Immunoperoxidase assay for the detection of specific IgG antibodies to Hantaan virus

Hantavirus: an increasing problem?

Hantaviruses are enveloped RNA viruses and members of the Bunyaviridae family. They are transmitted from various rodent hosts by inhalation of infected urine, saliva or faeces. Infection in rodent hosts is inapparent but persists for life. Person-to-person spread of hantavirus has not been described. Two main presentations of the disease occur. Haemorrhagic fever with renal syndrome (HFRS) is due to Hantaan, Seoul, Puumala, Porogia and Belgrade viruses. In general HFRS due to Hantaan, Porogia and Belgrade viruses is more severe and has higher mortality than that due to Puumala (nephropathia epidemica) or Seoul viruses. Hantaan is predominant in the Far East (Korea, Japan, China), Porogia and Belgrade in the Balkans, and Puumala in Western Europe; Seoul has a world-wide distribution. Hantavirus pulmonary syndrome (HPS) is a recently described infection with high mortality (60%) due to adult respiratory distress syndrome. The virus (Muerto Canyon Virus) is a hantavirus but different genotypically from previous strains. Management of hantavirus infections may require bed-rest, sedation, circulatory and ventilatory support and renal dialysis. Ribavirin if administered early in the illness may be of benefit.

IgG avidity assay for estimation of the time after onset of hantavirus infection in colonized and wild bank voles

An immunoglobulin G avidity assay was used to determine recent and past hantavirus infection in bank voles (Clethrionomys glareolus). Sera of experimentally infected bank voles were studied at different time intervals. The avidity of specific IgG increased over time after infection. This experimental data were used to estimate the time after onset of hantavirus infection in naturally infected bank voles caught in an endemic area. The possibility to discriminate between recently infected animals and animals infected some time ago is important since the proportion of recently infected bank voles represents the intensity of the epizootic which in turn correlates to the risk of humans to contract the disease.

Eradication of hantavirus infection among laboratory rats by application of caesarian section and a foster mother technique

Hantavirus antibodies were demonstrated by the indirect immunofluorescent antibody assay, in the serum of inbred strains of laboratory rats, during the period 1973-1982, at the Unit of Experimental Immunology in the Catholic University of Louvain, Brussels, Belgium. LOU rats, as well as immunocytomas, which were requested by laboratories in the U.K. and The Netherlands, were supplied at a time when the infection was unknown and unsuspected in Europe. Hantavirus-infected laboratory rats were rendered free of virus through re-derivation by caesarian section and suckling by virus-free foster mothers. Immunocytomas were tested for the presence of hantaviruses by implantation into seronegative laboratory rats. The strain of hantavirus causing the laboratory infection was clearly different from the one circulating in free-living bankvoles in Belgium. The exchange of laboratory rats and rat tumours in relation to the potential risk of laboratory-acquired hantavirus infection, is discussed.

Comparison of immunofluorescence and enzyme-linked immunosorbent assays for the serology of Hantaan virus infections

Three enzyme-linked immunosorbent assay (ELISA) systems based upon different principles were developed for the serology of Hantaan virus infections and compared with an indirect immunofluorescence assay (IFA). The indirect IFA was carried out with gamma-irradiated Hantaan virus-infected and uninfected Vero E6 cells fixed with ethanol (-70 degrees C) or acetone (20 degrees C) on drop slides and a FITC-coupled sheep anti-human Ig preparation. Atypical staining in the IFA was avoided by using ethanol (-70 degrees C) instead of acetone (20 degrees C) fixation. In the first ELISA ('cell-assay'), Hantaan virus-infected or uninfected Vero E6 cells were used as antigens, which after gamma-irradiation were seeded into microtiter ELISA strips. Serial dilutions of human sera were incubated and specific antibodies were demonstrated with a horseradish peroxidase (HRPO)-conjugated sheep anti-human Ig preparation. In the second ELISA ('competition-assay') an affinity-purified human Ig preparation was used as a capture antibody for Hantaan virus antigen. After incubation of serial dilutions of human sera with this coat, the reactivity of the affinity purified anti-Hantaan virus Ig coupled to HRPO was determined. In the third ELISA ('complex trapping blocking [CTB]-assay') the same capture antibody was used to react with a mixture of the antigen and serial dilutions of human sera. The reactivity with the same HRPO conjugate was then determined. The results obtained in the respective assay systems with sera from people at risk or suspected of Hantaan virus infection coincided well. The CTB-ELISA proved to be faster and more sensitive than both the other ELISA systems, without giving more non-specific reactions: it detected almost all the IFA positive samples.(ABSTRACT TRUNCATED AT 250 WORDS)