (<10,000 copies/ml) had renal impairment. Based on these results, an algorithm was introduced at the study center in 2006 and to date, August 2011, no cases of PVAN with loss of graft have been observed. The concept of including different PCR protocols in a common qPCR platform allows laboratories with small sample numbers to perform regularly a variety of assays at a reasonable cost. Med. Virol. 83:1959-1965, 2011. (C) 2011 Wiley-Liss, Inc.
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| 8. |
- Jourdain, Elsa, et al.
(författare)
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Surveillance for West Nile virus in wild birds from northern Europe.
- 2011
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Ingår i: Vector Borne and Zoonotic Diseases. - : Mary Ann Liebert Inc. - 1530-3667 .- 1557-7759. ; 11:1, s. 77-79
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Tidskriftsartikel (refereegranskat)abstract
- A total of 1935 migratory birds from 104 different species were captured in southeastern Sweden in 2005-2006 and tested for antibodies against West Nile virus (WNV). Overall, 46 birds (2.4%; binomial confidence limits, 1.8-3.2) were positive by blocking-ELISA, but only 2 (0.10%; binomial confidence limits, 0.0-0.4) had antibodies detectable by both blocking-ELISA and WNV neutralization test. ELISA-positive birds included long- and short-distance migrants likely exposed to WNV while wintering in or migrating through areas enzootic for WNV. Exposure to a cross-reactive Flavivirus was suspected for short-distance migrants of the Turdidae family, but no cross-neutralization with tick-borne encephalitis and Usutu viruses was observed.
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| 9. |
- Kalbina, Irina, 1961-, et al.
(författare)
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Arabidopsis thaliana plants expressing Rift Valley fever virus antigens : Mice exhibit systemic immune responses as the result of oraladministration of the transgenic plants
- 2016
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Ingår i: Protein Expression and Purification. - San Diego, USA : Elsevier. - 1046-5928 .- 1096-0279. ; 127, s. 61-67
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Tidskriftsartikel (refereegranskat)abstract
- The zoonotic Rift Valley fever virus affects livestock and humans in Africa and on the Arabian Peninsula.The economic impact of this pathogen due to livestock losses, as well as its relevance to public health,underscores the importance of developing effective and easily distributed vaccines. Vaccines that can bedelivered orally are of particular interest.Here, we report the expression in transformed plants (Arabidopsis thaliana) of Rift Valley fever virusantigens. The antigens used in this study were the N protein and a deletion mutant of the Gn glycoprotein.Transformed lines were analysed for specific mRNA and protein content by RT-PCR and Westernblotting, respectively. Furthermore, the plant-expressed antigens were evaluated for their immunogenicityin mice fed the transgenic plants. After oral intake of fresh transgenic plant material, a proportionof the mice elicited specific IgG antibody responses, as compared to the control animals that were fedwild-type plants and of which none sero-converted.Thus, we show that transgenic plants can be readily used to express and produce Rift Valley Fever virusproteins, and that the plants are immunogenic when given orally to mice. These are promising findingsand provide a basis for further studies on edible plant vaccines against the Rift Valley fever virus.
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| 10. |
- Kinch, Amelie, et al.
(författare)
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Post-transplant lymphoproliferative disease and other Epstein-Barr virus diseases in allogeneic haematopoietic stem cell transplantation after introduction of monitoring of viral load by polymerase chain reaction
- 2007
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Ingår i: Scandinavian Journal of Infectious Diseases. - : Informa UK Limited. - 0036-5548 .- 1651-1980. ; 39:3, s. 235-244
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Tidskriftsartikel (refereegranskat)abstract
- The clinical value of monitoring of Epstein-Barr virus (EBV) viraemia by quantitative polymerase chain reaction during 1 y was evaluated. 39 recipients of allogeneic hematopoietic stem cell transplantation (SCT) were followed. More than 100 EBV genome equivalents (gEq)/ml in blood or plasma were found in 16/39 patients (41%) at 34 d (range 1-139) post-transplant. Seven of these 16 patients developed EBV disease; 3 post-transplant lymphoproliferative disease (PTLD), 1 myelitis, 1 encephalitis and 2 reactivations with fever. EBV diseases were only found in the high-risk group among recipients of mismatched related or unrelated donor grafts or in patients who underwent reduced-intensity conditioning. In this group, 3/20 (15%) developed PTLD. Conditioning with antithymocyte globulin was significantly associated with EBV disease (p<0.01). EBV load in plasma was more strongly associated with EBV disease than viral load in blood. A cut-off level of 1000 gEq/ml plasma distinguished EBV disease from asymptomatic viraemia, but not PTLD from other EBV diseases. Weekly monitoring of EBV load in plasma in high-risk patients in the first 3 months following SCT seems to be of value for prediction of EBV disease. Therapy for PTLD including rituximab was evaluated during 2 y and showed response in 4/6 cases.
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| 11. |
- Sikkema, Lisa, et al.
(författare)
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An integrated cell atlas of the lung in health and disease
- 2023
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Ingår i: Nature Medicine. - : Springer Nature. - 1078-8956 .- 1546-170X. ; 29:6, s. 1563-1577
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Tidskriftsartikel (refereegranskat)abstract
- Single-cell technologies have transformed our understanding of human tissues. Yet, studies typically capture only a limited number of donors and disagree on cell type definitions. Integrating many single-cell datasets can address these limitations of individual studies and capture the variability present in the population. Here we present the integrated Human Lung Cell Atlas (HLCA), combining 49 datasets of the human respiratory system into a single atlas spanning over 2.4 million cells from 486 individuals. The HLCA presents a consensus cell type re-annotation with matching marker genes, including annotations of rare and previously undescribed cell types. Leveraging the number and diversity of individuals in the HLCA, we identify gene modules that are associated with demographic covariates such as age, sex and body mass index, as well as gene modules changing expression along the proximal-to-distal axis of the bronchial tree. Mapping new data to the HLCA enables rapid data annotation and interpretation. Using the HLCA as a reference for the study of disease, we identify shared cell states across multiple lung diseases, including SPP1 + profibrotic monocyte-derived macrophages in COVID-19, pulmonary fibrosis and lung carcinoma. Overall, the HLCA serves as an example for the development and use of large-scale, cross-dataset organ atlases within the Human Cell Atlas.
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| 12. |
- Smedby, Karin Ekström, et al.
(författare)
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Variation in DNA repair genes ERCC2, XRCC1, and XRCC3 and risk of follicular lymphoma
- 2006
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Ingår i: Cancer Epidemiology, Biomarkers and Prevention. - 1055-9965 .- 1538-7755. ; 15:2, s. 258-265
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Tidskriftsartikel (refereegranskat)abstract
- The reasons for the positive association between skin cancer and non-Hodgkin's lymphoma are not known but may be due to common susceptibility involving suboptimal DNA repair. Therefore, we investigated selected polymorphisms and haplotypes in three DNA repair genes, previously associated with skin cancer and DNA repair capacity, in risk of follicular lymphoma, including possible gene interaction with cigarette smoking and sun exposure. We genotyped 19 single nucleotide polymorphisms (SNP) in the ERCC2, XRCC1, and XRCC3 genes in 430 follicular lymphoma patients and 605 controls within a population-based case-control study in Denmark and Sweden. Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated using unconditional logistic regression and haplotype associations were assessed with a global score test. We observed no associations between variation in the ERCC2 and XRCC1 genes and follicular lymphoma risk. In XRCC3, increased risk of follicular lymphoma was suggested for rare homozygotes of three SNPs [Rs3212024: OR, 1.8 (95% CI, 1.1-2.8); Rs3212038: OR, 1.5 (95% CI, 1.0-2.4); Rs3212090: OR, 1.5 (95% CI, 1.0-2.5)]. These results were strengthened in current cigarette smokers. However, evidence of differences in XRCC3 haplotype distributions between follicular lymphoma cases and controls was weak, both overall and in current smokers. We conclude that polymorphic variation in the XRCC3 gene, but not in ERCC2 or XRCC1, may be of importance for susceptibility to follicular lymphoma, perhaps primarily in current smokers. The link between skin cancer and follicular lymphoma is unlikely to be mediated through common variation in the studied DNA repair gene polymorphisms.
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| 13. |
- Strid, Åke, 1960-, et al.
(författare)
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Expression of Rift Valley Fever virus antigens in Arabidopsis thaliana for oral consumption
- 2012
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Ingår i: Molecular farming. - Bryssel : COST.
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Konferensbidrag (refereegranskat)abstract
- Rift Valley Fever (RVF) is a viral disease affecting both domesticated ruminants and humans. Since 1931, when the causative agent was first discovered in Kenya [1], there have been several severe outbreaks mostly in Sub-Saharan Africa [2]. RVF is now considered as one of Africa’s most important viral zoonoses and is endemic in large parts of the continent. In recent years, RVF has also emerged into Saudi Arabia and the Yemen, where it now is endemic [3]. Common symptoms of an ongoing RVF infection in humans are influenza-like, although more severe clinical manifestations such as hemorrhagic fever, ocular disease and encephalitis are often observed [4]. Outbreaks in livestock may have large economic impact. The etiological agent, the RVF virus (RVFV), is an enveloped negative sense RNA virus, which belongs to the genus Phlebovirus in the Bunyaviridae family. As the other members of this family, RVFV has three gene segments; the L, M, and S segments. The L segment encodes an RNA-dependent RNA polymerase and the M-segment the glycoproteins and a non-structural protein. By using an ambisense strategy, the S-segment codes for the highly immunogenic nucleocapsid protein (N) and a non-structural protein [4]. The main focus of this project is to establish the plant production of an RVF vaccine candidate, primarily for oral administration. This is an attractive model for vaccination, especially of livestock. The two currently available vaccines for animals are a live attenuated variant, albeit teratogenic, or a weaker inactivated vaccine which requires annual boosters. There is no human vaccine available for general use. Similarly to our previous expression studies with the HIV p24 protein [5-7], the Helicobacter pylori TonB protein [8], and the Chlamydia trachomatis MOMP chimera [9], we have used Agrobacterium tumefaciens-mediated gene transfer to introduce genes encoding RVFV antigens into Arabidopsis thaliana. Transformed model plants have been created that express the full length RVFV N protein or deletion mutants of the two RVF glycoproteins. Analyses of transformants are on-going (PCR for genomic insertion, cDNA synthesis and RT-PCR for mRNA occurrence, and Western blotting for protein production) and in at least some cases have been shown to carry the corresponding recombinant protein. Mice are being fed fresh transgenic A. thaliana and the subsequent immune response towards the N protein and the glycoproteins will be closely monitored and evaluated by neutralisation test, Western blot and ELISA. Thereafter, the mice will be challenged with the wild-type virus and the protective efficacy of the edible vaccine will be determined. References1. Daubney R, Garnham P (1931) J Patol Bacterio 34: 8922-8926; 2. Gerdes G (2004) Rev Sci Tech 23: 613-623; 3. Balkhy H, Memish Z (2003) Int J Antimicrob Agents 21: 153-157; 4. Flick R, Bouloy M (2005) Curr Mol Med 5: 827-834; 5. Lindh, I., Kalbina, I., Thulin, S., Scherbak, N., Sävenstrand, H., Bråve, A., Hinkula, J., Strid, Å. & Andersson, S. (2008) APMIS 116, 985-994; 6. Lindh, I., Wallin, A., Kalbina, I., Sävenstrand, H., Engström, P., Andersson, S. & Strid, Å. (2009) Prot. Expr. Purif. 66, 46-51; 7. Lindh, I., Andersson, S. & Strid, Å. (2010) In vivo 24, 368-370; 8. Kalbina, I., Engstrand, L., Andersson, S. & Strid, Å. (2010) Helicobacter 15, 430-437; 9. Kalbina I., Wallin A., Lindh I., Engström P., Andersson S. & Strid Å. (2011) Prot. Expr. Purif. 80, 194-202.
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| 14. |
- Waldenström, Jonas, et al.
(författare)
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Migrating birds and tickborne encephalitis virus
- 2007
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Ingår i: Emerging Infectious Diseases. - : Centers for Disease Control and Prevention (CDC). - 1080-6040 .- 1080-6059. ; 13:8, s. 1215-8
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Tidskriftsartikel (refereegranskat)abstract
- During spring and autumn 2001, we screened 13,260 migrating birds at Ottenby Bird Observatory, Sweden, and found 3.4% were infested with ticks. Four birds, each a different passerine species, carried tickborne encephalitis virus (TBEV)-infected ticks (Ixodes ricinus). Migrating birds may play a role in the geographic dispersal of TBEV-infected ticks.
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| 15. |
- Wallerström, Sofie, et al.
(författare)
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Detection of antibodies against H5 and H7 strains in birds : evaluation of influenza pseudovirus particle neutralization tests
- 2014
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Ingår i: Infection Ecology & Epidemiology. - : Informa UK Limited. - 2000-8686. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: Avian influenza viruses circulate in bird populations, and it is important to maintain and uphold our knowledge of the viral strains that are currently of interest in this context. Here, we describe the use of hemagglutinin-pseudotype retroviruses based on highly pathogenic influenza viruses for the screening of avian sera for influenza A antibodies. Our aim was also to determine whether the pseudovirus neutralization tests that we assessed were sensitive and simple to use compared to the traditional methods, including hemagglutination inhibition assays and microneutralization tests.MATERIAL AND METHODS: H5 and H7 pseudovirus neutralization tests were evaluated by using serum from infected rabbits. Subsequently, the assays were further investigated using a panel of serum samples from avian species. The panel contained samples that were seropositive for five different hemagglutinin subtypes as well as influenza A seronegative samples.RESULTS AND DISCUSSION: The results suggest that the pseudovirus neutralization test is an alternative to hemagglutination inhibition assays, as we observed comparable titers to those of both standard microneutralizations assays as well as hemagglutinin inhibition assays. When evaluated by a panel of avian sera, the method also showed its capability to recognize antibodies directed toward low-pathogenic H5 and H7. Hence, we conclude that it is possible to use pseudoviruses based on highly pathogenic avian influenza viruses to screen avian sera for antibodies directed against influenza A subtypes H5 and H7.
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