Unrecognized norovirus infections in health care institutions and their clinical impact.
Noroviruses (NoVs) have emerged as the leading cause of acute viral gastroenteritis (GE) in humans. Although diagnostic facilities have greatly improved, significant underdiagnosis of NoV in hospitals may still occur, thereby increasing clinical burden and nosocomial spread. We evaluated the underdiagnosis of sporadic NoV infections in a tertiary care hospital and estimated its clinical impact. From December 2008 until July 2009, fecal samples specifically referred for bacterial but not viral examination were retrospectively tested for NoV by real-time PCR. The clinical and virological data from patients with undiagnosed NoV infection (missed patients) were evaluated and compared with those from patients with recognized NoV. During the study period, 45 patients with undiagnosed NoV were detected, whereas 50 patients were regularly diagnosed. The missed NoV cases were more frequently adults than children (80% versus 46%; P < 0.001). The viral load levels did not differ between the diagnosed and missed patients, but missed patients more frequently presented without diarrhea (20% versus 4%; P < 0.07). The newly admitted missed NoV cases with GE underwent more diagnostic imaging (24% versus 4%; P < 0.01) and tended to be hospitalized longer. When missed-NoV patients were included, the number of nosocomial clusters doubled and missed patients were index cases in 5 of the 6 clusters. These data indicate that NoV infections are frequently missed despite routine laboratory testing and demonstrate that underdiagnosis of NoV patients is associated with costly abdominal imaging and nosocomial clustering. Awareness of NoV infection in adult patients and education about the importance of viral GE should be increased.
Department of Virology, Erasmus Medical Center, Rotterdam, The Netherlands. m.beersma@erasmusmc.nl
Matthias F C
MF
Beersma
Faizel H A
FH
Sukhrie
Jolanda
J
Bogerman
Linda
L
Verhoef
Mariana
M
Mde Melo
Alieke G
AG
Vonk
Marion
M
Koopmans
D000328:Adult; D017250:Caliciviridae Infections / Q000453:epidemiology* / Q000821:virology*; D002648:Child; D002675:Child, Preschool; D003428:Cross Infection / Q000453:epidemiology* / Q000821:virology*; D005243:Feces / Q000821:virology; D005260:Female; D005759:Gastroenteritis / Q000453:epidemiology* / Q000821:virology*; D006801:Humans; D015994:Incidence; D008297:Male; D029322:Norovirus / Q000302:isolation & purification*; D012367:RNA, Viral / Q000235:genetics / Q000302:isolation & purification; D060888:Real-Time Polymerase Chain Reaction; D062606:Tertiary Care Centers
D012367:RNA, Viral