On January 30, 2013, a free-ranging 11-year-old female moose (Alces alces) was captured, equipped with a satellite-linked global positioning system collar by the Minnesota Department of Natural Resources, and released. The moose was part of a study to examine the causes of death in Minnesota's declining moose population. A mortality signal was emitted from the collar on December 7, 2013. The carcass was found intact without signs of predation or scavenging, was extracted from the field, and underwent necropsy at the Minnesota Veterinary Diagnostic Laboratory 2 days after the mortality signal was first received.
In January 2013, a free-ranging moose cow was captured (in accordance with the guidelines of the American Society of Mammalogists1), equipped with a collar by field biologists of the Minnesota Department of Natural Resources, and released. The animal was sedated with carfentanil (4.5 mg) and xylazine (150 mg) administered by a dart fired from a helicopter; sedation was reversed with naltrexone (500 mg) and tolazoline (400 mg).2,3 The moose was part of a study to examine the sudden decrease in Minnesota’s moose population. The collar had GPS capabilities and a device that would trigger
OBJECTIVE To develop a noninvasive biomarker-based detection system specific for Mycobacterium bovis for monitoring infection in wild animals.
SAMPLE Serum samples from 8 experimentally infected yearling white-tailed deer (Odocoileus virginianus) and 3 age-matched control deer and from 393 Minnesota Department of Natural Resources hunter-harvested white-tailed deer in northwest Minnesota.
PROCEDURES 8 yearling deer were inoculated with 2 × 108 CFUs of virulent M bovis strain 1315 (day 0), and sera were obtained on days 0, 19, 48, and 60; sera were obtained from 3 uninoculated control deer on those same days. Sera from these deer and 9 M bovis-positive hunter-harvested deer were tested for 3 Mycobacterium-specific biomarkers (MB1895c, MB2515c, and polyketide synthase 5) by use of an indirect ELISA. That same ELISA was used to test sera obtained from 384 exposed noninfected deer in northwest Minnesota from 2007 through 2010, concurrent with an outbreak of tuberculosis involving cattle and deer in that region.
RESULTS ELISA results revealed that tuberculosis infection could be detected as early as 48 days after inoculation in experimentally infected deer. Results for 384 deer sera revealed that prevalence of tuberculosis decreased over the 4-year period.
CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that the prevalence of tuberculosis in Minnesota deer decreased after 2009 but tuberculosis may have persisted (as subclinical disease) at extremely low levels, as indicated by the presence of low concentrations of circulating biomarkers. Biomarker-based diagnostic tests may offer a specific approach for early identification of M bovis infection.