Usutu virus infections in humans: a retrospective analysis in the municipality of Modena, Italy.
OBJECTIVE
To monitor the spread and to evaluate the role for public health of Usutu virus (USUV) in an endemic area of Italy.


METHODS
The survey was retrospectively conducted by detecting USUV RNA and USUV antibodies in cerebrospinal fluid and serum samples collected between 2008 and 2011 from 915 patients with or without neurologic impairments in the area of the municipality of Modena, Italy. Organs of birds and pools of mosquitoes were also tested for USUV RNA. Positive samples were partially sequenced and used for phylogenetic analysis.


RESULTS
The presence of USUV RNA (1.1%; 95% confidence interval (CI) 0.6-2.0) was significantly (p <0.05) higher than that of West Nile virus (0%; 95% CI 0-0.33). USUV antibody level was 6.57% (95% CI 4.87-8.82), and it was significantly higher (p <0.05) compared to that of West Nile virus (p 2.96, 95% CI 1.89-4.62). Partial genome sequencing of USUV strains detected in humans, birds and mosquitoes revealed high nucleotide sequence identity within them and with the USUV strains isolated in Central Europe.


CONCLUSIONS
USUV infection in humans is not a sporadic event in the studied area, and USUV neuroinvasiveness has been confirmed.
Dipartimento di Medicina Diagnostica, Clinica e di Sanità pubblica, Università di Modena e Reggio Emilia, Modena, Italy; S.C. Microbiologia e Virologia, Modena, Italy.
A
A
Grottola
OIE Reference Laboratory for West Nile Fever, Istituto Zooprofilattico Sperimentale dell'Abruzzo e Molise, Teramo, Italy.
M
M
Marcacci
S.C. Microbiologia e Virologia, Modena, Italy.
S
S
Tagliazucchi
S.C. Microbiologia e Virologia, Modena, Italy.
W
W
Gennari
OIE Reference Laboratory for West Nile Fever, Istituto Zooprofilattico Sperimentale dell'Abruzzo e Molise, Teramo, Italy.
A
A
Di Gennaro
OIE Reference Laboratory for West Nile Fever, Istituto Zooprofilattico Sperimentale dell'Abruzzo e Molise, Teramo, Italy.
M
M
Orsini
OIE Reference Laboratory for West Nile Fever, Istituto Zooprofilattico Sperimentale dell'Abruzzo e Molise, Teramo, Italy.
F
F
Monaco
Servizio di Prevenzione e Protezione, Azienda Ospedaliero, Universitaria Policlinico, Modena, Italy.
P
P
Marchegiano
OIE Reference Laboratory for West Nile Fever, Istituto Zooprofilattico Sperimentale dell'Abruzzo e Molise, Teramo, Italy.
V
V
Marini
S.C. Microbiologia e Virologia, Modena, Italy.
M
M
Meacci
S.C. Microbiologia e Virologia, Modena, Italy.
F
F
Rumpianesi
OIE Reference Laboratory for West Nile Fever, Istituto Zooprofilattico Sperimentale dell'Abruzzo e Molise, Teramo, Italy.
A
A
Lorusso
S.C. Microbiologia e Virologia, Modena, Italy.
M
M
Pecorari
OIE Reference Laboratory for West Nile Fever, Istituto Zooprofilattico Sperimentale dell'Abruzzo e Molise, Teramo, Italy. Electronic address: g.savini@izs.it.
G
G
Savini
D000328:Adult; D000368:Aged; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D001717:Birds / Q000821:virology; D003465:Culex / Q000821:virology; D005260:Female; D005416:Flavivirus / Q000302:isolation & purification*; D018177:Flavivirus Infections / Q000097:blood / Q000134:cerebrospinal fluid / Q000453:epidemiology / Q000821:virology*; D006801:Humans; D007558:Italy; D008297:Male; D008875:Middle Aged; D000072138:Mosquito Vectors / Q000821:virology; D010802:Phylogeny; D012367:RNA, Viral / Q000097:blood; D012189:Retrospective Studies; D012698:Serologic Tests; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism
D000914:Antibodies, Viral; D012367:RNA, Viral; D014764:Viral Proteins
Birds; Humans; Infection; Italy; Mosquitoes; Neurologic signs; Usutu virus; West Nile virus