A RETROSPECTIVE SEROLOGICAL SURVEY FOR INFECTIOUS BURSAL DISEASE VIRUS IN FREE-RANGING SANDHILL CRANES IN SOUTH-CENTRAL WISCONSIN

Authors

RICHARD R. SIM, University of Wisconsin
BARRY K. HARTUP, International Crane FoundationFollow

Date of this Version

2010

Document Type

Article

Citation

Sim, R.R., and B.K. Hartup. A retrospective serological survey for infectious bursal disease virus in free-ranging sandhill cranes in south-central Wisconsin. In: Hartup, Barry K., ed., Proceedings of the Eleventh North American Crane Workshop, Sep 23-27, 2008, Wisconsin Dells, Wisconsin (Baraboo, WI: North American Crane Working Group, 2010), pp. 193.

Comments

Reproduced by permission of the North American Crane Working Group.

Abstract

A retrospective serosurvey of resident sandhill cranes (Grus candensis pratensis) in Florida suggested Infectious Bursal Disease Virus (IBDV, family Birnaviridae) may have been enzootic there as early as 1992, with 13-63% seroprevalence among age classes and wide geographic distribution of seropositive cranes. The purpose of our study was to describe the prevalence of antibodies to IBDV serotype 2 in a local population of greater sandhill cranes (G. c. tabida) near Briggsville, Wisconsin, that overlapped with resident Florida birds in winter during the same time period. Blood samples were collected June through October between 1996 and 1999 as part of a long-term ecological research project. Samples were from hatchyear (minimally 6 weeks of age, n = 47) and adult cranes (n = 42). All birds were captured on breeding territories, were banded with colored leg markers, and were observed periodically post-release. Archived serum samples were tested at the Poultry Diagnostic and Research Center, University of Georgia, Athens, Georgia, in July 2007. Serum neutralization titers ³32 were considered positive for IBDV exposure. Zero of 47 hatch-year cranes were seropositive for IBDV (geometric mean = 2, titer range 2-2), while 1 of 42 adult cranes was seropositive (geometric mean = 4.9, titer range 2-64). This adult female, sampled in September 1999, had 4 2-3 mm oropharyngeal granulomatous lesions and a normal body weight on examination. Though the oral pathology observed in this crane is similar to previously described lesions associated with an IBDV-associated wasting syndrome in whooping cranes (Grus americana), similar presentations are associated with other diseases. Her mate and chick were also captured; both were seronegative. The female was recaptured in September 2000 with a new mate, and both cranes were seronegative. She was last observed alive in late October that year. These results show that greater sandhill cranes in south-central Wisconsin were exposed to IBDV serotype 2 as early as 1999, but exhibited much lower seroprevalence compared to resident Florida sandhill cranes during approximately the same time period. The source of this viral exposure remains unknown.