Differential susceptibility of geographically distinct populations to tick-borne encephalitis virus and louping ill virus.

Tick-borne encephalitis virus (TBEV) is an emerging pathogen in the Netherlands. Multiple divergent viral strains are circulating and the focal distribution of TBEV remains poorly understood. This may, however, be explained by differences in the susceptibility of tick populations for specific viruses and viral strains, and by viral strains having higher infection success in their local tick population.

Multiplex Serology for Sensitive and Specific Flavivirus IgG Detection: Addition of Envelope Protein Domain III to NS1 Increases Sensitivity for Tick-Borne Encephalitis Virus IgG Detection.

Tick-borne encephalitis is a vaccine-preventable disease of concern for public health in large parts of Europe, with EU notification rates increasing since 2018. It is caused by the orthoflavivirus tick-borne encephalitis virus (TBEV) and a diagnosis of infection is mainly based on serology due to its short viremic phase, often before symptom onset. The interpretation of TBEV serology is hampered by a history of orthoflavivirus vaccination and by previous infections with related orthoflaviviruses.

Rescue and in vitro characterization of a divergent TBEV-Eu strain from the Netherlands.

Tick-borne encephalitis virus (TBEV) may cause tick-borne encephalitis (TBE), a potential life-threatening infection of the central nervous system in humans. Phylogenetically, TBEVs can be subdivided into three main subtypes, which differ in endemic region and pathogenic potential. In 2016, TBEV was first detected in the Netherlands.

SARS-CoV-2 RNA and antibody dynamics in a Dutch household study with dense sampling frame.

This study investigated the dynamics of SARS-CoV-2 infection and diagnostics in 242 household members of different ages and with different symptom severity after SARS-CoV-2 exposure early in the pandemic (March-April 2020). Households with a SARS-CoV-2 confirmed positive case and at least one child in the Netherlands were followed for 6 weeks. Naso (NP)- and oropharyngeal (OP) swabs, oral fluid and feces specimens were analyzed for SARS-CoV-2 RNA and serum for SARS-CoV-2-specific antibodies.

Heterologous Immune Responses of Serum IgG and Secretory IgA Against the Spike Protein of Endemic Coronaviruses During Severe COVID-19.

Defining immune correlates of disease severity is important to better understand the immunopathogenesis in COVID-19. Here we made use of a protein microarray platform to detect IgG- and IgA-reactive antibodies in sera and saliva respectively, and assess cross-reactivity between SARS-CoV-2 and endemic coronaviruses (eCoVs). IgG responses against the full protein of spike, but not the S1 subunit, were significantly higher in convalescent sera of patients with severe disease compared to mild disease and healthy controls.

Robust innate responses to SARS-CoV-2 in children resolve faster than in adults without compromising adaptive immunity.

SARS-CoV-2 infection in children is less severe than it is in adults. We perform a longitudinal analysis of the early innate responses in children and adults with mild infection within household clusters. Children display fewer symptoms than adults do, despite similar initial viral load, and mount a robust anti-viral immune signature typical of the SARS-CoV-2 infection and characterized by early interferon gene responses; increases in cytokines, such as CXCL10 and GM-CSF; and changes in blood cell numbers.

Emerging SARS-CoV-2 variants of concern evade humoral immune responses from infection and vaccination.

Emerging SARS-CoV-2 variants of concern (VOCs) pose a threat to human immunity induced by natural infection and vaccination. We assessed the recognition of three VOCs (B.1.

Test, trace, isolate: evidence for declining SARS-CoV-2 PCR sensitivity in a clinical cohort.

Real-time reverse transcription-polymerase chain reaction (RT-PCR) on upper respiratory tract (URT) samples is the primary method to diagnose SARS-CoV-2 infections and guide public health measures, with a supportive role for serology. We reinforce previous findings on limited sensitivity of PCR testing, and solidify this fact by statistically utilizing a firm basis of multiple tests per individual. We integrate stratifications with respect to several patient characteristics such as severity of disease and time since onset of symptoms.

Emerging SARS-CoV-2 variants of concern evade humoral immune responses from infection and vaccination.

Emerging SARS-CoV-2 variants pose a threat to human immunity induced by natural infection and vaccination. We assessed the recognition of three variants of concern (B.1.

Validation and clinical evaluation of a SARS-CoV-2 surrogate virus neutralisation test (sVNT).

To understand SARS-CoV-2 immunity after natural infection or vaccination, functional assays such as virus neutralising assays are needed. So far, assays to detect SARS-CoV-2 neutralising antibodies rely on cell-culture based infection assays either using wild type SARS-CoV-2 or pseudotyped viruses. Such assays are labour-intensive, require appropriate biosafety facilities and are difficult to standardize.

Accurate serology for SARS-CoV-2 and common human coronaviruses using a multiplex approach.

Serology is a crucial part of the public health response to the ongoing SARS-CoV-2 pandemic. Here, we describe the development, validation and clinical evaluation of a protein micro-array as a quantitative multiplex immunoassay that can identify S and N-directed SARS-CoV-2 IgG antibodies with high specificity and sensitivity and distinguish them from all currently circulating human coronaviruses. The method specificity was 100% for SARS-CoV-2 S1 and 96% for N antigen based on extensive syndromic (n=230 cases) and population panel (n=94) testing that also confirmed the high prevalence of seasonal human coronaviruses.

Serological Evidence of MERS-CoV Antibodies in Dromedary Camels (Camelus dromedaries) in Laikipia County, Kenya.

Middle East respiratory syndrome coronavirus (MERS-CoV) is a recently identified virus causing severe viral respiratory illness in people. Little is known about the reservoir in the Horn of Africa. In Kenya, where no human MERS cases have been reported, our survey of 335 dromedary camels, representing nine herds in Laikipia County, showed a high seroprevalence (46.

Occupational Exposure to Dromedaries and Risk for MERS-CoV Infection, Qatar, 2013-2014.

We determined the presence of neutralizing antibodies to Middle East respiratory syndrome coronavirus in persons in Qatar with and without dromedary contact. Antibodies were only detected in those with contact, suggesting dromedary exposure as a risk factor for infection. Findings also showed evidence for substantial underestimation of the infection in populations at risk in Qatar.

High proportion of MERS-CoV shedding dromedaries at slaughterhouse with a potential epidemiological link to human cases, Qatar 2014.

Two of the earliest Middle East respiratory syndrome (MERS) cases were men who had visited the Doha central animal market and adjoining slaughterhouse in Qatar. We show that a high proportion of camels presenting for slaughter in Qatar show evidence for nasal MERS-CoV shedding (62/105). Sequence analysis showed the circulation of at least five different virus strains at these premises, suggesting that this location is a driver of MERS-CoV circulation and a high-risk area for human exposure.

Spot the difference-development of a syndrome based protein microarray for specific serological detection of multiple flavivirus infections in travelers.

Background: The family Flaviviridae, genus Flavivirus, holds many of the world's most prevalent arboviral diseases that are also considered the most important travel related arboviral infections. In most cases, flavivirus diagnosis in travelers is primarily based on serology as viremia is often low and typically has already been reduced to undetectable levels when symptoms set in and patients seek medical attention. Serological differentiation between flaviviruses and the false-positive results caused by vaccination and cross-reactivity among the different species, are problematic for surveillance and diagnostics of flaviviruses.

Geographic distribution of MERS coronavirus among dromedary camels, Africa.

We found serologic evidence for the circulation of Middle East respiratory syndrome coronavirus among dromedary camels in Nigeria, Tunisia, and Ethiopia. Circulation of the virus among dromedaries across broad areas of Africa may indicate that this disease is currently underdiagnosed in humans outside the Arabian Peninsula.

Antibodies against MERS coronavirus in dromedary camels, United Arab Emirates, 2003 and 2013.

Middle East respiratory syndrome coronavirus (MERS-CoV) has caused an ongoing outbreak of severe acute respiratory tract infection in humans in the Arabian Peninsula since 2012. Dromedary camels have been implicated as possible viral reservoirs. We used serologic assays to analyze 651 dromedary camel serum samples from the United Arab Emirates; 151 of 651 samples were obtained in 2003, well before onset of the current epidemic, and 500 serum samples were obtained in 2013.

Middle East respiratory syndrome coronavirus in dromedary camels: an outbreak investigation.

Background: Middle East respiratory syndrome coronavirus (MERS-CoV) causes severe lower respiratory tract infection in people. Previous studies suggested dromedary camels were a reservoir for this virus. We tested for the presence of MERS-CoV in dromedary camels from a farm in Qatar linked to two human cases of the infection in October, 2013.

Middle East respiratory syndrome coronavirus neutralising serum antibodies in dromedary camels: a comparative serological study.

Background: A new betacoronavirus-Middle East respiratory syndrome coronavirus (MERS-CoV)-has been identified in patients with severe acute respiratory infection. Although related viruses infect bats, molecular clock analyses have been unable to identify direct ancestors of MERS-CoV. Anecdotal exposure histories suggest that patients had been in contact with dromedary camels or goats.

Detection of influenza A virus homo- and heterosubtype-specific memory B-cells using a novel protein microarray-based analysis tool.

The emergence of the A(H1N1) 2009 pandemic influenza virus was initially seen as a major world-wide health concern since a low degree of immunity to this virus strain was anticipated. However, age-specific infection attack rates and age-specific differences in seroresponse indicate that pre-existing immunity may have played a significant role in protection especially in older age groups. This study describes the use of a protein microarray as a multiplex analysis tool for detection of influenza virus H1 strain-specific memory B-cells before and after infection with A(H1N1)pdm09.

Lack of evidence for zoonotic transmission of Schmallenberg virus.

The emergence of Schmallenberg virus (SBV), a novel orthobunyavirus, in ruminants in Europe triggered a joint veterinary and public health response to address the possible consequences to human health. Use of a risk profiling algorithm enabled the conclusion that the risk for zoonotic transmission of SBV could not be excluded completely. Self-reported health problems were monitored, and a serologic study was initiated among persons living and/or working on SBV-affected farms.

Come fly with me: review of clinically important arboviruses for global travelers.

Western tourists are increasingly traveling to exotic locations often located in tropical or subtropical regions of the world. The magnitude of international travel and the constantly changing dynamics of arbovirus diseases across the globe demand up-to-date information about arbovirus threats to travelers and the countries they visit. In this review, the current knowledge on arbovirus threats to global travelers is summarized and prioritized per region.

Quantitative performance of antibody array technology in a prenatal screening setting.

Background: Antibody microarrays (Ab-array) represent a new, innovative proteomics platform for high-throughput protein expression profiling in body fluids. Because they allow for multiplexed measurements in small sample volumes, Ab-arrays are an interesting alternative to conventional indirect sandwich immunoassay (ELISA or DELFIA) tests in clinical or population screening if sets of markers are to be analyzed simultaneously. However, to allow implementation of Ab-arrays in clinical or population screening programs, it is of vital importance to establish that this method is both sensitive and quantitative.

Syndromic surveillance in the Netherlands for the early detection of West Nile virus epidemics.

West Nile virus (WNV) is an arthropod-borne flavivirus that is endemic in Africa, Europe, and Eastern Asia. The recent introduction and rapid dissemination of the virus in the United States as well as an increase in WNV outbreaks in Europe, has raised concerns for its spread in Europe. A surveillance system was developed to allow timely detection of an introduction of WNV infections in The Netherlands.

Structural protein requirements in equine arteritis virus assembly.

Equine arteritis virus (EAV) is an enveloped, positive-stranded RNA virus belonging to the family Arteriviridae of the order Nidovirales. EAV particles contain seven structural proteins: the nucleocapsid protein N, the unglycosylated envelope proteins M and E, and the N-glycosylated membrane proteins GP(2b) (previously named G(S)), GP(3), GP(4), and GP(5) (previously named G(L)). Proteins N, M, and GP(5) are major virion components, E occurs in virus particles in intermediate amounts, and GP(4), GP(3), and GP(2b) are minor structural proteins.