title: Development and use of an indirect enzyme-linked immunosorbent assay for detection of iridovirus exposure in gopher tortoises (Gopherus polyphemus) and eastern box turtles (Terrapene carolina carolina).
abstract: Iridoviruses, pathogens typically associated with fish and amphibians, have recently been shown to cause acute respiratory disease in chelonians including box turtles, red-eared sliders, gopher tortoises, and Burmese star tortoises. Case reports of natural infections in several chelonian species in the United States have been reported, however the prevalence remains unknown in susceptible populations of free-ranging chelonians. To determine the prevalence of iridovirus exposure in free-ranging gopher tortoises (Gopherus polyphemus) in the southeast United States, an indirect enzyme-linked immunosorbent assay (ELISA) was developed and used to evaluate plasma samples from wild gopher tortoises (G. polyphemus) from: Alabama (n=9); Florida (n=658); Georgia (n=225); Louisiana (n=12); Mississippi (n=28); and unknown locations (68) collected between 2001 and 2006. Eight (1.2%) seropositive tortoises were identified from Florida and seven (3.1%) from Georgia for an overall prevalence of 1.5%. Additionally, a population of eastern box turtles was sampled from a private nature sanctuary in Pennsylvania that experienced an outbreak of iridovirus the previous year, which killed 16 turtles. Only 1 turtle out of 55 survivors tested positive (1.8%). Results suggest a low exposure rate in chelonians to this pathogen; however, it is suspected that this is an underestimate of the true prevalence. Since experimental transmission studies and past outbreaks have shown a high rate of mortality in infected turtles, turtles may die before they develop an antibody response. Further, the duration of the antibody response is unknown and may also cause an underestimate of the true prevalence.
authors.affiliation: Department of Small Animal Clinical Sciences, University of Florida, College of Veterinary Medicine, Gainesville, FL 32608, USA. JohnsonAJ@purdue.edu
authors.forename: April J
authors.initials: AJ
authors.lastname: Johnson
authors.forename: Lori
authors.initials: L
authors.lastname: Wendland
authors.forename: Terry M
authors.initials: TM
authors.lastname: Norton
authors.forename: Bill
authors.initials: B
authors.lastname: Belzer
authors.forename: Elliott R
authors.initials: ER
authors.lastname: Jacobson
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D004266:DNA Virus Infections / Q000175:diagnosis* / Q000453:epidemiology*; D004797:Enzyme-Linked Immunosorbent Assay; D017994:Iridovirus / Q000276:immunology*; D015995:Prevalence; D014426:Turtles / Q000821:virology*; D014481:United States / Q000453:epidemiology
chemical_list: D000914:Antibodies, Viral