Cross-sectional survey on hantavirus seroprevalence in Canton St. Gallen, Switzerland.

BACKGROUND AND OBJECTIVES: In 2002 the first endemic hantavirus infection in Switzerland was detected only by chance following a broad spectrum of diagnostics. This raised the question, whether Hantavirus infection should be included in the differential diagnosis of febrile illness of patients in Switzerland. In order to estimate the frequency of hantavirus infections in Switzerland, this survey on hantaviral seroprevalence was conducted in the Canton St. Gallen. METHODS: A total of 1693 sera from farmers, forestry workers, and young soldiers as well as blood donors, as a cross-section of the average adult population of the Canton St. Gallen, were screened for hantavirus-specific antibodies by a microsphere-based assay. All volunteers with positive screening results obtained a questionnaire for assessment of details of previous rodent encounter and illnesses compatible with hantavirus infection. RESULTS: This first survey on hantavirus-specific IgG in populations of eastern Switzerland revealed low seroprevalence-rates not significantly different among populations with higher risk for hantavirus infection (0.0%-1.9%) and the average adult population (0.5%). CONCLUSIONS: As hantavirus infections among different populations are rare, and no evidence for hantaviral nephropathy could be found, serological investigation of suspected endemic hantavirus infection in eastern Switzerland should be confined to patients with acute nephropathy and/or a history of recent rodent encounter.

Phylogenetic analysis of clinical mumps virus isolates from vaccinated and non-vaccinated patients with mumps during an outbreak, Switzerland 1998-2000.

During the past decade mumps outbreaks have occurred in several European countries with universal vaccination programs probably due to poor efficacy of the Rubini vaccine strain. However, the evolution of vaccine escape mutants has also been considered. A phylogenetic analysis was undertaken on 69 clinical mumps isolates obtained from 39 vaccinated and 22 non-vaccinated mumps cases (and six cases with unknown vaccination status) during an outbreak in 1998-2000. Two major strain clusters (SWI-H, SWI-C) with two subgroups each (SWI-H1/2, SWI-C1/2) were identified, which belonged to genotypes C and H. No association between viral clusters and vaccination status or a specific vaccine strain (Jeryl-Lynn or Rubini) was found. Cluster SWI-C1 occurred more frequently in the Western part of Switzerland (P < 0.001). Isolates causing complicated disease tended to cluster more frequently with SWI-H1 (P = 0.11). Wild-type strains homologous or similar to the Rubini vaccine strain (isolated in Switzerland in 1974) were no longer circulating. Therefore, there was no evidence for vaccine escape mutants. Strain redistribution may have occurred during the past decades. Continuous monitoring of circulating mumps virus populations is needed.

Comparison of the effectiveness of two mumps vaccines during an outbreak in Switzerland in 1999 and 2000: a case-cohort study.

In two recent nation-wide outbreaks of mumps in Switzerland two-thirds of young children with clinical mumps had a history of primary vaccination. On average, measles-mumps-rubella (MMR) vaccination coverage is 80%. Two types of vaccine are commonly used: Jeryl-Lynn and Rubini. The effectiveness of the latter has been questioned in several publications. The authors therefore compared Rubini to Jeryl-Lynn in a case-cohort study. The study included 111 young children with clinical mumps who had been reported to the Swiss Federal Office of Public Health (SFOPH) by primary care physicians of the Swiss Sentinel Surveillance Network (SSSN) between January 1999 and May 2000. Sentinel physicians also sampled 661 children from the same birth cohort as the cases. While we found no evidence for the effectiveness of the Rubini strain, vaccination with the Jeryl-Lynn strain was 70% effective against clinical mumps. Furthermore, children vaccinated with the Rubini strain attended primary health care more frequently with clinical mumps than those who had received Jeryl-Lynn (odds ratio: 2.4; 95% confidence interval (CI): 1.3, 4.7). Restricting the analysis to laboratory confirmed cases increased the odds ratio to 18.4 (95% CI: 2.5, 811.2). Our study confirms the low effectiveness of the Rubini strain vaccine in the field. This vaccine should therefore be considered inappropriate for the control and elimination of mumps and its use should be discontinued. As other vaccines with comparable quality and safety standards and a substantially higher effectiveness are available the MMR vaccination program in Switzerland will not be compromised if the use of Rubini is no longer recommended.

Nationwide surveillance of nasopharyngeal Streptococcus pneumoniae isolates from children with respiratory infection, Switzerland, 1998-1999.

The surveillance of pneumococcal antibiotic resistance and serotype distribution is hampered by the relatively low numbers of invasive pneumococcal infections. In Switzerland, a nationwide sentinel surveillance network was used to assess antibiotic resistance and serotype distribution among 1179 pneumococcal isolates cultured from 2769 nasopharyngeal swabs obtained from outpatients with acute otitis media or pneumonia during 1998 and 1999. The proportion of penicillin-susceptible pneumococcal isolates overall (87%) and among infants <2 years old (81%) was comparable to that of invasive isolates (90% and 81%, respectively). The high number of nasopharyngeal isolates allowed for the detection of a rapid increase in the number of penicillin-nonsusceptible pneumococcal (PNSP) strains in the West region of Switzerland, partly because of an epidemic caused by the 19F clone of Streptococcus pneumoniae. Clustering of risk factors for the carriage of PNSP isolates further explained the geographic variation in resistance rates. The nationwide sentinel surveillance of nasopharyngeal pneumococcus proved to be valuable for the monitoring of antibiotic resistance, risk factors for carriage of PNSP isolates, and serotype distribution and for the detection of the emergence of a new epidemic clone.

National laboratory reports of Chlamydia trachomatis seriously underestimate the frequency of genital chlamydial infections among women in Switzerland.

BACKGROUND: Public health authorities want to evaluate their sexually transmitted disease (STD) surveillance systems to promote the most effective use of health resources. GOAL: The goal of this study was to estimate the sensitivity of national laboratory reports of in Switzerland (the proportion of cases detected by national laboratory reports). STUDY DESIGN: A cross sectional prevalence study was conducted by the Swiss Sentinel Surveillance Network of Gynecologists in 1998. Two groups of women aged less than 35 years were included in the study: those having a first consultation for pregnancy and those having a routine check-up. RESULTS: A total of 1589 women were tested for. The prevalence among pregnant women (n = 817) was 1.3%, and that among sexually active women (n = 772) was 2.8%. Using the prevalences observed among check-up women, we estimate that there were at least 24,400 infections in Switzerland among women aged 20 to 34 years in 1998 (95% CI: 14,300-34,300). The number of laboratory reports of in this age group was 1,150 in 1998. CONCLUSION: Our study suggests that the sensitivity of national laboratory reports of in 1998 was less than 5% for women aged 20 to 34 years.