Gert van der Hoek
In Memoriam - Editor, Senior Moderator
Expanding Usutu virus circulation in Italy: detection in the Lazio region, central Italy, 2017 to 2018
In the summer and autumn seasons of 2017 and 2018, following serological identification of West Nile virus (WNV) infection in horses, mandatory WNV screening with nucleic acid amplification test (NAT) was established for blood donations in some provinces of the Lazio Region in central Italy: Viterbo (starting from 18 August 2017), Latina (12 Seaptember 2018) and Rome (10 October 2018). During this period, five blood donations were reactive in WNV NAT screening. In none of these samples could WNV positivity be established by further tests conducted at the Regional Reference Laboratory.
In the present study, we describe serological, detailed molecular and phylogenetic analyses undertaken to better characterise the WNV positivity observed during the screening.
This is the first report showing circulation of USUV virus in the Lazio region, both in mosquito vectors and in human hosts, while so far, USUV has not been detected in other animal hosts (neither equids nor birds).
This study corroborates the hypothesis that USUV can cause clinically asymptomatic infection in humans [17]; this, in turn, may be of concern regarding the safety of the blood supply in areas where the virus is active. Although there is no evidence of human-to-human transmission of USUV in the transfusion (or transplant) setting, asymptomatic infected donors may donate USUV-infectious blood, which may cause severe disease in immunocompromised patients [18].
Public health authorities, blood transfusion services and clinicians should be aware of the expanding risk of USUV infection in humans, especially during the summer, and advanced laboratory support is required to address the problem of possible virus misidentification by screening tests.
Lazio Region - wikipedia
In the summer and autumn seasons of 2017 and 2018, following serological identification of West Nile virus (WNV) infection in horses, mandatory WNV screening with nucleic acid amplification test (NAT) was established for blood donations in some provinces of the Lazio Region in central Italy: Viterbo (starting from 18 August 2017), Latina (12 Seaptember 2018) and Rome (10 October 2018). During this period, five blood donations were reactive in WNV NAT screening. In none of these samples could WNV positivity be established by further tests conducted at the Regional Reference Laboratory.
In the present study, we describe serological, detailed molecular and phylogenetic analyses undertaken to better characterise the WNV positivity observed during the screening.
This is the first report showing circulation of USUV virus in the Lazio region, both in mosquito vectors and in human hosts, while so far, USUV has not been detected in other animal hosts (neither equids nor birds).
This study corroborates the hypothesis that USUV can cause clinically asymptomatic infection in humans [17]; this, in turn, may be of concern regarding the safety of the blood supply in areas where the virus is active. Although there is no evidence of human-to-human transmission of USUV in the transfusion (or transplant) setting, asymptomatic infected donors may donate USUV-infectious blood, which may cause severe disease in immunocompromised patients [18].
Public health authorities, blood transfusion services and clinicians should be aware of the expanding risk of USUV infection in humans, especially during the summer, and advanced laboratory support is required to address the problem of possible virus misidentification by screening tests.
Lazio Region - wikipedia