Lh. Herbst et al., SEROLOGICAL ASSOCIATION BETWEEN SPIRORCHIDIASIS, HERPESVIRUS-INFECTION, AND FIBROPAPILLOMATOSIS IN GREEN TURTLES FROM FLORIDA, Journal of wildlife diseases, 34(3), 1998, pp. 496-507
Serodiagnostic tests for detecting green turtle (Chelonia mydas) antib
ody responses were developed to test the strength of association betwe
en exposure to spirorchid trematode antigens or herpesvirus antigens a
nd having green turtle fibropapillomatosis (GTFP). Plasma samples from
46 captive-reared green turtles, including paired pre- and 1-yr post-
inoculation samples from 12 turtles with experimentally induced GTFP.
were found by enzyme-linked immunosorbent assay (ELISA) to be negative
for antibodies to adult spirorchid (Learedius learedi) antigens. In c
ontrast, all 12 turtles that developed experimentally induced GTFP con
verted within 1 yr from having negative to positive antibody reactivit
y to GTFP-associated herpesvirus antigens, whereas the three controls
and four turtles that failed to develop tumors remained negative. Plas
ma samples from 104 free-ranging green turtles from two Florida (USA)
coastal feeding grounds with different GTFP prevalences were tested by
ELISA for antibodies to L. learedi adult antigens: and there was no s
tatistically significant association between antibody prevalence and s
ampling site. When a low optical density cutoff value (0.15) was used
to interpret ELISA results, 98% of the turtles from each site were spi
rorchid antibody-positive and there was no association between antibod
y reactivity to spirorchids and GTFP status. When a higher negative cu
toff value was used, however, a statistically significant association
between antibody reactivity to spirorchids and GTFP-free status was fo
und. These results suggest that spirorchids do not have a role in GTFP
pathogenesis. All 20 of the tumor-bearing lagoon turtles had antibodi
es to herpesvirus antigens whereas only two (10%) of the turner-free r
eef turtles had detectable anti-herpesvirus reactivity. The strong ass
ociation between antibody reactivity to herpesvirus antigens and GTFP
status in both captive-reared and free-ranging turtles is consistent w
ith the hypothesis that the transmissible agent that causes GTFP is a
herpesvirus.