Brodifacoum contamination of synthetic cannabinoid causing unexplained coagulopathy in multiple trauma: A case report

An 18-year-old female presented to the emergency department after a motor vehicle collision. Initial imaging revealed a liver laceration. Subsequent labs showed significantly elevated prothrombin time, international normalized ratio, and activated partial thromboplastin time. Thromboelastography demonstrated a flatline tracing. The patient denied use of anticoagulation but admitted to synthetic cannabinoid use. It was believed the patient had taken synthetic cannabinoid contaminated by brodifacoum. She was therefore given prothrombin complex concentrate and vitamin K with blood products. The patient underwent sequential embolization, laparotomy, thoracotomy, and repair of the vena cava with a shunt. Thirty minutes postoperatively, her coagulation tests and thromboelastography were much improved. Two and a half hours postoperatively, it was determined she had sustained non-survivable injuries. The patient experienced brain death due to prolonged hypotension as a result of hemorrhagic shock with bleeding exacerbated by brodifacoum. To our knowledge, this is the first case reported of a trauma-induced coagulopathy exacerbated by brodifacoum-contaminated synthetic cannabinoid. Her coagulopathy was clearly not due to trauma alone and contributed greatly to the difficulty in controlling hemorrhage. The synthetic cannabinoid-associated coagulopathy rendered her otherwise potentially survivable injuries fatal. Given the frequency of multiple trauma and the recent increase in the prevalence of synthetic cannabinoid, it can be expected that the incidence of trauma complicated by synthetic cannabinoid-associated coagulopathy will increase in the near future. For patients that present with prolonged prothrombin time and/or activated partial thromboplastin time, it is important to inquire about recent synthetic cannabinoid use.

A facile fluorescence microplate immunoassay based on an in situ fluorogenic reaction for the detection of two highly toxic anticoagulant rodenticides in food and biological matrix

Bromadiolone and brodifacoum, the most frequently used anticoagulant rodenticides, are highly toxic and pose a threat to public health by causing food poisoning incidents. Here, we developed a fluorescence microplate immunoassay for facile and sensitive detection of bromadiolone and brodifacoum by introducing three commercial chemicals (p-phenylenediamine, polyethyleneimine, H2O2) as a new substrate of horseradish peroxidase and then generating fluorescence signals based on an in situ fluorogenic reaction (detection time within 75 min). This assay exhibited higher efficiency in generating fluorescence signals, thereby exhibiting a 6-fold improvement in sensitivity compared with colorimetric ELISA. The limit of detection was 0.23-0.28 ng/mL (ng/g) for bromadiolone and 0.34-0.61 ng/mL (ng/g) for brodifacoum in corn and human serum, with recovery ratios higher than 82.3 %. These satisfactory results illustrated our proposed assay was a potential tool for food analysis and poisoning diagnosis caused by bromadiolone and brodifacoum.

First evidence of widespread positivity to anticoagulant rodenticides in grey wolves (Canis lupus)

Second-generation Anticoagulant Rodenticides (ARs) can be critical for carnivores, due to their widespread use and impacts. However, although many studies explored the impacts of ARs on small and mesocarnivores, none assessed the extent to which they could contaminate large carnivores in anthropized landscapes. We filled this gap by exploring spatiotemporal trends in grey wolf (Canis lupus) exposure to ARs in central and northern Italy, by subjecting a large sample of dead wolves (n = 186) to the LC-MS/MS method. Most wolves (n = 115/186, 61.8 %) tested positive for ARs (1 compound, n = 36; 2 compounds, n = 47; 3 compounds, n = 16; 4 or more compounds, n = 16). Bromadiolone, brodifacoum and difenacoum, were the most common compounds, with brodifacoum and bromadiolone being the ARs that co-occurred the most (n = 61). Both the probability of testing positive for multiple ARs and the concentration of brodifacoum, and bromadiolone in the liver, systematically increased in wolves that were found at more anthropized sites. Moreover, wolves became more likely to test positive for ARs through time, particularly after 2020. Our results underline that rodent control, based on ARs, increases the risks of unintentional poisoning of non-target wildlife. However, this risk does not only involve small and mesocarnivores, but also large carnivores at the top of the food chain, such as wolves. Therefore, rodent control is adding one further conservation threat to endangered large carnivores in anthropized landscapes of Europe, whose severity could increase over time and be far higher than previously thought. Large-scale monitoring schemes for ARs in European large carnivores should be devised as soon as possible.

Potential exposure of native wildlife to anticoagulant rodenticides in Gran Canaria (Canary Islands, Spain): Evidence from residue analysis of the invasive California Kingsnake (Lampropeltis californiae)

Anticoagulant rodenticides (ARs), particularly second-generation compounds (SGARs), are extensively used in pest management, impacting non-target wildlife. The California kingsnake (Lampropeltis californiae), an invasive species in Gran Canaria, is under a control plan involving capture and euthanasia. This research aimed to detect 10 different ARs in these snakes, explore geographical and biometrical factors influencing AR exposure, and assess their potential as sentinel species for raptors, sharing similar foraging habits. Liver samples from 360 snakes, euthanized between 2021 and 2022, were analysed for ARs using LC-MS/MS. Results showed all detected rodenticides were SGARs, except for one instance of diphacinone. Remarkably, 90 % of the snakes tested positive for ARs, with over half exposed to multiple compounds. Brodifacoum was predominant, found in over 90 % of AR-positive snakes, while bromadiolone and difenacoum were also frequently detected but at lower levels. The study revealed that larger snakes and those in certain geographic areas had higher AR concentrations. Snakes in less central or more peripheral areas showed lower levels of these compounds. This suggests a correlation between the snakes' size and distribution with the concentration of ARs in their bodies. The findings indicate that the types and prevalence of ARs in California kingsnakes on Gran Canaria mirror those in the island's raptors. This similarity suggests that the kingsnake could serve as a potential sentinel species for monitoring ARs in the ecosystem. However, further research is necessary to confirm their effectiveness in this role.

Intraspecific and geographical variation in rodenticide exposure among common kestrels in Tenerife (Canary Islands)

This study assesses the impact of second-generation anticoagulant rodenticides (SGARs) on the common kestrel (Falco tinnunculus canariensis) in Tenerife, Canary Islands. The analysis of 390 liver samples over 19 years using HPLC-MS/MS showed that 93.1 % of kestrels were exposed to SGARs in this island. A notable shift in SGAR profiles was observed, with bromadiolone and flocoumafen decreasing, while brodifacoum levels increased sharply from 2018 onwards. Comparatively, Tenerife kestrels had a higher detection frequency of SGARs (93.1 %) than those in the rest of the islands of the archipelago (68.2 %), with median concentrations nearly double (∑AR = 180.9 vs 102.4 ng/g liver, P < 0.0001). Furthermore, on average, kestrels from Tenerife were found to have a higher number of different rodenticide compounds per individual. A Generalized Linear Model (GLM) analysis revealed that several factors contribute to the likelihood of SGAR exposure: being an adult kestrel, the enactment of legal restrictions on SGAR bait concentrations in 2018, higher livestock density, and greater human population density. These findings suggest that both bioaccumulation over the birds' lifespans and environmental factors related to human and agricultural activity are influencing the levels of SGARs detected. Alarmingly, 44.7 % of kestrels had SGAR levels above the toxicity threshold established for other raptor species (200 ng/g liver), signaling a high poisoning risk. This is despite EU regulations to protect wildlife, with our findings indicating an increase in both exposure rates and SGAR concentrations since these laws were enacted. The data highlight a critical environmental threat to endemic species on islands like Tenerife. The common kestrel, not considered globally endangered, is nonetheless facing regional threats from SGAR contamination. These results emphasize the urgent need for effective regulations to address the persistent and growing impact of SGARs on island biodiversity.

An open dataset of anticoagulant rodenticides in liver samples from California kingsnakes and raptors in Gran Canaria (Canary Islands, Spain)

It is well known that rodenticides are widely used, and there are multiple routes by which they can reach non-target wildlife species. Specifically, in the Canary Islands, a high and concerning incidence of these compounds has been reported. However, in this scenario, reptiles remain one of the least studied taxa, despite their potential suitability as indicators of the food chain and environmental pollution has been noted on several occasions. In this context, the California Kingsnake (Lampropeltis Californiae), widely distributed on the island of Gran Canaria, occupies a medium trophic level and exhibits feeding habits that expose it to these pollutants, could be studied as a potential sentinel of exposure to these compounds. For this reason, 360 snake livers were analyzed by LC-MS/MS. Similarly, 110 livers of birds of prey were sampled. Thus, we present the analysis of 10 anticoagulant rodenticides (warfarin, diphacinone, chlorophacinone, coumachlor, coumatetralyl, brodifacoum, bromadiolone, difethialone, difenacoum and flocoumafen) in both data series; snakes, and raptors. Furthermore, this dataset includes biological data (weight, length, sex, colour, and design pattern), geographic data (distribution area and municipalities) and necropsy findings that could be of interest for a better understanding of this snake species and for future studies.

Fast and sensitive method for the diagnosis and follow-up of anticoagulant rodenticides poisoning in animal whole blood

Rodent control strategies are primarily based on the use of anticoagulant rodenticides (ARs), making them widely used worldwide. However, due to their high toxicity and availability, ARs are among the leading causes of animal poisoning in Europe. They are the primary agents involved in intoxication in cats and the second in dogs. Additionally, their long persistence in the body can lead to secondary exposure, particularly in wild predators. The laboratory findings and clinical signs of intoxication can range from increased clotting time (prolonged prothrombin time and activated partial thromboplastin time) to severe bleeding and death. Despite the prevalence and severity of this intoxication, only a few methods are available for the identification and quantification of ARs in animals, and most of them are suitable only for post-mortem diagnosis. In this study, we present the validation of a rapid and sensitive method for the identification and quantification of ARs in animal whole blood, using a small sample volume. The developed LC-MS/MS method demonstrated high accuracy and precision at the limit of quantification (LOQ), as well as at low, medium, and high concentrations. It exhibited higher sensitivity (LOQ 0.1 - 0.3 ng/mL) compared to previously published methods. After validation, the method was successfully applied to real cases of suspected poisoning events, resulting in the identification of several positive samples. The examples presented in this study highlight the utility of this method for diagnosis and follow-up, emphasizing the importance of method sensitivity in order to avoid misclassifying truly positive samples as negative.

Anticoagulant rodenticides are associated with increased stress and reduced body condition of avian scavengers in the Pacific Northwest

Anticoagulant rodenticides (AR) have been used globally to manage commensal rodents for decades. However their application has also resulted in primary, secondary, and tertiary poisoning in wildlife. Widespread exposure to ARs (primarily second generation ARs; SGARs) in raptors and avian scavengers has triggered considerable conservation concern over their potential effects on populations. To identify risk to extant raptor and avian scavenger populations in Oregon and potential future risk to the California condor (Gymnogyps californianus) flock recently established in northern California, we assessed AR exposure and physiological responses in two avian scavenger species (common ravens [Corvus corax] and turkey vultures [Cathartes aura]) throughout Oregon between 2013 and 2019. AR exposure was widespread with 51% (35/68) of common ravens and 86% (63/73) of turkey vultures containing AR residues. The more acutely toxic SGAR brodifacoum was present in 83% and 90% of AR exposed common ravens and turkey vultures. The odds of AR exposure in common ravens were 4.7-fold higher along the coastal region compared to interior Oregon. For common ravens and turkey vultures that were exposed to ARs, respectively, 54% and 56% had concentrations that exceeded the 5% probability of toxicosis (>20 ng/g ww; Thomas et al., 2011), and 20% and 5% exceeded the 20% probability of toxicosis (>80 ng/g ww; Thomas et al., 2011). Common ravens exhibited a physiological response to AR exposure with fecal corticosterone metabolites increasing with sum ARs (ΣAR) concentrations. Both female common raven and turkey vultures' body condition was negatively correlated with increasing ΣAR concentrations. Our results suggest avian scavengers in Oregon are experiencing extensive AR exposure and the newly established population of California condors in northern California will likely experience similar AR exposure if they feed in southern Oregon. Understanding the sources of ARs across the landscape is an important first step in reducing or eliminating AR exposure in avian scavengers.

The stop-feed effect of cholecalciferol (vitamin D3) and the efficacy of brodifacoum combined with cholecalciferol in Y139C-resistant Norway rats (Rattus norvegicus)

Second-generation anticoagulant rodenticides potentially build persistent residues in animals and accordingly pose a risk of secondary poisoning. We examined the effect of a low concentration of cholecalciferol in brodifacoum bait on bait consumption by Norway rats (Rattus norvegicus Berkenhout 1769) and on the control success in a laboratory study and in field trials. Additionally, the efficacy of both baits was determined against resistant Y139C rats. Cholecalciferol caused a strong stop-feed effect after two days in the laboratory study. On two field study sites each, bait containing either 25 mg kg-1 brodifacoum or 25 mg kg-1 brodifacoum and 100 mg kg-1 cholecalciferol was applied to treat infestations of Norway rats. Infestations were assessed pre- and post-treatment. Rats were radio-tagged, and carcasses were searched for during the treatment period. DNA of each rat was genotyped to determine the resistance status conferred by the VKORC1 gene. On all farms, control success exceeded 90%. On farms treated with brodifacoum only, the ratio of total bait consumption to pre-treatment census was significantly higher (6.6 and 4.8 times) than on farms treated with the combination (2.7 and 2.9 times). 78.8% of 183 rats were confirmed Y139C resistant. Bait ingestion was reduced by almost fifty per-cent when cholecalciferol was added to the bait with no impact on control success. All treatments resulted in control levels exceeding 90%, despite a high proportion of anticoagulant-resistant rats. When the use of highly toxic compounds is required in resistance management, addition of cholecalciferol to these baits may reduce the transfer of residues to the environment.

Widespread resistance to anticoagulant rodenticides in Mus musculus domesticus in the city of Barcelona

Control of rodent populations is a big challenge because of the rapid evolution of resistance to commonly used rodenticides and the collateral negative impacts that these products may have on biodiversity. Second-generation anticoagulants are very efficient but different single nucleotide polymorphisms (SNPs) in the Vkorc1 gene may confer resistance in rodents. We sequenced exons 1, 2 and 3 of the Vkorc1 gene from 111 mice (Mus musculus domesticus) captured across the city of Barcelona and found SNPs associated with resistance to first- and second-generation anticoagulants in all of them. Although most of the SNPs were associated with resistance to bromadiolone, we also found SNPs associated with resistance to brodifacoum. Out of all the individuals analyzed, 94.59 % carried mutations associated to introgression events with Mus spretus, a sympatric rodent species. Currently most of the chemical products for rodent control commercialized in the area are based on bromadiolone, although recent public control campaigns have already shifted to other products. Thus, the widespread occurrence of resistant mice to bromadiolone represents a challenge for rodent control in Barcelona and may increase the risk of secondary poisoning of animals preying on this species. Public health managers, pest control companies and citizens should be aware that the use of bromadiolone based products is ineffective and represents a risk for the environment, including human and animal health.

Collateral damage: Anticoagulant rodenticides pose threats to California condors

Anticoagulant rodenticides (ARs) are widespread environmental contaminants that pose risks to scavenging birds because they routinely occur within their prey and can cause secondary poisoning. However, little is known about AR exposure in one of the rarest avian scavengers in the world, the California condor (Gymnogyps californianus). We assessed AR exposure in California condors and surrogate turkey vultures (Cathartes aura) to gauge potential hazard to a proposed future condor flock by determining how application rate and environmental factors influence exposure. Additionally, we examined whether ARs might be correlated with prolonged blood clotting time and potential mortality in condors. Only second-generation ARs (SGARs) were detected, and exposure was detected in all condor flocks. Liver AR residues were detected in 42% of the condors (27 of 65) and 93% of the turkey vultures (66 of 71). Although concentrations were generally low (<10 ng/g ww), 48% of the California condors and 64% of the turkey vultures exposed to ARs exceeded the 5% probability of exhibiting signs of toxicosis (>20 ng/g ww), and 10% and 13% exceeded the 20% probability of exhibiting signs toxicosis (>80 ng/g ww). There was evidence of prolonged blood clotting time in 16% of the free-flying condors. For condors, there was a relationship between the interaction of AR exposure index (legal use across regions where condors existed) and precipitation, and the probability of detecting ARs in liver. Exposure to ARs may complicate recovery efforts of condor populations within their current range and in the soon to be established northern California experimental population. Continued monitoring of AR exposure using plasma blood clotting assays and residue analysis would allow for an improved understanding of their hazard to condors, particularly if paired with recent movement data that could elucidate exposure sources on the landscape occupied by this endangered species.

The effects of brodifacoum cereal bait pellets on early life stages of the rice coral Montipora capitata

Midway Atoll in the Northwestern Hawaiian Islands is home to ground nesting birds that are threatened by invasive mice. Planned rodent eradication efforts for the island involve aerial application of cereal bait pellets containing the chemical rodenticide brodifacoum. Given the nature of the application method, drift of cereal bait pellets into the coastal waters surrounding Midway Atoll is unavoidable. To understand whether cereal bait pellets impact marine invertebrates, gametes and larvae of the reef-building coral Montipora capitata were exposed to brodifacoum, cereal bait pellets containing brodifacoum, and inert cereal bait pellets without the rodenticide. Fertilization success and larval survival were assessed at nominal brodifacoum concentrations of 1, 10, and 100 ppb. Fertilization success decreased by 15% after exposure to 100 ppb brodifacoum solutions. Larval survival was not reduced by exposure to brodifacoum solutions. Cereal bait pellets containing brodifacoum reduced fertilization success at 10 ppb brodifacoum in 0.4 g per L pellet solutions by 34.84%, and inhibited fertilization at 100 ppb brodifacoum in 4 g of pellet per L solution. Inert cereal bait pellets had similar effects, reducing fertilization success at 0.4 g of pellet per L by 40.50%, and inhibiting fertilization at 4 g per L pellet solutions. Larval survival was reduced by >43% after prolonged exposure to 4 g per L pellet solutions. The highest concentration used in this study was meant to represent an extreme and unlikely condition resulting from an accidental spill. Our findings indicate large amounts of cereal bait pellets entering the coastal environment of Midway Atoll, if occurring during a coral spawning event, would reduce coral reproduction by decreasing fertilization success. It is difficult to know the ecologically relevant concentrations of cereal bait pellets in coastal environments due to unavoidable bait drift after land applications, but results indicate small amounts of pellet drifting into coastal environments would not severely reduce coral reproductive capacity. Best management practices should consider known coral reproductive periods when scheduling applications of pellets on tropical islands to reduce the risk of negative impacts of large-scale accidents on corals.

Anticoagulant rodenticide exposure in raptors from Ontario, Canada

Anticoagulant rodenticides (ARs) are used globally to control rodent pest infestations in both urban and agricultural settings. It is well documented that non-target wildlife, including predatory birds, are at risk for secondary anticoagulant exposure and toxicosis through the prey they consume. However, there have been no large-scale studies of AR exposure in raptors in Ontario, Canada since new Health Canada legislation was implemented in 2013 in an attempt to limit exposure in non-target wildlife. Our objective was to measure levels of ARs in wild raptors in southern Ontario to assess their exposure. We collected liver samples from 133 raptors representing 17 species submitted to the Canadian Wildlife Health Cooperative (CWHC) in Ontario, Canada, between 2017 and 2019. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to quantitatively assess the level of exposure to 14 first- and second-generation ARs. Detectable levels of one or more ARs were found in 82 of 133 (62%) tested raptors, representing 12 species. The most commonly detected ARs were bromadiolone (54/133), difethialone (40/133), and brodifacoum (33/133). Of AR-positive birds, 34/82 (42%) contained residues of multiple (> 1) anticoagulant compounds. Our results indicate that AR exposure is common in raptors living in southern Ontario, Canada. Our finding that brodifacoum, difethialone, and bromadiolone were observed alone or in combination with one another in the majority of our sampled raptors indicates that legislative changes in Canada may not be protecting non-target wildlife as intended.

Widespread exposure of powerful owls to second-generation anticoagulant rodenticides in Australia spans an urban to agricultural and forest landscape

The powerful owl (Ninox strenua) is a threatened apex predator that consumes mainly arboreal marsupial prey. Low density populations reside in urban landscapes where their viability is tenuous. The catalyst for this research was the reported death of eight powerful owls around Melbourne, Australia, in less than one year (2020/2021). Eighteen deceased owls were toxicologically screened. We assessed toxic metals (Mercury Hg, Lead Pb, Cadmium Cd and Arsenic As) and anticoagulant rodenticides (ARs) in liver (n = 18 owls) and an extensive range of agricultural chemicals in muscle (n = 14). Almost all agricultural chemicals were below detection limits except for p,p-DDE, which was detected in 71% of birds at relatively low levels. Toxic metals detected in some individuals were generally at low levels. However, ARs were detected in 83.3% of powerful owls. The most common second-generation anticoagulant rodenticide (SGAR) detected was brodifacoum, which was present in every bird in which a rodenticide was detected. Brodifacoum was often present at toxic levels and in some instances at potentially lethal levels. Presence of brodifacoum was detected across the complete urban-forest/agriculture gradient, suggesting widespread exposure. Powerful owls do not scavenge but prey upon arboreal marsupials, and generally not rodents, suggesting that brodifacoum is entering the powerful owl food web via accidental or deliberate poisoning of non-target species (possums). We highlight a critical need to investigate SGARs in food webs globally, and not just in species directly targeted for poisoning or their predators.

Short-term exposure of anticoagulant rodenticides leads to the toxin accumulation from prey (Rattus losea) to predator (Elanus caeruleus)

Rodenticides are widely used around the world since the 1950s. In Taiwan, an anti-rodent operation initiated 1977 and became a regular action annually implied by the government until 2014. This anti-rodent operation caused many animals of non-target species being exposed by rodenticides and became an environmental issue. The Black-winged Kite (Elanus caeruleus) is a small-sized diurnal raptor widely distributed in the Old World continent. Since 2000, a newly colonized population of this species occurred in Taiwan. Although the Black-winged Kites may suffer from the threats of rodenticides, the population is still growing and soon became the most abundant raptor in farmlands of Taiwan. Whether the Black-winged Kite accumulates higher anticoagulant rodenticide residues than other raptors are still unclear. In this study, liver samples of Black-winged Kites were collected from 2013 to 2016, when the detected residues of anticoagulant rodenticides increased annually. The concentration of residue rodenticide was above 0.2 ppm among 30% of the detected samples, which is the toxicity threshold concentration of other raptors. In the meanwhile, the lesser ricefield rat (Rattus losea), the most common prey of Black-winged Kites, also extended the survival period after fed on rodenticide. The longer survival days after being poisoned can enhance the predation opportunity of raptors, thus affect the accumulated rodenticides in the raptors. This study demonstrates that the Black-winged Kite has higher concentration of anticoagulant rodenticide than most other raptors, which provide the case that the raptor can quickly accumulate rodenticide residues within a short period of time.

Rapid method for the detection of rodenticides in contaminated foods

Rodenticides are toxic chemicals used to control rodent populations and are among the most common household toxicants. Ingestion of foods contaminated with rodenticides may cause severe illness or death in humans and animals. A rapid analytical method was developed for the identification of nine common rodenticides in foods using solid-liquid extraction followed by dispersive-solid phase extraction prior to the analysis by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and UV detection. The method validation on a variety of food matrices including cornmeal, peanut, whole wheat flour and pork liver produced average recoveries between 91.2 and 107% with relative standard deviations between 2.6 and 14% for all studied rodenticides. The method detection limits ranged from 2.7 to 8.2 μg/kg (ppb) for eight rodenticides analyzed by LC-MS/MS and between 0.10 and 0.21 mg/kg (ppm) for bromethalin which was analyzed by LC with UV detection. This method could be useful in preparedness for emergency response situations involving widespread food contamination, terrorist acts or for forensic studies.

Effects of anticoagulant rodenticide poisoning on spatial behavior of farm dwelling Norway rats

Commensal rodent species cause damage to crops and stored products, they transmit pathogens to people, livestock and pets and threaten native flora and fauna. To minimize such adverse effects, commensal rodents are predominantly managed with anticoagulant rodenticides (AR) that can be transferred along the food chain. We tested the effect of the uptake of the AR brodifacoum (BR) by Norway rats (Rattus norvegicus) on spatial behavior because this helps to assess the availability of dead rats and residual BR to predators and scavengers. BR was delivered by oral gavage or free-fed bait presented in bait stations. Rats were radio-collared to monitor spatial behavior. BR residues in rat liver tissue were analyzed using liquid chromatography coupled with tandem mass spectrometry. Norway rats that had consumed BR decreased distances moved and had reduced home range size. Treatment effects on spatial behavior seemed to set in rapidly. However, there was no effect on habitat preference. Ninety-two percent of rats that succumbed to BR died in well-hidden locations, where removal by scavenging birds and large mammalian scavengers is unlikely. Rats that ingested bait from bait stations had 65% higher residue concentrations than rats that died from dosing with two-fold LD₅₀. This suggests an overdosing in rats that are managed with 0.0025% BR. None of the 70 BR-loaded rats was caught/removed by wild predators/scavengers before collection of carcasses within 5-29 h. Therefore, and because almost all dead rats died in well-hidden locations, they do not seem to pose a significant risk of AR exposure to large predators/scavengers at livestock farms. Exposure of large predators may originate from AR-poisoned non-target small mammals. The few rats that died in the open are accessible and should be removed in routine searches during and after the application of AR bait to minimize transfer of AR into the wider environment.

Intensive livestock farming as a major determinant of the exposure to anticoagulant rodenticides in raptors of the Canary Islands (Spain)

The Canary Islands (Spain) is a biodiversity hotspot, with more than 4500 registered endemic species. However, it is subject to high anthropogenic pressure that threatens its wildlife in various ways. In the context of forensic toxicological surveys, the presence of anticoagulant rodenticides (AR) has been investigated in the liver of 831 animal carcasses with georeferenced data from 2011 to May 2020. The high concentrations of toxic pesticides in carcasses and in baits found close to the corpses indicated that all the reptiles and most of the mammals tested positive for AR were intentionally poisoned, although mainly by other substances. The frequency of detection of AR in non-raptor birds (n = 343) was only 4.1%, being the Canary raven the most frequently affected species (7/97, 7.2%). On the contrary, in raptors (n = 308) the detection frequency was almost 60%, with an average of more than 2 ARs per animal. The highest concentrations were found in the common kestrel. We present for the first-time results of AR contamination in two species of raptors that are very rare in Europe, Eleonora's falcon (n = 4) and Barbary falcon (n = 13). The temporal trend of positive cases remains stable, but since the entry into force of the restriction to the concentration of the active ingredient in baits (<30 ppm), a decrease in the concentrations of these compounds in the raptors' liver has been detected. Conversely, we registered an increase in the number of ARs per animal. From the study of the geographic information system (GIS) it can be deduced that intensive livestock farms are an important determinant in the exposure of raptors to ARs. Those birds that have their territory near intensive production farms have higher levels of exposure than those of birds that live far from such facilities.

Brodifacoum pharmacokinetics in acute human poisoning: implications for estimating duration of vitamin K therapy

Standard of care follow-up therapy for patients poisoned by long-acting anticoagulant rodenticides (LAARs) is daily high-dose (up to 100 mg per day) oral vitamin K1 (VK₁) for weeks to months to over a year. The availability of CLIA-certified quantitative testing for plasma LAAR concentrations can now assist health care providers in determining when to safely discontinue VK₁ therapy. We present estimates of treatment duration required to reach safe concentrations (< =10ng/ml) using serial measurements of plasma brodifacoum (BDF, a potent LAAR) concentrations obtained from patients poisoned after inhaling synthetic cannabinoids containing BDF. We fit the data to zero-order (linear) and first-order (exponential) curves, the latter to account for enterohepatic circulation of BDF. The results show that estimates of therapy duration are significantly longer when exponential clearance is assumed. Accordingly, we recommend that plasma BDF concentrations be monitored simultaneously with international normalization ratio (INR) during follow-up of poisoned patients, and that concentrations be determined after VK₁ therapy is discontinued to document persistence of safe concentrations.

Chiral liquid chromatography-tandem mass spectrometry analysis of superwarfarin rodenticide stereoisomers - Bromadiolone, difenacoum and brodifacoum - In human plasma

Superwarfarins are second-generation long-acting anticoagulant rodenticides that can cause unintended human and wildlife toxicity due, in part, to their prolonged half-lives. Commercially available superwarfarin rodenticides are synthesized as racemates with two asymmetric carbons, producing four stereoisomers. To support studies of human plasma half-lives of individual superwarfarin stereoisomers, a method was developed based on LC-MS/MS to separate and quantify stereoisomers of the commercially important superwarfarins bromadiolone, difenacoum and brodifacoum. Human plasma samples were prepared using protein precipitation and centrifugation. Chiral-phase HPLC separation was carried out on-line with tandem mass spectrometric quantitative analysis of the eluting stereoisomers using selected-reaction monitoring with positive ion electrospray on a triple quadrupole mass spectrometer. All four stereoisomers of each superwarfarin were resolved within 12.5 min with calibration curves spanning 2-3 orders of magnitude and lower limits of quantitation between 0.87 and 2.55 ng/mL. This method was used to determine the half-lives of superwarfarin stereoisomers in plasma from patients who had inhaled synthetic cannabinoid products contaminated with superwarfarins. These data may be used to guide the development of safer next generation anticoagulant rodenticides stereoisomers.

Sudden nasal bleeding and brodifacoum: A case of accidental exposure or attempted homicide?

A 50-year-old man was admitted to the emergency department with abrupt massive epistaxis. An accurate anamnesis and physical evaluation could not reveal any other anomalies, while coagulation tests showed potentially life threatening prolonged prothrombin time, with activated partial thromboplastin and thrombin time, with fibrinogen and antithrombin III within limits. Despite the prompt pharmacological and compressive local treatment, bleeding continued and the patient was therefore hospitalized. Highly specific coagulation and toxicological testing-among others high-performance liquid chromatography assessment on plasma-were performed, leading to the unexpected identification of brodifacoum. Police and criminal justice authorities revealed the source of exposure to brodifacoum after several months of investigation, residing in his everyday life. Brodifacoum is a long-lasting anticoagulant, acting as a vitamin K antagonist, and belongs to the family of superwarfarins. Brodifacoum use is authorized as rodenticide in many countries worldwide, but has been reported as cause of severe coagulopathies in humans, both intentional or involuntary, even consumed as a contaminant of herbal drugs, such as cannabis. The original contribution of this case to the knowledges of human brodifacoum intoxication resides in the multidisciplinary approach and the collaborative interplay of clinical and toxicology experts as well as judicial authorities.

Ultrasensitive surface-enhanced Raman scattering detection of biological pollutants by controlled evaporation on omniphobic substrates

A simple and highly sensitive method, combining slippery liquid-infused porous substrates and surface-enhanced Raman spectroscopy (SLIPSERS) was used to detect biological pollutants at very low concentrations. Two commonly used rodenticides (brodifacoum and sodium monofluoroacetate) with long biological half-lives were selected as analytes. The SLIPSERS platform gives reproducible SERS enhancement and this allows “label-free” SERS detection of these environmental pollutants.

Analyte ions were detected down to a concentration of 10⁻¹⁴ M for brodifacoum and 10⁻⁹ M for sodium monofluoroacetate. The limit of detection, limit of quantification and limit of linearity for brodifacoum are 10⁻¹² M, 10⁻¹⁰ M and 10⁻⁶ M respectively. The SLIPSERS method uses a physical process to significantly increase analyte concentration, and SERS enhancement and therefore can be generally applied to a range of environmental pollutants. The method can be successfully used for ultra-sensitive detection of several chemical and biological contaminants and meet the emerging needs of environmental monitoring and food safety analysis.

Determination of anticoagulant rodenticides in faeces of exposed dogs and in a healthy dog population

Background

Exposure to anticoagulant rodenticides (ARs) in dogs is among the most common causes of poisoning in small animal practice, but information about toxicokinetic of these rodenticides in dogs is lacking. We analysed blood and faeces from five accidentally exposed dogs and 110 healthy dogs by reversed phase ultra-high performance liquid chromatography-tandem mass spectrometry. The aim of the study was to estimate elimination of brodifacoum, bromadiolone and difenacoum after acute exposure, calculate the half-lives of these rodenticides in dogs, estimate faecal elimination in a litter of puppies born, and further to identify the extent of AR exposure in a healthy dog population.

Results

Three dogs were included after single ingestions of brodifacoum; two dogs ingested bromadiolone and one dog ingested difenacoum. Maximum concentrations in faeces were found after day 2–3 for all ARs. The distribution half-lives were 1–10 days for brodifacoum, 1–2 days for bromadiolone and 10 days for difenacoum. Brodifacoum and difenacoum had estimated terminal half-lives of 200–330 days and 190 days, respectively. In contrast, bromadiolone had an estimated terminal half-life of 30 days. No clinical signs of poisoning or coagulopathy were observed in terminal elimination period. In blood, the terminal half-life of brodifacoum was estimated to 8 days. Faeces from a litter of puppies born from one of the poisoned dogs were examined, and measurable concentrations of brodifacoum were detected in all samples for at least 28 days after parturition. A cross-sectional study of 110 healthy domestic dogs was performed to estimate ARs exposure in a dog population. Difenacoum was detected in faeces of one dog. Blood and faecal samples from the remaining dogs were negative for all ARs.

Conclusions

Based on the limited pharmacokinetic data from these dogs, our results suggest that ARs have a biphasic elimination in faeces using a two-compartment elimination kinetics model. We have shown that faecal analysis is suitable and reliable for the assessment of ARs exposure in dogs and a tool for estimating the AR half-lives. Half-lives of ARs could be a valuable indicator in the exposed dogs and provides important information for veterinarians monitoring AR exposure and assessment of treatment length in dogs.

Acute toxicity and clotting times of anticoagulant rodenticides to red-toothed (Odonus niger) and black (Melichthys niger) triggerfish, fathead minnow (Pimephales promelas), and largemouth bass (Micropterus salmoides)

Anticoagulant rodenticides (ARs) are used in rat eradication efforts on island wildlife refuges. AR bait pellets can get into coral reef areas during broadcasting and lead to exposure of non-target organisms, such as marine fishes. The objective of this study was to determine the sensitivity of representative saltwater fishes, Red-toothed triggerfish (Odonus niger) and Black triggerfish (Melichthys niger), and common freshwater fishes, fathead minnow (Pimephales promelas), and largemouth bass (Micropterus salmoides) to first generation ARs, diphacinone (DPN) and chlorophacinone (CPN), as well as a second-generation AR, brodifacoum (BROD). Acute toxicity of ARs was evaluated by single dose, intraperitoneal injections. The median lethal dose (LD50) ranges were 137-175 μg DPN/g, 155-182 μg CPN/g, and 36-48 μg BROD/g for Red-toothed triggerfish and 90-122 μg DPN/g, 125-164 μg CPN/g, and 50-75 μg BROD/g for black triggerfish. Laboratory surrogate test fish species fathead minnow and largemouth bass were of similar sensitivity toward AR-induced toxicity compared to triggerfish based on LD50 values. Sublethal effects on elevated clotting time occurred in dose-dependent fashion in all fish tested. Fish appear to have low sensitivity to AR chemicals as compared to other taxa, in particular mammals and birds, based on across-taxa comparisons of species sensitivity distributions of whole body, single dose acute lethality (LD50 values). The sensitivity of fish to waterborne exposures of ARs has yet to be fully evaluated and indeed may prove more hazardous to fish.

Effects of vitamin K1 treatment on plasma concentrations of long-acting anticoagulant rodenticide enantiomers following inhalation of contaminated synthetic cannabinoids

Background: An outbreak of synthetic cannabinoid (SC)-associated coagulopathy and bleeding in Illinois, USA was determined to be due to inhalation of SC contaminated with brodifacoum (BDF), difenacoum (DiF), and bromadiolone (BDL), highly potent long-acting anticoagulant rodenticides (LAARs). Treatment with high-dose vitamin K1 (VK1) prevented mortality; however, plasma LAAR levels were not measured risking recurrence of coagulopathy and bleeding due to premature discontinuation. The goal of this study was to determine if plasma LAAR levels were reduced following standard of care treatment to normalize coagulopathy.Methods: Blood samples were collected from a cohort of 32 patients, and ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis used to quantify plasma LAAR levels including enantiomers.Results: BDF was detected in 31 samples; 30 also contained DiF and 18 contained BDL. Initial plasma levels were 581 ± 87, 11.0 ± 1.9, and 14.9 ± 5.9 ng/mL for BDF, DiF, and BDL, respectively (mean ± SE). At discharge plasma, BDF levels remained elevated at 453 ± 68 ng/mL. Plasma half-lives for BDF, DiF, and BDL were 7.5 ± 1.3, 7.2 ± 1.9, and 1.8 ± 0.3 days, respectively. The half-life for trans-BDF enantiomers (5.7 ± 0.8 days) was shorter than for cis-enantiomers (7.6 ± 1.9 days). BDF half-lives were shorter, and coagulopathy normalized faster in patients receiving intravenous VK1 as compared to oral VK1. Patients prescribed VK1 at discharge had fewer re-admittances.Conclusions: These results demonstrate that plasma LAAR levels at discharge were elevated in poisoned patients despite normal coagulation, and that the route of VK1 administration affected LAAR pharmacokinetics and INR normalization. We propose plasma LAAR levels and coagulation be monitored concomitantly during follow-up of patients with LAAR poisoning. KEY POINTSIn patients treated with high-dose vitamin K1 for LAAR poisoning, plasma levels remained 40-fold above safe levels upon discharge from hospital.LAAR half-lives, normalization of coagulopathy, and readmittances were reduced by treatment with intravenous vitamin K1.

Brodifacoum toxicosis and abortion in an Arabian mare

A 3-year-old pregnant Arabian mare was referred to the Veterinary Teaching Hospital of Shahid Chamran University of Ahvaz with a history of bleeding and rodenticide ingestion. The results of paraclinical examinations showed severe normocytic and normochromic anemia, decreased serum total protein, albumin, and fibrinogen concentrations, increased serum total bilirubin, urea, and creatinine concentrations, as well as increased serum aspartate aminotransferase and creatine kinase activity. Three days after treatment, all the clinical signs were resolved, however, fetus abortion occurred. In order to confirm the suspected cause of abortion and toxicosis, high-performance liquid chromatography was performed on serum sample of mare and liver tissue of the aborted fetus and toxicosis was confirmed. Poisoning with brodifacoum is considered as an important and lethal poisoning for both human being and animals. To our knowledge, this is the first report of spontaneous toxicosis and abortion with brodifacoum. Brodifacoum toxicosis can be effectively managed with early diagnosis, good paraclinical examinations and appropriate treatment.

Adherence to Long-Term Follow-Up of Patients with Life-Threatening, Inhaled Synthetic Cannabinoids-Associated Coagulopathy in Chicago

A large-scale outbreak of life-threatening, inhaled synthetic cannabinoids (Spice/K2)-associated coagulopathy with bleeding complications was recently reported in Illinois. The causative agents were brodifacoum, difenacoum, and bromadiolone, potent, long-acting, 4-hydroxycoumarin anticoagulant rodenticides (LAAR) that were mixed with Spice/K2 products procured and then inhaled by the victims. We report on 3 poisoned patients who reside in underserved, socioeconomically disadvantaged neighborhoods of Chicago that were admitted and treated successfully at two inner-city, tertiary care hospitals in Chicago. The patients were discharged from the hospitals on daily long-term high-dose oral vitamin K₁ (VK₁), provided free of charge. However, 2 patients were lost to follow-up prior to safe discontinuation of oral VK₁ therapy. The third patient was treated and followed successfully for 7 months when VK₁ was discontinued. We conclude that prolonged oral VK₁ therapy and follow-up of acute, life-threatening LAAR poisoning are variable and present challenges to healthcare providers. Appropriate practice guidelines to improve patient access and adherence to daily high-dose oral VK₁ therapy and follow-up should be developed and implemented.

The relative toxicity of brodifacoum enantiomers

Brodifacoum (BDF) is a potent, long-acting anticoagulant rodenticide that can cause fatal poisoning in humans. The chemical structure of BDF includes 2 chiral carbons, resulting in 2 pairs of diastereomers, BDF-cis (R/S and S/R) and BDF-trans (R/R and S/S). However, the relative potency of these molecules is not known. The purpose of this study was to compare the in vitro and in vivo toxic effects of the 2 BDF diastereomer pairs. In adult Sprague-Dawley rats BDF-cis was significantly more toxic than BDF-trans (LD₅₀ values of 219 versus 316 μg/kg, respectively) while racemic BDF had intermediate potency (266 μg/kg). In adult New Zealand white rabbits, BDF-cis had a longer half-life than BDF-trans which could contribute to its observed increased toxicity. Lastly, BDF-cis (10 μM), but not BDF-trans, damaged cultured SH-SY5Y human neuroblastoma cells by attenuating mitochondrial reductive capacity. Taken together, these data suggest that different toxic manifestations of BDF poisoning in mammals could be attributed, in part, to differences in relative enantiomer concentrations present in racemic formulations of this commercially-available toxicant.

Investigating spatial patterns of mercury and rodenticide residues in raptors collected near the Charlotte, NC, USA, metropolitan area

Raptor population growth is dynamic and trends vary across species and by location in the United States. For those species that are declining, it is important to identify potential causes including chemical contaminants. Sampling wild raptors is problematic due to their small population sizes and role as a top predator. Therefore, we obtained liver samples (n = 56) from carcasses of several raptor species, including common species like red-tailed hawks, red-shouldered hawks, barred owls, great horned owls, and osprey that arrived dead or were euthanized from a non-profit rehabilitation center in Charlotte, North Carolina. Raptors were found or collected in South Carolina, North Carolina, and Virginia, but most samples were located near the metropolitan region of Charlotte, NC. We analyzed livers for total mercury residue (mg/kg, dry weight) and five anti-coagulant rodenticides (μg/kg wet weight). Mercury was analyzed using a direct mercury analyzer approach and rodenticides were quantified by LC-MS. Mercury residues were high in piscivorous birds (15.09 mg/kg for osprey and 6.93 mg/kg for great blue herons, dry weight) and relatively high in red-shouldered hawks and one eastern screech owl tested. Six of our samples exceeded a health threshold of 1 mg/kg (wet weight) including three osprey and one each of great blue heron, red-shouldered hawk, and eastern screech owl. Brodifacoum was the only rodenticide consistently detected in our samples. Brodifacoum detections exceeded 75% in barred owls, great horned owls, and red-shouldered hawks. Sixty-nine percent of owl samples were within (or exceeded) a threshold of brodifacoum residue associated with a 10-20% risk of acute toxicity. Correlations between residues and human population density were not significant for either mercury or brodifacoum. Our data suggest that mercury residues for most raptors were not of significant concern with the exception of osprey and possibly red-shouldered hawks. Rodenticide exposures associated with a risk of acute toxicity appear to be common and warrant further investigation.

Fixed dose 4-factor prothrombin complex concentrate for bleeding caused by long acting anticoagulant rodenticides

Acute, unintentional drug-related poisonings lead to an estimated 418,313 ED visits in 2014, according to the latest statistics from the Center for Disease Control and Prevention. While most of these were opiate-related poisonings, anticoagulant rodenticides were the most common cause of rodenticide-related poisoning in the United States. Many clinical syndromes and treatment algorithms have been described for patients with anticoagulant rodenticide poisoning. We report a case of an acute ingestion of two anticoagulant rodenticides and successful reversal of coagulation parameters using 4-factor prothrombin complex concentrate in a fixed-dose approach.

Long-term increase in secondary exposure to anticoagulant rodenticides in European polecats Mustela putorius in Great Britain

As a result of legal protection and population recovery, European polecats (Mustela putorius) in Great Britain are expanding into areas associated with greater usage of second-generation anticoagulant rodenticides (SGARs). We analysed polecat livers collected from road casualties from 2013 to 2016 for residues of five SGARs. We related variation in residues to polecat traits and potential exposure pathways, by analysing stable isotopes of carbon (δ¹³C) and nitrogen (δ¹⁵N) in their whiskers. 54 of 68 (79%) polecats had detectable residues of at least one SGAR. Bromadiolone (71%) was the most frequently detected compound, followed by difenacoum (53%) and brodifacoum (35%). Applying historical limits of detection to allow comparison between these new data and previous assessments, we show that in the 25 years from 1992 to 2016 inclusive, the rate of detection of SGARs in polecats in Britain has increased by a factor of 1.7. The probability of SGAR detection was positively related to increasing values of δ¹⁵N, suggesting that polecats feeding at a higher trophic level were more likely to be exposed. Total concentrations of SGARs in polecats with detectable residues were higher in polecats collected in arable compared to pastoral habitats, and in the west compared to the east of Britain. The number of compounds detected and total concentrations of SGARs increased with polecat age. There was no evidence of regional or seasonal variation in the probability of detecting SGARs, suggesting that the current risk of exposure to SGARs does not vary seasonally and has increased (from that in the 1990s) throughout the polecat's range. We recommend quantification of current practices in rodenticide usage, particularly in the light of recent regulatory changes, to enable assessment and mitigation of the risks of secondary exposure to rodenticides in non-target wildlife.

Retrospective Study of the Characteristics of Anticoagulant-Type Rodenticide Poisoning in Hong Kong

INTRODUCTION

Warfarin- and superwarfarin-type anticoagulants are commonly used as rodenticides. Exposure to these agents, especially superwarfarins with long-acting anticoagulant effect, can cause life-threatening coagulopathy in humans. Most superwarfarin poisoning cases had an obvious history of exposure, though occult cases without exposure history have also been reported. The current study aims to examine anticoagulant-type rodenticide poisoning in Hong Kong and to identify the similarities and differences between patients with known exposure history and those whose exposure is recognized only through laboratory testing.

METHODS

The present study was conducted in a tertiary referral clinical toxicology laboratory in Hong Kong. This was a retrospective cohort study of all patients with biochemically confirmed anticoagulant-type rodenticide exposure, from 2010 to 2014.

RESULTS

Superwarfarin was the most common group of anticoagulant-type rodenticides identified (87.8%), in which bromadiolone and brodifacoum were the most frequently encountered. Among the 41 cases identified, 31 had an obvious exposure history, and 10 were occult poisoning in which the context of exposure remained unidentified. All occult poisoning patients without exposure history presented with bleeding events. These occult poisoning cases often went unrecognized by frontline clinicians, leading to delayed investigation and initiation of treatment. This group of patients was associated with a longer time to diagnose coagulopathy (p < 0.001) and confirm rodenticide poisoning (p < 0.05), a higher rate of international normalized ratio (INR) rebound after initiation of antidote (p < 0.001), and a longer time needed for normalizing INR (p < 0.05).

CONCLUSION

Occult superwarfarin poisoning is an important yet under-recognized differential cause of unexplained coagulopathy. A high index of clinical suspicion and availability of specialized toxicological test for superwarfarins play a vital role in diagnosis and early initiation of appropriate management. The underlying cause of such poisoning remains obscure and warrants further study.

Grass is not always greener: rodenticide exposure of a threatened species near marijuana growing operations

OBJECTIVE

Marijuana (Cannabis spp.) growing operations (MGO) in California have increased substantially since the mid-1990s. One environmental side-effect of MGOs is the extensive use of anticoagulant rodenticides (AR) to prevent damage to marijuana plants caused by wild rodents. In association with a long-term demographic study, we report on an observation of brodifacoum AR exposure in a threatened species, the northern spotted owl (Strix occidentalis caurina), found freshly dead within 669-1347 m of at least seven active MGOs.

RESULTS

Liver and blood samples from the dead northern spotted owl were tested for 12 rodenticides. Brodifacoum was the only rodenticide detected in the liver (33.3-36.3 ng/g) and blood (0.48-0.54 ng/ml). Based on necropsy results, it was unclear what role brodifacoum had in the death of this bird. However, fatal AR poisoning has been previously reported in owls with relatively low levels of brodifacoum residues in the liver. One likely mechanism of AR transmission from MGOs to northern spotted owls in California is through ingestion of AR contaminated prey that frequent MGOs. The proliferation of MGOs with their use of ARs in forested landscapes used by northern spotted owls may pose an additional stressor for this threatened species.

Quantitative method for analysis of six anticoagulant rodenticides in faeces, applied in a case with repeated samples from a dog

Background

Accidental poisoning with anticoagulant rodenticides is not uncommon in dogs, but few reports of the elimination kinetics and half-lives in this species have been published. Our objectives were to develop and validate a new method for the quantification of anticoagulant rodenticides in canine blood and faeces using reversed phase ultra-high performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) and apply the method on a case of anticoagulant rodenticide intoxication.

Results

Sample preparation was liquid–liquid extraction. Six anticoagulant rodenticides were separated using a UPLC^® BEH C₁₈-column with a mobile phase consisting of 5 mM ammonium formate buffer pH 10.2 and methanol. MS/MS detection was performed with positive electrospray ionization and two multiple reaction monitoring transitions. The limits of quantification were set at the levels of the lowest calibrator (1.5–2.7 ng/mL or ng/g). The method was successfully applied to a case from a dog accidentally poisoned with anticoagulant rodenticide. Coumatetralyl and brodifacoum concentrations were determined from serial blood and faecal samples. A terminal half-life of at least 81 days for coumatetralyl in blood was estimated, which is longer than previous reported in other species. A slow elimination of brodifacoum from the faeces was found, with traces still detectable in the faeces at day 513.

Conclusions

This study offers a new method of detection and quantification of six frequently used anticoagulant rodenticides in canine faeces. Such drugs might cause serious health effects and it is important to be able to detect these drugs, to initiate proper treatment. The very long elimination half-lives detected in our study is important to be aware of in assessment of anticoagulant rodenticide burden to the environment.

Mortality of Western Burrowing Owls ( Athene cunicularia hypugaea) Associated with Brodifacoum Exposure

Western Burrowing Owls ( Athene cunicularia hypugaea) frequently occupy periurban areas, where they may be exposed to pest control agents. This short communication describes necropsy findings and detected brodifacoum rodenticide levels for four Western Burrowing Owls in Lake Havasu City, Arizona, US, 2013-15. Levels detected ranged from 0.077 mg/kg to 0.497 mg/kg. Brodifacoum, one of several second-generation anticoagulant rodenticides recently removed from the general consumer market, is still available for use by licensed pesticide applicators. Despite recent regulatory actions, second-generation anticoagulant pesticides continue to threaten predatory species in periurban areas.

Plasma metabolic profiling analysis of toxicity induced by brodifacoum using metabonomics coupled with multivariate data analysis

Brodifacoum is one of the most widely used rodenticides for rodent control and eradication; however, human and animal poisoning due to primary and secondary exposure has been reported since its development. Although numerous studies have described brodifacoum induced toxicity, the precise mechanism still needs to be explored. Gas chromatography mass spectrometry (GC-MS) coupled with an ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was applied to characterize the metabolic profile of brodifacoum induced toxicity and discover potential biomarkers in rat plasma. The toxicity of brodifacoum was dose-dependent, and the high-dose group obviously manifested toxicity with subcutaneous hemorrhage. The blood brodifacoum concentration showed a positive relation to the ingestion dose in toxicological analysis. Significant changes of twenty-four metabolites were identified and considered as potential toxicity biomarkers, primarily involving glucose metabolism, lipid metabolism and amino acid metabolism associated with anticoagulant activity, nephrotoxicity and hepatic damage. MS-based metabonomics analysis in plasma samples is helpful to search for potential poisoning biomarkers and to understand the underlying mechanisms of brodifacoum induced toxicity.

Structural perturbation of a dipalmitoylphosphatidylcholine (DPPC) bilayer by warfarin and its bolaamphiphilic analogue: A molecular dynamics study

Compounds with nominally similar biological activity may exhibit differential toxicity due to differences in their interactions with cell membranes. Many pharmaceutical compounds are amphiphilic and can be taken up by phospholipid bilayers, interacting strongly with the lipid-aqueous interface whether or not subsequent permeation through the bilayer is possible. Bolaamphiphilic compounds, which possess two hydrophilic ends and a hydrophobic linker, can likewise undergo spontaneous uptake by bilayers. While membrane-spanning bolaamphiphiles can stabilize membranes, small molecules with this characteristic have the potential to create membrane defects via disruption of bilayer structure and dynamics. When compared to the amphiphilic therapeutic anticoagulant, warfarin, the bolaamphiphilic analogue, brodifacoum, exhibits heightened toxicity that goes beyond superior inhibition of the pharmacological target enzyme. We explore, herein, the consequences of anticoagulant accumulation in a dipalmitoylphosphatidylcholine (DPPC) bilayer. Coarse-grained molecular dynamics simulations reveal that permeation of phospholipid bilayers by brodifacoum causes a disruption of membrane barrier function that is driven by the bolaamphiphilic nature and size of this molecule. We find that brodifacoum partitioning into bilayers causes membrane thinning and permeabilization and promotes lipid flip-flop - phenomena that are suspected to play a role in triggering cell death. These phenomena are either absent or less pronounced in the case of the less toxic, amphiphilic compound, warfarin.

Prey composition modulates exposure risk to anticoagulant rodenticides in a sentinel predator, the barn owl

Worldwide, small rodents are main prey items for many mammalian and avian predators. Some rodent species have pest potential and are managed with anticoagulant rodenticides (ARs). ARs are consumed by target and non-target small mammals and can lead to secondary exposure of predators. The development of appropriate risk mitigation strategies is important and requires detailed knowledge of AR residue pathways. From July 2011 to October 2013 we collected 2397 regurgitated barn owl (Tyto alba) pellets to analyze diet composition of owls on livestock farms in western Germany. 256 of them were fresh pellets that were collected during brodifacoum baiting. Fresh pellets and 742 liver samples of small mammals that were trapped during baiting in the same area were analyzed for residues of ARs. We calculated exposure risk of barn owls to ARs by comparing seasonal diet composition of owls with AR residue patterns in prey species. Risk was highest in autumn, when barn owls increasingly preyed on Apodemus that regularly showed AR residues, sometimes at high concentrations. The major prey species (Microtus spp.) that was consumed most frequently in summer had less potential to contribute to secondary poisoning of owls. There was no effect of AR application on prey composition. We rarely detected ARs in pellets (2 of 256 samples) but 13% of 38 prey individuals in barn owl nests were AR positive and substantiated the expected pathway. AR residues were present in 55% of 11 barn owl carcasses. Fluctuation in non-target small mammal abundance and differences in AR residue exposure patterns in prey species drives exposure risk for barn owls and probably other predators of small mammals. Exposure risk could be minimized through spatial and temporal adaption of AR applications (avoiding long baiting and non-target hot spots at farms) and through selective bait access for target animals.

Cluster of cases of massive hemorrhage associated with anticoagulant detection in race horses

Five horses originating from 4 different California race tracks were submitted to the California Animal Health and Food Safety Laboratory for necropsy and diagnostic workup. The 5 horses had a history of sudden collapse and death during exercise. In all of them, massive hemoperitoneum and hemorrhages in other cavities or organs were observed. The liver from these 5 animals and from 27 horses that had been euthanized due to catastrophic leg injuries (controls) were subjected to a rodenticide anticoagulant screen. Traces of brodifacoum, diphacinone, or bromadiolone were detected in the 5 horses with massive bleeding (5/5), and no traces of rodenticides were detected in control horses (0/27). Other frequent causes of massive hemorrhages in horses were ruled out in 4 of the cases; one of the horses had a pelvic fracture. Although only traces of anticoagulants were found in the livers of these horses and the role of these substances in the massive bleeding remains uncertain, it is speculated that exercise-related increases in blood pressure may have reduced the threshold for toxicity of these anticoagulants.

Long-Acting Anticoagulant Rodenticide (Superwarfarin) Poisoning: A Review of Its Historical Development, Epidemiology, and Clinical Management

Long-acting anticoagulant rodenticides (LAARs) inhibit vitamin K epoxide reductase (VKOR). Related bleeding may present a diagnostic challenge and require administration of blood component therapy, hemostatic agents, and vitamin K. This article intends to provide the reader a comprehensive understanding of LAAR poisoning. An exhaustive literature search of PubMed, Science Direct, US National Library of Medicine Toxicology Data Network, and Google Scholar yielded 174 reported cases of LAAR poisoning from which clinical data were extracted and reviewed. In addition, 25 years of epidemiologic data from the American Association of Poison Control Centers was reviewed. In the United States, on average, there were 10413 exposures reported with 2750 patients treated annually. For 25 years, there were 315951 exposures reported with nearly 90% among children and more than 100000 patients treated in a health care facility. Fortunately, only 2% of all exposures result in morbidity or mortality. Inhalational, transcutaneous, and oral routes of exposure have been documented. Most exposures are unintentional. The most frequently reported bleeding sites are mucocutaneous, with hematuria being the most common feature. Deaths were most commonly associated with intracranial hemorrhage. Long-acting anticoagulant rodenticide-induced paradoxical thrombosis and thrombotic complications accompanying hemostatic therapy have also been observed. Most patients present with coagulation assay values beyond measurable limits. Long-acting anticoagulant rodenticides have an extremely high affinity for VKOR compared with warfarin, characterized by rebound coagulopathy and bleeding after initial treatment and the need for high-dose, long-term therapy with vitamin K1. Treatment of acute hemorrhagic symptoms often required intravenous vitamin K1 in excess of 50 to 100 mg; chronic maintenance with 100 mg PO vitamin K1 daily was the most frequently used dose required to suppress coagulopathy. Treatment courses averaged 168 days. Adjunctive hemostatic therapy with recombinant factor VIIa and prothrombin complex concentrate has been reported, and phenobarbital has been used to expedite LAAR metabolism.

Evaluation of risk factors in patients with vitamin K-dependent coagulopathy presumed to be caused by exposure to brodifacoum

BACKGROUND/AIMS

Recently, many cases of vitamin K-dependent coagulopathy of unknown origin have been reported. Such patients lack any relevant family history and have no systemic disease, raising suspicion of superwarfarin intoxication. We evaluated individual risk factors causing coagulopathy and hemorrhagic symptoms in patients with suspected superwarfarin intoxication. In addition, we determined how to effectively treat vitamin K-dependent coagulopathy caused by suspected superwarfarin intoxication.

METHODS

Seven patients with suspected superwarfarin intoxication who lacked any definitive history of rodenticide ingestion were included. Thirty-one patients initially diagnosed with rodenticide poisoning were also included. We performed a retrospective chart review of all subjects and examined clinical data including patient demographics and medical histories.

RESULTS

Patients initially diagnosed with rodenticide poisoning were divided into two groups, one of which had a laboratory abnormality (prothrombin time [PT] > 13 seconds) and another group with PTs in the normal range. There was no significant difference between the two groups in any of age, gender, the extent of chronic alcohol consumption, the causative rodenticide, psychiatric problems, ingestion of drugs interacting with warfarin, the extent of intoxication, or the type of ingestion attempt. The albumin level of the former group was significantly lower than that of the latter group (p = 0.014). Furthermore, a significant difference between the two groups was evident in terms of simultaneous ingestion of rodenticide and alcohol (p = 0.023).

CONCLUSIONS

Most patients with superwarfarin poisoning did not exhibit any complication. When such complications were evident, they were associated with serum albumin level and coingestion of rodenticide and alcohol.

Assessment of anticoagulant rodenticide exposure in six raptor species from the Canary Islands (Spain)

Anticoagulant rodenticides are highly toxic compounds that are widely used for pest control of rodents, but that also may threaten the wildlife's health. This work aimed to assess the exposure to first- and second-generation anticoagulant rodenticides (ARs) in six birds of prey species from the Canary Islands (Spain). The concentrations of seven widely used ARs were determined by LC-MS/MS in 104 liver samples of six species of birds of prey (Buteo buteo, Accipiter nisus, Falco pelegrinoides, Falco tinnunculus, Asio otus, and Tyto alba). We determined that 61% of the livers had detectable residues of at least one AR. The most frequently detected AR was bromadiolone, which was detected in 60.3% of the positive cases. The detection frequencies of these compounds varied widely, depending on the species. More than 75% of the A. nisus, T. alba, and A. otus individuals had detectable rodenticide residues in the liver. However, F. tinnunculus exhibited the highest concentrations of AR, with median values above 100 ng/g w.w. We did not detect first-generation ARs in any of the samples. When grouped, nocturnal species exhibited higher AR concentrations than diurnal species (P<0.001). The residue levels were higher among small mammal-eaters than bird-eaters (P<0.01). While most animals exhibited no macroscopic signs of coagulation disorders, approximately 35% exceeded the threshold levels of toxicity, which suggests that these compounds could weaken these animals in their natural environment. In conclusion, the control of rodent populations by ARs suggests that these compounds will enter the food chain and thus threaten the vulnerable populations of raptors on the Canary Islands. Our findings require authorities to ban or strictly control the use of these rodenticides in the natural environment for the conservation of raptors and other predatory species.

Outcomes of patients with rodenticide poisoning at a far east poison center

BACKGROUND

Rodenticide poisoning remains a major public health problem in Asian countries. Nevertheless, very few data are available in world literature regarding the outcomes of these patients. Therefore, the purpose of this study was to investigate the clinical outcomes of rodenticide poisonings in our hospital and to compare these data with published reports from other international poison centers.

FINDINGS

We retrospectively examined the records of 20 patients with rodenticide poisoning (8 brodifacoum, 12 bromadiolone) who were referred to Chang Gung Memorial Hospital between 2000 and 2011. It was found that most of the rodenticide patients were middle-aged adults. Both genders were equally affected and many patients had a past history of major depressive disorder or schizophrenia. Nevertheless, patients with bromadiolone were referred significantly sooner than patients with brodifacoum poisoning (0.1 ± 0.1 versus 5.5 ± 10.5, P < 0.001). Furthermore, it was found that patients with brodifacoum suffered higher incidences of ecchymosis (50.0% versus 0%, P = 0.006) and hematuria (50.0% versus 0%, P = 0.006) than patients with bromadiolone poisoning. Laboratory analysis also demonstrated a poorer hemostatic profile of patients with brodifacoum [prothrombin time (PT), international normalized ratio (INR), 4.3 ± 4.8 versus 1.0 ± 0.1, P = 0.032; PT prolongation, 50.0% versus 0%, P = 0.006; activated partial thromboplastin time (aPTT) prolongation, 50.0% versus 0%, P = 0.006] than patients with bromadiolone poisoning. At the end of analysis, no patient died of the poisoning.

CONCLUSION

The favorable outcome (zero mortality rate) is comparable to the published reports from other international poison centers. Further studies are warranted.

Korean patients with superwarfarin intoxication and their outcome

This observational study aimed at evaluating recent superwarfarin intoxication of Korean patients. Ten patients were diagnosed as or highly suspicious for superwarfarin intoxication. Case report forms described by attending hematologists of the patients were collected and analyzed. Bleeding symptoms were varied among the patients. Patients uniformly showed prolonged prothrombin time (PT) and activated thromboplastin time (aPTT) with decreased activity of vitamin K dependent coagulation factors. Positive serum brodifacoum test results in 4 of 5 requested patients contributed to confirmatory diagnosis. Psychiatric interview revealed an attempted ingestion in one patient. High dose vitamin K1 therapy promptly corrected prolonged PT and aPTT, but hasty discontinuation caused repeated bleeding diathesis in 6 patients. Route of intoxication was unknown or not definite among 8 of 10 patients. Three patients had a possibility of environmental exposure considering their occupations: there might be intoxication by transdermal absorption or inhalation. Therefore, high dose and prolonged use of vitamin K1 therapy is necessary for effective detoxification. Further detailed investigation on environmental exposure and efforts to improve availability of the blood level test in clinic are requested.