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.

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.

Variabilidade clínica na determinação da dose tóxica oral em intoxicação experimental por fluoroacetato de sódio em gatos / Clinical variability in the determination of oral toxic dosis in the experimental intoxication with sodium fluoroacetate in cats

O fluoroacetato de sódio (FAS) ou composto 1080 é um potente rodenticida utilizado no controle de roedores e predadores manúferos. Sua utilização está proibida por lei em diversos países devido à sua alta toxicidade, mas no Brasil há evidências do uso ilegal e sem critérios causando intoxicações, principalmente em crianças e animais domésticos. O FAS age por meio do seu metabólito tóxico, o fluorocitrato, no bloqueio do ciclo de Krebs com consequente diminuição da produção de energia do organismo, provocando principalmente manifestações clínicas neurológicas e cardíacas. No presente estudo compararam quatro doses orais tóxicas do fluoroacetato de sódio, descritas em gatos, na literatura, observando-se o aparecimento dos sinais clínicos predominantes da intoxicação, as diferenças entre as doses quanto a variabilidade clínica em relação ao período de latência para o aparecimento dos sinais clínicos e sua respectiva intensidade. A dose oral tóxica que melhor caracterizou o quadro clínico da intoxicação por FAS em gatos, sem causar a letalidade aguda, foi de 0,4Smg/kg. As diferenças entre as manifestações clínicas foram dose-dependentes e em ordem crescente de intensidade, caracterizando-se como sinais leves (dose 1: 0,3mg/kg), leves a moderados (dose 2: 0,4mg/kg), moderados a graves (dose 3: 0,45mg/ kg) e graves (dose 4: 0,5mg/kg). Houve também variabilidade clínica individual entre animais intoxicados com a mesma dosagem do tóxico.

The sodium monofluoroacetate (FAC) or compound 1080 is a potent rodenticide used for a rodents and vertebrate pest control. lt was prohibited in many countties because of its high toxicity, but in Brazil exist evidences of ilegal use causing the intoxication in children and domestic animals. The fluoroacetate metabolite, fluorocitric acid, blocks body energy production by inhibit the Krebs cycle, resulting in neurological and cardiacs signs. ln the present study, four group of oral toxic dosis of the FAC were compared in cats. The best oral toxic dose for clinical signs presentation, without cause acute lethality, was 0,45mg/kg. The clinical variability was dosis dependent and its intensity , in crescent order, was: light signs (dose 1: 0,3mg/kg), light to moderate (dose 2: 0,4mg/kg), moderate to severe (dose 3: 0,45mg/ kg) and severe (dose 4: 0,5mg/kg). There was individual clinical variability between animals that received the same oral toxic dose.

Toxicologic and histopathologic response of the terrestrial salamander Plethodon cinereus to soil exposures of 1,3,5-trinitrohexahydro-1,3,5-triazine.

Red-backed salamanders (Plethodon cinereus) were exposed to four different concentrations of 1,3,5-trinitrohexahydro-1,3,5-triazine (RDX) in soil under controlled laboratory conditions for 28 days. Wild-caught P. cinereus (N = 20/treatment) were exposed to target concentrations of 5,000, 1000, 100, 10, and 0 mg RDX/kg soil (dry wt) using a microcosm design. Animals were fed 5 to 10 uncontaminated mutant Drosophila flies every 3 days and monitored daily. Animals were weighed 1 day before being placed in treatment and weekly thereafter. RDX concentrations in soil were analytically determined after the compound was added and mixed at the beginning, the midpoint, and the end of exposure. RDX soil concentrations were relatively stable throughout the exposure period. Signs of overt toxicity were observed primarily in the highest exposure group. Salamanders exposed to 5,000 mg RDX/kg soil exhibited signs of neuromuscular effects (lethargy, gaping, hypersensitivity, tremors) and exhibited significant weight loss. A single moribund animal from this group lost >20% of its original body weight and was killed. Animals in this exposure group also lost weight relative to animals in other treatments. Histopathologic evaluations, including an evaluation of melanomacrophage parameters, indicated no strong treatment-related findings. This study provided information regarding the effects from subchronic dermal exposure of a terrestrial amphibian species to RDX in soil and provides a microcosm approach to the evaluation of toxicity of contaminants in soil to a terrestrial vertebrate.

Combined superwarfarin and ethylene glycol ingestion. A unique case report with misleading clinical history.

A markedly elevated prothrombin time (PT) and activated partial thromboplastin time (APTT) were observed in a 24-year-old man who was admitted with a history of ethylene glycol ingestion. Further laboratory evaluation suggested that the coagulopathy was related to acquired factor deficiencies. The PT and APTT improved transiently on usual doses of vitamin K, but rapidly became abnormal again. The coagulopathy was controlled only after large doses of vitamin K for at least 37 days. On further questioning, the patient admitted to consuming a large quantity of a rodenticide. The second generation anticoagulant rodenticides (superwarfarins) result in a potent and prolonged anticoagulant effect by reducing the activity of the vitamin K dependent factors (II, XII, IX, and X). To our knowledge, this is the first reported concomitant ingestion of both ethylene glycol and a superwarfarin compound. This case serves to illustrate how a logical laboratory evaluation can lead to the proper diagnosis, despite a misleading clinical history.

Functional and morphological aspects of thallium-induced nephrotoxicity in rats.

Until now the effect of thallium (Tl) on renal function has not been investigated systematically. Therefore, the dose (5, 10, 15, 20 mg Tl2SO4/kg body wt., intraperitoneally) and time-dependence of renal damage was investigated in diuresis experiments on conscious rats. Morphology was evaluated after perfusion fixation in situ. Morphologic changes were localized in the thick ascending limb of the loop of Henle, mostly expressed at the 2nd day after Tl administration, which were completely normalized again at the 10th day. Other parameters such as Tl concentration, changes in water content and the activity of Na+/K(+)-ATPase as well as the diuretic effect of furosemide confirmed the Tl effect to be localized in the renal medulla. One single Tl administration is followed by a decrease in glomerular filtration rate (GFR) and urine volume and an increase of proteinuria. Electrolyte excretion was only slightly changed. All changes were reversible within the 10-day investigation period.

A boric acid-rodenticide mixture used in the control of coexisting rodent-cockroach infestations.

Rodent bait combined with a commercially available boric acid compound was found in laboratory experiments to be completely effective in eliminating American cockroaches given the mixture as a food source. The presence of boric acid compound did not interfere with the rodenticidal capacity of the rodent bait.