Susan M. Jojola

ORAL RABIES VACCINE (ORV) BAIT UPTAKE BY CAPTIVE STRIPED SKUNKS

Aerial delivery of oral rabies vaccine (ORV) baits has proven effective in large-scale efforts to immunize wildlife against rabies, and in North America this strategy currently is being used to immunize foxes (Urocyon cinereoargenteus and Vulpes vulpes), raccoons (Procyon lotor), and coyotes (Canis latrans). Skunks are also a major reservoir and vector of rabies, but at present oral vaccines for use in skunks are not licensed. Furthermore, given differences in morphology (smaller jaws) and behavior (food handling and consumption), it is unknown if baits currently used in ORV campaigns would be effective for skunks. Because oral vaccine delivery is contingent upon puncture of the vaccine container (VC), baits need to be sufficiently attractive to elicit selection and consumption. Manipulation of the bait to facilitate vaccine ingestion by the target species is a critical element for an effective ORV bait. The objectives of this study were to assess manipulation and consumption of current ORV baits by striped skunks (Mephitis mephitis). We conducted four independent trials with penned animals and various baits to assess bait selection frequency, VC puncture frequency, and consumption. Video recorded trials were used to assess attractiveness of baits and consumption behavior of skunks. Bait characteristics, such as texture, size, and flavor influenced selection and consumption. Fish and chicken flavors were preferred and vaccine containers within selected baits were likely to be punctured. Vaccine ingestion seemed more likely if VCs were directly coated with the bait matrix. To make baits attractive to skunks and to ensure puncture of the VC, modifications to current baits should consider a smaller size, a meat-flavored matrix, a slightly pressurized VC, and a direct coating of matrix on the VC.

A live trap model and field trial of a nutria (Rodentia) multiple capture trap

, also known as coypu) arelarge semi-aquatic rodents native to South America. Thespecies was first introduced to the United States in 1899for the establishment of a fur farm in California. Sincethen, accidental and intentional releases have permittednutria to become established in wetlands in at least 15states (Carter and Leonard 2002). Today, nutria are animportant resource for the Louisiana fur industry. Despitethis economic advantage, nutria can be detrimental to anarea. Burrowing and foraging by nutria often inflictseveredamage and can be devastating to native vegetation andcrops (LeBlanc 1994). Nutria are recognized as a con-tributing factor in the decline of the native Louisianacoastal marsh (Grace and Ford 1996, Evers et al. 1998).Management plans to control nutria impacts typicallyinvolve population reduction or eradication (Gosling andBaker 1989). At present, public hunting and trapping,encouraged by an incentive payment program, are theprimary approaches used to reduce overabundant pop-ulations in Louisiana. Alternative tools, however, includ-ing toxicants and attractants used to increasing trappingsuccess, need to be assessed for possible use (GenesisLaboratories, Inc. 2002, Nolte et al. 2004).One possible method that could increase nutria cap-ture rates would be a multiple capture trap (MCT). Tra-ditional control methods have involved either single-setleg-hold traps or shooting of individual nutria. Bothmeth-ods are quite labor intensive per nutria collected. Addi-tionally, leg-hold traps, toxicants, and shooting cannotbeused in many urban-suburban settings because of non-target hazards to children, pets, livestock, and protectedwildlife. An effective multiple capture trap could reducethe amount of effort required to capture multiple animalsand reduce non-target animal losses. For populationmanagement purposes, it is also important that an MCTis able to capture target animals of both sexes and bothjuvenile and adult animals. The MCT would also be usefulto capture nutria for research purposes with less chanceof injury than the use of leg-hold traps.This study evaluated one MCT in two different config-urations with two different types of bait. This field studywas conducted on the Mandalay National WildlifeRefugein Terrebonne Parish, southeastern Louisiana. The refugewas approximately 97 km southwest of New Orleans andencompassed 1700 ha. The area was comprised offreshwater marsh and bald cypress (

Determination of Sulfadimethoxine Residues in Skunk Serum by HPLC

Abstract Sulfadimethoxine (SDM) was extracted from skunk serum and isolated by reversed‐phase high performance liquid chromatography. SDM was detected by ultra‐violet absorbance at 270 nm and quantified by comparison to an external calibration standard. Recovery data were determined by analyzing SDM fortified control serum. The overall mean recovery with relative standard deviations of SDM in fortified skunk serum samples was 99±7%. The recovery for 0.38, 5.2, and 14.2 µg/mL SDM was 96.0±7.5%, 102±6.1%, and 97.3±5.1%, respectively. The method limit of detection for SDM in skunk serum ranged from 0.032 to 0.057 µg/mL SDM with a mean value of 0.040 µg/mL SDM. The method reported is much simpler and equally efficient as previous methods developed for the determination of SDM residues in serum.