Te. Rocke et al., PRELIMINARY EVALUATION OF A SIMPLE IN-VITRO TEST FOR THE DIAGNOSIS OFTYPE-C BOTULISM IN WILD BIRDS, Journal of wildlife diseases, 34(4), 1998, pp. 744-751
An enzyme-linked immunosorbent assay (ELISA) was developed for the det
ection of type C botulinum toxin (Clostridium botulinum) in wild birds
. This simple, antigen-capture ELISA utilizes polystyrene immunosticks
as the solid substrate, chicken antitoxin (IgY) as the coating antibo
dy, rabbit antitoxin as the primary antibody, and peroxidase-labeled g
oat-anti-rabbit as the secondary antibody. To evaluate the immunostick
ELISA as a diagnostic test for avian botulism, known concentrations o
f to;toxin were added to heparinized blood collected from healthy bird
s and tested by both the ELISA and mouse bioassay. Also, blood samples
from 236 bird carcasses submitted to the National Wildlife Health Cen
ter (NWHC) for cause of death determinations were tested by both proce
dures. Using less than or equal to 0.5 ml as the test volume for both
procedures, the ELISA was less sensitive, detecting 0.25 ng/ml of toxi
n compared to 0.12 ng/ml for the mouse bioassay. Using the same volume
of test sample for diagnostic submissions (less than or equal to 0.5
ml), the ELISA was positive for 60% of the 149 clinically-diagnosed ca
ses of botulism, whereas the mouse bioassay was positive for 79%. Howe
ver, we demonstrated that with larger sample volumes (greater than or
equal to 1.0 ml), the sensitivity of the ELISA may be equivalent or be
tter than the mouse test due to the concentrating effect of the ELISA
procedure. These preliminary results suggest that when adequate sample
volumes are available, the immunostick ELISA can replace the mouse te
st for the diagnosis of botulism in wild birds.