Usutu virus infection in Dutch blood donors

Abstract

BACKGROUND The screening of Dutch blood donations for West Nile virus (WNV) may be imminent, as WNV emerges in nearby countries and more donors travel to WNV‐affected regions. Since 2016 the related, mosquito‐borne Usutu virus (USUV) causes seasonal mortality in Dutch birds. To what extent will human USUV infections affect Dutch WNV donor screening? STUDY DESIGN AND METHODS From April through September 2018, plasma samples from blood donations in blackbird‐rich regions were stored. When increased bird mortality was reported in August, samples from July, August, and September were tested for USUV‐RNA in pools of eight, using a home‐brew combined WNV/USUV‐PCR assay. Reactive pools were deconstructed. Original plasma units and samples of previous and follow‐up donations of reactive donors were tested for USUV‐ and WNV‐RNA, and for antibody responses. RESULTS The number of USUV RNA‐positive, WNV RNA‐negative donations was 0 of 2688 donations in July, 6 of 4416 in August (1:736), and 1 of 4936 in September. The seven infected donors tested negative for USUV‐RNA in preceding and follow‐up donations. For 6 donors, seroconversion for USUV‐antibodies was demonstrated. All index donations tested positive in a commonly used PCR‐assay for WNV donor screening. Three exposed recipients did not show signs of infection. Screening a random subset of 1092 donations from September for USUV‐IgG antibodies showed that 22 donors tested reactive; for three donors retrospective testing identified an USUV PCR‐positive pre‐seroconversion donation. CONCLUSION Seasonal USUV infection in Dutch blood donors is common. Cross‐reactivity in molecular assays for WNV‐screening occurs, but can be resolved using USUV‐ and WNV‐specific PCR‐primers and sequencing of viral RNA.

West Nile or Usutu Virus? A Three-Year Follow-Up of Humoral and Cellular Response in a Group of Asymptomatic Blood Donors

“…Studies revealed an increase of USUV seroprevalence in northern Italy [25][26][27], especially among forest rangers [28]. In the present study, an increasing number of USUV and WNV cases was reported, in line with other European studies [18,[29][30][31][32].…”

Study of Usutu virus neuropathogenicity in mice and human cellular models

“…In Europe, the recent epizootics were also accompanied by several descriptions of human neurological disorders, including facial paralysis, encephalitis, meningitis and meningoencephalitis, in immunocompromised and immunocompetent patients, representing to date around 30 cases [7,[18][19][20][21][22][23][24][25]. Moreover, molecular and serologic evidence of USUV infection in Italian, German, Austrian and Dutch blood donors indicates that the virus is also circulating silently among asymptomatic humans in Europe and could potentially be a concern PLOS NEGLECTED TROPICAL DISEASES for blood transfusions [26][27][28][29]. Very little is known about USUV pathogenicity.…”

Genomic monitoring to understand the emergence and spread of Usutu virus in the Netherlands, 2016–2018

“…The circulation of USUV in birds can be linked to an increased human exposure to zoonotic risk. Indeed, the detection of viremic blood donations in the Netherlands co-incided with months of active USUV circulation in birds 22 , human cases described in Italy were from an area with demonstrated concomitant circulation of USUV in mosquitoes and birds [16][17][18][19] , and in Austria an increase in human cases was observed alongside the increased USUV activity in birds 23 .…”