West Nile virus infection among pregnant women in a northern Colorado community, 2003 to 2004.
OBJECTIVE
Since West Nile virus (WNV) was first detected in New York in 1999, it has spread across North America and become a major public health concern. In 2002, the first documented case of intrauterine WNV infection was reported, involving an infant with severe brain abnormalities. To determine the frequencies of WNV infections during pregnancy and of intrauterine WNV infections, we measured WNV-specific antibodies in cord blood from infant deliveries after a community-wide epidemic of WNV disease.


METHODS
Five hundred sixty-six pregnant women who presented to Poudre Valley Hospital (Fort Collins, CO) for delivery between September 2003 and May 2004 provided demographic and health history data through self-administered questionnaires and hospital admission records. Umbilical cord blood was collected from 549 infants and screened for WNV-specific IgM and IgG antibodies with enzyme-linked immunosorbent assays, with confirmation by plaque-reduction neutralization tests. Newborn growth parameters, Apgar scores, and hearing test results were recorded.


RESULTS
Four percent (95% confidence interval: 2.4-5.7%) of cord blood samples tested positive for WNV-specific IgG antibodies. No cord blood samples were positive for WNV-specific IgM antibodies. There were no significant differences between infants of seropositive and seronegative mothers with respect to any of the growth parameters or outcomes measured.


CONCLUSIONS
Intrauterine WNV infections seemed to be infrequent. In our study, WNV infection during pregnancy did not seem to affect adversely infant health at birth. Larger prospective studies are necessary to measure more completely the effects of maternal WNV infection on pregnancy and infant health outcomes.
Paisley
Jan E
JE
Department of Pediatrics and Neonatology, University of Colorado Health Sciences Center, Denver, Colorado, USA. pais@pvhs.org
Hinckley
Alison F
AF
O'Leary
Daniel R
DR
Kramer
William C
WC
Lanciotti
Robert S
RS
Campbell
Grant L
GL
Hayes
Edward B
EB
D000914:Antibodies, Viral / Q000032:analysis; D003120:Colorado / Q000453:epidemiology; D005260:Female; D005312:Fetal Blood / Q000276:immunology; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D007231:Infant, Newborn; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000175:diagnosis / Q000453:epidemiology*; D011256:Pregnancy Outcome; D016036:Seroepidemiologic Studies; D014901:West Nile Fever / Q000150:complications / Q000151:congenital / Q000175:diagnosis / Q000453:epidemiology*; D014902:West Nile virus / Q000276:immunology / Q000302:isolation & purification
D000914:Antibodies, Viral; D007070:Immunoglobulin A; D007074:Immunoglobulin G