FREE-RANGING OCELOTS (LEOPARDUS PARDALIS): HEMATOLOGY AND SERUM CHEMISTRY REFERENCE VALUES.

Acquiring baseline physiologic data for animals from a free-ranging wildlife species is an elusive objective. Between 1990 and 2020, a monitoring program on the last population of ocelot (Leopardus pardalis) to inhabit public land in the United States yielded 139 blood samples from 67 individual animals. Ocelots were live trapped and anesthetized for census and radiotelemetric studies. The protocol included morphometrics, photographs, electronic identification, and blood collection. Complete blood count and serum chemistry were performed, and after sorting of the data to remove unhealthy individuals and occasional outliers, the dataset provided sufficient information to compute reliable reference intervals (RI). According to the American Society of Veterinary Clinical Pathology consensus guidelines, RI should be elaborated by using data from each reference individual only once. RI by random selection was determined when several measurements were available over time from one same animal. Second, RI were also computed allowing repeat measurements for reference individuals, exclusively to characterize and quantify the effect on the data distribution and on the generated RI. A summary of published RI for various species of wild felids is also presented. The variations observed between species is due not only to species differences but also to variation in measurement methods and RI study design. Overall, accurate blood work interpretation requires RI generated from a healthy population, with defined measurement methods and state-of-the-art RI study design. Of note, calcium is typically tightly regulated in all mammals, as illustrated by the narrow RI (8.5-10.8 mg/dl); conversely, finding a narrow RI in calcium across as many as 49 healthy individuals suggests a high-quality design study.

Loss of genetic diversity among ocelots in the United States during the 20th century linked to human induced population reductions.

Ocelots (Leopardus pardalis) in the United States currently exhibit low levels of genetic diversity. One hypothesis for this observation is that habitat fragmentation, resulting from human induced changes in the landscape during the 20(th) century, created island populations with highly reduced gene flow and increased genetic drift and inbreeding. In an effort to investigate this, we used a portion of the mitochondrial control region and 11 autosomal microsatellite loci to examine historical levels of genetic diversity and infer temporal changes in ocelot populations between 1853 and 2005. Levels of genetic diversity were higher in historical ocelot populations than in extant populations from Texas. The earliest documented loss of mitochondrial haplotype diversity occurred at Laguna Atascosa National Wildlife Refuge. The second extant population inhabiting private lands in Willacy County retained higher levels of genetic diversity through the 1990s, but subsequently lost diversity over the next decade. A similar pattern was observed for autosomal microsatellite loci. This supports the argument that low levels of genetic diversity in Texas are related to human induced population reductions and fragmentation, both of which threaten the remaining ocelots in the United States. At this time, the best means of mitigating the continued erosion of genetic variation are translocation of individuals either from larger populations in Mexico to Texas, or between the Texas populations.

Helminths of the ocelot from southern Texas.

In the USA, the ocelot (Leopardus pardalis) is a highly endangered felid found only in a few remaining vestiges of native thornshrub brushland in the Lower Rio Grande Valley (LRGV) of extreme southern Texas. From 1987-1998, carcasses of 15 adult ocelots that died of vehicular accidents or natural causes were examined for helminths. All cats had 1-8 (mean = 3) helminth species. All were infected with 1-101 (mean +/- SE = 32 +/- 7) Toxascaris leonina. Other helminths from these ocelots were Alaria marcianae, Brachylaima sp., Mesocestoides lineatus, Taenia rileyi, Oncicola canis, Dirofilaria immitis, Physaloptera rara, Ancylostoma tubaeformae, Cylicospirura chevreuxi, Vogeloides felis, and Metathelazia californica. Additionally, two cats had scarring of the aorta with lesions typical of those caused by Spriocerca lupi, although larval nematodes were not seen. A clinal variation in size of nearly three orders of magnitude was noted in the diplostomatid trematodes in the small intestine of one adult male ocelot. Despite the differences in size, all specimens appeared morphologically identical and were regarded as A. marcianae. Helminth prevalences and abundances, including those of potentially pathogenic species like D. immitis, were low. Although a single heartworm infection may have contributed to the death of one ocelot, helminth infections in general seemed to be of no great consequence to this endangered ocelot population. The helminth fauna of ocelots in the LRGV is reflective of that from wild felids in general; all have been reported previously from the bobcat (Lynx rufus) and mountain lion (Puma concolor) elsewhere in Texas.