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Biomedical subjects

R Mehl

Publications and source records attributed to R Mehl.

At least 19 recordsLinked to original sources
PubMed1998

[Communicable disease control in connection with international air traffic to Norway].

International air traffic has increased the risk of importation of infectious diseases to Norway. We have used notification data and a theoretical framework to assess the risk of importation and subsequent disemination of serious infectious diseases in Norway. Every year, a few cases of these diseases are imported to Norway, especially malaria, shigellosis and typhoid fever. A few secondary cases of enteric diseases may occur, but epidemics are unlikely. Counselling and immunisation of Norwegians going abroad is the first step in prevention. Secondly, health services all over the country should be able to diagnose imported diseases early and institute infection control measures. However, there is no need for concentrating resources for disease control at international airports in Norway.

Aerospace Medicine↗
PubMed1998

Ixodes ricinus strains in Europe.

An analysis of cuticular hydrocarbons (CH) of unfed adult Ixodes ricinus ticks collected throughout Europe showed that there are 10 distinct I. ricinus groups. Studies on the seasonal and annual consistency of CH composition and possible effects of host and environmental factors suggested that CHs may be used as a genuine genetic marker for I. ricinus. Preliminary studies compared the vector competence of ticks from three of the most separated I. ricinus groups and the results suggested that there may be significant differences in tick susceptibility to Borrelia afzelii.

Animals↗
PubMed1998

European reservoir hosts of Borrelia burgdorferi sensu lato.

Existing knowledge on reservoir hosts of Borrelia burgdorferi sensu lato was collated and reviewed and several species, particularly birds, were identified as reservoir competent. At the present time, 9 small mammals, 7 medium-sized mammals and 16 bird species, including passerines, sea birds and pheasants, appear to be capable of transmitting spirochaetes to ticks and thus of participating in the natural circulation of B. burgdorferi s.l. in Europe. The house mouse, Mus musculus is strongly suspected of reservoir competence and many other small rodent species, particularly in eastern Europe and Russia, have been implicated. Ungulates are not thought to play a major role as reservoir hosts, though co-feeding transmission may permit some tick infection. The criteria for establishment of reservoir status are outlined and a method for identification of host blood meals of previous instars of unfed ticks, developed in a participant laboratory, is briefly described.

Animals↗
PubMed1998

Isolation and characterization of Puumala hantavirus from Norway: evidence for a distinct phylogenetic sublineage.

Puumala (PUU) hantavirus is the aetiological agent of nephropathia epidemica (NE), a mild form of haemorrhagic fever with renal syndrome, which occurs in Fennoscandia, central Europe and Russia. In Norway, NE-like disease has been reported since 1946 and about 50 cases are diagnosed annually; however, the causative agent has not been characterized. In this study, a virus originating from bank voles (Clethrionomys glareolus) trapped near the town of Eidsvoll (Akershus county) was isolated and passaged in laboratory-bred bank voles. The bank vole strain was identified as a PUU virus by serological typing and by sequence analysis of the S and M gene segments. For comparison, complete or partial S sequences were determined for wild-type PUU strains from five locations in Sweden, two inhabited by the southern variant of bank vole present in Fennoscandia, and three by the northern variant. Phylogenetic analysis showed that Norwegian PUU strains are clustered together with Swedish strains from the first group forming a well-supported sublineage within the PUU genotype, distinct from other sublineages from northern Sweden, Finland, Russia and France. The results are consistent with the view of a complex evolutionary history of PUU strains in post-glacial Fennoscandia. Analyses of the current collection of nucleotide sequences suggest that PUU is the most variable genotype of the known hantaviruses.

Base Sequence↗
PubMed1998

Occurrence of mites in Norway and the rest of Scandinavia.

This paper gives a faunistic review of mites that have been recorded in the indoor environment, particularly homes, barns, and stored products, in Norway and the other Scandinavian countries. Some preliminary results are given from unpublished investigations in Norway. Seven species of pyroglyphid mites have been recorded: Dermatophagoides pteronyssinus, D. microceras, D. farinae, D. evansi, Euroglyphus maynei, Gymnoglyphus longior, and Hirstia chelidonis. D. pteronyssinus was the predominant species, followed by D. microceras in Scandinavia and D. farinae in Denmark. D. evansi was detected in poultry houses in Norway. Lepidoglyphus destructor was the predominant species in barn dust, but large populations of Acarus, Tyrophagus, Tydeus, and Tarsonemidae also occurred. In humid homes, Glycyphagus domesticus was found in high numbers. The result of quantification of mites depends on the method for examination of dust. When one proposes limits for the concentration of mites in relation to risk of allergic sensitization and provocation of symptoms, reference should be made to a well-described method for sampling and analyzing dust. The number of mites should be given per area, not only per weight unit of dust. The number of mites per area indicates the number of mites in the home. The number of mites per weight unit of dust describes the concentration of mites in the vacuum cleaner.

Animals↗
PubMed1998

Characteristics of four cowpox virus isolates from Norway and Sweden.

We report the first isolation of cowpox virus from a domestic cat in Norway, and the first confirmed isolation of cowpox virus from a human case in Norway. These two Norwegian cowpox virus isolates, as well as two Swedish human isolates, were partially characterized and compared with each other and with cowpox virus Brighton and vaccinia virus strain Western Reserve. Restriction enzyme analysis of the genomes revealed differences between all six viruses examined, but suggested that the two Norwegian isolates are closely related, as are the two Swedish isolates. Restriction endonuclease digestion of genomic DNA demonstrated that one of the Swedish isolates and the two Norwegian isolates have larger genomes than vaccinia virus strain Western Reserve, but smaller than cowpox Brighton. All four Scandinavian isolates lacked a 72 base-pair region within the A-type inclusion body protein gene which is present in the prototype cowpox virus Brighton.

Adolescent↗
PubMed1998

Naturally occurring orthopoxviruses: potential for recombination with vaccine vectors.

Orthopoxviruses are being increasingly used as live recombinant vectors for vaccination against numerous infectious diseases in humans, domestic animals, and wildlife. For risk assessments and surveillance, information about the occurrence, distribution and ecology of orthopoxviruses in western Europe is important but has mainly been based on serological investigations. We have examined kidneys, lungs, spleens, and livers of Norwegian small rodents and common shrews (Sorex araneus) for the presence of orthopoxvirus DNA sequences by PCR with primers complementary to the viral thymidine kinase (TK) gene. PCR amplicons were verified as orthopoxvirus specific by hybridization with a vaccinia virus TK-specific probe. A total of 347 animals (1,388 organs) from eight locations in different parts of Norway, collected at different times of the year during 1993 to 1995, were examined. Fifty-two animals (15%) from five locations, up to 1,600 km apart, carried orthopoxvirus DNA in one or more of their organs, most frequently in the lungs. These included 9 of 68 (13%) bank voles (Clethrionomys glareolus), 4 of 13 (31%) gray-sided voles (Clethrionomys rufocanus), 3 of 11 (27%) northern red-backed voles (Clethrionomys rutilus), 16 of 76 (21%) wood mice (Apodemus sylvaticus), and 20 of 157 (13%) common shrews. The previous isolation of cowpox virus from two clinical cases of infection (human and feline) at two of the locations investigated suggests that the viruses detected are cowpox and that some of the virus-carrying small mammalian species should be included among the cowpox virus natural reservoir hosts in Scandinavia and western Europe.

Animals↗
PubMed1998

Residential dampness problems and symptoms and signs of bronchial obstruction in young Norwegian children.

To assess the role of dampness problems and house dust mite exposure in the development of bronchial obstruction in early life, a cohort of 3,754 children born in Oslo during 1992 and 1993 was followed for 2 yr. Bronchial obstruction was defined as two or more episodes with symptoms and signs of obstruction or one lasting 1 mo or more. A matched case-control study was carried out in 251 cases of bronchial obstruction (response rate: 98%) and their 251 paired controls. Information on home dampness problem(s), house dust mite exposure, and potential confounders was collected during home visits and by questionnaires. Dampness problems were confirmed in the homes of 27% of the cases and 14% of the controls, while a concentration of Dermatophagoides pteronyssinus allergens > 2 microg/g dust was found in the beds of 11 (4.5%) cases and three (1.2%) controls. In conditional logistic regression analysis controlling for potential confounders, confirmed dampness problems increased the risk of bronchial obstruction (adjusted odds ratio: 3.8; 95% confidence interval: 2.0-7.2). Exposure to D. pteronyssinus allergens > 2 microg/g dust increased the risk of bronchial obstruction (adjusted odds ratio: 2.8; 95% confidence interval: 0.7-11.7). Residential dampness problems in Oslo dwellings seem to increase symptoms and signs of bronchial obstruction in young children, apparently without increasing their exposure to house dust mites.

Airway Obstruction↗
PubMed1998

Serosurvey for orthopoxviruses in rodents and shrews from Norway.

Two hundred and twenty one blood samples representing eight different rodent species and the common shrew (Sorex araneus), collected in Norway between 1993 and 1995, were examined for anti-orthopoxvirus antibodies by a competition enzyme linked imunnosorbent assay (ELISA) and, when possible, an indirect immunofluorescence assay. The serological results indicated that the bank vole (Clethrionomys glareolus), woodmouse (Apodemus sylvaticus) and Norway lemming (Lemmus lemmus) may be reservoir species for orthopoxviruses in Norway, with antibody prevalences of 17 (12/69), 30 (24/81) and 56% (19/34), respectively. Orthopoxvirus infection in lemmings has not been reported previously. On some other small rodent species such as field voles (Microtus agrestis), common rats (Rattus norvegicus), and common shrews, seropositive individuals were detected. However, the total number of tested animals was low, and the role of these species in the epidemiology of orthopoxvirus infections remains unclear. Attempts to isolate orthopoxviruses from these small mammals failed, although orthopoxvirus specific DNA sequences were detected previously in the same animals by the polymerase chain reaction (PCR). The serological results were compared with and discussed in the context of the occurrence of orthopoxvirus-specific DNA sequences, and it is concluded that orthopoxviruses are widely distributed among wildlife in Norway.

Animals↗
PubMed1996

Field investigations of tularemia in Norway.

In Norway, tularemia is a common disease in small rodent and hare populations, where large outbreaks can be observed. In humans, the yearly number of cases is low, usually less than ten, with peaks up to 44 recorded in recent years. Serological investigations on hunters and healthy school children nevertheless indicate, with up to 4.7% positivity in the latter group, that Francisella tularensis low-grade infection is widespread. F. tularensis in co-culture with amoebae, e.g. Achantamoeba castellanii, may grow after internalization and kill the amoeba. As with Legionella, Francisella virulence may be enhanced after protozoan ingestion. This suggests a mechanism that can explain the pattern of dissemination and infection in our region.

Adolescent↗
PubMed1994

[Lyme borreliosis].

In Norway, physicians and patients alike are becoming increasingly aware of Lyme borreliosis. This fact has created a need for information on different aspects of this disease. This paper reviews the historical background for Lyme borreliosis and the epidemiological situation in Norway, based on data collected by the national system for notification of infectious diseases (MSIS) in 1993. The role of the tick vector and the overall clinical picture is presented briefly. The authors discuss indications for and possibilities of different microbiological diagnostic methods, and finally list the recommendations for treatment and prophylaxis.

Humans↗
PubMed1993

Predictors of frequent middle school health room use.

Disproportionately high use of school health room (HR) services by small groups of users has been reported. This study investigated predictors of frequent HR use in two suburban middle schools involving 1089 students who made at least one HR visit during a single academic year. Subsets of high and low users were compared using logistic regression. Predictor variables included gender, grade, academic ability, and existence of a chronic health condition. Although demographic characteristics of the study schools varied significantly, a pattern of increasing HR use associated with progressive lowering of academic ability was demonstrated in both schools. Existence of a chronic health condition was associated with increased HR use, even when controlling for routine medication visits. Gender and grade were not predictive. These findings suggest that HR use reflects more than medical concerns. Patterns of HR use by students with chronic health conditions deserve additional study to determine whether current strategies to meet their needs are adequate.

Adolescent↗
PubMed1992

Fleas (Siphonaptera) from seabirds and their nests in mainland Norway and Spitzbergen.

Ceratophyllus vagabundus insularis was recorded in all typical nesting cliffs in mainland Norway in nests of puffins, shags, cormorants, and kittiwakes, but not in nests of gulls. Ceratophyllus vagabundus vagabundus was recorded in Spitzbergen associated with geese and gulls. Ceratophyllus garei, the only flea species in Larus gull's nests, was present in small numbers in nests of kittiwakes and shags in the southern part of the investigation area. Mioctenopsylla arctica arctica was recorded in kittiwake nests on Spitzbergen and in one nesting cliff in the most arctic part of mainland Norway, where it also was the dominating species. C. vagabundus was reported to attack man.

Animals↗