Anticoagulant rodenticides in urban bobcats: exposure, risk factors and potential effects based on a 16-year study.

Anticoagulant rodenticides (ARs) are increasingly recognized as a threat to nontarget wildlife. High exposure to ARs has been documented globally in nontarget predatory species and linked to the high prevalence of an ectoparasitic disease, notoedric mange. In southern California, mange associated with AR exposure has been the proximate cause of a bobcat (Lynx rufus) population decline. We measured AR exposure in bobcats from two areas in southern California, examining seasonal, demographic and spatial risk factors across landscapes including natural and urbanized areas. The long-term study included bobcats sampled over a 16-year period (1997-2012) and a wide geographic area. We sampled blood (N = 206) and liver (N = 172) to examine exposure ante- and post-mortem. We detected high exposure prevalence (89 %, liver; 39 %, blood) and for individuals with paired liver and blood data (N = 64), 92 % were exposed. Moreover, the animals with the most complete sampling were exposed most frequently to three or more compounds. Toxicant exposure was associated with commercial, residential, and agricultural development. Bobcats of both sexes and age classes were found to be at high risk of exposure, and we documented fetal transfer of multiple ARs. We found a strong association between certain levels of exposure (ppm), and between multiple AR exposure events, and notoedric mange. AR exposure was prevalent throughout both regions sampled and throughout the 16-year time period in the long-term study. ARs pose a substantial threat to bobcats, and likely other mammalian and avian predators, living at the urban-wildland interface.

The use of mammals as sentinels for human exposure to toxic contaminants in the environment.

The use of sentinel species shows the potential to bridge the gap between animal-based and human-based environmental health research. With regard to the assessment of environmental contamination, the use of the terms "indicator," "monitor," and "sentinel" has often been confusing and ambiguous. A set of definitions is proposed as a standard to rectify this situation. The advantages of the use of sentinel species are provided, as well as criteria for sentinel selection, based on species characteristics. The recent use of mammals as sentinels for human exposure to toxic environmental contaminants is reviewed. A tabulated review of mammals proposed as indicators or monitors is included, as these may act as a database for the selection of sentinel species for future research efforts. The complexity and subtlety of factors interacting between an organism and its environment make it imperative that one provide a focused definition of what one wants the sentinel to assess and for what particular aspect of human health. Some examples of how sentinels might be selected for particular research questions are provided. While the potential for sentinel use in the field of environmental health is enormous, future investigators need to choose sentinels carefully, based on well-defined research questions, and confine conclusions drawn to the particular problem the sentinel was chosen to assess.

Assessment of potential therapies for acute T-2 toxicosis in the rat.

The efficacy of a variety of approaches for the treatment of animals with acute T-2 toxicosis was assessed utilizing young female rats. A single large dose of the water soluble salt of methylprednisolone significantly prolonged survival times in T-2 toxin treated animals. The use of diltiazem hydrochloride, dazemgrel, N-acetylcysteine, dimethyl sulfoxide, adenosine triphosphate (ATP), ATP combined with magnesium chloride, ascorbic acid, and aprotinin did not prolong survival times at the dosages administered. Trichodermin, a trichothecene similar in structure and biochemical activity to T-2 toxin but much less acutely toxic, had a detrimental effect on survival times whether given 1 hr prior to or after T-2 toxin.

Confirmation of indandione rodenticide toxicoses by mass spectrometry/mass spectrometry.

Mass spectrometry/mass spectrometry (MS/MS) with collision-activated dissociation (CAD) was utilized to unequivocally distinguish 1,3-indandione rodenticides in 2 cases of anticoagulant toxicosis. Anecdotal evidence provided by the veterinarian in a case involving feedlot cows and physical evidence at the site of occurrence in a similar case involving lambs strongly implicated diphenadione (diphacinone; DP) in both instances. However, high performance liquid chromatography indicated chlorophacinone (CP), not DP, was present in the blood samples obtained from both cows and lambs. Intact 1,3-indandiones exhibit poor gas chromatographic properties, so procedures were developed for analysis by MS/MS using a direct exposure probe for sample introduction. The EI mass spectra of DP and CP contained a base peak at m/z 173, with molecular ions (M+) at m/z 340 and m/z 374 (Cl isotope cluster), respectively. Corresponding MS/MS CAD parent ion spectra of m/z 173 showed an ion of m/z 340 for DP and 374 (Cl cluster) for CP. CAD analysis of the blood extracts showed a parent ion scan of m/z 173 identical to that of CP, with the m/z 374 (Cl cluster). (Additional evidence was obtained by MS/MS examination of the CAD daughter ion spectrum of m/z 374.) Blood extracts from the affected animals revealed CAD daughter ion spectra for m/z 374 identical to that of reference CP. Positive confirmation of CP in both cases led to identification of the source of the toxicant and prevention of further animal exposures.

Toleration of high concentrations of dietary zinc by mink.

Adult and kit male and female natural dark ranch mink (Mustela vison) were fed a conventional diet supplemented with 0, 500, 1,000, or 1,500 ppm zinc, as ZnSO4.7H2O, for 144 days. No marked adverse effects were observed in feed consumption, body weight gains, hematologic parameters, fur quality, or survival. Zinc concentrations in liver, kidney, and pancreas of the mink increased in direct proportion to the zinc content of the diet. Histopathologic examination of the livers, kidneys, and pancreata revealed no lesions indicative of zinc toxicosis. The results indicate that mink can tolerate at least 1,500 ppm dietary zinc, as ZnSO4.7H2O, for several months without apparent adverse effects.

Hexachlorophene toxicosis in a litter of Doberman pinschers.

A litter of 5-week-old Doberman Pinschers with pustular dermatitis was treated dermally with a hexachlorophene-containing emulsion. Shortly after a second treatment, all of the puppies developed neurologic signs consisting of muscle tremors, ataxia, and apparent muscle weakness. The clinical history and signs, histologic lesions within the central nervous system, and measurement of hexachlorophene in liver and kidney tissue confirmed a diagnosis of hexachlorophene toxicosis.

Winter poisoning of coyotes and raptors with Furadan-laced carcass baits.

Three bald eagles (Haliaeetus leucocephalus), a red-tailed hawk (Buteo jamaicensis), and two coyotes (Canis latrans) found in a field in north-central Kansas (USA) in December 1992 were poisoned by flowable carbofuran (Furadan 4F) placed on sheep (Ovis aries) carcasses to kill coyotes. The carbofuran was placed on the carcasses in October 1992, but the coyotes and raptors apparently were killed in late December. Thus, flowable Furadan can cause direct and secondary deaths of wildlife under some circumstances for at least 60 days following placement.

Hepatic cirrhosis and hemochromatosis in three horses.

Hemochromatosis, an iron storage disease, was diagnosed in 3 horses with hepatic cirrhosis. Each horse had bridging portal fibrosis and abundant iron deposits in the cytoplasm of hepatocytes. Serum concentrations of liver-derived enzymes and total bile acids were high. However, serum iron concentration was not high, and iron binding capacity was only 46% saturated in the 1 horse in which it was measured. However, the concentration of iron in the liver of this horse was 20 times the reference limits. Hemochromatosis is common in mynah birds and human beings. There are several types of this iron storage disease. In human beings, there is a familial disease with iron absorption inappropriate for the level of stored iron. Hemochromatosis also occurs secondary to cirrhosis of the liver, and in certain anemia diseases. Another type of hemochromatosis is seen in association with dietary iron overload. These horses were not related, and there was not any evidence of high dietary iron intake.

Pennyroyal oil toxicosis in a dog.

A dog was treated for fleas with the application of pennyroyal oil obtained by the owner at a health food store. Vomiting ensued within 2 hours, and despite emergency treatment, the dog died within 48 hours. At necropsy, pennyroyal oil was determined to be the cause of death.

Pemoline toxicosis in a dog.

A 3-year-old German Short-haired Pointer was examined because of extreme agitation, hyperactivity, and vomiting that began within 24 hours after ingestion of approximately 750 mg of pemoline, a CNS stimulant. On physical examination, the dog was agitated, tachycardic, hyper-responsive, pyrectic, disoriented, and had mydriasis. These signs were consistent with excessive stimulation of the CNS and sympathomimetic effects resulting from pemoline toxicosis. Serial blood and urine samples were obtained, and toxicologic analyses were performed. Extrapolation of the plasma pemoline concentration 32 hours after ingestion provided an estimated peak plasma concentration of 368 micrograms/ml, dramatically higher than a therapeutic concentration of 1.7 to 7.0 micrograms/ml reported for children. Several sedatives were administered intravenously to alleviate clinical signs and to allow administration of activated charcoal (PO) and fluids (IV). Clinical signs resolved approximately 72 hours after ingestion of pemoline.

Respiratory failure attributable to moxidectin intoxication in a dog.

A 5-month-old 22-kg (48.4-lb) sexually intact male Collie was examined after ingesting a moxidectin-containing deworming medication. The dog was comatose and had respiratory arrest after progressively worsening lethargy, ataxia, and seizures. Exposure was confirmed by isolation of moxidectin from a biopsy specimen of adipose tissue, using liquid chromatography-mass spectroscopy methods. Treatment included use of intermittent positive-pressure ventilation, activated charcoal and cathartic administered enterally, nutrients administered via nasogastric tube, and intensive supportive care. The dog was weaned from a ventilator on day 6 after ingestion and was discharged on day 10. The dog was considered clinically normal during examination 24 days after ingestion. On the basis of the dog reported here and toxicologic data provided by the manufacturer of the deworming product, some Collies may have increased susceptibility to products containing high doses of moxidectin.

Effective use of analytical laboratories for the diagnosis of toxicologic problems in small animal practice.

The increasing sophistication of toxicologic analyses offered by veterinary diagnostic laboratories provides the practitioner with a valuable resource for the diagnosis of companion and exotic animal toxicoses. The availability of such testing is a valuable service that can be offered to veterinary clientele. Appropriate and timely toxicologic testing may permit more successful treatment of affected patients and protect animals and humans from hazardous exposure that might occur if a responsible toxicant goes unrecognized. Perhaps the most critical point to keep in mind, however, is that no matter how sophisticated the toxicologic laboratory is, a correct diagnosis is dependent upon the submission of appropriate biologic and environmental samples.

Current environmental threats to animal health and productivity.

Livestock can be exposed to literally thousands of environmental contaminants. Fortunately, most do not cause significant livestock morbidity or mortality and relatively few present significant residue concerns in animal products intended for human consumption. Some environmental contaminants, however, present livestock health or residue concerns. The significance of specific environmental contaminants on livestock health and productivity can change with time and unforeseen threats can emerge as new chemicals or technologies are introduced or new knowledge about health effects of established chemicals emerges.

Zinc toxicosis in a captive striped hyena (Hyaena hyaena).

An 11-yr-old captive-born female striped hyena (Hyaena hyaena) acutely developed lameness and swelling of the left front foot with anorexia, depression, and lethargy. Hematologic evaluation revealed regenerative anemia, azotemia, and other mild serum electrolyte and mineral abnormalities. Twenty radiographically visible coins and 10 coin fragments were removed by laparotomy and gastrotomy following unsuccessful medical therapy. The animal died during anesthetic recovery. Zinc serum levels were 41.0 ppm at first presentation and 36.0 ppm at the time of surgery, compared with concentrations of 1.78 ppm and 2.82 ppm for serum taken from this female and a male hyena 3 mo previously. Zinc toxicosis was diagnosed based on the similarity of clinical signs to those described in dogs, presence in the stomach of pennies minted after 1982 (when the zinc content of U.S. pennies was increased substantially), necropsy findings, and elevated serum and liver zinc values. The case highlights the risk posed by penny ingestion for subsequent zinc toxicosis in captive omnivores.

Death by caffeine: presumptive malicious poisoning of a dog by incorporation in ground meat.

BACKGROUND: A 4-year-old, 37 kg, male German shepherd developed hyperthermia, tachycardia, and agitation following consumption of ground meat found in the backyard of its owner. When presented to a veterinary clinic, plasma ethylene glycol (EG) testing was positive, and the dog was given ethanol and lactated Ringer's solution intravenously. Approximately 11 h postexposure the dog died. DISCUSSION: Among tissues submitted for toxicological analysis, urine was negative for EG, ground meat was negative for certain drugs of abuse, and gastric contents were negative for zinc/aluminum phosphide and metaldehyde. Analysis of gastric contents by gas chromatography-mass spectrometry confirmed the presence of caffeine. Caffeine concentration in the ground meat was estimated at 1 %. Caffeine is a methylxanthine alkaloid with a reported canine oral median lethal dose (MLD(50)) of 140 mg/kg (range 120-200 mg/kg). A commercially available 200-mg tablet formulation of caffeine was considered to be a possible source but this was not confirmed. By conservative estimates, the dog would need to ingest approximately 500-550 g of the meat to reach the MLD(50). Acute intoxication affects the cardiovascular, pulmonary, neurologic, gastrointestinal, and metabolic systems. Although no tablet remnants were observed in the bait, tablets could have been crushed and/or dissolved. Other potential caffeine sources include guarana, brewed and concentrated coffee, and caffeine-containing beverages. Based on the history, clinical signs, and the detection of caffeine in the gastric contents and meat, a presumptive diagnosis of malicious caffeine poisoning was made. A suggested treatment regimen for caffeine intoxication in dogs is described. While few cases of accidental ingestion of caffeine by dogs have been described, the intentional use of a concentrated caffeine source to cause mortality in a dog has not been previously reported.

Blood leak alarm interference by hydoxocobalamin is hemodialysis machine dependent.

CONTEXT: Hydroxocobalamin has been reported to interfere with the blood leak alarm on hemodialysis machines making it difficult to use this treatment modality after hydroxocobalamin infusion. OBJECTIVE: The objective was to determine if this interference with hydroxocobalamin occurs across hemodialysis machines by different manufacturers. Additionally, we aimed to see if this represented a colorimetric interference alone or if it is the optical properties of hydroxocobalamin. MATERIALS AND METHODS: Hydroxocobalamin was reconstituted per package insert. Food coloring was added to 0.9% saline to create the colors of the visual spectrum. Optical properties of absorbance and transmittance were measured. Hydroxocobalamin and the saline solutions were infused into the Fresenius 2008K™ and the Gambro Phoenix X36™ machines. Times were recorded from the start of the machine until the solution finished or the alarm triggered. RESULTS: When evaluating the Gambro Phoenix X36™ machine and dialysis circuit; the alarm did not trigger. In contrast, the blood leak alarm on the Fresenius 2008K™ machine was tripped by both the red solution and hydoxocobalamin infused per the package insert. The alarm stopped the machine between 128 and 132 seconds for the red solution and between 30 and 35 seconds with the hydroxocobalamin. Membranes of the circuits where the alarm tripped were examined and remained intact without blood. Results were validated on different machines with new circuits. DISCUSSION: Hydroxocobalamin infusion per package insert and the red saline solution prepared with Red Dye 40 both triggered the blood leak alarm and stopped the Fresenius 2008K™ machine. However, this was not true for the Gambro Phoenix X36™ machine as the alarm never triggered. The interference with the Fresenius 2008K™ appears colorimetric due to normal saline with Red Dye 40 triggering the alarm. CONCLUSION: We alert physicians to become familiar with the properties of individual dialysis machines prior to use of hydroxocobalamin. When facing difficulties with hemodialysis after the administration of hydroxocobalamin, consider attempting with a different manufactures machine or model if available or contact the manufacturer directly.

Clostridium piliforme infection in two farm-raised white-tailed deer fawns (Odocoileus virginianus) and association with copper toxicosis.

Necropsy of 2 white-tailed deer fawns who died acutely revealed diarrhea and melena in case No. 1 and no gross changes in case No. 2. Histologically, the livers of both deer displayed multifocal coagulative necrosis, with infiltrations of neutrophils, macrophages, and lymphocytes. By Warthin-Starry staining, bundles of filamentous bacteria were identified within hepatocytes at the periphery of the necrotic foci in case No. 1. There was multifocal myocardiocyte necrosis in case No. 1 and multifocal lymphoid necrosis of the Peyer's patches in case No. 2. Clostridium piliforme 16S ribosomal ribonucleic acid gene was detected in both livers by polymerase chain reaction (PCR) with C. piliforme-specific primers. The liver copper levels in both cases were normal to slightly elevated. The kidney copper level in case No. 2 was elevated. This represents the first published cases of Tyzzer's disease in deer, a novel use of PCR for the diagnosis of C. piliforme infection, and a possible association between copper toxicosis and Tyzzer's disease.

Risks associated with the use of herbs and other dietary supplements.

The use of dietary supplements (herbs, vitamins, minerals, amino acids, enzymes, and other compounds) is common in horses. They are heavily marketed in retail stores, magazines, and on the Internet. There is the perception that since these compounds are "natural" they are devoid of toxicity, and, therefore, they are safe to use. Some of the active compounds in supplements, however, have inherent toxicity, and using them may cause adverse effects. Even relatively non-toxic ingredients may be toxic if used over-zealously or for a long period of time. By and large, these compounds have not been tested for safety or efficacy when used as marketed, and, unfortunately, there is little regulatory oversight for such products. Other deleterious consequences of dietary supplement use include interaction of compounds in the products with conventional drugs, resulting in unexpected adverse effects, or the occurrence of violative residues in urine samples collected from show or performance horses. This article provides a brief overview of potential problems associated with dietary supplements, primarily focusing on products containing herbs and essential oils.