Phylogenetic Relationships and co-evolution Between Hantaan Virus and Rodent Host , Striped-field Mice ( Apodemus agrarius ) by Mitochondrial DNA Sequences

Hantaviruses, members of the family Bunyaviridae, are causative agents of hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS). Hantaan (HTN) virus, the etiologic agent of clinically severe HFRS in Far East Asia, Russia and the Balkans, was first isolated in 1976 from lung tissues of striped-field mice (Apodemus agrarius) captured in Songnae-ri, Kyungki-do, Korea. Mitochondrial DNA (mtDNA) in vertebrates evolve very rapidly, and hence it can provide a high resolution for distinguishing between closely related organism and species. To clarify the phylogenetic relationship of HTN viruses with their natural rodent host, a part of M segment of HTN virus and 424-nucleotide region of cytochrome b gene of mtDNA were amplified and sequenced from tissues of striped-field mice by reverse transcription-polymerase chain reaction (RT-PCR) and PCR, respectively. A 324-nucleotide region of G2 glycoprotein-encoding M segment of HTN virus was amplified from lung tissues of A. agrarius mice, revealed 84-86% sequence similarity with Apodemus-borne HTN virus strains from China. The co-speciation of Apodemus-borne hantaviruses with its natural reservoir rodents, A. agrarius and A. flavicollis, be found. A. agrarius rodent population from South Korea had almost same genetic background irrespective of their geographic origin. HTN virus strains from South Korea shared a common ancestry and were evolutionarily distinct from HTN viruses kom China. We have found no evidence for the presence of phylogenetic relationship of A. agrarius-borne Korean HTN virus strains with the genetic diversity of their rodent host captured in Korea based on cytochrome b gene of mtDNA.

Comparison of Nucleotide Sequences of Hantaan and Seoul viruses Passed in Suckling Mouse Brains

Hantaan (HTN) virus and Seoul (SEO) virus, two murid rodent-borne hantaviruses harbored by the striped-field mouse (Apodemus agrarius) and the Norway rat (Rattus norvegicus), respectively, were known to cause hemorrhagic fever with renal syndrome (HFRS). After inoculation of HTN and SEO viruses into suckling mice intracerebrally, mice became ill and were morbibund by 15 or 16 days postinfection. Viral antigens were present in brain, heart, lung, liver, kidney, spleen, pituitary gland, thymus, lymph nodes, adrenal, pancreas, salivary glands, trigeminal ganglia, adipose tissue, intestine and muscle. Moreover, the time period appearing illness and morbidity were gradually decreased from 15 or 16 days to 8 or 9 days postinfection increasing the passage number. Therefore to evaluate the relationship between these adaptation process and genomic change of HTN and SEO viruses, we sequenced corresponding regions of the 3' G1 and 5' G2 encoding M genomic segments of two HTN and six SEO virus strains, and compared the nucleotide changes between the original stocks and five to nine passed virus strains in suckling mice brains. There was no nucleotide changes in HTN virus strains and zero to four nucleotide changes in SEO virus strains. However, only one base change resulted in amino acid change at the position 1691 (Gln to Glu) of 5' G2 encoding M genomic segment. This amino acid change didn't effect any conformational change in the beta-sheet, hydrophilicity, antigenicity and surface probability of protein structure of G2 glycoprotein. Our present data suggested that the genomic changes in the 3' G1 and 5' G2 encoding M genomic segment was not related with adaptation process of HTN and SEO viruses passed in suckling mice brains.

Seroepidemiologic Analysis and Antigen Detection from Patients with Hemorrhagic Fever with Renal Syndrome / 감염

BACKGROUND: Hantaan (HTN) and Seoul (SEO) viruses, harbored by the striped-field mouse(Apodemus agrarius) and the Norway or common rat (Rattus rattus & Rattus norvegicus), respectively, were known to cause hemorrhagic fever with renal syndrome(HFRS) in Korea. We evaluated the seroepidemiologic patterns of hantaviral infections and detect the hantaviral antigens from patients' sera. METHODS: Total 8,102 HFRS patients' sera were collected from 1994 to 1996, and examined by indirect immunofluorescent antibody technique (IFA), hemagglutination inhibition test (HI), IgM emzyme-linked immunosorbent assay (IgM-ELISA) and nested reverse transcription-polymerase chain reaction(RT-PCR). RESULTS: The seropositive rate against hantaviral antigen was 12.0% (973/8102) with the high incidence rate (68.3%) in the period from October to January, and males in the thirties were mostly affected. HTN viral infections were detected 3.5 and 5.2 times higher than SEO viral infections by HI and RT-PCR, respectively, and patients in the fifties were the mostly affected age-group in SEO viral infections, IgM antibodies were detected in the 717 sera of the 905 IFA positive cases (79.2%), and the antigen detection rate of HTN and SEO viruses was 7.7% (56/724). Interestingly, 40 sera (4.4%), showed higher antibody titers against the Puumala (PUU) virus than those against HTN or SEO viruses. CONCLUSION: The results showed HTN and SEO viruses were the main causative agents of HFRS in Korea, and also suggested the possible presence of PUU-related hantaviral infections.