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Chronic wasting disease (CWD) has become a major concern among those involved in managing wild and captive cervid populations. CWD is a fatal, highly transmissible spongiform encephalopathy caused by an abnormally folded protein, called a prion. Prions are present in a number of tissues, including feces and urine in CWD infected animals, suggesting multiple modes of transmission, including animal-to-animal, environmental, and by fomite. CWD management is complicated by the lack of practical, non-invasive, live-animal screening tests. Recently, there has been a focus on how the volatile odors of feces and urine can be used to discriminate between infected and noninfected animals in several different species. Such a tool may prove useful in identifying potentially infected live animals, carcasses, urine, feces, and contaminated environments. Toward this goal, dogs were trained to detect and discriminate CWD infected individuals from non-infected deer in a laboratory setting. Dogs were tested with novel panels of fecal samples demonstrating the dogs' ability to generalize a learned odor profile to novel odor samples based on infection status. Additionally, dogs were transitioned from alerting to fecal samples to an odor profile that consisted of CWD infection status with a different odor background using different sections of gastrointestinal tracts. These results indicated that canine biodetectors can discriminate the specific odors emitted from the feces of non-infected versus CWD infected white-tailed deer as well as generalizing the learned response to other tissues collected from infected individuals. These findings suggest that the health status of wild and farmed cervids can be evaluated non-invasively for CWD infection via monitoring of volatile metabolites thereby providing an effective tool for rapid CWD surveillance. [ABSTRACT FROM AUTHOR]

North American horned lizards of the genus Phrynosoma are largely myrmecophagous and squirt systemic blood from circumocular sinuses during encounters with certain mammalian predators. The predators react with distinct revulsion. Using bioassay-guided fractionation of blood plasma, we endeavored to identify the source and characteristics of the active chemical compound(s) responsible for this negative oral response. Our results of coyote bioassays and a series of novel mouse bioassay experiments were largely concordant. The active compound(s) was likely plasma-borne with a molecular weight (mw) of between 800 and 1,600. To identify the source of the active compound(s), we noted bioassay responses of different species of horned lizards. The active compound(s) was present in plasma fractions of species known to eat Pogonomyrmex and squirt blood, and it was absent in the plasma fractions of species that do not squirt blood and eat other ants or arthropods. Plasma fractions from individuals of P. cornutum, a blood-squirting species, fed Pogonomyrmex had more aversive levels of the active compound(s) compared to those given a cricket diet. In addition, extracts from Pogonomyrmex indicate that the active compound(s) in lizard plasma is associated with the abdomen of these ants, where venom is stored. The toxic enzymes of ant venom may be metabolized by horned lizards resulting in one or more small peptides that act as the active ingredient(s) in the lizard's circulating blood. We suggest that utilization of this widely dispersed, venomous, and abundant diet only became available to stem horned lizards with the evolution of unique prey capture techniques. This broadened diet then led to incorporation of the compound(s) from Pogonomyrmex spp. into their blood plasma, facilitating the evolution of antipredator blood-squirting. These transformative events apparently established an evolutionarily stable configuration that led to or expanded the unique "Phrynosoma suite" of characteristics from which subsequent diverse clades have evolved across arid North America. [ABSTRACT FROM AUTHOR]