Disease in Wild Animals

ABSTRACT:Chronic wasting disease (CWD) is a fatal, transmissible spongiform encephalopathy that affects free-ranging and captive North American cervids. Although the impacts of CWD on cervid survival have been documented, little is known about the disease impacts on reproduction and recruitment. We used genetic methods and harvest data to reconstruct parentage for a cohort of white-tailed deer (Odocoileus virginianus) fawns born in spring 2002 and evaluate the effects of CWD infection on reproduction and fawn harvest vulnerability. There was no difference between CWD-positive and CWD-negative male deer in the probability of being a parent. However, CWD-positive females were more likely to be parents than CWD-negative females. Because our results are based on harvested animals, we evaluated the hypothesis that higher parentage rates occurred because fawns with CWD-positive mothers were more vulnerable to harvest. Male fawns with CWD-positive mothers were harvested earlier (.1 mo relative to their mother's date of harvest) and farther away from their mothers than male fawns with CWDnegative mothers. Male fawns with CWD-positive mothers were also harvested much earlier and farther away than female fawns from CWD-positive mothers. Most female fawns (86%) with CWD-positive mothers were harvested from the same section as their mothers, while almost half of male and female fawns with CWD-negative mothers were farther away. We conclude that preclinical stages of CWD infection do not prohibit white-tailed deer from successfully reproducing. However, apparently higher harvest vulnerability of male fawns with CWD-positive mothers suggests that CWD infection may make females less capable of providing adequate parental care to ensure the survival and recruitment of their fawns.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effects of Chronic Wasting Disease on Reproduction and Fawn Harvest Vulnerability in Wisconsin White-Tailed Deer

Blanchong

Grear

Weckworth

et al. 2012

“…Finding diseased or dead animals is the most direct evidence that disease is occurring in an area or population, but this technique has limited application and, invariably, results in an underestimation of the occurrence of disease (Wobeser, 2006). The number of submitted and reported animals is, therefore, not a good measurement of prevalence of disease.…”

Section: Discussionmentioning

confidence: 99%

Hair-Loss Epizootic in Moose (Alces Alces) Associated With Massive Deer Ked (Lipoptena Cervi) Infestation

Madslien

Ytrehus

Vikøren

et al. 2011

ABSTRACT:Deer keds (Lipoptena cervi) are blood-sucking flies in the family Hippoboscidae; moose (Alces alces) are their main host in Scandinavia. There are no detailed reports of the negative impacts of deer keds on moose. In 2006 and 2007, hunters in southeastern Norway and midwestern Sweden found several moose cadavers with severe alopecia; numerous moose had extensive hair loss. Between February 2006 and June 2007, materials from 23 moose were submitted for laboratory examination and large numbers of deer keds were found in the coat of most animals. The body condition of the moose varied but was poor in animals with severe alopecia. The findings of enormous numbers of deer keds in the coat of the majority of the affected animals and a consistent histologic image (acute to chronic, multifocal to coalescing, eosinophilic to lymphocytic dermatitis), concurrent with the absence of any other lesions, trace element deficiencies, or dermal infections which are known to cause alopecia, suggest that the hair-loss epizootic was linked to massive infestations with deer keds. The emergence of this hair-loss syndrome implies that the dynamics between parasite and host have been disrupted by a currently unknown environmental or ecological factor. A high moose density, combined with extraordinarily mild weather June 2006-June 2007 and a particularly long period with the absence of night-frost in autumn of 2006, may have been ideal for deer ked development, survival, and optimal host acquisition.

“…Feral swine (Sus scrofa) are a reservoir of diseases of domestic livestock and are a potential disease threat to livestock production (Wobeser, 2006). Worldwide, exposure rates to several pathogens, such as Mycobacterium bovis (Vicente et al, 2006), Type A influenza virus (Hall et al, 2008), pseudorabies virus (PRV; Campbell et al, 2008), and Brucella suis , can be high (30-80%).…”

mentioning

confidence: 99%

Absence of Mycobacterium bovis in Feral Swine (Sus scrofa) from the Southern Texas Border Region

Campbell

Long

Bazan

et al. 2011

ABSTRACT:Free-ranging wildlife, such as feral swine (Sus scrofa), harbor a variety of diseases that are transmissible to livestock and could negatively impact agricultural production. Information is needed regarding the exposure and infection rates of Mycobacterium bovis and many other diseases and parasites in feral swine occurring in the Texas border region. Our main objective was to determine exposure rates and possible infection rates of M. bovis in feral swine by opportunistically sampling animals from the Texas border region. From June to September 2010, we obtained samples from 396 feral swine and tested 98 samples for M. bovis by histopathology and mycobacteriologic culture. We found no evidence of M. bovis infection. We believe that it is important to periodically and strategically sample feral swine for M. bovis in high-risk areas of the United States because they are capable of becoming reservoirs of the disease.