spatial and temporal variation in the seroprevalence of canine heartworm antigen in the island fox. | island foxes (urocyon littoralis) are endemic to six of the eight california channel islands (usa). the island fox is classified as a threatened species by the state of california, and recently three of the six subspecies have experienced abrupt population declines. as part of a continuing effort to determine the cause of the declines, we tested island fox serum samples collected in 1988 (n = 176) and 1997-98 (n = 156) over the entire geographic range of the species for seroprevalence of canine ... | 2000 | 11085434 |