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R Visakorpi

Publications and source records attributed to R Visakorpi.

At least 19 recordsLinked to original sources
PubMed2001

Acceptable protective efficacy of influenza vaccination in young military conscripts under circumstances of incomplete antigenic and genetic match.

Commercial inactivated parenteral influenza vaccines reduced febrile (> or = 38 degrees C) respiratory illness by 53% (95% CL: 41-63%) during a 3 week outbreak in 1998 when A/Sydney/5/97(H3N2)-like influenza viruses were shown to be the predominant etiological agents and an older antigenic variant, A/Nanchang/933/95, served as the vaccine virus. The calculatory efficacy for preventing virologically diagnosed influenza infections was 57% (95% CL: 40-68%). The study population consisted of 1374 young male military conscripts. Vaccination coverage on a voluntary basis was 67%. Vaccination was ineffective in preventing febrile illness during a second epidemic wave lasting 2 weeks when mainly adenoviruses were shown to have been circulating in the garrison. Out of the 36 nasopharyngeal aspirates positive for influenza A by antigen detection, 18 A/Sydney/5/97-like strains (10 from non-vaccinated and eight from vaccinated subjects) and two A/Nanchang/933/95-like strains (both from non-vaccinated subjects) were isolated in MDCK cell cultures. Intraepidemic variation was detected among the A/Sydney/5/97-like field strains in their HA1 sequences and reactivity in HI tests, but no evidence was obtained that this variation would have been of significance to the virus in breaking through the vaccination-induced immunity.

Adult↗
PubMed2001

Vaccination-induced HI antibody response to intraepidemic influenza A(H3N2) virus variants of the 1996-1997 epidemic season.

Intraepidemic antigenic and genetic variation was indicated when H3N2-subtype influenza A virus strains isolated during the 1996-1997 epidemic season in Finland were studied for reactivity in the haemagglutination inhibition (HI) assay and for nucleotide sequences coding for the variable HA1 domain of viral haemagglutinin. Thirty prevaccination- and postvaccination-paired sera taken from subjects who had been vaccinated against influenza during the previous autumn were studied for the presence of HI antibody to the homologous vaccine virus A/Nanchang/933/95, and five field strains representing the genetic and antigenic variability of the 1996-1997 epidemic season. The lowest vaccination-induced HI titres in each of the three age groups were detected in the two field strains that had been isolated from vaccinated patients and belonged to two different genetic sublineages. The intraepidemic variability of the 1996-1997 field strains in HI reactivity may be indicative of circulation of virus strains that may be capable of breaking through vaccination-induced immunity better than the other strains.

Adult↗
PubMed1995

Arcanobacterium haemolyticum and streptococcal pharyngitis in army conscripts.

Arcanobacterium haemolyticum was found in 1.4% and beta-haemolytic streptococci in 23% of throat cultures from army conscripts with sore throat (n = 498). 38% of the beta-haemolytic streptococci were of group A. Patients culture-positive for A. haemolyticum or beta-haemolytic streptococci had pharyngeal exudate, cervical lymphadenopathy and ear ache significantly more often--but cough less often--than culture-negative patients. The pharyngeal colonization rate of healthy conscripts (n = 232) by A. haemolyticum was 0.4% and by beta-haemolytic streptococci, 6.5%.

Actinomycetaceae↗
PubMed1994

Early kinetics of antibody response to inactivated influenza vaccine.

The aim was to examine the rapidity of haemagglutination inhibiting (HI) antibody response induced by immunization with a current inactivated trivalent influenza vaccine. Five to six sequential serum samples collected in autumn 1992 from each of 68 vaccinees in three age groups were studied for HI antibodies to ten influenza virus strains representing vaccine and epidemic viruses. Geometric mean titres, response rates and protection rates are presented. Response rates of > 70% were overall, but not until two weeks after the vaccination. Significant two- and four-day post-vaccination antibody responses were detected only occasionally. In previously vaccinated persons, average antibody titres to some of the viruses decreased during the first days after the vaccination. In the subsequent samples, the titres remained lower than in persons who were not vaccinated against influenza in preceding years. Protection against influenza infection may be frequently developed not until two weeks after vaccination. This has relevance to prophylactic administration of amantadine and rimantadine when an influenza A outbreak is imminent and the vaccination is late.

Journal Article↗
PubMed1993

An epidemic of infections due to Chlamydia pneumoniae in military conscripts.

A prospective observational study of an epidemic of infection due to Chlamydia pneumoniae strain TWAR in Finnish military trainees provided new information on immunity following infection, the range of clinical syndromes and complications, and cell culture isolation. One-half of the trainees studied (43 of 86) had laboratory evidence of C. pneumoniae infection. The etiologic association of C. pneumoniae with disease was strengthened by the sharp increase in cases of pneumonia and in outpatient visits for acute respiratory disease along with the laboratory evidence of infection. The pattern of serological response suggested that 23 of the trainees had a primary TWAR infection and 20 had a reinfection. Evidence that prior infection modified the illness included the frequency of hospitalization (12 with primary infections vs. 1 with reinfection), the development of pneumonia (10 vs. 0), and the requirement for repeated courses of antibiotic therapy (13 courses vs. 0). Isolation was more frequent in HL cells (n = 25) than in HeLa 229 cells (n = 10).

Adolescent↗
PubMed1991

Late complications after a Yersinia enterocolitica epidemic: a follow up study.

Ninety four Finnish conscripts were affected by a Yersinia enterocolitica epidemic in 1973. Thirteen years later 75 men completed a questionnaire about their present health. One half had no health problems, and the most common complaints in the other subjects were musculoskeletal disorders. Sixteen men wanted to be re-examined. In three cases a chronic connective tissue disease was diagnosed. Two men had ankylosing spondylitis. The most notable results of this study were (a) the fairly low number of late complications, (b) the close correlation between complications and the HLA-B27 antigen, and (c) the correlation between raised yersinia antibody titres and the late complications. The nature of the primary causative agent may affect the development of late complications.

Adult↗
PubMed1989

Ciprofloxacin in meningococcal carriers.

Chemoprophylaxis of meningococcal disease is still necessary in spite of the availability of an effective vaccine against group A, C, Y and W135 strain meningococci. After emergence of sulphonamide resistant meningococcal strains, rifampin has been the drug used for chemoprophylaxis. Development of rifampin resistance in meningococci during short term prophylactic treatments makes this treatment less suitable. At present, there are several studies where ciprofloxacin has shown good effect in eradication of meningococci from nasopharyngeal carriers. It also seems obvious that one single dose of ciprofloxacin is enough for the purpose. Ciprofloxacin can be recommended for chemoprophylaxis of meningococcal disease in adults.

Carrier State↗
PubMed1988

Epidemics of pneumonia caused by TWAR, a new Chlamydia organism, in military trainees in Finland.

Four epidemics of pneumonia in military trainees in Finland have been shown, by microimmunofluorescence serology, to have been caused by TWAR, a recently described, unique Chlamydia organism. The epidemics occurred in four different garrisons from 1957 to 1985. Each lasted approximately six months, and epidemics occurred during all seasons of the year. The attack rate varied from 60 to 80 per 1000 men. Routine laboratory tests for respiratory agents suggested that these epidemics represented the only clusters of patients since 1970 who were positive for antibody to Chlamydia by complement fixation. From these epidemics, 62 of 70 paired sera that were positive for Chlamydia had antibody diagnostic of recent TWAR infection. Although the conscripts with pneumonia were hospitalized, the illnesses were relatively mild, and none were life threatening. Three conscripts had two episodes of TWAR pneumonia separated by three weeks to three months. Prompt treatment with tetracycline depressed the antibody response.

Adult↗
PubMed1986

Intraepidemic heterogeneity of influenza A (H3N2) viruses in 1985: antigenic analysis and sensitivity to non-specific inhibitors.

During the influenza outbreak of 1984-85 22 strains of H3N2 viruses were isolated in Finland. An intra-epidemic heterogeneity was demonstrated in an antigenic analysis by haemagglutination inhibition test with antisera produced in rats. The strains could be classified into three groups which corresponded to the following reference strains: group I: A/Hong Kong/1/84, A/Hong Kong/3/84; group II: A/Philippines/2/82; group III: A/Caen/1/84. Seven of the isolates were entirely insensitive to gamma-inhibitors of guinea-pig sera, which is in contrast to the small number of these viruses found among H3N2 strains isolated in the 1970s. The insensitive strains could not be isolated until the second or third passage through the eggs, whereas about half of the sensitive and intermediate strains were already isolated during the first passage. Conversions in reactivity with gamma-inhibitors could be detected only from an intermediate or an insensitive virus to a sensitive virus when several strains were passed serially in ovo and in MDCK cultures. The findings suggest that the gamma-inhibitor-insensitive strains corresponded well to the viruses of the human host or arose from dimorphic virus populations under an arbitrary selection of terminal dilution conditions prevailing during isolation in eggs. The insensitive strains did not differ substantially from the sensitive viruses in their ability to agglutinate erythrocytes of different laboratory animals or in their disagglutination patterns. On the other hand, propagation of viruses in MDCK cultures had an effect on these properties. The results are discussed with respect to Q phase variants and receptor binding properties.

Antigens, Viral↗
PubMed1985

The HI test modified by ether treatment in the sero-epidemiological surveillance of influenza B.

Ether-treated influenza B haemagglutination inhibition (HI) antigen was used in a study of serum collections from three different epidemic seasons. For diagnostic purposes, ether treatment increased the efficacy of the HI test by about 50% over the conventional HI technique, raising it to the same level of sensitivity as the complement fixation (CF) test. The treatment reduced the specificity of the HI test, but its reliability in the diagnosis of influenza B infections was only slightly diminished. With regard to evaluation of the immune status of a given population, an HI test using ether-treated antigen from the epidemic influenza B strain seems to give more relevant information about the antibody level associated with protection than a conventional HI test using untreated virus antigen.

Antibodies, Viral↗
PubMed1983

Psychophysiological measurements after oral atropine in man.

Eight healthy male volunteers received double-blind and cross-over placebo or atropine (0.85 or 1.7 mg). Various physiological, psychological and psychomotor measurements were made before a single oral dose and 1, 2 and 4 hrs after it. Typical peripheral antimuscarinic effects were found after atropine, maximally at 2-4 hrs. Atropine impaired flicker recognition, reaction time, short-time, short-term memory, coordination, time anticipation and standing steadiness. The CNS-impairment was maximal at 1 hr and dose-related in most instances.

Adult↗
PubMed1980

Evaluation of amantadine in the prophylaxis of influenza A (H1N1) virus infection: a controlled field trial among young adults and high-risk patients.

The usefulness of amantadine in the protection of humans against influenza A (H1N1) virus was evaluated in a double-blind field trial with 555 volunteers in Finland in the winter of 1978. Three populations--patients in a general hospital, adults in a home for the aged, and two groups of military conscripts--were chosen. Epidemic influenza occurred only in the two groups of conscripts: the incidence of serologically verified influenza was 66% and 83% in the groups that received placebo and 43% and 51% in the groups that received amantadine, giving protection rates of 36% (P = 0.05) and 39% (P = 0.001). The evaluation of the effect of amantadine on the occurrence of illness was obscured by concomitant adenoviral infections that caused influenza-like symptoms. No clear difference in the occurrences of side effects was observed between the placebo and amantadine-treated groups; however, a significantly greater number of participants who took 200 mg of amantadine/day (16.9%) stopped medication during the trial as compared with the placebo groups (7.6%) (P < 0.02).

Adult↗
PubMed1980

ABO associated genetic determinant in H1N1 influenza.

Young people, in the winter of 1977-78 lacked all prior antigenic experience with H1N1 influenza. The attack rate among them was observed to be lowest (42%) in blood group O subjects and highest (59%) in blood group AB subjects. This indicates that there is an ABO associated genetic determinant in resistance against H1N1 influenza. The antibody response to the viral hemagglutinin did not vary substantially according to the ABO status.

ABO Blood-Group System↗
PubMed1979

Influenza A(H1N1) viruses of the 1977/78 outbreak: isolation and haemagglutination properties.

During the H1N1 outbreak of 1977/8, the virus was isolated in embryonated eggs from 59 out of 76 patients (78%) with the serologically confirmed infection. A similar isolation frequency has been achieved during a period of six H3N2 outbreaks since 1972/3. The H1N1 strains were isolated less frequently from late specimens (collected 4--6 days from the onset of illness) and more often only in the second passage compared with the H3N2 viruses. The new H1N1 strains resembled those prevalent in the 1950s with respect to their ability to agglutinate erythrocytes of certain laboratory animals and to be eluted from these, and thus differed from the H3N2 viruses.

Disease Outbreaks↗
PubMed1979

Seroepidemiology of H1N1 influenza: striking differences in the attack rate among young people.

The H1N1 influenza outbreak in winter 1977-78 covered the whole of Finland in a uniform fashion, whereas striking differences emerged between various population segments in the susceptible age group. The attack rate was 68 per cent among young servicemen who had been in the armed forces during the epidemic and 33 per cent among those who had entered the service after the epidemic, but only 6 per cent among pregnant women of the same age. Based on routine specimens sent to the laboratory for reasons unrelated to influenza, the attack rate was 4 per cent among children born in 1973-76 and increased by age up to 45 per cent among subjects born in 1957-62. The findings on pregnant women and small children suggest a novel mechanism of innate resistance operating specifically against H1N1 influenza.

Adolescent↗