Superoxide Dismutase Activity within Caribou Serum as an Indicator of Copper Status

Copper concentrations measured in liver are the gold standard for evaluating the copper status of ruminants. For live ruminants, measuring copper status is problematic because serum copper concentrations fluctuate and are not consistently correlated to liver copper values. In an attempt to establish an accurate evaluation of copper status from serum in caribou, we examined the correlation between liver copper concentrations and superoxide dismutase (SOD), which uses the oxidation and reduction reactions of a bound copper ion in order to catalyze superoxide radicals. Our study focuses on SOD activity in the serum of 16 individual adult female caribou and compares that to known copper levels within the liver. Determining copper levels in ruminants has proven difficult and currently a true proxy to determine liver copper levels in a live animal is unknown

Persistence of plague : determining which environmental factors contribute to maintenance of Yersinia pestis within sylvatic cycles

[EMBARGOED UNTIL 5/1/2024] Plague is a prioritized zoonotic disease caused by Yersinia pestis, a gram-negative bacterium. Sylvatic cycles of rodent host and flea vectors have established endemic foci responsible for the long-term maintenance of Y. pestis. Within the geographic range of prairie dogs, it is not understood why regions have recurrent epizootics while others remain plague-free. Abiotic factors have been correlated to epizootics and field surveys have led to hypotheses on the role other rodent species and flea or host population fluctuations may have in initiating these occurrences. Field and laboratory studies analyzing how these variables may impact vector competency have led to contradictory results and disparity in experimental design. Vector competency is often studied in the context of early-phase transmission or biofilm-mediated transmission applying temporal or genetic restrictions to the design and subsequent analysis. Corresponding analyses with these transmission models results in the neglect of unique geographic variables and flea:host interactions associated with the natural system. The purpose of this work was to investigate edaphic factors associated with epizootic occurrences throughout the geographic range of prairie dogs and determine if these factors influence vector competency of the flea. Soil moisture, temperature, and characteristics influencing water infiltration and storage had positive associations to plague occurrences. The depth at which these factors were associated, and the soil taxonomy varied based on geographic location, leading to site specific soil sensor installation for long-term evaluation. Investigating the infection in the flea under different abiotic and biotic components indicated host bloodmeal, temperature, and humidity influenced proventricular colonization and transmission efficiency. Variation in these components can alter vector competency, suggesting ecological factors drive disease spread or long-term maintenance. Another mechanism for long-term maintenance was discovered and strong evidence that Y. pestis leaves the alimentary canal and is transovarially transmitted is provided. The presence of bacteria throughout development from egg to F1 progeny illustrates processes independent of defined transmission models contribute to disease spread and maintenance.Includes bibliographical references

Fecal parasite identification by microscopy and PCR in scimitar-horned oryx, Oryx dammah, managed at two sites

The scimitar-horned oryx, Oryx dammah, an endangered species extinct in the wild, is managed in various captive management programs and is the focus of reintroduction efforts. Management variability can contribute to substantial parasite load differences, which can affect deworming programs and potentially transfer parasites to different regions with translocations. Parasite studies in O. dammah are lacking. In this study, we determined fecal egg/oocyst counts of O. dammah in two captive herds, Fossil Rim Wildlife Center (FRWC) and Kansas City Zoo (KCZ). Fecal egg counts (FEC) were performed on O. dammah feces collected seasonally using the modified McMaster method, and microscopy provided additional identification of parasite genera ova and oocysts. To identify parasites to species level, homogenized fecals provided DNA subjected to the polymerase chain reaction (PCR) using genus specific primers. Microscopy and sequencing results indicated the presence of Strongylus (Strongylus vulgaris, Angiostrongylus cantonensis), Trichostrongylus (Haemonchus contortus, Camelostrongylus mentulatus), Trichuris (T. leporis, T. ovis, and T. discolor), Isospora (Isospora gryphoni) and Eimeria (E. zuernii and E. bovis), with Strongylus being the most common. Nematodirus was identified through microscopy at FRWC. Fecal egg counts were significantly higher in (FRWC) than in (KCZ) in all samplings (P = <0.001). No significant difference was seen between parasite load and seasons (P = 0.103), nor site and season (P = 0.51). Both study sites maintained most animals within commonly accepted FEC levels found in domestic livestock. Individuals with high numbers of EPG or OPG were subordinate males, pregnant females, or neonates. Several significant interactions were found between genera of parasites, age, sex, season, and pregnancy status in the FRWC herd. Sampling limitations prevented further analysis of the KCZ herd. Understanding interactions between parasite loads and physiological, environmental, and regional differences can help determine inter-specific transfer of parasites, and establish appropriate anthelmintic programs for O. dammah herds