Applications of dot-blot, ELISA, and immunoelectron microscopy to field detection of bluetongue virus in Culicoides variipennis sonorensis: an ecological perspective.
An avidin-biotin complex (ABC) dot-blot, an antigen capture enzyme-linked immunosorbent assay (ELISA), and immunoelectron microscopy (IEM) were used to detect bluetongue (BLU) virus and viral antigen in field-collected C. varriipennis sonorensis Wirth & Jones from an enzootic BLU area in northeastern Colorado. This is the 1st attempt to apply these immunodiagnostic methods to an epidemiologically relevant, large-scale ecological system. One of the 1,800 midges (0.0005%) was positive by the dot-blot procedure, 2 (0.0011%) were positive by the ELISA, and BLU virus was identified in 8 midges (0.0044%) by IEM. These data are interpreted in context of the "whole system" of the disease to provide a framework for determining the knowledge gaps in our understanding and directing future studies in these areas. Our basic model of BLU ecology suggests that the infection rates found by the diagnostic methods are within expected ranges, thus strongly supporting the proposed ecological model and the work used to parameterize the model. This integration of immunodiagnostic methods and ecology makes it evident that further investigations of daily mortality during the extrinsic incubation period are vital to a better understanding of BLU virus occurrence in Culicoides vector and vertebrate host populations.
Nunamaker
R A
RA
Arthropod-Borne Animal Diseases Research Laboratory, USDA-ARS, Laramie, WY 82071, USA.
Mecham
J O
JO
Holbrook
F R
FR
Lockwood
J A
JA
D000818:Animals; D000956:Antigens, Viral / Q000032:analysis; D001820:Bluetongue virus / Q000276:immunology / Q000302:isolation & purification* / Q000648:ultrastructure; D002519:Ceratopogonidae / Q000821:virology*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005069:Evaluation Studies as Topic; D005260:Female; D016253:Microscopy, Immunoelectron; D008954:Models, Biological
D000956:Antigens, Viral