Concordance of cerebrospinal fluid real-time quaking-induced conversion across the European Creutzfeldt-Jakob Disease Surveillance Network.

BACKGROUND AND PURPOSE: Cerebrospinal fluid (CSF) real-time quaking-induced conversion (RT-QuIC) has a high degree of sensitivity and specificity for the diagnosis of sporadic Creutzfeldt-Jakob disease (sCJD) and this has led to its being included in revised European CJD Surveillance Network diagnostic criteria for sCJD. As CSF RT-QuIC becomes more widely established, it is crucial that the analytical performance of individual laboratories is consistent. The aim of this ring-trial was to ascertain the degree of concordance between European countries undertaking CSF RT-QuIC. METHODS: Ten identical CSF samples, seven from probable or neuropathologically confirmed sCJD and three from non-CJD cases, were sent to 13 laboratories from 11 countries for RT-QuIC analysis. A range of instrumentation and different recombinant prion protein substrates were used. Each laboratory analysed the CSF samples blinded to the diagnosis and reported the results as positive or negative. RESULTS: All 13 laboratories correctly identified five of the seven sCJD cases and the remaining two sCJD cases were identified by 92% of laboratories. Of the two sCJD cases that were not identified by all laboratories, one had a disease duration >26 months with a negative 14-3-3, whilst the remaining case had a 4-month disease duration and a positive 14-3-3. A single false positive CSF RT-QuIC result was observed in this study. CONCLUSIONS: This study shows that CSF RT-QuIC demonstrates an excellent concordance between centres, even when using a variety of instrumentation, recombinant prion protein substrates and CSF volumes. The adoption of CSF RT-QuIC by all CJD surveillance centres is recommended.

Evaluation of 11 SARS-CoV-2 antibody tests by using samples from patients with defined IgG antibody titers.

We evaluated the performance of 11 SARS-CoV-2 antibody tests using a reference set of heat-inactivated samples from 278 unexposed persons and 258 COVID-19 patients, some of whom contributed serial samples. The reference set included samples with a variation in SARS-CoV-2 IgG antibody titers, as determined by an in-house immunofluorescence assay (IFA). The five evaluated rapid diagnostic tests had a specificity of 99.0% and a sensitivity that ranged from 56.3 to 81.6% and decreased with low IFA IgG titers. The specificity was > 99% for five out of six platform-based tests, and when assessed using samples collected ≥ 22 days after symptom onset, two assays had a sensitivity of > 96%. These two assays also detected samples with low IFA titers more frequently than the other assays. In conclusion, the evaluated antibody tests showed a heterogeneity in their performances and only a few tests performed well with samples having low IFA IgG titers, an important aspect for diagnostics and epidemiological investigations.

Retrospective meta-transcriptomic identification of severe dengue in a traveller returning from Africa to Sweden, 1990.

Pathogens associated with haemorrhagic fever commonly have zoonotic origins. The first documented imported case of likely viral severe haemorrhagic fever in Sweden occurred in 1990. Despite extensive study, no aetiological agent was identified. Following retrospective investigation with total RNA-sequencing of samples collected between 7 and 36 days from onset of symptoms we identified dengue virus 3 (DENV-3) and a human pegivirus (HPgV). We conclude that the patient likely suffered from haemorrhagic symptoms due to an atypical severe and undiagnosed dengue infection.

Genetic analyses of Seoul hantavirus genome recovered from rats (Rattus norvegicus) in the Netherlands unveils diverse routes of spread into Europe.

Seoul virus (SEOV) is the etiologic agent of hemorrhagic fever with renal syndrome. It is carried by brown rats (Rattus norvegicus), a commensal rodent that closely cohabitates with humans in urban environments. SEOV has a worldwide distribution, and in Europe, it has been found in rats in UK, France, Sweden, and Belgium, and human cases of SEOV infection have been reported in Germany, UK, France, and Belgium. In the search of hantaviruses in brown rats from the Netherlands, we found both serological and genetic evidence for the presence of SEOV in the local wild rat population. To further decipher the relationship with other SEOV variants globally, the complete genome of SEOV in the Netherlands was recovered. SEOV sequences obtained from three positive rats (captured at close trapping locations at the same time) were found highly similar. Phylogenetic analyses demonstrated that two lineages of SEOV circulate in Europe. Strains from the Netherlands and UK, together with the Baxter strain from US, constitute one of these two, while the second includes strains from Europe and Asia. Our results support a hypothesis of diverse routes of SEOV spread into Europe. These findings, combined with other indications on the expansion of the spatial European range of SEOV, suggest an increased risk of this virus for the public health, highlighting the need for increased surveillance.

Discovery of Novel Viruses in Mosquitoes from the Zambezi Valley of Mozambique.

Mosquitoes carry a wide variety of viruses that can cause vector-borne infectious diseases and affect both human and veterinary public health. Although Mozambique can be considered a hot spot for emerging infectious diseases due to factors such as a rich vector population and a close vector/human/wildlife interface, the viral flora in mosquitoes have not previously been investigated. In this study, viral metagenomics was employed to analyze the viral communities in Culex and Mansonia mosquitoes in the Zambezia province of Mozambique. Among the 1.7 and 2.6 million sequences produced from the Culex and Mansonia samples, respectively, 3269 and 983 reads were classified as viral sequences. Viruses belonging to the Flaviviridae, Rhabdoviridae and Iflaviridae families were detected, and different unclassified single- and double-stranded RNA viruses were also identified. A near complete genome of a flavivirus, tentatively named Cuacua virus, was obtained from the Mansonia mosquitoes. Phylogenetic analysis of this flavivirus, using the NS5 amino acid sequence, showed that it grouped with 'insect-specific' viruses and was most closely related to Nakiwogo virus previously identified in Uganda. Both mosquito genera had viral sequences related to Rhabdoviruses, and these were most closely related to Culex tritaeniorhynchus rhabdovirus (CTRV). The results from this study suggest that several viruses specific for insects belonging to, for example, the Flaviviridae and Rhabdoviridae families, as well as a number of unclassified RNA viruses, are present in mosquitoes in Mozambique.

Hantavirus in new geographic regions, Sweden.

In Sweden, human cases of Puumala hantavirus (PUUV) infections are reported from the northern endemic regions. We found hantavirus-specific antibodies in yellow-necked mice (Apodemus flavicollis) trapped in human dwellings in the surroundings of the cities of Uppsala and Stockholm, which are situated far south from the traditional endemic areas of PUUV. Because the yellow-necked mouse is the most common rodent in human dwellings, hantaviruses in this rodent species may be important for the public health.

Two clinical cases of renal syndrome caused by Dobrava/Saaremaa hantaviruses imported to the Netherlands from Poland and Belarus, 2012-2014.

We report the rare event of two imported cases in the Netherlands presenting with renal syndrome caused by Dobrava (DOBV)/Saaremaa (SAAV) hantaviruses. DOBV/SAAV hantaviruses are not circulating in the Netherlands and their clinical manifestation is typically more severe than that of the endemic Puumala virus (PUUV). This report aims to increase awareness among healthcare professionals and diagnostic laboratories to consider different hantaviruses as a cause of renal failure.

Emerging Viruses in the Republic of Suriname: Retrospective and Prospective Study into Chikungunya Circulation and Suspicion of Human Hantavirus Infections, 2008-2012 and 2014.

INTRODUCTION: Suriname is a country on the northeastern Atlantic coast of South America. It is unique in the sense that different ethnic cultures live together within the country, resulting in high levels of transport of both humans and products between the Asian, African, and European continents as well as the Caribbean. Travel is only one of the many factors present in Suriname contributing to the risk for the emergence or introduction of any infectious disease. Recently, circulation of both chikungunya virus (CHIKV) and hantavirus was reported in areas neighboring Suriname. Here we report a retrospective and prospective study into chikungunya and hantavirus circulation. METHODS: A chikungunya and hantavirus retrospective serological study was conducted on samples submitted for dengue, leptospirosis, and/or influenza virus diagnostics between 2008 and 2012 to the Bureau of Public Health in Suriname. This was followed by a prospective CHIKV serological and molecular surveillance study until the detection of the first autochthonous CHIKV cases in Suriname in May and June of 2014. RESULTS: None of the tested samples showed the presence of CHIKV antibodies in the retrospective serological study. Prospective testing of CHIKV-suspected patients resulted in the detection of the first autochthonous CHIKV cases in Suriname in May, 2015. In one sample, we were able to isolate and sequence the virus. Retrospective testing for the presence of hantavirus antibodies showed a relative high response in both pan-hantavirus enzyme-linked immunosorbent assay (ELISA) and immunofluorescence assay (IFA). However, neutralization tests did not yield any evidence for infection with either Seoul or Andes hantavirus. CONCLUSION: Here we report the presence of CHIKV in the republic of Suriname and the first serological indication of hantavirus infections in symptomatic patients.

Culex torrentium Mosquito Role as Major Enzootic Vector Defined by Rate of Sindbis Virus Infection, Sweden, 2009.

We isolated Sindbis virus (SINV) from the enzootic mosquito vectors Culex torrentium, Cx. pipiens, and Culiseta morsitans collected in an area of Sweden where SINV disease is endemic. The infection rate in Cx. torrentium mosquitoes was exceptionally high (36 infections/1,000 mosquitoes), defining Cx. torrentium as the main enzootic vector of SINV in Scandinavia.

First evidence of Seoul hantavirus in the wild rat population in the Netherlands.

We report the first detection of Seoul hantavirus (SEOV)-specific antibodies in the wild brown rat population in the Netherlands. SEOV-reactive antibodies were found in three rats out of 16 in a repeated series of tests including immunofluorescence assay, immunoblot, and enzyme-linked immunosorbent assay. Focus reduction neutralization test confirmed the presence of SEOV-specific antibodies, and reverse-transcription polymerase chain reaction (RT-PCR) confirmed the presence of hantaviral RNA. This discovery follows the recent findings of SEOV infections in wild and pet brown rats and humans in England, Wales, France, Belgium, and Sweden, indicating an even higher importance of this hantavirus for public health in large areas of Europe.