Long-lived memory T lymphocyte responses after hantavirus infection.
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Puumala virus (PUUV) is a hantavirus that causes hemorrhagic fever with renal syndrome (HFRS), which is an important public health problem in large parts of Europe. We examined the memory cytolytic T lymphocyte (CTL) responses in 13 Finnish individuals who had HFRS between 1984 and 1995. In seven of these donors, we detected virus-specific CTL responses against the PUUV nucleocapsid (N) protein after in vitro stimulation with PUUV. Six novel CD8(+) CTL epitopes were defined on the N protein and were found to be restricted by various HLA alleles including A2, A28, B7, and B8. This is the first demonstration of PUUV-specific CTL responses in humans, and the first identification of CTL epitopes on PUUV. In addition, this study provides one of the few characterizations of a human antiviral memory T cell response, without the complicating issues of virus persistence or reinfection. Interferon (IFN)-gamma ELISPOT analysis showed that memory CTL specific for these epitopes were present at high frequency in PUUV-immune individuals many years after acute infection in the absence of detectable viral RNA. The frequencies of PUUV-specific CTL were comparable to or exceeded those found in other viral systems including influenza, EBV and HIV, in which CTL responses may be boosted by periodic reinfection or virus persistence. (+info)
Hantaan virus antibody prevalence in rodent populations of several provinces of northeastern Thailand.
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We conducted a serological survey of 632 rodents from the northeast region of Thailand in order to assess the presence of Hantaan-like viruses that may be a risk to the human population. Rodents were collected from rice fields, houses and domestic gardens in five northeastern provinces and tested for IgG reacting sera to Hantaan antigen using enzyme-linked immunoassays. The overall prevalence of Hantavirus infection in rodents was 2.1% (13/632). Species that tested positive included Bandicota indica (4.3% positive within species), Rattus exulans (2.1%), R. losea (1.6%) and R. rattus (0.9%). Species such as R. exulans and R. losea are candidate hosts of unidentified Hantaan-like viruses in Thailand. (+info)
Pathogenic and nonpathogenic hantaviruses differentially regulate endothelial cell responses.
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Hantaviruses cause two human diseases: hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS). Hantaviruses infect human endothelial cells but cause little or no damage to the infected endothelium. We analyzed with Affymetrix DNA Arrays (Santa Clara, CA) the endothelial cell transcriptional responses directed by hantaviruses associated with HPS [New York-1 virus (NY-1V)], HFRS [Hantaan virus (HTNV)], or by a hantavirus not associated with human disease [Prospect Hill virus (PHV)]. Hantavirus infections induced 117 cellular genes and repressed 25 genes by >3-fold, 4 days postinfection (p.i.). Although >80% of cells were infected by each virus 1 day p.i., PHV induced or repressed 67 genes at this early time compared with three genes altered by HTNV or NY-1V. The early high-level induction of 24 IFN-stimulated genes by PHV (4- to 229-fold) represents a fundamental difference in the temporal regulation of cellular responses by pathogenic and nonpathogenic hantaviruses. Because all hantaviruses induced >23 IFN-stimulated genes at late times p.i., pathogenic hantaviruses appear to suppress early cellular IFN responses that are activated by nonpathogenic hantaviruses. At late times p.i., 13 genes were commonly induced by HTNV and NY-1V that were not induced by PHV. In contrast to NY-1V, HTNV uniquely induced a variety of chemokines and cell adhesion molecules (i.e., IL-8, IL-6, GRO-beta, ICAM), as well as two complement cascade-associated factors that may contribute to immune components of HFRS disease. NY-1V failed to induce most cellular chemokines directed by HTNV (3/14) or genes primarily activated by NF-kappaB. However, NY-1V uniquely induced beta3 integrin-linked potassium channels, which could play a role in HPS-associated vascular permeability. These studies provide a basic understanding of hantavirus-directed cellular responses that are likely to differentiate pathogenic and nonpathogenic hantaviruses, contribute to HFRS and HPS pathogenesis, and provide insight into disease mechanisms and potential therapeutic interventions. (+info)
Dinara - new natural focus of hemorrhagic fever with renal syndrome in Croatia.
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AIM: To investigate the characteristics and determine risk factors for hantanvirus infection in natural focus of hemorrhagic fever with renal syndrome (HFRS) on the Dinara Mountain, where outbreak of disease emerged among Croatian soldiers in 1995, and to describe the features of HFRS acquired on the Dinara mountain and determine the scale of the largest HFRS epidemic so far in Croatia. METHODS: During 1996, small mammals were captured in the region of Dinara Mountain where infected Croatian soldiers had sojourned. By taxonomic classification of 42 captured small mammals, three species were determined: 23 yellow-necked mouse, 9 wood mouse, and 5 bank vole. Hantavirus antigen was determined in the lungs of the captured animals by means of direct immunofluorescence assay. The most important features of HFRS were retrospectively determined in 37 soldiers with HFRS treated in the Department for Infectious Diseases of the Split University Hospital. The degree of inapparent exposure to infection was determined by indirect immunofluorescence in 103 soldiers sojourning in this region of natural focus with no apparent signs of HFRS. Epidemiological questionnaire included 50 soldiers with negative serum antibodies, as well as 33 available out of total 37 soldiers with HFRS. Chi-square test was used to determine risk factors. RESULTS: Hantavirus was found in the lungs of 5/42 (12%) captured animals. Mild form of the disease, with few hemorrhagic symptoms and pronounced renal insufficiency, was present in 19/37 patients. The epidemiological questionnaire determined the following risk factors for hantanvirus infection in this focus: service in artillery corps (p=0.040), sleep in wooden barracks (p=0.004), station in forest biotope (p=0.037), usage of natural camouflage (p=0.024), smoking (p=0.010), and the presence of rodents in the place of housing (p<0.001). CONCLUSION: A new natural focus of HFRS in Croatia, and the first one in Dalmatia, was defined by seroepidemiologic, mamologic, and virologic analysis. The risk factors for infection in the new focus have been identified. Our patients suffered from a mild form of HFRS, which predominates in south-eastern Europe, without lethal outcome. (+info)
Epidemiologic characteristics and military implications of hemorrhagic fever with renal syndrome in croatia.
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AIM: To analyze epidemiologic characteristics of hemorrhagic fever with renal syndrome in Croatia, including military implications of the disease and measures for its prevention. METHOD: We analyzed data from obligatory infectious disease reports and notification of deaths due to infectious diseases, data on the hemorrhagic fever with renal syndrome epidemics in Croatia, and data collected by survey of the population, serological findings, and studies of wild rodents serving as reservoirs of the infection. RESULTS: During the 1987-2001 period, 235 cases of hemorrhagic fever with renal syndrome were recorded in Croatia, with 147 (62.6%) of them among Croatian Army soldiers. Mortality rate was up to 15.4% (mean 2.2%) (5/235). The highest number of cases was recorded in months of June and July, ie, during the warm season characterized by increased activity of both the animals acting as infection reservoirs and humans as hosts. The known natural foci of hemorrhagic fever with renal syndrome have been Plitvice and Slunj areas, Velika and Mala Kapela mountains, Zagreb area (Velika Gorica and Jastrebarsko), west Slavonia, Novska area, and Dinara Mountain. The disease has not been recorded in the littoral area and Adriatic islands. The identified causative agents include Dobrava and Puumala viruses of the genus Hantavirus, whereas rodents Clethrionomys glareolus, Apodemus flavicollis, Apodemus agrarius, and Apodemus sylvaticus serve as the main reservoirs of the infection. Typical biotopes of the infection in Croatia are deciduous woods. The measures of prevention in Croatia include pest control, disinfection, hygienic waste disposal, preventing rodent access to food and water, proper choice of camping sites, and health education. CONCLUSION: Hemorrhagic fever with renal syndrome occurs predominantly in soldiers, in a sporadic or epidemic form. Because of the course of disease and potentially lethal outcome, the disease has a considerable impact on the field task performance and combat readiness of military units, and is of great importance for a military community. Accommodation in permanent buildings with appropriate common and personal hygiene standards is recommended. (+info)
Immune parameters in hemorrhagic fever with renal syndrome during the incubation and acute disease: case report.
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We describe immune parameters in a Croatian soldier who presented with mild flu-like symptoms and interstitial inflammatory infiltrate in the lungs on an X-ray during the incubation phase of hemorrhagic fever with renal syndrome (HFRS). Enzyme-linked immunosorbent assay (ELISA) IgM and polymerase chain reaction (PCR) were negative. Two weeks later, he developed HFRS caused by the Puumala virus. We performed two-color immunofluorescence cytometry with monoclonal antibodies identifying the activation markers on T cells. Serum samples were also examined by enzyme immunoassay (EIA) for the presence of interleukins IL-2 and IL-6 and their soluble receptors (sR). The analysis of early and late activation markers during the period of incubation revealed a small increase in the percentage of helper (CD4+CD25+) T cells and no significant increase in total activated (HLA-DR+TCR+) and cytotoxic (CD8+CD71+) T cells as compared with healthy controls. In the serum, only the concentration of soluble IL-6 receptor was increased. However, when the patient developed HFRS, all activation markers on T cells increased. Concentrations of sIL-2Ralpha and IL-6 remained increased two and six days after HFRS onset, respectively, whereas sIL-6R increased six days after HFRS onset. IL-2 concentration did not change. Our case indicates that rapid, modern diagnostic tools are necessary in the diagnosis of infectious diseases and their differential diagnosis. Immunological tests, which provide information on the patient immune status and especially on early changes in immune parameters, may contribute to the improvement of the diagnosis, prognosis, and therapy of HFRS. (+info)
Puumala hantavirus infection in humans and in the reservoir host, Ardennes region, France.
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We compared the occurrence of nephropathia epidemica cases, over a multi-annual population cycle, in northeastern France with the hantavirus serology for bank voles captured in the same area. We discuss hypotheses to explain the pattern of infection in both humans and rodents and their synchrony. (+info)
Use of vesicular stomatitis virus pseudotypes bearing hantaan or seoul virus envelope proteins in a rapid and safe neutralization test.
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A vesicular stomatitis virus (VSV) pseudotype bearing hantavirus envelope glycoproteins was produced and used in a neutralization test as a substitute for native hantavirus. The recombinant VSV, in which the enveloped protein gene (G) was replaced by the green fluorescent protein gene and complemented with G protein expressed in trans (VSVDeltaG*G), was kindly provided by M. A. Whitt. 293T cells were transfected with plasmids for the expression of envelope glycoproteins (G1 and G2) of HTNV or SEOV and were then infected with VSVDeltaG*G. Pseudotype VSV with the Hantaan (VSVDeltaG*-HTN) or Seoul (VSVDeltaG*-SEO) envelope glycoproteins were harvested from the culture supernatant. The number of infectious units (IU) of the pseudotype VSVs ranged from 10(5) to 10(6)/ml. The infectivity of VSVDeltaG*-HTN and VSVDeltaG*-SEO was neutralized with monoclonal antibodies, immune rabbit sera, and sera from patients with hemorrhagic fever with renal syndrome, and the neutralizing titers were similar to those obtained with native hantaviruses. These results show that VSVDeltaG*-HTN and -SEO can be used as a rapid, specific, and safe neutralization test for detecting hantavirus-neutralizing antibodies as an effective substitute for the use of native hantaviruses. Furthermore, the IU of VSVDeltaG*-HTN and -SEO did not decrease by more than 10-fold when stored at 4 degrees C for up to 30 days. The stability of the pseudotype viruses allows distribution of the material to remote areas by using conventional cooling boxes for use as a diagnostic reagent. (+info)