Filter-Paper Blood Samples for Elisa Detection of Brucella Antibodies in Caribou

Abstract

We evaluated blood collected on Nobuto filter-paper (FP) strips for use in detecting Brucella spp. antibodies in caribou. Whole blood (for serum) and blood-saturated FP strips were obtained from 185 killed arctic caribou (Rangifer tarandus groenlandicus). Sample pairs (serum and FP eluates) were simultaneously tested in duplicate using competitive enzyme-linked immunosorbent assay (c-ELISA) and indirect ELISA (i-ELISA) for Brucella spp. Prior work based on isolation of Brucella spp. revealed sensitivity (SE) and specificity (SP) of 100% and 99%, respectively, for both these serum assays in caribou. Infection status of the animals in the current study was unknown but recent sampling had revealed clinical brucellosis and >40% Brucella antibody prevalence in the herd. To assess the performance of FP relative to serum in these assays, serum was used as the putative gold standard. On both assays, the findings for duplicate runs (A and B) were similar. For c-ELISA run A, the FP Brucella prevalence (47%) was lower than serum prevalence (52%), with SE 89% (95% confidence interval [CI]: 82-95%) and SP 99% (97-100%). For i-ELISA run A, serum and FP Brucella prevalence rates were identical (43%), and the SE and SP of FP testing were 100% and 99% (97-100%), respectively. The findings suggest better FP test performance with i-ELISA than with c-ELISA; however, i-ELISA does not distinguish cross-reacting antibodies induced by Brucella vaccination or exposure to certain other Gram-negative pathogens. Results for duplicate FP eluates (prepared using separate FP strips from each animal) were strongly correlated for both protocols (r=0.996 and 0.999 for c-ELISA and i-ELISA, respectively), indicating minimal variability among FPs from any individual caribou. Dried caribou FP blood samples stored for 2 mo at room temperature are comparable with serum for use in Brucella spp. c-ELISA and i-ELISA. Hunter-based FP sampling can facilitate detection of disease exposure in remote regions and under adverse conditions, and can expand wildlife disease surveillance across temporospatial scales.

Investigating the Use of Protein Saver Cards for Storage and Subsequent Detection of Bovine Anti-Brucella abortus Smooth Lipopolysaccharide Antibodies and Gamma Interferon

“…Since the development of these cards, they have been used in hospital laboratories for testing card eluates by ELISA and PCR for the clinical diagnosis of multiple diseases (12)(13)(14)(15)(16)(17)(18). These cards have also been used in veterinary diagnostics, most recently for the detection of anti-Brucella antibodies in caribou (19)(20)(21). To our knowledge, the use of these cards to directly store and elute bovine blood serum and plasma samples for the detection of anti-Brucella lipopolysaccharide (LPS) antibodies and IFN-␥ is a novel use for a well-established method.…”

Standardized monitoring of Rangifer health during International Polar Year

“…Collection of blood samples allowed for more in-depth examination of pathogen diver- sity (Curry et al, 2011). Blood was extracted from the lter paper in the lab and tested for exposure to a variety of pathogens using standard serological tests (Curry et al, 2011).…”

“…Blood was extracted from the lter paper in the lab and tested for exposure to a variety of pathogens using standard serological tests (Curry et al, 2011). Additional testing for Trypanosoma spp.…”

Evaluation of Trapper-Collected Nobuto Filter-Paper Blood Samples for Distemper and Parvovirus Antibody Detection in Coyotes (Canis latrans) and Raccoons (Procyon lotor)

“…Ideally, whole blood is collected by venipuncture using sterile equipment, and kept cool until serum is separated. Wildlife investigations where blood samples are collected from carcasses may not allow for sterile collection techniques or optimal blood handling (Curry et al 2011), but samples collected by hunters or trappers may be easy to obtain. We investigated whether trapper-collected FP blood samples and bloody fluid collected from the body cavity could render consistent antibody results for CDV and CPV-2 in and coyotes (Canis latrans) and raccoons (Procyon lotor).…”

“…Hunter-or trapper-harvested animals have been a useful resource for sample collections in wildlife health studies (Stallknecht and Davidson 1992;Curry et al 2011). We asked trappers to collect bodycavity blood and FP strip samples from each harvested coyote and raccoon.…”