Bee Pollinator Mortality Due to Pesticide-Laden Particulate Matter from Beef Cattle Feedyards.

Wild and managed bees are critical for the stability of trophic webs, angiosperm reproduction, and agricultural productivity. Unfortunately, as many as 40% of crop pollinators are in a steep decline due to habitat loss and exposure to agrochemicals. Pyrethroids, neonicotinoids, and macrocyclic lactones are among the many agrochemicals toxic to pollinating insects that are used extensively in industrial beef cattle feeding operations throughout the world. Fugitive feedyard particulate matter (PM) transports agrochemicals into the surrounding environs. To determine the impact of agrochemical-laden feedyard particulate matter on bee pollinators, we conducted in situ experiments wherein honeybees and mason bees were placed downwind and upwind of feedyards (N = 40). Concurrent, colocated total suspended particulate matter samples contained multiple insecticides and parasiticides including pyrethroids, neonicotinoids, and macrocyclic lactones, in significantly higher concentrations downwind of feedyards (bifenthrin, 8.45 ± 4.92; permethrin, 1032.34 ± 740.76; clothianidin, 3.61 ± 1.48; imidacloprid, 73.32 ± 47.52; thiamethoxam, 5.81 ± 3.16; abamectin, 0.45 ± 0.29; ivermectin, 8.88 ± 5.06 ng/g). Honeybees and mason bees sited downwind of feedyards always experienced higher mortality than those correspondingly sited upwind, and male mason bees experienced significantly higher mortality compared to females when both were sited downwind. Bees occurring downwind of beef cattle feedyards for 1 h are 232-260% more likely to die than those occurring upwind. Thus, agrochemicals used on and emitted from beef cattle feedyards are significant threats to bee pollinators.

Dung beetle community assemblages in a southern African landscape: niche overlap between domestic and wild herbivore dung.

Dung beetles provide important ecosystem functions in semiarid environments, improving the physiochemical characteristics of the soil through tunnelling and burying nutrient-rich dung. In sub-Saharan Africa, diverse indigenous mammal communities support highly abundant dung beetle populations in savannah ecosystems. However, the conversion of landscapes to livestock agriculture may result in changes in the abundance and diversity of wild mammal species. This is likely to have significant impacts on dung beetle communities, particularly because domestic livestock dung may be contaminated with toxic residues of veterinary parasiticides. The environmental impact is likely to be affected by the degree of niche overlap between the beetle communities that colonize cattle dung and those that colonize the dung of wild mammals. We compared dung beetle communities between a pristine national park habitat dominated by large wild herbivores, and a pastoral farming community dominated by domestic livestock. Diurnal dung beetles were attracted to cattle dung in greater abundance and diversity compared to elephant, zebra or giraffe dung. Nocturnal/crepuscular dung beetles were attracted to non-ruminant dung (elephant and zebra) in higher abundance compared to ruminant dung (cattle and giraffe). Although there were no clear trophic specializations, three diurnal species showed an association with cattle dung, whereas eight nocturnal/crepuscular species showed an association with non-ruminant (elephant and zebra) dung. Diurnal species may be at greater risk from the toxic effects of residues of veterinary parasiticides in domestic livestock dung. Although many species showed trophic associations with wild herbivore dung, these beetles can utilize a wide range of dung and will readily colonize cattle dung in the absence of other options. As more land is converted to livestock agriculture, the contamination of dung with toxic residues from veterinary parasiticides could therefore negatively impact the majority of dung beetle species.

In vitro efficacies of solubility-improved mebendazole derivatives against Echinococcus multilocularis.

Recently, we introduced an epoxy group to mebendazole by a reaction with epichlorohydrin and obtained two isoforms, mebendazole C1 (M-C1) and mebendazole C2 (M-C2). The in vitro effects of mebendazole derivatives at different concentrations on Echinococcus multilocularis protoscoleces and metacestodes as well as cytotoxicity in rat hepatoma (RH) cells were examined. The results demonstrated that the solubility of the two derivatives was greatly improved compared to mebendazole. The mortality of protoscoleces in vitro reached to 70-80% after 7 days of exposure to mebendazole or M-C2, and M-C2 showed higher parasiticidal effects than mebendazole (P > 0.05). The parasiticidal effect of M-C1 was low, even at a concentration of 30 µm. The percentage of damaged metacestodes that were treated with mebendazole and M-C2 in vitro at different concentrations were similar, and M-C1 exhibited insignificant effects on metacestodes. Significant morphological changes on protoscoleces and metacestodes were observed after treatment with mebendazole and M-C2. In addition, the introduction of an epoxy group to mebendazole also reduced its cytotoxicity in RH cells. Our results demonstrate that the introduction of an epoxy group not only improved the solubility of mebendazole, but also increased its parasiticidal effects on E. multilocularis and reduced its cytotoxicity in RH cells.

Potential risks of dietary exposure to chlorpyrifos and cypermethrin from their use in fruit/vegetable crops and beef cattle productions.

The active ingredients (a.i.) used as pesticides vary across regions. Diet represents the main source of chronic exposure to these chemicals. The aim of this study was to look at the pesticides applied in fruit, vegetable, and beef cattle productions in Mendoza (Argentina), to identify those that were simultaneously used by the three production systems. Local individuals (n = 160), involved in these productions, were interviewed. Glyphosate was the a.i. most often used by fruit-vegetable producers, and ivermectin by beef cattle producers. Chlorpyrifos (CPF) and cypermethrin (CYP) were the only a.i. used by the three production systems. The survey revealed that CPF, CYP, alpha CYP, and CPF+CYP were used by 22, 16, 4, and 20% of the fruit and vegetable producers, respectively. Regarding beef cattle, CYP was used by 90% of producers, CYP + CPF formulation by 8%, and alpha CYP by 2%. The second approach of this study was to search the occurrence of CYP and CPF residues in food commodities analyzed under the National Plan for Residue Control (2012-2015). CYP residues found above the LOD were reported in 4.0% and CPF in 13.4% of the vegetable samples tested, as well as in 1.2 and 28.8%, respectively, of the fruit samples tested. Regarding beef cattle, CYP residues were reported in 2.3% and organophosphates (as a general pesticide class) in 13.5% of samples tested. In conclusion, consumers may be exposed simultaneously to CPF and CYP, from fruits, vegetables, and beef intake. Accordingly, the policy for pesticide residues in food and human risk assessment should account for the combined exposure to CPF and CYP. Moreover, appropriate toxicological studies of this mixture (including genotoxicity) are warranted.

Two in vitro methods for screening potential parasiticides against Ichthyophthirius multifiliis using Tetrahymena thermophila.

Ichthyophthirius multifiliis (Ich) is a ciliate parasite that infects many species of freshwater fishes worldwide and causes heavy economic losses in aquaculture. Currently, parasiticides for controlling this parasite are limited, and few pond-practical chemical therapies exist. Hence, the search for new parasiticides is urgently needed. One challenge confronting the screening of potential parasiticides is the difficulty in raising enough parasite for efficacy testing as Ich is an obligate parasite. This study used species of Tetrahymena, Ich-related and cultivable ciliate protozoa, to evaluate two in vitro methods to test parasiticides. Plate counting and MTS assays (CellTiter 96® AQueous Non-Radioactive Cell Proliferation Assay) were used to compare lethal concentrations or median lethal concentrations (LC50) of copper sulphate, formalin and malachite green between T. thermophila and Ich theronts or between T. thermophila and Ich tomonts. The parasiticides that killed T. thermophila have been demonstrated to kill theronts or tomonts. These in vitro methods using T. thermophila can be used to screen novel parasiticides against Ich.

Down-the-drain pathways for fipronil and imidacloprid applied as spot-on parasiticides to dogs: Estimating aquatic pollution.

Fipronil and imidacloprid have been widely detected in UK surface waters in recent years, often at concentrations that ecotoxicological studies have shown can harm aquatic life. Down-the-drain (DTD) passage of pet flea and tick treatments are being implicated as an important source, with many of the UK's 22 million cats and dogs receiving routine, year-round preventative doses containing these parasiticides. The UK Water Industry's 3rd Chemical Investigation Programme (UKWIR CIP3) has confirmed wastewater as a major entry pathway for these chemicals into surface waters, but the routes by which they enter the wastewater system remain unclear. We addressed this knowledge gap by conducting the first quantification of DTD emissions from 98 dogs treated with spot-on ectoparasiticides containing fipronil or imidacloprid, through bathing, bed washing and washing of owners' hands. Both chemicals were detected in 100 % of washoff samples, with bathing accounting for the largest emissions per event (up to 16.8 % of applied imidacloprid and 24.5 % of applied fipronil). Modelled to account for the frequency of emitting activities, owner handwashing was identified as the largest source of DTD emissions from the population overall, with handwash emissions occurring for at least 28 days following product application and an estimated 4.9 % of imidacloprid and 3.1 % of fipronil applied in dog spot-ons passing down-the-drain via this route. The normalised daily per capita emissions for all routes combined were 8.7 µg/person/day for imidacloprid and 2.1 µg/person/day for fipronil, equivalent to 20-40 % of the daily per capita load in wastewater, as estimated from UKWIR CIP3 data. Within the current international regulatory framework adhered to by the UK, the environmental exposure of veterinary medicines intended for use in small companion animals is assumed to be low, and DTD pathways are not considered. We recommend a systematic review of regulations and practices to address this overlooked pollution pathway.

Parasiticide use and obesity in dogs with sudden acquired retinal degeneration syndrome.

OBJECTIVE: To investigate parasiticide use and describe signalment features in patients with sudden acquired retinal degeneration syndrome (SARDS). ANIMALS: Retrospective case-control study of dogs with (n = 71) and without (136) SARDS. METHODS: Parasiticide use, presentation season, weight, body condition, and signalment were compared between dogs diagnosed with SARDS and the reference population by use of descriptive statistics and logistic regression. RESULTS: Animals with SARDS were at a 5.99 times higher odds of having previously used imidacloprid (95% CI, 1.6 to 22.2; P = .003). However, time of last imidocloprid administration was > 6 years prior to diagnosis in 6 SARDS-affected individuals and 15, 26, or 42 months before diagnosis (n = 1 each). No other class of parasiticide had a significant association with SARDS. Seasonal variation was observed with a negative association identified between incidence of SARDS and tick season (October to January; P < .001). Overweight and obese dogs were 4.42 (95% CI, 1.9 to 10.4) and 4.96 (95% CI, 2.1 to 11.6) times more likely to have SARDS (P ≤ .001). History of polyphagia or weight gain was not associated with an increased likelihood of being overweight or obese within the SARDS-affected population (P > .108). CLINICAL RELEVANCE: While a statistically significant association was found between imidacloprid use and SARDS, this is unlikely to be clinically significant given the lack of a temporal association, sparse exposure numbers, and low point estimate of the OR. A positive association between being overweight or obese and a diagnosis of SARDS was found independent of polyphagia and weight gain, suggesting that it may be a risk factor for the development of SARDS.

To flea or not to flea: survey of UK companion animal ectoparasiticide usage and activities affecting pathways to the environment.

Due to the convenience and efficacy of modern ectoparasiticides, routine prophylactic use has become commonplace for dogs and cats. However, the environmental consequences of this large-scale use are not well-understood, and multiple potential pathways for ectoparasiticides to the environment exist. Of particular concern is the potential for topically applied ectoparasiticides to pass to waterways, both down-the-drain via wastewater treatment plants and directly through swimming. In this online cross-sectional survey of 1,009 UK cat and dog owners, we investigated ectoparasiticide usage and the frequency of activities that are likely to result in transfer of the active substance to the environment, with a focus on pathways to waterways. A total of 603 dog owners and 406 cat owners completed the survey. Amongst dog and cat owners, 86.1% and 91.1% had administered an ectoparasiticide treatment to their pet in the preceding 12 months. Imidacloprid was the most frequently administered ectoparasiticide in both cats and dogs, followed by fluralaner in dogs and fipronil in cats. Eighty-four percent of owners who applied topical ectoparasiticides to their dog said they were aware of product warnings regarding swimming and bathing after application. Spot-on treated dogs were reported to swim significantly less frequently than non spot-on treated dogs (p = 0.007); however, 36.2% were reported to swim at least monthly. Similarly, significant differences were found in bathing frequency between spot-on treated and non spot-on treated dogs, with treated dogs less likely to be bathed at frequent (weekly) intervals, however 54.6% were reported to be bathed at least monthly. Washing of bedding was unaffected by ectoparasiticide treatment, and 87.8% of dog owners and 69.1% of cat-owners reported washing their pet's bedding at least every 3 months, suggesting that residue washoff from bedding may be occurring for most topically treated animals. Results suggest that transfer of ectoparasiticides to the environment is likely to occur for many of the millions of animals treated annually in the UK, with imidacloprid spot-on treated dogs estimated to swim, be bathed and have their bedding washed over 3.3 million, 5 million and 6.3 million times per year, respectively.

Perception of UK companion animal veterinarians on risk assessment based parasite control.

Parasites can pose a risk to companion animals and potentially their owners. Current parasiticide use is possibly impacting the environment, increasing adverse reaction and resistance risk. As such parasiticides should be dispensed by the veterinary team proportional to individual risk, including owners in their approach. A mixed-methods questionnaire was designed and distributed using snowball sampling to ascertain overall awareness, observance, and attitude towards utilising a risk assessment based approach to parasite prophylaxis by UK companion animal veterinarians. 85.7% of veterinarians surveyed reported that they were aware of risk assessment based parasite control whereas only 53.9% said they utilise it always or often. Significant correlations were found between more frequent risk assessment based parasite control utilisation and increased owner involvement (P = 0.0007) and prescription confidence (P = 0.0001). Most attitudes towards adopting risk assessment based parasite control were positive. There was significant association with positive attitude and greater utilisation frequency (P = 0.0010), as well as working in corporate practice (P = 0.0126). Awareness of risk assessment based parasite control has potential to increase responsible utilisation of parasiticides by veterinarians, and therefore mitigate risks associated. Most veterinarians would like to see the profession move towards risk assessment based control use, but institutional changes are required. Further research, and education is also needed.

How pet owners choose antiparasitic treatments for their dogs: A discrete choice experiment.

BACKGROUND: External and internal parasites can cause significant pathology to pets, posing distress to their owners. Antiparasitic treatment is complex because there are many antiparasitic products and dog owners have a limited understanding of parasiticides. The aim of this study was to investigate the characteristics of antiparasitic treatments available at veterinary offices to help veterinarians understand what pet owners value when selecting parasiticides for their dogs. METHODS: Discrete choice experiment (DCE) methodology was used. A list of important treatment attributes was developed based on semi-structured interviews with six dog owners with a total of nine dogs and six veterinarians. The questionnaire including 12 choices between pairs of hypothetical products defined according to treatment attributes was developed. The questionnaire was administered to UK dog owners recruited through an internet panel. It was tested in a pilot study with 17 dog owners, and then was completed by 160 dog owners in the main study. RESULTS: The selected treatment attributes were price, spectrum of action, veterinarian recommendation, treatment schedule, mode of administration, and place of obtention. The main analysis showed the first four of these attributes significantly influenced the preferences of dog owners for antiparasitic treatments. The most important factor was spectrum of action; most owners expressed a preference for products treating multiple parasites. The influence of price was comparable to that of spectrum of action. Pet owners were more likely to choose a product recommended by their veterinarian. Willingness-to-pay estimates were £11.22 [€12.68; $15.38] for extending protection from fleas and ticks only to intestinal worm and lungworm and £7.21 [€8.14; $9.87] for recommendation from veterinarian. CONCLUSIONS: A broad spectrum of action, veterinarian recommendation, and price are key drivers for choosing antiparasitic products among dog owners. These results may help veterinarians with recommendations of antiparasitic treatment for pet owners based on the key drivers pet owners value.

Indirect Effect of Pesticides on Insects and Other Arthropods.

Pesticides released to the environment can indirectly affect target and non-target species in ways that are often contrary to their intended use. Such indirect effects are mediated through direct impacts on other species or the physical environment and depend on ecological mechanisms and species interactions. Typical mechanisms are the release of herbivores from predation and release from competition among species with similar niches. Application of insecticides to agriculture often results in subsequent pest outbreaks due to the elimination of natural enemies. The loss of floristic diversity and food resources that result from herbicide applications can reduce populations of pollinators and natural enemies of crop pests. In aquatic ecosystems, insecticides and fungicides often induce algae blooms as the chemicals reduce grazing by zooplankton and benthic herbivores. Increases in periphyton biomass typically result in the replacement of arthropods with more tolerant species such as snails, worms and tadpoles. Fungicides and systemic insecticides also reduce nutrient recycling by impairing the ability of detritivorous arthropods. Residues of herbicides can reduce the biomass of macrophytes in ponds and wetlands, indirectly affecting the protection and breeding of predatory insects in that environment. The direct impacts of pesticides in the environment are therefore either amplified or compensated by their indirect effects.

Evaluation of the genotoxic potential of cypermethrin, chlorpyrifos and their subsequent mixture, on cultured bovine lymphocytes.

Cypermethrin (CYP) and chlorpyrifos (CPF) are insecticides/parasiticides used in the production of fruits, vegetables and beef cattle. These substances or their metabolites are frequently reported as residues in food, whose consumption in a diet implies a genotoxic risk. The potential for chronic toxicity of CYP and CPF is unclear, and only a few genotoxicological evaluations based on their mixture have been performed. The aim of this study was to evaluate the genotoxic potential of CYP, CPF and CYP + CPF in five concentrations, from 5.9 to 175 µg/mL, on bovine lymphocytes. By means of the cytokinesis-block micronucleus cytome assay, a decrease in the cell proliferation index was observed (r = -0.89 p = 0.04); and also an increase in the frequencies of binucleated cells (BN) with micronuclei (BNMn) (r = 0.93, p = 0.02) and BN with nuclear buds (BNBud) (r = 0.778 p = 0.04), depending on the concentrations of CPF. An increase in BNMn frequencies was observed as a function of CYP concentrations (r = 0.89, p = 0.04) and also of the CYP + CPF mix (r = 0.99, p = 0.008). CYP caused greater genotoxic damage (BNMn) than CPF and the mixture on bovine lymphocytes. Cells with simultaneous presentation of micronuclei and nuclear buds were detected, as well as cells with irregular nuclei, something never previously reported, whose origin and significance should be investigated. The genotoxic effect of chlorpyrifos, cypermethrin and their mixture on bovine lymphocytes was observed. We recognized the value of the use of primary bovine cultures, animal species adjacent to man in the food chain, for genotoxicity studies.

Flea Control: An Overview of Treatment Concepts for North America.

Résumé- L'approche d'un contrôle anti puces souligne Pimportance de la communication entre le vétérinaire et le propriétaire d'un animal de compagnie, communication qui implique la connaissance de chaque cas de figure individuel. Une revue des antiparasitaires usuels est brièvement présentée incluant les principes actifs et leur classification. Les concepts de mise en place d'un programme de contrôle anti puces qui sont présentés incluent aussi bien les aspects de contrôle des puces à l'intérieur des habitations et dans le milieu exérieur, que les produits et méthodes utilisées pour traiter l'animal. Les produits les plus récents utilisés dans la lutte antipuces sont présentés, comme les régulateurs de croissance des insectes, les inhibiteurs de croissance des insectes, les traitements utilisant des nématodes, et les composés à base de borate. [MacDon-ald, J. M. Flea control: an overview of treatment concepts for North America (Contrôle antipuces: revue des concepts de traitement en Amérique du Nord). Resumen- El enfoque al control de pulgas pone de manifiesto la importancia de la interrelación entre el veterinario y el propietario del animal, siendo necesario un conocimiento de las condiciones especiales en casos individuales. Se presenta una breve revisión de los parasiticidas más comunes, con un listado de los compuestos activos y su clasificación. Se presentan los principios para el diseño de un programa de control de pulgas, incluyendo el control dentro y fuera de la vivienda, asi como productos y métodos para tratar el animal. Se revisan los productos más recientes utilizados para el control de pulgas como reguladores del crecimiento de insectos, reguladores del desarrollo de insectos, tratamiento de nemátodos y compuestos de borato. [MacDonald, J. M. Flea control: an overview of treatment concepts for North America (Control de pulgas: un repaso a los principios sobre tratamiento en Norte-América). Abstract- The approach to flea control emphasizes the importance of interrelationships between veterinarian and pet owner requiring knowledge of the unique environment of individual cases. A review of common parasiticides is briefly presented listing active ingredients and their classification. Concepts of developing a flea control program are presented that include aspects of inside and outside flea control as well as products and methods used to treat the pet. Newer products used in flea control are reviewed including insect growth regulators, insect development inhibitors, nematode treatment and borate compounds.