Cylicospirura species (Nematoda: Spirocercidae) and stomach nodules in cougars (Puma concolor) and bobcats (Lynx rufus) in Oregon.
ABSTRACT The stomachs and proximal duodena of 160 cougars (Puma concolor) and 17 bobcats (Lynx rufus), obtained throughout Oregon during 7 yr, were examined for Cylicospirura spp. and associated lesions. Prevalence in cougars was 73%, with a range in intensity of 1-562 worms. The mean diameter of nodules was 1.2 cm (SD=0.5), and many extended through the submucosa to the muscularis. About 83% of cougars had nodules; most nodules contained worms, but 14% of the smaller nodules (<0.2 cm) contained porcupine (Erethizon dorsatum) quills. A mean of 12.4 worms/nodule (SD=34.1) was observed, with a maximum of 340 worms/nodule. Prevalence in bobcats was 53%, with an intensity of 1-25 worms. About 65% of bobcats had nodules, which were slightly smaller than those in cougars but appeared to involve similar layers of gastrointestinal tissue. One to 25 Cylicospirura sp. were found in all but two small nodules in bobcats. Cougars killed for livestock damage or safety concerns had a significantly higher median worm intensity than did those that died of other causes. Also, the median worm intensity of older cougars was higher than that of younger lions. There were more males than females killed for livestock damage or safety concerns. The cylicospirurid from cougars was Cylicospirura subaequalis, and that of bobcats was Cylicospirura felineus. These two similar species were separated morphologically by differences in tooth and sex organ morphology. They were also differentiated by DNA sequence analysis of the mitochondrial cytochrome c oxidase subunit 1 gene (cox1). Worm sequences from cougars differed from those from bobcats by 11%, whereas essentially no difference was found among worms from the same host. Phylogenetic analysis showed that within the order Spirurida, both cylicospirurids were most closely related to Spirocerca lupi, based on this gene sequence.
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ABSTRACT: Cougar (Puma concolor) management in Oregon is unique because hunting cougars with dogs was allowed through the 1994 hunting season, but thereafter Ballot Initiative Measure 18 prohibited the use of dogs to pursue cougars. Since 1995, hunting seasons have become increasingly longer with more tags sold. The effects of changing management structure on survival rates and causes of mortality of cougars are not well understood. We investigated survival and documented causes of mortality of radiocollared cougars at 3 study areas in Oregon from 1989 to 2011 under contrasting management strategies. The Catherine Creek (1989–1996) and Jackson Creek (1993–2002) studies overlapped the prohibition of hunting cougars with dogs, and the Wenaha, Sled Springs, and Mt. Emily (WSM) study was conducted from 2002 to 2011 when hunting cougars with dogs was illegal. Hunting mortality was the most common cause of death for sub-adult and adult cougars in Catherine Creek pre- (18 of 23 mortalities) and post-Measure 18 (1 of 2 mortalities) and WSM (24 of 53 mortalities) study areas in northeast Oregon. In contrast, natural mortality was the most common cause of death of sub-adults and adults at the Jackson Creek (25 of 38 mortalities) study area in southwest Oregon, but hunting mortality was most common prior to the passage of Measure 18 (3 of 3 mortalities). We estimated annual survival rates of cougars using known fate models in Program MARK. Annual survival rates of adult males were lowest at Catherine Creek prior to the passage of Measure 18 ( = 0.57; 95% CI = 0.39–0.73) and increased after Measure 18 ( = 0.86; 95% CI = 0.79–0.92), which were similar to those rates observed at Jackson Creek pre- and post-Measure 18 ( = 0.78; 95% CI = 0.65–0.88) and WSM ( = 0.82; 95% CI = 0.69–0.91). Regardless of hunting regulations, annual survival rates of adult females was similar among study areas (Catherine Creek pre- and post-Measure 18 [ = 0.86; 95% CI = 0.79–0.92]; Jackson Creek pre- and post-Measure 18 [ = 0.85; 95% CI = 0.77–0.91]; WSM [ = 0.85; 95% CI = 0.76–0.90]). At Jackson Creek pre- and post-Measure 18 and WSM, sub-adult males (1–3 years) had significantly lower survival than sub-adult females, but survival rates of males and females were similar by age 4 or 5 years. At WSM, survival declined for both sexes at older ages (8–13 years), but this decline was not observed at Jackson Creek pre- or post-Measure 18. The effect of increasing age on cougar survival should be considered when using survival rates to estimate population growth rates. We did not detect an effect of age on cougar survival at the Catherine Creek study area pre- or post-Measure 18, which we attributed to selective harvest of prime-aged, male cougars prior to the passage of Measure 18 and lack of mortality post-Measure 18. Managers should understand local sources of mortality when setting harvest regulations because sources of mortality may vary widely within and among jurisdictions, even if management practices are similar. Because of low hunter success rates when hunting cougars without dogs, survival rates of cougars managed under this hunting regime should be substantially higher than areas where use of dogs is legal. This suggests the ability of managers to effectively manipulate survival rates of cougars to meet population management objectives will be dependent on available hunting methods. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.Journal of Wildlife Management 07/2014; 78(5). DOI:10.1002/jwmg.717 · 1.61 Impact Factor
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ABSTRACT: Spirocerca lupi causes formation of nodules that may transform into sarcoma in the walls of aorta, esophagus and stomach of infected canids. In February 2013, post mortem examination of a red fox (Vulpes vulpes) hunted in Denmark revealed the presence of several nodules containing adult worms of Spirocerca sp. in the stomach and the omentum. The nodules largely consisted of fibrous tissue with infiltration of mononuclear cells, neutrophilic granulocytes and macrophages with hemosiderin deposition. Parasitological examination by three copromicroscopic methods, sedimentation, flotation with saturated sugar-salt solution, and sieving failed to detect eggs of Spirocerca sp. in feces collected from the colon. This is the first report of spirocercosis in Denmark, and may have been caused by a recent introduction by migrating paratenic or definitive host. Analysis of two overlapping partial sequences of the cox1 gene, from individual worms, revealed distinct genetic variation (7-9%) between the Danish worms and isolates of S. lupi from Europe, Asia and Africa. This was confirmed by phylogenetic analysis that clearly separated the Danish worms from other isolates of S. lupi. The distinct genetic differences of the current worms compared to other isolates of S. lupi may suggest the presence of a cryptic species within Spirocerca.Veterinary Parasitology 09/2014; 205(1-2). DOI:10.1016/j.vetpar.2014.07.002 · 2.55 Impact Factor
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ABSTRACT: The nematode worm Spirocerca lupi has a cosmopolitan distribution and can cause the death of its final canid host, typically dogs. While its life cycle, which involves a coprophagous beetle intermediate host, a number of non-obligatory vertebrate paratenic hosts and a canid final host, is well understood, surprisingly little is known about its transmission dynamics and population genetic structure. Here we sequenced cox1 to quantify genetic variation and the factors that limit gene flow in a 300 km(2) area in South Africa. Three quarters of the genetic variation, was explained by differences between worms from the same host, whereas a quarter of the variation was explained by differences between worms from different hosts. With the help of a newly derived model we conclude that while the offspring from different infrapopulations mixes fairly frequently in new hosts, the level of admixture is not enough to homogenize the parasite populations among dogs. Small infrapopulation sizes along with clumped transmission may also result in members of infrapopulations being closely related.Veterinary Parasitology 12/2011; 187(1-2):259-66. DOI:10.1016/j.vetpar.2011.12.008 · 2.55 Impact Factor