In vitro assessment of the dermal penetration potential of sodium fluoroacetate using a formulated product.

This paper presents experimental data on the skin absorption of sodium fluoroacetate from a formulated product using an in vitro approach and human skin. Sodium fluoroacetate is a pesticide, typically applied in formulation (1080) for the control of unwanted vertebrate invasive species. It has been assigned a Skin Notation by the ACGIH, and other international workplace health regulatory bodies, due to its predicted ability to permeate intact and abraded human skin. However, there is a distinct lack of experimental data on the skin absorption of sodium fluoroacetate to support this assignment. This study found that sodium fluoroacetate, as a formulated product, permeated the human epidermis when in direct contact for greater than 10 hr. A steady-state flux (Jss) of 1.31 ± 0.043 µg/cm2/hr and a lag time of 6.1 hr was calculated from cumulative skin permeation data. This study provides important empirical evidence in support of the assignment of a Skin Notation.

Transcriptomic Characterization of Inhalation Phosphine Toxicity in Adult Male Sprague-Dawley Rats.

Phosphine (PH3) is a highly toxic, corrosive, flammable, heavier-than-air gas that is a commonly used fumigant. When used as a fumigant, PH3 can be released from compressed gas tanks or produced from commercially available metal phosphide tablets. Although the mechanism of toxicity is unclear, PH3 is thought to be a metabolic poison. PH3 exposure induces multiorgan toxicity, and no effective antidotes or therapeutics have been identified. Current medical treatment consists largely of supportive care and maintenance of cardiovascular function. To better characterize the mechanism(s) driving PH3-induced toxicity, we have performed transcriptomic analysis on conscious adult male Sprague-Dawley rats following whole-body inhalation exposure to phosphine gas at various concentration-time products. PH3 exposure induced concentration- and time-dependent changes in gene expression across multiple tissues. These gene expression changes were mapped to pathophysiological responses using molecular pathway analysis. Toxicity pathways indicative of cardiac dysfunction, cardiac arteriopathy, and cardiac enlargement were identified. These cardiotoxic responses were linked to apelin-mediated cardiomyocyte and cardiac fibroblast signaling pathways. Evaluation of gene expression changes in blood revealed alterations in pathways associated with the uptake, transport, and utilization of iron. Altered erythropoietin signaling was also observed in the blood. Upstream regulator analysis identified several therapeutics predicted to counteract PH3-induced gene expression changes. These include antihypertensive drugs (losartan, candesartan, and prazosin) and therapeutics to reduce pathological cardiac remodeling (curcumin and TIMP3). This transcriptomics study has characterized molecular pathways involved in PH3-induced cardiotoxicity. These data will aid in elucidating a precise mechanism of toxicity for PH3 and guide the development of effective medical countermeasures for PH3-induced toxicity.

Rodenticide ingestion is an important cause of acute hepatotoxicity in Tamil Nadu, southern India.

BACKGROUND AND AIM: Though rodenticidal hepatotoxicity is reported from India, there is no systematic study to assess its magnitude. This study aimed to assess exposure to rodenticide as a risk factor for acute hepatotoxicity in Tamil Nadu, India. METHODS: We retrospectively analyzed acute hepatotoxicity caused by ingestion of hepatotoxin or potentially hepatotoxic drug overdose across 15 hospitals in 6 districts of Tamil Nadu from 1 January 2019 to 30 June 2019. Study exclusion criteria were idiosyncratic drug-induced liver injury and chronic liver diseases. RESULTS: Of the 702 patients, 685 gave history of consuming rodenticide; hepatotoxicity in the other patients resulted from paracetamol overdose (n=10) and due to other drugs (n=7); 97% patients had a suicidal intent. Of 671 patients with complete data, ratio of number of patients with hepatotoxicity due to rodenticide to paracetamol overdose was 450:6 (i.e. 75:1). The 451 rodenticidal hepatotoxicity patients (255 males, 75% were 15-34 years old) underwent conservative management (n=396), plasma exchange (n=54) and plasma exchange followed by liver transplant (n=1); 159 patients (35%) had poor outcome (131 died, 28 discharged in moribund state). Based on our observations, we estimate a case burden of 1584 rodenticidal hepatotoxicity patients (95% CI: 265-6119) with poor outcome in 554 patients in Tamil Nadu from January 2019 to June 2019. Population attributable risk for rodenticide as cause of hepatotoxicity was 22.7%. CONCLUSION: Rodenticide ingestion was an important cause of acute hepatotoxicity in Tamil Nadu. Most patients were young and one-third had poor outcome. Public health interventions are needed to address this.

Accidental chlorophacinone exposure of lactating ewes: Clinical follow-up and human health dietary implications.

Anticoagulant rodenticides are widely used for rodent control in agricultural and urban settings. Their intense use can sometimes result in accidental exposure and even poisoning of livestock. Can milk, eggs or meat derived from such accidently exposed animals be consumed by humans? Data on the pharmacokinetics of chlorophacinone in milk of accidently exposed ewes were used to estimate the risk associated with its consumption. Three days after accidental ingestion, chlorophacinone was detected in plasma of 18 ewes, with concentrations exceeding 100 ng/mL in 11 animals. Chlorophacinone was detected in milk on day 2 post-exposure and remained quantifiable for at least 7 days in milk of these 11 ewes. Concentrations in milk were much lower than in plasma and decreased quickly (mean half-life of 2 days). This study demonstrated dose-dependent mammary transfer of ingested chlorophacinone. Variation in prothrombin time (PT) on Day 3 suggested that some of the ewes that ingested chlorophacinone may have been adversely affected, but PT did not facilitate estimation of the quantity of chlorophacinone consumed. Using safety factors described in the literature, consumption of dairy products derived from these ewes after a one-week withdrawal period would pose low risk to consumers.

Effect of Plumeriarubra(Apocynaceae) leaf extracts, a repellent of rice-field rats (Rattusargentiventer), on its metabolism and daily activity / Efecto del extracto foliar de Plumeria rubra (Apocynaceae), repelente de la rata (Rattus argentiventer), en su metabolismo y actividad diaria

Introduction: Rice-field rats are one of the most important pests because it can give large losses in all planting seasons including the storehouse. Synthetic rodenticide is the most commonly used of chemical technique for controlling rice-field rats. The application of these materials indirectly causes negative impacts; one of them is for the environment. As an alternative for controlling rice-field rats, natural materials can be used as a repellent. Objective: To examine the effects of methanol extract of Plumeriarubra leaves on metabolism, daily activity patterns, and its potency as a repellent of the rice-field rat. Methods: The experiments were conducted at the Laboratory of Pests, UniversitasPadjadjaran involves choice test (T-maze arena), and the Laboratory of Rats, Indonesian Center for Rice Research involves no-choice test (metabolic cage) from February until May 2019. The observations including food (g), water consumption (ml), feces production (g), urine production (ml), body weight (g), and its changes (%), also the daily activities (time spent for locomotion, foraging, and resting).The treatment was done with three replications for twelve mature male and twelve mature non-pregnant females. Data experiments analysis followed by a T-test. Results: Rice-field rats on the T-Maze arena avoided consuming food and beverage that close to methanol extract of Plumeriarubra leaves treatment. The treatment of methanol extract of Plumeria leaves in metabolic cage caused metabolic disorder of rice-field rat, which was significantly indicated by the decrease of the average consumption of food by 2.28 g and excretion of feces by 0.34 g, and also the increase of average consumption of beverage by 3.89 ml, excretion of urine by 3.15 ml, and body weight by 6.67 g. The treatment also caused daily activity patterns disorder of rice-field rats, which was significantly indicated by the increase of the average percentage of time for movement activities (locomotion) by 7.64 % and the decrease of time for eating and drinking activities (foraging) by 16.46 %. Conclusion: Methanol extract of Plumeria leaves affects a repellent for the rice-field rat.

Introducción: Las ratas arroceras son una de las plagas más importantes porque pueden producir grandes pérdidas en todas las temporadas de siembra, incluso en el almacenaje. La técnica química más utilizada para controlar las ratas de los arrozales es el raticida sintético. Sin embargo, la aplicación de estos químicos provoca indirectamente impactos negativos, por ejemplo, en el ambiente. Una alternativa para controlar la rata arrocera es la utilización de compuestos naturales como repelentes. Objetivo: Examinar los efectos del extracto metanólico de hojas de Plumeria rubra sobre el metabolismo, los patrones de actividad diaria en las ratas arroceras y su potencial como repelente. Métodos: Los experimentos se llevaron a cabo en Laboratory of Pests, UniversitasPadjadjaran usando la prueba T-maze arena, y en Laboratory of Rats, Indonesian Center for Rice Research usando la prueba metaboliccage, desde febrero hasta mayo 2019. Las observaciones incluyeron consumo de alimentos (g), consumo de agua (ml), producción de heces (g), producción de orina (ml), peso corporal (g) y cambios (%), además actividades diarias (tiempo dedicado a la locomoción, búsqueda de alimento, y reposo). El tratamiento se realizó con tres repeticiones para 12 machos maduros y 12 hembras maduras no gestantes. Los análisis de experimentos de datos se realizaron con la prueba T. Resultados: Las ratas arroceras en la T-maze arena evitaron consumir alimentos y bebidas cercanos al extracto de metanol de hojas de Plumeria rubra. El tratamiento del extracto metanólico de hojas de Plumeria rubra en la prueba metaboliccage provocó un trastorno metabólico en estas ratas, lo cual se demostró significativamente en la disminución del consumo promedio de alimento en 2.28 g y la excreción de heces en 0.34 g, además en el aumento del consumo promedio de bebida en 3.89 ml, excreción de orina en 3.15 ml y peso corporal en 6.67 g. El tratamiento también provocó un trastorno en los patrones de actividad diaria de las ratas, lo cual fue demostrado por el aumento significativo en el porcentaje promedio de tiempo para actividades de movimiento (locomoción) en un 7.64 % y la disminución del tiempo para comer y beber (búsqueda de alimento) en un 16.46 %. Conclusión: El extracto metanólico de hojas de Plumeria rubra tiene un efecto repelente en las ratas arroceras.

An assessment of vegetation management practices and burrow fumigation with aluminum phosphide as tools for managing voles within perennial crop fields in California, USA.

Voles (Cricetidae) cause extensive damage to a variety of crops throughout much of the Northern Hemisphere. The removal of vegetation from crop fields at the end of the growing season, combined with a subsequent burrow fumigant application of aluminum phosphide, has the potential to substantially curtail vole activity but has not been thoroughly examined. We set up a study to test the impact of these management tools in perennial globe artichoke (Cynara cardunculus var. scolymus) fields in Monterey County, CA, during 2010 and 2011, to determine their potential utility as part of an integrated pest management (IPM) program for managing California voles (Microtus californicus). We used both chewing indices and mortality estimates derived via radiotelemetry to assess the efficacy of aboveground vegetation removal and aluminum phosphide applications on vole abundance. We determined the impact of plowing artichoke fields on vole activity as well. Both removal of vegetation and applications of aluminum phosphide substantially reduced vole presence within treated fields. Plowing also reduced vole abundance to the point of little residual activity following treatment. These management practices appear to be effective at eliminating voles from crop fields. Combining these tools with management practices designed to slow down reinvasion by neighboring vole populations (e.g., barriers, repellents, traps) has the potential to substantially reduce farmer reliance on rodenticides for vole management, although rodenticides will still be needed to curtail populations that reestablish within crop fields. Such an IPM approach should substantially benefit both farmers and agro-ecosystems.

The Long-Lasting Rodenticide Brodifacoum Induces Neuropathology in Adult Male Rats.

Superwarfarins are very long-lasting rodenticides effective in warfarin-resistant rodents at extremely low doses. The consequences of chronic superwarfarin levels in tissues, due to biological half-lives on the order of 20 days, have not been examined. We now characterized the neurological effects of brodifacoum (BDF), one of the most widely used superwarfarins, in adult male Sprague Dawley rats. Dosing curves established the acute oral lethal dose for BDF as 221 ± 14 µg/kg. Measurement of tissue BDF levels showed accumulation throughout the body, including the central nervous system, with levels diminishing over several days. Immunocytochemical staining showed that both astrocyte and microglial activation was increased 4 days after BDF administration, as were levels of carbonylated proteins, and neuronal damage assessed by fluorojade B staining. Direct toxic effects of BDF on neurons and glia were observed using enriched cultures of cerebellar neurons and cortical astrocytes. Proteomic analysis of cerebellar lysates revealed that BDF altered expression of 667 proteins in adult rats. Gene ontology and pathway analysis identified changes in several functional pathways including cell metabolism, mitochondria function, and RNA handling with ribosomal proteins comprising the largest group. In vitro studies using primary astrocytes showed that BDF suppressed de novo protein synthesis. These findings demonstrate that superwarfarin accumulation increases indices of neuroinflammation and neuropathology in adult rodents, suggesting that methods which minimize BDF toxicity may not address delayed neurological sequelae.

An in-vitro-in-vivo model for the transdermal delivery of cholecalciferol for the purposes of rodent management.

The natural selection of anticoagulant resistant rats has resulted in a need for an alternative to anticoagulant rodenticides which differs in both active ingredient and in the method of dosing. Cholecalciferol toxicity to rodents using the dermal route is demonstrated using a variety of penetration enhancing formulations in two in-vitro models and finally in-vivo. A 1 ml dose of 50/50 (v/v) DMSO/ethanol containing 15% (v/v) PEG 200 and 20% (w/v) cholecalciferol was judged as 'sufficiently effective' in line with the European Union's Biocidal Products Regulation (No. 528/2012) during in-vivo studies. This dose was found to cause 100% mortality in a rat population in 64.4h (± 22h).

Assessment of toxicity and coagulopathy of brodifacoum in Japanese quail and testing in wild owls.

Based on detection of hepatic residues, scavenging and predatory non-target raptors are widely exposed to second generation anticoagulant rodenticides (SGARs). A small proportion, generally <10%, of tested birds are diagnosed as acutely poisoned. Little is known, however, of sub-lethal effects of SGARs, such as interaction of clotting capacity with traumatic injury. Assessment of coagulation function of birds submitted live to wildlife rehabilitators or veterinarians may provide a means of establishing the proportion of animals suffering sub-lethal coagulopathies, as well as identifying individuals requiring treatment. As a first step in exploring the potential of this approach, we dosed Japanese quail (Coturnix japonica) with the SGAR, brodifacoum, at 0, 0.8, 1.4, 1.9, and 2.5 mg/kg and sampled birds at 1, 3, 5 and 7 days post-dosing. Prothrombin time (PT), which measures the extrinsic coagulation pathway, was significantly prolonged in 98% of brodifacoum-exposed quail in a dose- and time-dependent manner. 50-fold prolongation of PT occurred at higher brodifacoum dosages and correlated to hemorrhage found at necropsy. Activated clotting time (ACT), a measure of the intrinsic pathway also increased with dose and time. Hemoglobin (Hb) and hematocrit (Hct) decreased dose- and time-dependently at doses ≥1.4 mg/kg with no significant change at 0.8 mg/kg. Reference intervals for PT (10.0-16.2 s), ACT (30-180 s), Hb (9.6-18.4 g/dl), and Hct (34-55%) were established in Japanese quail. Species-specific reference intervals are required as barn owl PT (17-29 s) and quail PT were different. The proportion of brodifacoum-exposed quail with hemorrhage was not correlated with liver residues, but was correlated with PT, suggesting that this assay is a useful indicator of avian anticoagulant rodenticide exposure. PTs measured in free-living barn owls sampled between April 2009 and August 2010 in the lower Fraser Valley of BC do not suggest significant exposure to SGARs.

Retrospective study of twenty-four patients with prolonged coagulopathy due to long-acting anti-vitamin K rodenticide poisoning.

Second generation anticoagulant rodenticides are now the most common rat killers used in China; however, poisoning incidents are frequently reported. The authors retrospectively reviewed 24 patients with vitamin K-dependent coagulation factor deficiency caused by rodenticide poisoning in the past 2 years. The main clinical presentation was hemorrhage, although intracranial bleeding and life-threatening symptoms were not seen. All patients responded to vitamin K, the specific antidote, along with fresh frozen plasma and cryoprecipitate, although prolonged treatment was sometimes required. To avoid such incidents, rodenticide should be safely stored and protective measures used during production and application. Once poisoning has occurred, vitamin K should be administered as soon as possible along with fresh frozen plasma and cryoprecipitate.

Relative abundance of American badger (Taxidea taxus) and red fox (Vulpes vulpes) in landscapes with high and low rodenticide poisoning levels.

Over the past decade, extensive poisoning campaigns have been conducted in southern Saskatchewan to control Richardson's ground squirrel Spermophilus richardsonii (Sabine, 1822) populations. Such campaigns might impact on predator abundance by decreasing prey levels, and also through secondary poisoning. Using spotlighting, we investigated the relative abundance of American badgers Taxidea taxus (Schreber, 1777) and red fox Vulpes vulpes (Linnaeus, 1758) in 2 study areas with road access and crops, but with different levels of poisoning. In the study area with relatively low poisoning (19.6% of the area traversed by roads), there were 2.2 times more American badgers per km of road and 6.4 times more red foxes per km than in the study area with high poisoning (89.7% of the area). It is recommended that an Integrated Pest Management program be developed to conserve natural predators across landscapes.

Notable pink excreta and severe myocardial suppression in superwarfarin (difethialone) intoxication.

Patients rarely consult physicians before developing coagulopathy or bleeding in most reported cases of superwarfarin intoxication. A 57-year-old woman ingested red-dyed pellets of anticoagulant rodenticide containing difethialone and warfarin as well as tablets of nitrazepam. Although she presented to the hospital in a comatose state, notable pink-colored excreta hinted at the consumption of anticoagulant rodenticide, which led to the early diagnosis of superwarfarin intoxication. Supplementation of large doses of intravenous and oral vitamin K successfully prevented coagulopathy and bleeding. On the other hand, temporary and reversible myocardial suppression was extremely severe, and required the introduction of percutaneous cardiopulmonary support.

Quinestrol treatment induced testicular damage via oxidative stress in male Mongolian gerbils (Meriones unguiculatus).

The hypothesis that quinestrol exerts testicular damage via oxidative stress was investigated in male gerbils using a daily oral gavage of 3.5 mg/kg body weight for 2 weeks (the multidose-treated group) or 35 mg/kg body weight (the single-dose-treated group). The testicular histological morphology, antioxidant capacity and malondialdehyde (MDA) concentration in testicular tissue and plasma were assessed at 15, 30, and 60 days following treatment. The results showed that the activity of the antioxidant enzymes, including superoxide dismutase (SOD) and glutathione peroxide (GSH-Px), and total antioxidant capacity (T-AOC), at 15 days after treatment in testicular tissue decreased, which led to the MDA concentration increasing while at the same time germ cells were rarefied and showed an irregular distribution in seminiferous tubules of quinestrol-treated gerbils. At 30 days, the testicular weight and antioxidant capacity continued to decrease, while the MDA concentration continued to increase, and testicular histopathological changes were more pronounced. Single-dose and multidose drug treatment had a similar effect on the antioxidant enzymes and MDA, but testicular damage was relatively severe at 15 and 30 days after multidose treatment. By 60 days of treatment withdrawal, however, the above parameters recovered to control levels. The results show that quinestrol causes reversible damage to gerbil testes that might be caused by the oxidative stress and that multidose treatment has more effects on testicular damage compared with one-dose treatment.

Successful therapy of coumatetralyl rodenticide induced pericardial effusion with pericardiocentesis in a dog.

A 5-year-old, intact male, golden retriever was presented with an acute onset of lethargy and respiratory distress. The dog was diagnosed as having rodenticide intoxication with pericardial effusion. Pericardiocentesis was successfully performed and was followed with a blood transfusion. This case suggests that rodenticide intoxication might cause pericardial effusion in dogs.

Percutaneous toxicity of anticoagulant warfarin in rats.

Percutaneous toxicity of anticoagulant rodenticides is usually manifested by coagulopathy and/or fatal outcome. There are, however, virtually no data on other biological effects of this class of pesticides that gain access into the organism via skin. In this study, percutaneous toxicity of epicutaneously applied warfarin was evaluated by measuring changes in peripheral blood granulocytes in rats. Application of 10 mug (0.05 mg/kg) or 100 mug (0.5 mg/kg) of warfarin (WF) for 3 consecutive days resulted in an increase in prothrombin time, documenting the access of warfarin to systemic circulation. Application of warfarin led to an increase in relative numbers of granulocytes at higher dose, whereas both doses resulted in increased metabolical viability, evaluated by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2H-tetrazolium bromide (MTT) reduction assay. Higher warfarin dose resulted in both granulocyte activation and priming (evaluated by cytochemical nitroblue tetrazolium, NBT, reduction assay of respiratory burst), whereas only a tendency toward activation was noted at lower WF dose. Soluble mediators from the circulation seem responsible for the observed effects, as exogenous plasma from WF-treated animals stimulated NBT reduction by isologous or naïve granulocytes. Data presented in this study are relevant for the recognition of biological effects, other than those affecting hemostasis, of anticoagulant rodenticides that gain access to systemic circulation through the skin.

Effect of bromadiolone on haematology, liver and kidney in Mus musculus.

Bromadiolone, a second generation anticoagulant rodenticide was tested on Mus musculus to evaluate its effects on blood, liver and kidney at varied time intervals of 6, 12, 24 and 48 hrs. Groups of six animals each were selected for experiment. Animals were administered with bromadiolone in the form of bait at 6, 12, 24 and 48 hrs time intervals. Control animals were maintained for each time interval. After each time interval the experiment and the control animals were sacrificed and the effect of bromadiolone on blood, liver and kidney were studied.

Persistence of bromadiolone anticoagulant rodenticide in Arvicola terrestris populations after field control.

This paper documents the exposure pattern of a population of small mammals to bromadiolone over time in a field-scale follow up. This is the first assessment of the field-scale effect of such control operation on the availability of bromadiolone-exposed A. terrestris prey to nontarget predator species. It indicates that an important risk of poisoning of nontarget species does exist during large-scale field control operations with bromadiolone, which is contradictory to results obtained from laboratory experiments in the early 1980s and consistent with the secondary poisoning hazards due to repeated exposure regularly reported during the past 20 years.