An efficient method for isolation of Hantaan virus through serial passages in suckling mice.

OBJECTIVE: Hantaan virus (HTNV) is one of the main etiologic agents for hemorrhagic fever with renal syndrome in China. However, it is very difficult to isolate the virus from its original host, which hampers the viral characterization. This study describes an efficient method for isolating HTNV in suckling mice. METHODS: Hantavirus-infected Apodemus agrarius were screened by quantitative real-time PCR. The homogenates of one positive rodent lung tissue were inoculated into suckling mice for virus propagation through serial passages. RESULTS: During the three passages in suckling mice, the number of viral RNA copies/nanogram of GAPDH mRNA increased significantly ranging from 477 to 7,278 and 46 to 4,898 in the tissues of brain and lung, respectively. Hantaviral antigens could be detected by indirect immunofluorescence assay and around 100-nm virion-like structures were also observed in brain tissue by transmission electron microscopy. No nucleotide exchange was found except for one in the 3'-non-coding domain of S segment when comparing the complete genome sequences from hantavirus in the first and the third passages. CONCLUSION: These results suggest inoculation of suckling mice with suspected hantavirus-infected rodent samples is an efficient method for isolation and maintenance of HTNV.

Specific humoral reaction of hemorrhagic fever with renal syndrome (HFRS) patients in China to recombinant nucleocapsid proteins from European hantaviruses.

Hemorrhagic fever with renal syndrome (HFRS) is endemic in East Asia and Europe. This study was initiated to investigate the reactivity of antibodies in sera of Chinese HFRS patients with the recombinant nucleocapsid proteins (rNPs) of Hantaan virus (HTNV), Dobrava-Belgrade virus (DOBV), and Puumala virus (PUUV), which are the prevalent hantavirus strains in Europe. Forty-eight pairs of acute and convalescent sera were collected from HFRS patients in Hubei, China (1985-2002) and tested by indirect IgG, IgA, and IgM enzyme-linked immunosorbent assays with six rNPs of European hantaviruses as coated antigens, respectively. The results showed that the sensitivity of rNPs against IgG was HTNV-rNP > DOBV-rNP > PUUV-rNP, while the sensitivity against IgA was DOBV-rNP > HTNV-rNP > PUUV-rNP. Quantitative analysis revealed both acute and convalescent sera from HFRS patients predominantly exhibit high levels of IgA. Although PUUV-rNPs showed very weak reactivity to the three kinds of immunoglobulins in all samples, three pairs of sera unexpectedly cross-reacted strongly to all three PUUV-rNP subtypes. We first observe that HFRS patients' sera from Hubei Province show new prevalent characteristics of cross-reacting with PUUV-rNPs and continued high level of IgA in convalescent phase, as well as in China.

An evaluation of the effects of susceptibility changes on the water chemical shift method of temperature measurement in human peripheral muscle.

Divergencies between chemical shift measurements of temperature and directly measured values using optical sensors have been studied in vivo in human peripheral muscle with the assistance of a variety of experimental and theoretical techniques. These include the modelling of both thermal and susceptibility changes using two- and three-dimensional finite element methods, as well as the use of multi-wavelength near-infrared observations. The conclusion of these studies is that a simple temperature calibration is not accessible, with results affected by the complex response of the tissue itself.