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Biomedical subjects

B Niklasson

Publications and source records attributed to B Niklasson.

At least 73 records · Page 4Linked to original sources
PubMed1991

Viral haemorrhagic fever in Sweden: experiences from management of a case.

The first recognized case in Scandinavia with potential man to man transmission of viral haemorrhagic fever occurred in Linköping, Sweden, in January 1990. Following a visit to Kenya a 21-year-old male student suffered a very severe illness including extremely prolonged high grade fever, rash, disseminated intravascular coagulation with thrombocytopenia and severe bleedings. This necessitated one month of intensive care support including respirator treatment. The patient was discharged after 2 1/2 months in good condition, with a partial femoral nerve paresis. About 100 medical personnel were exposed to aerosol or blood before a strict containment regimen was established. No secondary cases occurred.

Adult↗
PubMed1991

Sandfly fever among Swedish tourists.

All clinical and serologically confirmed cases of sandfly fever among Swedish tourists during 1986-1989 were investigated. A total of 37 cases of Sicilian virus sandfly fever and 1 case of Naples virus sandfly fever were recorded from Cyprus. One case of Toscana virus infection was documented from Spain. The clinical and laboratory findings did not differ from those in previous reports, except for elevated aminotransferase levels. A questionnaire, that offered a possibility to estimate the number of cases that had not been reported, was sent to 713 tourists who had visited different hotels in Cyprus and Mallorca in September 1987. Serum samples from 95 of these tourists were tested for sandfly fever virus antibodies. These tests indicated that only some 20% of the real number of sandfly fever infections had been diagnosed. Both clinical cases and cases found by the questionnaire showed a focal distribution with an overrepresentation of certain hotels in Cyprus. The results were reported to the local health officers and possibly due to the measures undertaken hereafter the number of sandfly fever cases diagnosed have decreased.

Adult↗
PubMed1991

Hemorrhagic fever with renal syndrome: comparison of clinical course in Sweden and in the Western Soviet Union.

The severity of the clinical course in 355 Swedish and 603 Soviet patients with serologically confirmed hemorrhagic fever with renal syndrome (HFRS) was compared retrospectively. The overall frequency of hemorrhagic manifestations including also benign bleeding such as ecchymoses was higher among Soviet than among Swedish patients (37% vs. 10%). However, severe hemorrhagic complications (gastrointestinal and renal tract bleeding) were equally common in both countries. There were 2 fatal Soviet cases, whereas none of the Swedish patients died. We conclude that the clinical presentation of HFRS in Sweden and in the Western Soviet Union shows many similarities but there seems to be a higher frequency of life threatening complications among the patients in the Western USSR.

Adolescent↗
PubMed1991

Comparison of European isolates of viruses causing hemorrhagic fever with renal syndrome by a neutralization test.

Different virus isolates causing hemorrhagic fever with renal syndrome (HFRS) were compared using a neutralization test. Patient convalescent sera and antisera prepared in rabbits were used to compare Puumala-related Hantavirus isolates from Finland, Sweden, Belgium, and the USSR. The majority of European isolates were indistinguishable from each other using both homologous rabbit antisera and patient convalescent sera. The European isolates of HFRS were also compared with prototype Hantaan (the etiologic agent of Korean hemorrhagic fever). The one-way cross-reaction between the Hantaan and Puumala viruses, previously described using human convalescent sera tested by indirect immunofluorescence and immunoprecipitation, was also seen by the neutralization test.

Europe↗
PubMed1990

Transmission of Ockelbo virus by Aedes cinereus, Ae. communis, and Ae. excrucians (Diptera: Culicidae) collected in an enzootic area in central Sweden.

Studies were conducted to determine the ability of Aedes excrucians (Walker), Ae. cinereus Meigen, and Ae. communis (De Geer) group mosquitoes, collected in an Ockelbo (OCK) virus enzootic area in central Sweden, to transmit this virus. All three species were highly susceptible to infection; at least 96% of the specimens of each species became infected after ingesting blood from a viremic chicken. Recovery of virus from the legs of all 61 of the Ae. excrucians and from 51% (24 of 47) and 75% (6 of 8) of the Ae. cinereus and Ae. communis tested, respectively, indicated that OCK virus readily disseminated from the midgut to the hemocoel in these species. Although none of the Ae. communis refed, Ae. cinereus and Ae. excrucians successfully transmitted OCK virus by bite. Because these Aedes species are attracted to avian and mammalian hosts and because OCK virus has been isolated from field-collected specimens in Sweden and the USSR, Aedes mosquitoes should be considered a possible link between human infections and the enzootic cycle involving birds and Culex and Culiseta mosquitoes.

Aedes↗
PubMed1990

Swedish Culex torrentium and Cx. pipiens (Diptera: Culicidae) as experimental vectors of Ockelbo virus.

The ability of the sibling species Culex pipiens (L.) and Culex torrentium (Martini) from central Sweden to transmit Ockelbo (OCK) virus was determined. Both species became infected after ingesting OCK virus from a viremic chicken; they transmitted this virus to chickens after 21-28 d of extrinsic incubation. In Cx. torrentium, infection rates were 90% or higher, and all 10 refeeding mosquitoes transmitted virus after feeding on chickens with a viremia of at least 10(3.0) plaque-forming units (PFU)/ml. In contrast, only 1 of 28 (4%) of the Cx. pipiens that ingested blood containing 10(3.0-3.9) PFU/ml became infected, and none of 16 refeeding mosquitoes transmitted virus. However, 98 of 184 (53%) of the Cx. pipiens that ingested a blood meal containing at least 10(6.0) PFU/ml became infected. Transmission rates in Cx. pipiens increased with increasing virus concentration in the blood meal to a maximum of 37% in mosquitoes that ingested greater than 10(8.0) PFU/ml. Based on these data, both Cx. pipiens and Cx. torrentium are capable of transmitting OCK virus in an enzootic cycle involving birds as hosts. However, Cx. torrentium appears to be physiologically a more efficient vector than Cx. pipiens.

Alphavirus↗
PubMed1990

Incidence of sand fly fever among Swedish United Nations soldiers on Cyprus during 1985.

Members of a Swedish United Nations (UN) battalion of 362 soldiers were bled just before and immediately after their 6 month tour of duty in Cyprus during 1985. Sera were tested for presence of specific antibodies to sand fly fever (SF) Sicilian, SF Naples, and Toscana viruses by both indirect immunofluorescence antibody test (IFT) and plaque reduction neutralization test (PRNT). Of 298 serum pairs available, seroconversion was noted in 11 soldiers: 7 cases for SF Sicilian, 3 for SF Naples, and 1 for Toscana virus. IFT and PRNT revealed identical results. Seroconversion was associated with clinical disease in 7 out of 7, 2 out of 3, and 0 out of 1 for SF Sicilian, SF Naples, and Toscana infections, respectively. Virus isolation was attempted on acute-phase sera collected from febrile patients. Of 5 such acute-phase sera from patients with serologically verified SF, virus was recovered from 2: 1 strain of SF Sicilian virus and 1 strain of SF Naples virus.

Adult↗
PubMed1990

Effect of environmental temperature on the vector competence of Culex pipiens and Cx. torrentium for Ockelbo virus.

The effects of environmental temperature on Ockelbo virus infection, dissemination, and transmission were studied in Culex torrentium and in the Uppsala and the El Gabal strains of Cx. pipiens. Temperatures tested included 10 degrees C, 17 degrees C, 24 degrees C, and a cyclic (10-24 degrees C, mean = 17 degrees C) regimen designed to mimic typical hourly temperatures in an area endemic for Ockelbo disease in Sweden during the transmission season. The vector competence of both the Uppsala and the El Gabal strains of Cx. pipiens was directly related to environmental temperature. Mosquitoes held at 10 degrees C had a reduced ability to transmit virus as compared to those held at 17 degrees C, 24 degrees C, or in the cyclic temperature regimen. A rapid increase in dissemination rates was observed in mosquitoes exposed to a shift in temperature from 10 degrees C to 24 degrees C. After 4 days at 24 degrees C, these mosquitoes had vector competence similar to those held at 24 degrees C for the entire incubation time. In contrast, virus dissemination in Cx. torrentium was rapid at all temperatures tested and appeared unaffected by environmental temperature; infection and dissemination rates were consistently higher in Cx. torrentium than in either the Uppsala or the El Gabal strains of Cx. pipiens. It seems the transmission of Ockelbo virus by Cx. pipiens might be interrupted by a prolonged period of cold weather, while transmission by Cx. torrentium would continue.

Alphavirus↗
PubMed1989

Contact allergy to the UV-absorber Tinuvin P in plastics.

Contact allergy to the UV-absorber 2-(2-hydroxy-5-methylphenyl)benzotriazole (Tinuvin P) was revealed in a patient with wrist dermatitis caused by a plastic watch strap. A high-performance liquid chromatography method was developed and subsequent chemical analysis showed the presence of Tinuvin P in the watch strap. The possibility of cross-reactions between Tinuvin P and various substituted benzotriazole compounds was investigated. No cross-reactions were found.

Absorption↗
PubMed1989

Ecologic studies of mosquitoes and birds as hosts of Ockelbo virus in Sweden and isolation of Inkoo and Batai viruses from mosquitoes.

Field studies were conducted in central Sweden from 1983 through 1985 to obtain information on the etiologic agent of Ockelbo disease, described in Sweden in the 1960s and probably identical to Pogosta disease in Finland and to Karelian fever in the western USSR. Mosquitoes (63,644) collected during this 3 year period yielded 21 virus strains. Ockelbo virus isolations were from Culiseta morsitans (5 strains), Culex pipiens and/or Cx. torrentium (6 strains), and Aedes cinereus (3 strains). Inkoo (6 strains) and Batai (1 strain) viruses were recovered from Ae. communis. Blood samples collected March-May from migrating birds on the southeast and est coast of Sweden and in July and August from resident birds in east-central Sweden were tested for neutralizing antibody to Ockelbo virus. Antibody was not detected in 328 birds sampled during spring migrations. Two of 58 (3.4%) birds bled in July and 8 of 78 birds (10%) bled in August had antibody to Ockelbo virus. Ockelbo virus circulates in a mosquito-bird-mosquito cycle, with Cs. morsitans and Cx. pipiens and/or Cx. torrentium as enzootic vectors. Antibody was detected in passerine birds. Other classes of birds or other vertebrates were not sampled. Aedes cinereus may serve primarily to transmit virus to people. The role of other mosquito species as vectors for people is unknown.

Aedes↗
PubMed1988

Antigenic relationship between hantaviruses analysed by immunoprecipitation.

Antigenic relationships between seven hantaviruses isolated in Sweden, Belgium, Korea, European U.S.S.R. and Asian U.S.S.R. were studied by radioimmunoprecipitation assays (RIPA) and indirect immunofluorescence tests (IFT). Animal immune sera and haemorrhagic fever with renal syndrome (HFRS) patient sera from the above countries were used. The strains fell into three antigenic groups by both RIPA and IFT: nephropathia epidemica (NE)-type, Korean haemorrhagic fever (KHF)-type and urban rat-type. This antigenic grouping conforms to the clinical grouping of the respective HFRS patients. The major cross-reactive antigen between the antigenic groups was the nucleocapsid protein. Of the two viral glycoproteins, the G2 exhibited weak cross-reactivity between the groups, while the G1 protein appeared to be the least cross-reactive. Patient sera collected at different intervals after the onset of disease showed a marked difference in their capacity to immunoprecipitate the homologous viral glycoproteins, although by IFT all sera had high titres. Host species-related antibody response differences were found by both RIPA and IFT. Using patient sera, a one-way cross-reactivity was seen between the NE-type and the KHF-type viruses. However, animal immune sera clearly demonstrated a reciprocal cross-reactivity between the two virus groups.

Antigens, Viral↗
PubMed1988

Detection of nephropathia epidemica (Puumala virus)-specific immunoglobulin M by enzyme-linked immunosorbent assay.

Nephropathia epidemica (NE), a less severe form of hemorrhagic fever with renal syndrome, is caused by Puumala virus (PUU). This communication reports the development of a mu-capture enzyme-linked immunosorbent assay (ELISA) for detection of specific immunoglobulin M (IgM) antibodies to PUU virus in human sera. Acute- and early-convalescent-phase sera (collected 1 to 41 days after disease onset) from 29 Swedish patients with clinical NE were tested for PUU virus-specific IgG and IgM antibodies by the indirect immunofluorescence test and ELISA, respectively. Late-convalescent-phase serum was also collected from 18 of these patients 3 to 24 months postinfection and assayed. The IgM ELISA values were strongly positive in sera collected during the first 2 months; at 3 to 9 months, they were negative or in the lower range of significance, and at 24 months all sera were negative. Paired sera from NE patients often fail to show seroconversion or a significant titer rise when tested by indirect immunofluorescence. Since all acute- and early-convalescent-phase sera were positive by IgM ELISA, this test could become an important tool for early diagnosis of acute human NE infections.

Acute Disease↗
PubMed1987

Rift Valley fever: a sero-epidemiological survey among pregnant women in Mozambique.

Rift Valley fever (RVF) causes abortion in sheep and cattle. However, the teratogenic and abortogenic potential of RVF in humans is not known. Sera from a total of 1163 pregnant women in Mozambique were tested for RVF virus antibodies by ELISA and 28 (2%) were found to be positive. Mothers experiencing fetal death or miscarriage (155) had the same RVF virus antibody prevalence as those with normal deliveries. Analysis of maternity histories showed some indication of increased fetal wastage among women positive for RVF virus antibody. The ELISA used in this study was compared with a plaque reduction neutralization test and found to be equally sensitive and specific for the detection of RVF virus IgG antibodies.

Abortion, Spontaneous↗