Seroprevalence of hantavirus infections in Switzerland in 2009: difficulties in determining prevalence in a country with low endemicity

Abstract

In several European countries, diagnosis of nephropathia epidemica, a mild form of haemorrhagic fever with renal syndrome (HFRS) caused by Puumalavirus infection, has increased over the past 10-20 years. In Switzerland, despite its geographical proximity to regions with epidemic outbreaks in Germany and France, infections are detected only sporadically. To estimate the actual prevalence and potential risk factors of human hantavirus infections in Switzerland, a seroepidemiological study was performed in 2009 on serum samples from 4,559 blood donors and 1,810 military personnel. Sera were screened using commercial Puumala IgG and hantavirus IgG enzyme-linked immunosorbent assays indicating a seroprevalence of 1% and 9%, respectively. Subsequently, the samples were analysed by immunofluorescence assay and immunoblot assay, showing a much lower prevalence, of 0.4% and 0.3%, respectively. Two of the serum samples achieved an 80% reduction in plaque-forming units in a neutralisation test. Statistical evaluation of questionnaires only identified an association of age (above 50 years) with hantavirus seropositivity when adjusted for sex (odds ratio: 2.36; 95% confidence interval: 1.10-5.05). This study provides baseline data (0.3-0.4%) for future monitoring of hantavirus seroprevalence in Switzerland and highlights the challenges in estimating the seroprevalence of these viruses in a country with very low endemicity.

Serological investigation of orthohantaviruses in patients with fever of unknown origin in Kazakhstan

“…In our study, the high rate of positive IgG antibodies by ELISA shown here could be false‐positive, originating from the sensitivity of the screening test. Moreover, the difference between ELISA and confirmatory assays has been shown in several orthohantavirus seroprevalence studies (Engler et al, ; Sevancan et al, ). The different results by immunoblotting and IIFT can be explained by sensitivity (immunoblotting—96.1%, IIFT—99%) and specificity (immunoblotting—100%, IIFT—98%) of the used assays (mikrogen.de, euroimmun.de).…”

“…The different results by immunoblotting and IIFT can be explained by sensitivity (immunoblotting—96.1%, IIFT—99%) and specificity (immunoblotting—100%, IIFT—98%) of the used assays (mikrogen.de, euroimmun.de). However, immunoblotting assay is used as more suitable diagnostic and confirmatory test (Engler et al, ; Escadafal et al, ). In the Almaty region some rodent studies were conducted, in which in some areas rodents were found to be positive for orthohantaviruses, but no clinical case of HFRS has officially been registered in this region so far (Plyusnina et al, ; Sutyagin et al, ).…”

Detection and Genetic Characterization of Puumala Orthohantavirus S-Segment in Areas of France Non-Endemic for Nephropathia Epidemica

“…One possible reason for this discrepancy may be that human cases are being missed because local doctors do not know enough about NE. Several serological studies have already suggested that large numbers of undiagnosed human Hantavirus infections occur in various countries [ 38 , 39 , 40 , 41 , 42 ]. However, we think that a significant number of serious cases of NE would undoubtedly have led to medical investigations and more accurate diagnosis, so this possibility seems unlikely.…”

Serological Evidence of Human Orthohantavirus Infections in Barbados, 2008 to 2016

“…For ELISA testing, the use of >1.1 OD cut-off has been previously questioned with a preference for a more stringent cutoff of >2.0 being advanced to avoid the high number of false positives [ 70 , 71 ]. From the orthohantavirus-seropositive patients ( n = 861), samples were selected for confirmatory testing ( n = 157) using criteria for further confirmatory testing which entailed having orthohantavirus-seropositive IgM test results, less than two years of frozen storage and sufficient available sample volume ( Figure 1 A).…”