PHARMACOLOGICAL REVIEW OF CHEMICALS USED FOR THE CAPTURE OF ANIMALS

A review of the literature reveals that over 60 chemicals have been used for the capture of wild animals, but only 30 of the most widely used chemicals are discussed in the present paper. For practical considerations these chemicals can be classified as being either (l) neuromuscular blocking agents, or (2) central nervous system (CNS) depressants. Some common neuromuscular blocking agents are d-tubocurarine, gallamine, succiny1choline, and nicotine. M99 and its derivatives, phencyclidine, and xylazine are some of the more commonly used CNS depressants. Neuromuscular blocking agents have a relatively rapid onset and short duration of action but they do not possess sedative, analgesic, or anesthetic properties. CNS depressants do produce desirable sedative, analgesic, and anesthetic effects, and frequently a combination of CNS depressants results in more desirable immobilization characteristics

PHARMACOLOGICAL REVIEW OF CHEMICALS USED FOR THE CAPTURE OF ANIMALS

A review of the literature reveals that over 60 chemicals have been used for the capture of wild animals, but only 30 of the most widely used chemicals are discussed in the present paper. For practical considerations these chemicals can be classified as being either (l) neuromuscular blocking agents, or (2) central nervous system (CNS) depressants. Some common neuromuscular blocking agents are d-tubocurarine, gallamine, succiny1choline, and nicotine. M99 and its derivatives, phencyclidine, and xylazine are some of the more commonly used CNS depressants. Neuromuscular blocking agents have a relatively rapid onset and short duration of action but they do not possess sedative, analgesic, or anesthetic properties. CNS depressants do produce desirable sedative, analgesic, and anesthetic effects, and frequently a combination of CNS depressants results in more desirable immobilization characteristics

The toxic sheep collar for control of sheep-killing coyotes: A progress report

The toxic sheep collar is the most selective method known for killing coyotes that prey on domestic sheep. The concept dates back to the early 1900's and has been studied at the Denver Wildlife Research Center (DWRC) since 1974. Field tests with sodium cyanide (NaCN) in 1975 were unsuccessful due to repellent properties of the toxicant and to the apparent reluctance of coyotes to attack tethered lambs wearing bulky collars. Coyotes attacked one or more tethered, collared lambs in 7 of the 19 test pastures. In all, 14 collared lambs were attacked. Eight of the collars were punctured but no dead coyotes were recovered. A smaller collar containing diphacinone was field tested in 1976. The diphacinone-filled collars were readily accepted by coyotes and lethal to them, but the slow action (5-16 days between dosing and death) of diphacinone made it difficult to assess the effectiveness of these collars under field conditions. Target flocks containing 1 to 12 collared lambs plus uncollared ewes were placed in 15 fenced pastures from which the larger ranch flocks had been removed after repeated coyote predation. One or more collared lambs were attacked in 11 of the 15 tests. An unknown number of coyotes were killed, and in most tests the subsequent incidence of predation was lower than that before the test. Captive coyotes continued to kill sheep for 4 or 5 days after they received a lethal dose of diphacinone; therefore a faster-acting toxicant is needed. This research has shown that problem coyotes can be killed with toxic collars, but further studies are needed to determine the feasibility of this approach compared with traditional means of control. In most tests to date the frequency of coyote predation has been too low and too irregular to permit effective use of the collar; target flocks were in the field for an average of 10 days before being attacked. The known disadvantages of the method include the need to sacrifice live lambs, the human hazards associated with the use of toxicants under field conditions, and the costs of managing target flocks and other sheep in the problem areas

Acetaminophen as an Oral Toxicant for Nile Monitor Lizards (\u3ci\u3eVaranus niloticus\u3c/i\u3e) and Burmese Pythons (Python molurus bivittatus\u3c/i\u3e)

Context. Invasive species are a growing global problem. Biological invasions can result in numerous harmful impacts on local ecologies, and non-native herpetofauna are frequently ignored. Nile monitor lizards (Varanus niloticus) and Burmese pythons (Python molurus bivittatus, recently reassessed as Python bivittatus bivittatus), have become established in southern Florida. Both are large, semi-aquatic predators that pose serious threats to a variety of threatened and endangered species, as well as to the unique ecology of the area. Aims. Acetaminophen (CAS#103-90-2), a lethal oral toxicant for the invasive brown treesnake (Boiga irregularis) on Guam, was investigated as a possible toxicant in juvenile Burmese pythons and Nile monitors. Methods. Dead neonatal mouse (DNM) baits containing 0, 10, 20, or 40 mg acetaminophen were force-fed to Nile monitors, whereas DNM containing doses of 0, 20, 40, or 80 mg were freely consumed by Burmese pythons. Subjects were frequently observed post-treatment for general condition and position, with special attention paid to activity (if any), behaviour, respiration, bleeding, emesis, ataxia, and mortality. Key results. In Nile monitors, acetaminophen doses of 10, 20, or 40 mg resulted in 0, 50 and 100% mortality, respectively. In Burmese pythons, doses of 20, 40, or 80 mg resulted in 14.3, 85.7 and 100% mortality, respectively. No mortality was observed in control individuals of either species. A negative correlation between dosage (mg kg–1) and time-to-death was observed in both species. Dosages ranging from 522 to 2438 mg kg–1 and 263 to 703 mg kg–1 were uniformly lethal to monitors and pythons, respectively. Neither species exhibited signs of pain or discomfort following acetaminophen treatment. Conclusions. Acetaminophen is an effective toxicant in juvenile Nile monitors and Burmese pythons. Further investigation into acetaminophen toxicity in adults of these species is merited. Implications. Although further investigation into adult lethal dosages and strategies to optimize bait deployment while minimizing secondary hazards is required, acetaminophen may have a role to play in the control of these invasive species in Florida

FLOTATION MATERIALS FOR AERIAL DELIVERY OF ACETAMINOPHEN TOXIC BAITS TO BROWN TREESNAKES

Polyvinyl chloride (PVC) tubes are effective bait stations for delivering dead neonatal mice (DNM) treated with the oral toxicant, 80 mg acetaminophen, to brown treesnakes (Boiga irregularis) in accessible jungle forest on Guam. However, PVC tubes are not practical for delivery of baits to remote areas of jungle or the forest canopy. Further, it is important that baits entangle in the canopy and not fall to the ground where they can be scavenged by non-target animals such as crabs. Data from helicopter aerial deployment of untreated DNM with radio transmitters that landed on the ground in areas of high coconut crab (Birgus latro) and hermit crab (Coenobita spp.) abundance showed that 67% of DNM were taken by crabs and 11% by monitor lizards (Varanus indicus). In contrast, in low crab abundance areas crabs took 24% of the DNM that landed on the ground. It is evident from these data that a flotation system that delivers DNM to the canopy is needed; otherwise non-target animals will remove DNM, making them unavailable for snakes. Seven aerial flotation devices were evaluated. Promising aerial devices are two types of commercial cardboard paper streamers that resulted in 75% - 85% of the DNM becoming entangled in the canopy

Efficacy, effort, and cost comparisons of trapping and acetaminophen-baiting for control of brown treesnakes on Guam

Brown treesnakes (Boiga irregularis) are an invasive species to the island of Guam. Because they have extirpated the native forest avifauna on Guam and are a threat to other Pacific islands, the development of efficient and cost-effective methods to control them is desired. We compared the efficacy, cost, and effort required to remove brown treesnakes on 6-ha plots in forest scrub on Guam, using 2 methods: trapping and poison baiting. Toxic baits consisted of dead neonatal mice adulterated with 80-mg acetaminophen. To assess efficacy, we used mark-recapture methods to estimate snake abundance on plots 12 days before and 12 days after treatment. We also monitored bait-take or trap success for 20 days during treatment. From 6,304 trap-nights, we recorded 801 captures of 504 snakes on 6, 6-ha plots during a 51-day period. Snake populations on plots ranged from 41 to 107 prior to treatment. Using trapping to gauge survival of marked snakes, the 2 methods (trapping and baiting) had similar efficacies (0.05 to 0.1). Based on trapping, post-treatment population estimates ranged from 26 to 40, yielding reductions from estimated pre-treatment populations of 7 to 68% for both types of snake-removal treatments. Using post-treatment bait-take of unadulterated mice as an index of efficacy, poisoned baiting was twice as effective as trapping in diminishing snake activity. Trapped plots had post-treatment bait-take rates similar to reference plots (75%), whereas poison-baited plots had bait-take rates of 38%, suggesting that some snakes cannot be trapped and that baiting affects a wider range of the snake population. Because of the potential for baiting to impact more snakes, this method was about 1.67 times more cost effective than trapping. If baiting were to occur via aerial drop rather than via bait stations, the economic incentive for using baiting as a control strategy would be even greater. These observations will prove useful for managers making decisions about appropriate methods for control of brown treesnake populations

Acceptance of Simulated Oral Rabies Vaccine Baits by Urban Raccoons

In summer 1986, a study was conducted to evaluate raccoon (Procyon lotor) acceptance of oral baits that could be used for rabies vaccination, One thousand wax-coated sponge bait cubes were filled with 5 mg of a seromarker (iophenoxic acid), placed in polyethylene bags, and hand-distributed in an 80 ha area within an urban National Park in Washington, D.C. (USA), After 3 wk, target and nontarget animals were trapped and blood samples collected to evaluate bait uptake. Thirty-three of 52 (63%) raccoons had elevated blood iodine levels indicating they had eaten at least one bait, 13 (25%) were negative, and six (12%) had marginal values, These results indicate that sponge baits hand-placed at a density of 12,4/ha can reach a significant proportion of an urban raccoon population. Implications for oral rabies vaccination of raccoons are discussed

TOXIC CHARACTERISTICS OF FLUOROCITRATE, THE TOXIC METABOLITE OF COMPOUND 1080

This paper reviews toxicological research involving fluorocitrate, the toxic metabolite of sodium monofluoroacetate (fluoroacetate), which is the active ingredient in the pesticide Compound 1080. Many toxicological studies have been done with fluoroacetate and the results obtained are actually due to the fluorocitrate because it has been definitely proved that, from a biochemical perspective, fluoroacetate is not toxic but fluorocitrate is. The classical explanation of the toxic action of fluorocitrate is that it inhibits the enzyme aconitase in the tricarboxylic acid cycle. Deactivation of aconitase results in decreased energy production by cells and ultimately death of the organism. However, the more recent explanation of fluorocitrate\u27s mode of action is that it binds with mito-chondrial protein which prevents transport of citrate and its utilization by cells for energy production. Metabolism studies indicate that only small amounts, perhaps less than 3%, of fluorocitrate is formed from fluoroacetate. From the limited number of acute and chronic studies conducted with fluorocitrate it does not appear to be as potent as fluoroacetate by either the oral or parenteral routes of admini-stration. This decreased level of toxicity is thought to be due to the larger molecular weight of fluorocitrate which would not be as readily absorbed by tissues. Central nervous system toxic mani-festations (i.e., tremors, convulsions) are characteristic in many animals poisoned with fluoroacetate. Fluorocitrate administered directly into the brain was found to be 100 times more toxic than fluoro-acetate. The accumulation of citrate in organs is characteristic of fluorocitrate poisoning; from a quantitative point of view the liver is less affected than the brain, heart, kidney, or spleen. Fluorocitrate causes extensive kidney damage, but the testes are most sensitive to sublethal doses. Testicular damage may be either reversible or irreversible, depending upon the dose. Several plants have the ability to metabolize both fluoroacetate and fluorocitrate from either inorganic or atmospheric fluoride

PERSISTENCE OF TARTRAZINE IN MARKING SHEEP WOOL

Tartrazine was examined as a possible replacement marker for rhodamine B in the Livestock Protection Collar. Test solutions were formulated in six combinations; tartrazine at 0.5% and 1.07. concentrations, with and without compound 1080, and with and without nigrosin black. Each solution was examined for persistence of color in the laboratory and when applied to the wool of dried sheep hide. Hide pieces were allowed to weather naturally or were sprinkled to simulate rain. Tartrazine alone was also tested at concentrations of 0.5% and 1.0% on the necks of sheep. Over a 3—month period, no fading was noted in the laboratory for any test solution. When applied to wool, no loss of color was attributed to 1080 or nigrosin black and no long-term advantage was detected for a 1.0% over a 0.5% tartrazine solution, except on the sprinkled pieces. Tartrazine usually provided an identifiable mark on the wool of dried hides and on live sheep for 1 to 2+ months, depending on test conditions. Tartrazine is an acceptable replacement for rhodamine B in the Livestock Protection Collar