Serological and molecular screening of arenaviruses in suspected tick-borne encephalitis cases in Finland.

Lymphocytic choriomeningitis virus (LCMV) is one of the arenaviruses infecting humans. LCMV infections have been reported worldwide in humans with varying levels of severity. To detect arenavirus RNA and LCMV-reactive antibodies in different geographical regions of Finland, we screened human serum and cerebrospinal fluid (CSF) samples, taken from suspected tick-borne encephalitis (TBE) cases, using reverse transcriptase polymerase chain reaction (RT-PCR) and immunofluorescence assay (IFA). No arenavirus nucleic acids were detected, and the overall LCMV seroprevalence was 4.5%. No seroconversions were detected in paired serum samples. The highest seroprevalence (5.2%) was detected among individuals of age group III (40-59 years), followed by age group I (under-20-year-olds, 4.9%), while the lowest seroprevalence (3.8%) was found in age group IV (60 years or older). A lower LCMV seroprevalence in older age groups may suggest waning of immunity over time. The observation of a higher seroprevalence in the younger age group and the decreasing population size of the main reservoir host, the house mouse, may suggest exposure to another LCMV-like virus in Finland.

External quality assessment of orthohantavirus and lymphocytic choriomeningitis virus molecular detection and serology in Europe, 2021.

BackgroundRodent-borne viruses such as orthohantaviruses and arenaviruses cause considerable disease burden with regional and temporal differences in incidence and clinical awareness. Therefore, it is important to regularly evaluate laboratory diagnostic capabilities, e.g. by external quality assessments (EQA).AimWe wished to evaluate the performance and diagnostic capability of European expert laboratories to detect orthohantaviruses and lymphocytic choriomeningitis virus (LCMV) and human antibody response towards orthohantaviruses.MethodsWe conducted an EQA in 2021; molecular panels consisted of 12 samples, including different orthohantaviruses (Seoul, Dobrava-Belgrade (DOBV), Puumala (PUUV) and Hantaan orthohantavirus), LCMV and negative controls. Serological panels consisted of six human serum samples reactive to PUUV, DOBV or negative to orthohantaviruses. The EQA was sent to 25 laboratories in 20 countries.ResultsThe accuracy of molecular detection of orthohantaviruses varied (50‒67%, average 62%) among 16 participating laboratories, while LCMV samples were successfully detected in all 11 participating laboratories (91-100%, average 96%). The accuracy of serological diagnosis of acute and past orthohantavirus infections was on average 95% among 20 participating laboratories and 82% in 19 laboratories, respectively. A variety of methods was used, with predominance of in-house assays for molecular tests, and commercial assays for serological ones.ConclusionSerology, the most common tool to diagnose acute orthohantavirus infections, had a high accuracy in this EQA. The molecular detection of orthohantaviruses needs improvement while LCMV detection (performed in fewer laboratories) had 95% accuracy. Further EQAs are recommended to be performed periodically to monitor improvements and challenges in the diagnostics of rodent-borne diseases.

Serologic Surveillance for SARS-CoV-2 Infection among Wild Rodents, Europe.

We report results from serologic surveillance for exposure to SARS-CoV-2 among 1,237 wild rodents and small mammals across Europe. All samples were negative, with the possible exception of 1. Despite suspected potential for human-to-rodent spillover, no evidence of widespread SARS-CoV-2 circulation in rodent populations has been reported to date.Esitämme tulokset serologisesta tutkimuksesta, jossa seulottiin SARS-CoV-2 tartuntojen varalta 1,237 luonnonvaraista jyrsijää ja piennisäkästä eri puolilta Eurooppaa. Kaikki näytteet olivat negatiivisia, yhtä näytettä lukuun ottamatta. SARS-CoV-2:n läikkymisen ihmisistä jyrsijöihin on arveltu olevan mahdollista, mutta todisteet viruksen laajamittaisesta leviämisestä jyrsijäpopulaatioissa puuttuvat.

Incidence Trends for SARS-CoV-2 Alpha and Beta Variants, Finland, Spring 2021.

Severe acute respiratory syndrome coronavirus 2 Alpha and Beta variants became dominant in Finland in spring 2021 but had diminished by summer. We used phylogenetic clustering to identify sources of spreading. We found that outbreaks were mostly seeded by a few introductions, highlighting the importance of surveillance and prevention policies.

Lymphocytic Choriomeningitis Virus Infections and Seroprevalence, Southern Iraq.

Acute febrile neurological infection cases in southern Iraq (N = 212) were screened for lymphocytic choriomeningitis virus (LCMV). Two LCMV IgM-positive serum samples and 2 cerebrospinal fluid samples with phylogenetically distinct LCMV strains were found. The overall LCMV seroprevalence was 8.8%. LCMV infections are common and associated with acute neurological disease in Iraq.

Bombali Virus in Mops condylurus Bat, Kenya.

Bombali virus (genus Ebolavirus) was identified in organs and excreta of an Angolan free-tailed bat (Mops condylurus) in Kenya. Complete genome analysis revealed 98% nucleotide sequence similarity to the prototype virus from Sierra Leone. No Ebola virus-specific RNA or antibodies were detected from febrile humans in the area who reported contact with bats.

Evolution and genetic characterization of Seoul virus in wild rats Rattus norvegicus from an urban park in Lyon, France 2020-2022.

BACKGROUND: Seoul virus (SEOV) is an orthohantavirus primarily carried by rats. In humans, it may cause hemorrhagic fever with renal syndrome (HFRS). Its incidence is likely underestimated and given the expansion of urban areas, a better knowledge of SEOV circulation in rat populations is called for. Beyond the need to improve human case detection, we need to deepen our comprehension of the ecological, epidemiological, and evolutionary processes involved in the transmission of SEOV. METHODOLOGY / PRINCIPAL FINDINGS: We performed a comprehensive serological and molecular characterization of SEOV in Rattus norvegicus in a popular urban park within a large city (Lyon, France) to provide essential information to design surveillance strategies regarding SEOV. We sampled rats within the urban park of 'La Tête d'Or' in Lyon city from 2020 to 2022. We combined rat population genetics, immunofluorescence assays, SEOV high-throughput sequencing (S, M, and L segments), and phylogenetic analyses. We found low structuring of wild rat populations within Lyon city. Only one sampling site within the park (building created in 2021) showed high genetic differentiation and deserves further attention. We confirmed the circulation of SEOV in rats from the park with high seroprevalence (17.2%) and high genetic similarity with the strain previously described in 2011 in Lyon city. CONCLUSION/SIGNIFICANCE: This study confirms the continuous circulation of SEOV in a popular urban park where the risk for SEOV transmission to humans is present. Implementing a surveillance of this virus could provide an efficient early warning system and help prepare risk-based interventions. As we reveal high gene flow between rat populations from the park and the rest of the city, we advocate for SEOV surveillance to be conducted at the scale of the entire city.

Hibernating vesper bats are a weak source for biomonitoring of coronaviruses.

Background: Our study explores the role of bats as reservoirs of coronaviruses. Methods: We conducted virological screening of bats hibernating in military bunkers at the Natura 2000 site "Nietoperek" in Western Poland collecting oral and anal swab samples from 138 bats across six species to apply a combination of pan-coronavirus and SARS-CoV-2 specific PCR assays. Results: Only one anal swab tested positive for coronavirus. No SARS-CoV-2 was detected in any of the samples. The low prevalence of coronavirus in the studied colony contrasts with higher rates found in other regions and may be influenced by hibernation. Conclusions: Hibernating bats may show a low prevalence of coronavirus, potentially due to the hibernation process itself. This finding indicates that hibernating bats may not be the most optimal subjects for screening zoonotic pathogens. However, biomonitoring of bats for emerging and reemerging diseases is recommended for comprehensive epidemiological insights.

Puumala orthohantavirus circulation in its wild reservoir, the bank vole, during the 2021 outbreak of hemorrhagic fever with renal syndrome in Jura, France.

OBJECTIVE: A large and unprecedented outbreak of an attenuated form of hemorrhagic fever with renal syndrome called nephropathia epidemica (NE) and caused by Puumala virus (PUUV) occurred in 2021 in the southern Jura Mountains (France) leading to numerous hospitalizations. The aim of this study was to investigate the circulation of PUUV in its animal reservoir at the time of this outbreak. METHODS: We conjointly surveyed bank vole relative abundance, small mammal community composition, and PUUV circulation in bank voles (seroprevalence and genetic diversity) in the Jura NE epidemic area, between 2020 and 2022. RESULTS: Trapping results showed a higher relative abundance of bank voles in 2021 compared to 2020 and 2022. Extremely high levels of PUUV seroprevalence in bank voles were found at the time of the human NE epidemic with seropositive animals trapped in almost all trap lines as of spring 2021. Genetic analyses of PUUV (S segment) gathered in 2021 at two sampling sites revealed a strong clustering of these strains within the "Jura" clade. No significant genetic variation was detected compared to what was already known to be circulating in the Jura region. CONCLUSION: These results underline a need for enhanced monitoring of PUUV circulation in host reservoir populations in NE endemic areas. This would enable the relevant actors to better inform and sensitize the public on this zoonotic risk, and to implement prevention strategies in collaboration with physicians.

High prevalence of an alpha variant lineage with a premature stop codon in ORF7a in Iraq, winter 2020-2021.

Since the first reported case of coronavirus disease 2019 (COVID-19) in China, SARS-CoV-2 has been spreading worldwide. Genomic surveillance of SARS-CoV-2 has had a critical role in tracking the emergence, introduction, and spread of new variants, which may affect transmissibility, pathogenicity, and escape from infection or vaccine-induced immunity. As anticipated, the rapid increase in COVID-19 infections in Iraq in February 2021 is due to the introduction of variants of concern during the second wave of the COVID-19 pandemic. To understand the molecular epidemiology of SARS-CoV-2 during the second wave in Iraq (2021), we sequenced 76 complete SARS-CoV-2 genomes using NGS technology and identified genomic mutations and proportions of circulating variants among these. Also, we performed an in silico study to predict the effect of the truncation of NS7a protein (ORF7a) on its function. We detected nine different lineages of SARS-CoV-2. The B.1.1.7 lineage was predominant (80.20%) from February to May 2021, while only one B.1.351 strain was detected. Interestingly, the phylogenetic analysis showed that multiple strains of the B.1.1.7 lineage clustered closely with those from European countries. A notable frequency (43.33%) of stop codon mutation (NS7a Q62stop) was detected among the B.1.1.7 lineage sequences. In silico analysis of NS7a with Q62stop found that this stop codon had no considerable effect on the function of NS7a. This work provides molecular epidemiological insights into the spread variants of SARS-CoV-2 in Iraq, which are most likely imported from Europe.

Serological Evidence of Exposure to Onyong-Nyong and Chikungunya Viruses in Febrile Patients of Rural Taita-Taveta County and Urban Kibera Informal Settlement in Nairobi, Kenya.

Several alphaviruses, such as chikungunya (CHIKV) and Onyong-nyong (ONNV), are endemic in Kenya and often cause outbreaks in different parts of the country. We assessed the seroprevalence of alphaviruses in patients with acute febrile illness in two geographically distant areas in Kenya with no previous record of alphavirus outbreaks. Blood samples were collected from febrile patients in health facilities located in the rural Taita-Taveta County in 2016 and urban Kibera informal settlement in Nairobi in 2017 and tested for CHIKV IgG and IgM antibodies using an in-house immunofluorescence assay (IFA) and a commercial ELISA test, respectively. A subset of CHIKV IgG or IgM antibody-positive samples were further analyzed using plaque reduction neutralization tests (PRNT) for CHIKV, ONNV, and Sindbis virus. Out of 537 patients, 4 (0.7%) and 28 (5.2%) had alphavirus IgM and IgG antibodies, respectively, confirmed on PRNT. We show evidence of previous and current exposure to alphaviruses based on serological testing in areas with no recorded history of outbreaks.

Genome Sequence of an Early Imported Case of SARS-CoV-2 Delta Variant (B.1.617.2 AY.122) in Iraq in April 2021.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Delta variant was first reported in India. Thereafter, the Delta variant became the most prevalent variant globally. Here, we report the complete genome sequence of an early imported case of a SARS-CoV-2 B.1.617.2 AY.122 strain in Iraq. The strain was obtained from a flight passenger from India to Iraq on 20 April 2021.

The phylodynamics of SARS-CoV-2 during 2020 in Finland.

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused millions of infections and fatalities globally since its emergence in late 2019. The virus was first detected in Finland in January 2020, after which it rapidly spread among the populace in spring. However, compared to other European nations, Finland has had a low incidence of SARS-CoV-2. To gain insight into the origins and turnover of SARS-CoV-2 lineages circulating in Finland in 2020, we investigated the phylogeographic and -dynamic history of the virus. Methods: The origins of SARS-CoV-2 introductions were inferred via Travel-aware Bayesian time-measured phylogeographic analyses. Sequences for the analyses included virus genomes belonging to the B.1 lineage and with the D614G mutation from countries of likely origin, which were determined utilizing Google mobility data. We collected all available sequences from spring and fall peaks to study lineage dynamics. Results: We observed rapid turnover among Finnish lineages during this period. Clade 20C became the most prevalent among sequenced cases and was replaced by other strains in fall 2020. Bayesian phylogeographic reconstructions suggested 42 independent introductions into Finland during spring 2020, mainly from Italy, Austria, and Spain. Conclusions: A single introduction from Spain might have seeded one-third of cases in Finland during spring in 2020. The investigations of the original introductions of SARS-CoV-2 to Finland during the early stages of the pandemic and of the subsequent lineage dynamics could be utilized to assess the role of transboundary movements and the effects of early intervention and public health measures.

Seroevidence of Zoonotic Viruses in Rodents and Humans in Kibera Informal Settlement, Nairobi, Kenya.

Rodents are known reservoir hosts for a number of pathogens that can spillover into humans and cause disease. These threats are likely to be elevated in informal urban settlements (i.e., slums), where rodent and human densities are often high, rodents live in close proximity to humans, and human knowledge of disease risks and access to health care is often limited. While recent research attention has focused on zoonotic risks posed by urban rodents in major cities around the world, informal urban settlements have received far less attention. Here we report on a study in which samples were collected from 195 commensal rodents and 124 febrile human patients in the Kibera informal settlement in Nairobi, Kenya (one of the largest informal urban settlements in the world). Using immunofluorescence assays, samples were screened for antibodies against common rodent-borne zoonotic virus groups, namely orthopoxviruses, arenaviruses, and hantaviruses. We detected antibodies against orthopoxviruses in rodents (4.1% positive) and antibodies in humans against orthopoxviruses, arenaviruses, and hantaviruses (4.8%, 3.2%, and 8.1% positive, respectively). No rodents had antibodies against arenaviruses or hantaviruses. These results provide strong evidence for the circulation of zoonotic viruses in rodents and humans in Kibera urban settlement, but discordance between viruses detected in host groups indicates that other species or taxa may also serve as reservoirs for these zoonotic viruses or that humans testing positive could have been exposed outside of the Kibera settlement. More broadly, this study highlights the threat posed by zoonotic viruses in informal urban settlements and the need to mitigate human exposure risks.