WEST NILE VIRUS ANTIBODY DECAY RATE IN FREE-RANGING BIRDS.
Antibody duration, following a humoral immune response to West Nile virus (WNV) infection, is poorly understood in free-ranging avian hosts. Quantifying antibody decay rate is important for interpreting serologic results and for understanding the potential for birds to serorevert and become susceptible again. We sampled free-ranging birds in Chicago, Illinois, US, from 2005 to 2011 and Atlanta, Georgia, US, from 2010 to 2012 to examine the dynamics of antibody decay following natural WNV infection. Using serial dilutions in a blocking enzyme-linked immunosorbent assay, we quantified WNV antibody titer in repeated blood samples from individual birds over time. We quantified a rate of antibody decay for 23 Northern Cardinals (Cardinalis cardinalis) of 0.198 natural log units per month and 24 individuals of other bird species of 0.178 natural log units per month. Our results suggest that juveniles had a higher rate of antibody decay than adults, which is consistent with nonlinear antibody decay at different times postexposure. Overall, most birds had undetectable titers 2 yr postexposure. Nonuniform WNV antibody decay rates in free-ranging birds underscore the need for cautious interpretation of avian serology results in the context of arbovirus surveillance and epidemiology.
1  Science Division, Governors State University, 1 University Parkway, University Park, Illinois 60484, USA.|2  Veterinary Medical Technology Program, Joliet Junior College, 1215 Houbolt Road, Joliet, Illinois 60435, USA.
Eileen M
EM
McKee
3  Department of Microbiology and Molecular Genetics, Michigan State University, 220 Trowbridge Road, East Lansing, Michigan 48824, USA.
Edward D
ED
Walker
4  Department of Biology, Georgia Southern University, 4324 Old Register Road, Statesboro, Georgia 30458, USA.
Tavis K
TK
Anderson
5  Department of Environmental Studies, Emory University, 201 Dowman Drive, Atlanta, Georgia 30322, USA.
Uriel D
UD
Kitron
6  Department of Natural Resources and Environmental Sciences, University of Illinois, 1102 S Goodwin Avenue, Urbana, Illinois 61801, USA.
Jeffrey D
JD
Brawn
6  Department of Natural Resources and Environmental Sciences, University of Illinois, 1102 S Goodwin Avenue, Urbana, Illinois 61801, USA.
Bethany L
BL
Krebs
7  Department of Pathobiological Sciences, University of Wisconsin-Madison, 2015 Linden Drive, Madison, Wisconsin 53706, USA.
Christina
C
Newman
8  Department of Pathobiology, University of Illinois, 2001 S Lincoln Avenue, Urbana, Illinois 61802, USA.
Marilyn O
MO
Ruiz
5  Department of Environmental Studies, Emory University, 201 Dowman Drive, Atlanta, Georgia 30322, USA.
Rebecca S
RS
Levine
1  Science Division, Governors State University, 1 University Parkway, University Park, Illinois 60484, USA.
Mary E
ME
Carrington
9  US Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Wildlife Research Center, 4101 LaPorte Avenue, Fort Collins, Colorado 80521, USA.
Robert G
RG
McLean
7  Department of Pathobiological Sciences, University of Wisconsin-Madison, 2015 Linden Drive, Madison, Wisconsin 53706, USA.
Tony L
TL
Goldberg
10  Department of Entomology, Texas A&M University, 401 Joe Routt Boulevard, College Station, Texas 77843, USA.
Gabriel L
GL
Hamer
D000818:Animals; D000835:Animals, Wild / Q000276:immunology / Q000821:virology; D000914:Antibodies, Viral / Q000097:blood* / Q000276:immunology; D001715:Bird Diseases / Q000453:epidemiology / Q000276:immunology / Q000821:virology*; D001717:Birds / Q000276:immunology / Q000821:virology; D002641:Chicago / Q000453:epidemiology; D004797:Enzyme-Linked Immunosorbent Assay; D005845:Georgia / Q000453:epidemiology; D020308:Songbirds / Q000276:immunology / Q000821:virology; D014901:West Nile Fever / Q000453:epidemiology / Q000276:immunology / Q000662:veterinary*; D014902:West Nile virus / Q000276:immunology*
D000914:Antibodies, Viral
Antibody decay; Culex pipiens; Northern Cardinal; West Nile virus; serology; wild birds