No abstract

Usutu virus (USUV) is a mosquito-borne flavivirus circulating in Western Europe that causes die-offs of mainly common blackbirds (Turdus merula).In the Netherlands, USUV was first detected in 2016, when it was identified as the likely cause of an outbreak in birds. In this study, dead blackbirds were collected, screened for the presence of USUV and submitted to nanopore-based sequencing. Genomic sequences of 112 USUV were obtained and phylogenetic analysis showed that most viruses identified belonged to the USUV Africa 3 lineage, and molecular clock analysis evaluated their most recent common ancestor to 10 to 4 years before first detection of USUV in the Netherlands. USUV Europe 3 lineage, commonly found in Germany, was less frequently detected. this analyses further suggest some extent of circulation of USUV between the netherlands, Germany and Belgium, as well as likely overwintering of USUV in the netherlands.Usutu virus (USUV) is a mosquito-borne arbovirus of the genus Flavivirus. The virus has a positive-stranded RNA genome with a genome length of around 11,000 nucleotides which encodes a single polyprotein. The polyprotein is processed by viral and host proteases into structural and non-structural proteins 1 . The life cycle of USUV involves mosquitoes (mainly Culex sp. 2,3 ) as vectors and wild birds as the main amplifying hosts. Humans and other mammals can be infected by mosquito bites and are generally considered dead-end hosts. Recent studies revealed that USUV can also be detected in small mammals such as bats 4 , rodents and shrews 5 .USUV was first identified from a Culex neavei mosquito in South Africa in 1959 6 . Over subsequent decades, it was sporadically reported in several mosquito and bird species, and twice in a human patient with fever and rash in African countries 7 . USUV was for first identified in Europe in 2001, when it was determined to be the causative agent of a mass mortality event in several bird species in Austria 8 . This prompted retrospective analysis of archived tissue samples from dead wild birds in Italy in 1996, which revealed an earlier presence of the virus in Europe 9 . Our understanding of the USUV geographical range has since expanded to include the majority of European countries 10 , where outbreaks are marked by mass die-offs of wild birds, with the heaviest toll on common blackbird (Turdus merula) populations. In Germany, it has been demonstrated that five years after the first detection of USUV in the southwest of the country, circulation of the virus was associated with a 15.7% decline in the common blackbird population in USUV-suitable areas 11 .The recent emergence of USUV epizootics among wild bird populations in Europe has been accompanied by reports of USUV infections in humans. Pathogenicity in humans appears to range from asymptomatic or mild symptoms, as shown in seroprevalence studies among healthy blood donors in Italy 12 , Germany 13 , Austria 14 and the Netherlands 15 to neuroinvasive infections associated with encephalitis or meningo-encephalitis, m...

No abstract

We evaluated different approaches for diagnosing measles virus (MV) infection in unvaccinated children and in healthy contact persons (n=194) during a measles epidemic in The Netherlands. MV RNA was detected by reverse-transcriptase polymerase chain reaction in throat-swab specimens from 93% of the patients with clinical symptoms. MV RNA was detected from 5 days before until 12 days after the onset of symptoms. Most patients (88%) also secreted MV RNA in their urine until 5 weeks after the onset of symptoms. Oral fluid proved to be the most practical specimen for the simultaneous detection of MV-specific IgM antibody and viral RNA, which, together, confirmed 93% of measles cases. Viral RNA was also detected in oropharyngeal specimens from 3 healthy contact persons with serological proof of MV infection. The results of this study emphasize the feasibility of combined detection of viral RNA and MV-specific IgM antibodies in oropharyngeal specimens for the diagnosis of clinical and subclinical MV infection.