A cohort of 839 young girls at the ages of 14 and 15 years was screened for total antibodies to herpes simplex virus (HSV) and, if positive, for specific antibodies to HSV-2, by means of a sensitive, enzyme-linked immunosorbent assay (ELISA). The cohort was followed from 1972-1987. Blood samples were obtained on six occasions during these 16 years. In total, 2270 blood samples were taken. The number of sero-converting girls was studied in relation to calendar time. Two methods were constructed for the statistical analyses. The first of these gave an estimate of the sero-prevalence at different points in time. This analysis showed that the sero-prevalence which was 23% against HSV-1 in 1972 had increased to 36% in 1976. At the end of the study in 1987, 50% of the cohort had sero-converted against HSV-1. The proportion of girls who had sero-converted against HSV-2 was 0.4% in the 14-15-year-olds and had reached 22% by the end of the study. The second statistical method used all the available information implicit in the observations so as to obtain a maximum-likelihood (ML) estimate of the prevalence. The ML estimates were slightly more precise, but the two estimates did not differ significantly. The observations were further analysed by the Mantel-Haenszel test in order to see if there was any dependence between positivity to HSV-1 and HSV-2 respectively but none was found.
In 1994 the first human parvovirus B19 (B19) epidemic to be documented in Denmark was recorded from February 2 to September 30. In total, 10,333 serum samples were tested for specific B19 IgM and IgG antibodies, using IDEIA Parvovirus B19 IgM and IgG kits. The prevalence of B19 IgM positivity was 11% for the whole period and 29% at the peak of the epidemic in week 14, declining from week 39 and onwards to 1-3%. The prevalence of B19 IgG (IgM-negative samples) was 60%, indicating an earlier infection, and the same for men and women. The gender distribution of tested patients was the same at the beginning of the epidemic as at the end of the epidemic and a year after its peak, i.e. 86% of samples were from women and only 14% from men. Age distribution for women was the same for the three periods (median age 34 years). For men the median age was 32 years, 39 years and 31 years, respectively. Only a few samples from children were tested. No change in test pattern was observed during the three periods. Approximately 75% of all samples tested were from women of childbearing age (18-45 years old), suggesting a fear of fetal complications in an actual or future pregnancy, rather than a serological verification of clinical symptoms. From the sparse clinical information that accompanied the serum sample we were not able to demonstrate that women were more likely than men to have a symptomatic B19 infection. With reservations we estimate that 14% of adverse pregnancy outcome is correlated with a B19 infection.
Regular vaccination against poliomyelitis was started in 1960 with oral polio vaccine (OPV). Since 1992 a trivalent OPV has been administered in five doses within a nationwide vaccination campaign. The immunization coverage varies between 96.8% and 98.2% after 4 OPV doses, reaching 98.0% to 98.9% after the fifth dose. No case of indigenous poliomyelitis has been reported in the Czech Republic since the second half of 1960. In 2001, 3,230 sera were tested for the presence of antibodies against poliovirus of types 1, 2 and 3 using a virus neutralization microassay. The prevalence rates of antibodies vary between 96.0% and 100% for types 1 and 2 and between 95.1% and 100% for type 3, with the exception of the highest age group, in which the prevalence rates of antibodies against poliovirus of all three types are 92.2%.
The human bocavirus (HBoV), a newly discovered parvovirus, is closely related to the bovine parvovirus and the canine minute virus, which are known to cause adverse pregnancy outcomes. Another human parvovirus, B19, can lead to fetal hydrops, miscarriage and intrauterine fetal death (IUFD).
To determine the prevalence of HBoV DNA in aborted fetuses and IUFDs. The HBoV serology of the mothers was also studied.
We retrospectively studied all available fetuses (N=535) autopsied during 7/1992-12/1995, and 1/2003-12/2005 in Helsinki, Finland. All available formalin-fixed paraffin-embedded fetal tissues - placenta, heart and liver - of 120 miscarriages, 169 IUFDs, and 246 induced abortions were studied by quantitative PCR. We also measured the HBoV IgM and IgG antibodies in the corresponding maternal sera (N=462) mostly of the first trimester. The IgM-positive sera underwent HBoV PCR.
None of the fetal tissues harbored HBoV DNA. A total of 97% (448/462) of the mothers were positive for IgG antibodies to HBoV, while only 0.9% (4/462) exhibited HBoV-specific IgM antibodies without viremia or respiratory symptoms. One IgM-positive mother had an unexplained fetal loss.
We did not find HBoV DNA in any of the deceased fetuses. Almost all pregnant women were HBoV-IgG positive.
In the last several years, West Nile virus (WNV) was proven to be present especially in the neighboring countries of Austria, such as Italy, Hungary, and the Czech Republic, as well as in eastern parts of Austria, where it was detected in migratory and domestic birds. In summer 2010, infections with WNV were reported from Romania and northern Greece with about 150 diseased and increasingly fatal cases. We tested the sera of 1,607 blood donors from North Tyrol (Austria) and South Tyrol (Italy) for antibodies against WNV by using IgG enzyme-linked immunosorbent assay (ELISA). Initial results of the ELISA tests showed seroprevalence rates of 46.2% in North Tyrol and 0.5% in South Tyrol, which turned out to be false-positive cross-reactions with antibodies against tick-borne encephalitis virus (TBEV) by adjacent neutralization assays. These results indicate that seropositivity against WNV requires confirmation by neutralization assays, as cross-reactivity with TBEV is frequent and because, currently, WNV is not endemic in the study area.
The recently discovered human parvovirus 4 (PARV4) is found most frequently in injection drug users, HIV-positive patients, and in haemophiliacs. Studies from Ghana report the finding of PARV4 in plasma from 2 to 12% of children without acute infection, and in nasal secretions and faecal samples. Studies of PARV4 in children from industrialized countries are few.
We aimed to describe the occurrence of PARV4 in a population-based birth cohort of 228 Danish mothers and their healthy children who previously participated in a study of respiratory tract infections in infancy.
Children were included over a whole calendar year and were monitored through monthly home visits through the first year of life. Plasma samples for the present study were available from 228 mothers, 176 newborns, and 202 12-months-old children. All samples were analysed for the presence of PARV4 antibodies by enzyme immunoassay, and samples with detectable antibodies were in addition studied by real-time PCR.
One (0.4%) of 228 mothers had PARV4 IgG exceeding the cut-off absorbance level and another had borderline IgG reactivity. No mother among these two had an acute infection, as they were IgM and PARV4 DNA negative. All blood samples from newborns and one-year-old children had IgG and IgM reactivity below cut-off.
PARV4 is rare in Danish mothers and infants. Further studies are needed, in both rural and urban settings, to investigate the epidemiology and clinical significance of this novel human parvovirus.
The rhesus monkey virus Simian Virus 40 (SV40) is a member of the polyomavirus family. It was introduced inadvertently to human populations through contaminated polio vaccine during the years 1956-1963, can induce experimental tumors in animals and transform human cells in culture. SV40 DNA has been identified in mesothelioma and other human tumors in some but not all studies. We tested prediagnostic sera from 49 mesothelioma cases and 147 matched controls for antibodies against the viral capsid protein VP1 and the large T antigen of SV40 and of the closely related human polyomaviruses BK and JC, and for SV40 DNA. Cases and controls were identified among donors to the Janus Serum Bank, which was linked to the Cancer Registry of Norway. Antibodies were analyzed by recently developed multiplex serology based on recombinantly expressed fusions of glutathione-S transferase with viral proteins as antigens combined with fluorescent bead technology. BKV and JCV specific antibodies cross- reactive with SV40 were preabsorbed with the respective VP1 proteins. Sera showing SV40 reactivity after preabsorption with BKV and JCV VP1 were further analyzed in SV40 neutralization assays. SV40 DNA was analyzed by SV40 specific polymerase chain reactions. The odds ratio for being a case when tested positive for SV40 VP1 in the antibody capture assay was 1.5 (95% CI 0.6-3.7) and 2.0 (95% CI 0.6-7.0) when only strongly reactive sera where counted as positive. Although some sera could neutralize SV40, preabsorption with BKV and JCV VP1 showed for all such sera that this neutralizing activity was due to cross-reacting antibodies and did not represent truly SV40-specific antibodies. No viral DNA was found in the sera. No significant association between SV40 antibody response in prediagnostic sera and risk of mesothelioma was seen.
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.
Schoolchildren of 30 to 34 schools of Novgorod were vaccinated over a three-year period with Russian live cold-adapted attenuated vaccine for children and whole-virus inactivated vaccines and placebo for comparative field study of the vaccines properties and efficacy. In control trials both bi- and trivalent live attenuated vaccines were well tolerated and areactogenic. A whole-virus inactivated trivalent vaccine induced mild and moderate fever and local reactions in 2-4% of the vaccinees. Special observations are necessary to establish the possibility of use and to determine a dose of this inactivated vaccine for immunization of children, especially those of 7-10 years of age. All the vaccines induced HI antibody production in 50-80% and antineuraminidase in 50-70% of seronegative children. The pattern of the results was similar to that in revaccinated children with preexisting antibody at a level of 1:20, but much lower in children with the initial titre above 1:20. After the 3rd year of vaccination the immune response of the vaccinees was similar, most of the results depending on the initial antibody titre and also on the change of vaccine strains. This raises a question of the expediency of annual influenza revaccination of the same person after 2 years of successful immunization and of the necessity of vaccine strains replacement after 2-3 years of use.