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.

Chlamydia trachomatis in acute salpingitis.

In a study to evaluate the possible role of Chlamydia trachomatis and Neisseria gonorrhoeae in acute salpingitis, 26% of 106 patients with severe symptoms had positive culture results for C. trachomatis; 43% of the 72 patients from whom paired sera were obtained had either positive culture results for or seroconversion in the single antigen immunofluorescence test to C. trachomatis.

Risk of infection among seafarers: a prospective seroepidemiological survey of the crew of a passenger cruiser.

Serial blood specimens for various serological examinations were taken from the crew of a passenger ship which sailed on winter cruises. The study covered 3 successive seasons totalling about 150 years of observation. The figures on the rates of infection were compared with data available from the general population.

Family study of Reiter's disease and HLA B27 distribution.

Starting from index patients with confirmed Reiter's disease, a clinical and immunogenetic study was performed on 12 families in which there were further cases of arthritis. Altogether 51 family members were investigated and some information was available on 15 additional members. In most families there were two or three affected members in addition to the proband.

Association of bacteriuria and rheumatoid factors in a population sample.

To obtain further information on the possible association of bacteriuria and RFs on the population level, an epidemiological study was carried out among middle-aged women in a rural area. Fifty-five of ther 1223 women aged 40-64 years had bacteriuria and 31 were under treatment for urinary tract infection. The latex test was twice as often positive among the bacteriuria women as among the persons under treatment and the age-matched controls.

IgA deficiency and influenza infection.

A prospective study of influenza was carried out on 90 blood donors deficient for serum IgA as tested with double immunodiffusion. Half of them lacked IgA even by radioimmunoassay (RIA). A correlation existed between serum haemagglutination-inhibiting (HI) antibody and resistance to infection, suggesting that the serum HI antibody was an important determinant of protection.

Virus antibody levels in IgA deficiency.

IgA-deficient blood donors and their age- and sex-matched controls were compared for the occurrence of complement-fixing antibodies in serum against several viruses. The level in the IgA-deficient persons was slightly higher against several respiratory pathogens (adenoviruses, type B influenza virus, parainfluenza virus, and respiratory syncytial virus) that give rise to localized infections, and against coxsackie B group of viruses. No corresponding difference was observed in mumps, varicella, and cytomegalovirus infections, where viraemia is a characteristic feature, or in Mycoplasma pneumoniae infection.

Effect of antiepileptic drugs on the elimination of various tetracycline derivatives.

Elimination of the bacteriostatics tetracycline, doxycycline, methacycline, oxytetracycline, demethylchlortetracycline and chlortetracycline was studied in healthy control persons and in patients on long-term antiepileptic therapy. The half-life of doxycycline was significantly shorter in patients than in the controls. The half-lives of other tetracycline derivatives and their excretion in urine were not significantly different between the two groups.

Studies on the specificity of agglutinins against human erythrocytes modified by Newcastle disease virus.

The specificity of agglutinins in human sera against human erythrocytes modified by Newcastle disease virus (NDV-O agglutinins) was studied with agglutination and agglutination inhibition techniques. Virus grown in both embryonic eggs and tissue culture was used in the experiments. The findings were compatible with the existence of four specificities of agglutinins.

Serum HI antibody and protection against influenza: a follow-up survey at community level of three epidemics caused by different H3N2-variants.

Serial blood specimens from Rh-negative pregnant women sent to laboratory for Rh antibody testing were stored and used for influenza investigations. The study period covered three epidemics, each caused by a different variant of influenza A (H3N2) virus. The relationship between pre-epidemic haemagglutination inhibiting (HI) antibody level against the epidemic virus and serological evidence of infection was analysed.

Characteristics and survival of patients with brain stem infarction.

A retrospective study of 141 patients whith ischemic brain stem infarction admitted to the Department of Neurology, University of Helsinki, during 1966 to 1973 was performed. The patients were contacted by mail in January and February, 1974; in case of death, the death certificates were procured. The follow-up period was from 4 to 99 months (median 46.