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Biomedical subjects

R Mehl

Publications and source records attributed to R Mehl.

49 records · Page 3Linked to original sources
PubMed1984

Evidence for flavivirus(es) outside of the distribution area for Ixodes ricinus in Norway.

Small rodent (vole) sera were collected from three different locations in Norway. One of these was within the distribution area for Ixodes ricinus, and a tick-borne encephalitis (TBE) virus strain had been isolated from ticks collected there (Traavik & Mehl, 1977). The two other locations were outside the I. ricinus area, one in southern Norway, the other at nearly 70 degrees N. The sera were tested for TBE antibodies by hemagglutination inhibition (HI), hemolysis-in-gel (HIG) and complement fixation (CFT). All sera were also tested for HI antibodies to Uukuniemi (UUK) virus, and some positive TBE HI reactions were verified by separation of immunoglobulins and serum lipoproteins in NaBr gradients. Animals containing TBE virus antibodies reacting in all three serological tests and animals with UUK HI antibodies were detected only from the location within the I. ricinus area. From the two locations outside the I. ricinus area we found animals which had antibodies reacting with TBE virus in HI and HIG, but not in CFT. Antibodies to UUK were not detected. The results indicate that flavivirus(es) related to, but not identical with TBE viruses are transmitted by other vectors than I. ricinus in parts of Norway.

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PubMed1984

Nephropathia epidemica in Norway: antigen and antibodies in rodent reservoirs and antibodies in selected human populations.

Nephropathia epidemica (NE) antigen was detected by IFAT (indirect fluorescent antibody technique) in the lungs of 14 of 97 bank voles (Clethrionomys glareolus) collected in three endemic areas. The distribution of antigen positive voles within an endemic location was scattered. Antibodies to Korean hemorrhagic fever (KHF) virus antigens were detected by IFAT in 12 of 14 NE antigen positive bank voles and in 15 of 83 that were antigen negative. NE antigen positive voles exhibited higher antibody titres. Antibodies to KHF were demonstrated in sera from C. rutilus and C. rufocanus collected more than 200 km north of the distribution area for C. glareolus. It appears likely that these vole species can serve as virus vectors for NE cases occurring north of the bank vole area. NE antibodies cross-reacting with KHF virus seem to diminish with time after infection in some NE patients, while for others such cross-reacting antibodies were detected up to 12 years after the disease. Antibodies to KHF were detected in eight of 106 healthy forestry workers with no clinical history of NE. No serological cross-reactions were detected between NE/KHF antigens and representative Bunyaviridae present in Norway. NE/KHF-like viruses appear widespread in Norway, both within and outside of the distribution area of the bank vole.

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PubMed1983

Nephropathia epidemica in Norway: description of serological response in human disease and implication of rodent reservoirs.

In search for the Norwegian nephropathia epidemica (NE) agent, lung sections from small rodents and sera from human patients have been tested by indirect fluorescent antibody technique (IFAT). A cytoplasmatic antigen reacting with patient sera and a Korean hemorrhagic fever (KHF) reference antiserum was found in the lungs of 6 bank voles (Clethrionomys glareolus) from 2 different locations. Antibodies reacting with vole lung antigen (NE agent) and KHF agent in A-549 cells were detected in sera from 35/57 patients clinically suspected of having NE. Specific IgM antibodies were usually detected in "early" obtained sera. Positive sera had considerably higher titers against NE than KHF agent. One serum had an IgG titer of 160 against NE, but no detectable KHF antibodies. One patient had an atypical disease. Two NE patients must have been infected north of the distribution area for Cl. glareolus, suggesting the existence of other reservoir animals.

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PubMed1978

The first tick-borne encephalitis virus isolates from Norway.

Five virus strains with close serological relationship to the tick-borne encephalitis (TBE) complex have been isolated from Ixodes ricinus ticks. The ticks were collected in early June 1976 at three different locations in Sogn & Fjordane County, Norway. One of the virus-yielding pools was composed of ticks collected between the cabins on a tourist camping ground.

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PubMed1978

California encephalitis group viruses isolated from mosquitoes collected in Southern and Arctic Norway.

Three virus strains serologically related to the California encephalitis group (Bunyaviridae) of arboviruses were isolated from 7331 mosquitoes collected in Norway in June-August 1975. Two of the isolates (S 548 and S 618) seemed to be closely related and the third, S 568, more distantly related by serological techniques to Tahyna virus. Viruses were found in the mosquito species Aedes sticticus, A. diantaeus and A. hexodontus colllected (in order) from Oyern (59 degrees N, 11 degrees 12' E), Trandum (60 degrees 08' N, 11 degrees 10' E) and Masi (69 degrees 26' N, 23 degrees 39' E). The Masi isolate seems to be the northernmost arbovirus isolate in the world so far. Strain S 568 was from 16 male A. diantaeus, indicating transovarial transmission of the virus. An accidental infection demonstrated the potential human pathogenicity of one of the newly-isolated strains (S 568), and the ability of CE viruses to persistently infect suckling mouse brains was indicated by in vivo findings. The biological characteristics of the new strains so far investigated are consistent with those of the California encephalitis group. During this work the Aerosil absorption method for production of haemagglutinating antigens proved useful for Tahyna virus and the newly-isolated strains. Trypsinization of erythrocytes improved the haemagglutinating capacities of these viruses.

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PubMed1977

"Runde" viurs, a coronavirus-like agent associated with seabirds and ticks.

From 206 I. uriae collected in the seabird colonies at Runde, Norway, two identical virus strains demonstrating no antigenic relationships to major arbovirus groups were isolated. The new strains demonstrated a corona-virus like morphology, haemagglutinated chicken red cells and were sensitive to sodium desoxycholate. Multiplication with CPE was demonstrated in BHK 21/c13 and BSC-1 cells, and without CPE in Vero and GMK cell cultures. The mouse pathogenicity was relatively low. In gel precipitation three to five specific lines were seen. Precipitating antibodies have been found in seabird species commonly infested by I. uriae. The ecological cirucmstances of the isolates indicate an earlier unrecognized arbovirus circulating between seabirds and I. uriae. This corona-like virus has been tentatively termed Runde virus.

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PubMed1975

Tick-borne viruses in Norway.

The purpose of the investigation was to chart the existence and extent of arboviruses in Norway and provide information on their possible significance. Virus isolations have been attempted from ticks (I. ricinus, I. trianguliceps, I. uriae) and host animal blood from selected locations. Serological screenings have been performed with bird, small mammal, cattle and human blood. Five virus strians have been identified to date. Three of them are related to Uukuniemi virus group. Two identical strains from I. uriae demonstrate the morphology of coronaviruses and no antigenic relationship to major arbovirus groups. Within the distribution areas of I. ricinus, antibodies to tick-borne encephalitis virus are prevalent in cattle. Antibodies to Uukuniemi viruses are found in passerine birds, small mammals, cattle and man. Antibodies to the coronavirus like agents have been demonstrated in seabirds.

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