Canada Lynx in Maine: Disease Surveillance Study

Canada lynx live in moist boreal forest areas in the U.S. and Canada. Due to the patchiness of boreal forest in the U.S., there is a lower density of lynx compared to that of lynx populations in the forests of Canada. Since 1997, the lynx has been a species of Special Concern to the Maine Department of Inland Fisheries and Wildlife (MDIFW) and has been federally listed as Threatened since 2000. Once considered “irregular and anecdotal,” the population of lynx in Maine has been increasing since the late 1990s in response to the abundance of high quality habitat for lynx and their main prey, snowshoe hares. In 1999, six lynx were radio collared and results indicated that there was, in fact, a resident population of lynx in Maine. Over the next 10 years, another 79 lynx were equipped with radio collars to help assess the status of lynx in Maine. Since 2000biologists have been collecting lynx carcasses to identify potential causes of mortality. Initial work by diagnosticians at the University of Maine found evidence of lungworm as factor contributing to the mortality of lynx that were emaciated. Recently, MDIFW in concert with NWDC conducted a mortality study in collaboration with pathologists at the New Hampshire Veterinary Diagnostic Laboratory to build on the preliminary work.  

Results of the project:

  1. Of the 35 animals examined, direct evidence (parasites on gross or histological examination) of lungworm infection in 22 lynx, with 4 lynx in which lesions suggestive of lungworm were noted without directly visualizing the parasites. 
  2. A novel gammaherpesvirus of Canada lynx was identified and discovered in collaboration with Liam Hendrikee Ryan Troyer and others at University of Western Ontario. This worked was extended to identify the same virus in Newfoundland lynx, a distinct subspecies of the animal.
  3. Vitamin A and bone marrow fat analysis were undertaken on samples from the animals, with a manuscript forthcoming to begin to describe normal ranges for these parameters for wild lynx, and to aid in husbandry of lynx and related large cats in zoological collections.
  4. Histologic identification of what appears to be a Hepatozoon sp. parasite in a subset of animals. Confirmatory / investigational PCR and molecular identification are pending to attempt to confirm this finding.