Marta Martínez

Plasma and Tissue Depletion of Florfenicol and Florfenicol-amine in Chickens

Chickens were used to investigate plasma disposition of florfenicol after single intravenous (i.v.) and oral dose (20 mg kg-1 body weight) and to study residue depletion of florfenicol and its major metabolite florfenicol-amine after multiple oral doses (40 mg kg-1 body weight, daily for 3 days). Plasma and tissue samples were analyzed using a high-performance liquid chromatography (HPLC) method. After i.v. and oral administration, plasma concentration-time curves were best described by a two-compartment open model. The mean [ +/- standard deviation (SD)] elimination half-life (t1/2beta) of florfenicol in plasma was 7.90 +/- 0.48 and 8.34 +/- 0.64 h after i.v. and oral administration, respectively. The maximum plasma concentration was 10.23 +/- 1.67 microg mL-1, and the interval from oral administration until maximal concentration was 0.63 +/- 0.07 h. Oral bioavailability was found to be 87 +/- 16%. Florfenicol was converted to florfenicol-amine. After multiple oral dose (40 mg kg-1 body weight, daily for 3 days), in kidney and liver, concentrations of florfenicol (119.34 +/- 31.81 and 817.34 +/- 91.65 microg kg-1, respectively) and florfenicol-amine (60.67 +/- 13.05 and 48.50 +/- 13.07 microg kg-1, respectively) persisted for 7 days. The prolonged presence of residues of florfenicol and florfenicol-amine in edible tissues can play an important role in human food safety, because the compounds could give rise to a possible health risk. A withdrawal time of 6 days was necessary to ensure that the residues of florfenicol were less than the maximal residue limits or tolerance established by the European Union.

Permethrin-induced oxidative stress and toxicity and metabolism. A review

Permethrin (PER), the most frequently used synthetic Type I pyrethroid insecticide, is widely used in the world because of its high activity as an insecticide and its low mammalian toxicity. It was originally believed that PER exhibited low toxicity on untargeted animals. However, as its use became more extensive worldwide, increasing evidence suggested that PER might have a variety of toxic effects on animals and humans alike, such as neurotoxicity, immunotoxicity, cardiotoxicity, hepatotoxicity, reproductive, genotoxic, and haematotoxic effects, digestive system toxicity, and cytotoxicity. A growing number of studies indicate that oxidative stress played critical roles in the various toxicities associated with PER. To date, almost no review has addressed the toxicity of PER correlated with oxidative stress. The focus of this article is primarily to summarise advances in the research associated with oxidative stress as a potential mechanism for PER-induced toxicity as well as its metabolism. This review summarises the research conducted over the past decade into the reactive oxygen species (ROS) generation and oxidative stress as a consequence of PER treatments, and ultimately their correlation with the toxicity and the metabolism of PER. The metabolism of PER involves various CYP450 enzymes, alcohol or aldehyde dehydrogenases for oxidation and the carboxylesterases for hydrolysis, through which oxidative stress might occur, and such metabolic factors are also reviewed. The protection of a variety of antioxidants against PER-induced toxicity is also discussed, in order to further understand the role of oxidative stress in PER-induced toxicity. This review will throw new light on the critical roles of oxidative stress in PER-induced toxicity, as well as on the blind spots that still exist in the understanding of PER metabolism, the cellular effects in terms of apoptosis and cell signaling pathways, and finally strategies to help to protect against its oxidative damage.

Introduction of African Swine Fever into the European Union through Illegal Importation of Pork and Pork Products

Transboundary animal diseases can have very severe socio-economic impacts when introduced into new regions. The history of disease incursions into the European Union suggests that initial outbreaks were often initiated by illegal importation of meat and derived products. The European Union would benefit from decision-support tools to evaluate the risk of disease introduction caused by illegal imports in order to inform its surveillance strategy. However, due to the difficulty in quantifying illegal movements of animal products, very few studies of this type have been conducted. Using African swine fever as an example, this work presents a novel risk assessment framework for disease introduction into the European Union through illegal importation of meat and products. It uses a semi-quantitative approach based on factors that likely influence the likelihood of release of contaminated smuggled meat and products, and subsequent exposure of the susceptible population. The results suggest that the European Union is at non-negligible risk of African swine fever introduction through illegal importation of pork and products. On a relative risk scale with six categories from negligible to very high, five European Union countries were estimated at high (France, Germany, Italy and United Kingdom) or moderate (Spain) risk of African swine fever release, five countries were at high risk of exposure if African swine fever were released (France, Italy, Poland, Romania and Spain) and ten countries had a moderate exposure risk (Austria, Bulgaria, Germany, Greece, Hungary, Latvia, Lithuania, Portugal, Sweden and United Kingdom). The approach presented here and results obtained for African swine fever provide a basis for the enhancement of risk-based surveillance systems and disease prevention programmes in the European Union.

Distribution, abundance and density of the wild boar on the Iberian Peninsula, based on the CORINE program and hunting statistics

Abstract. Wild boar population size in the Iberian Peninsula was estimated using hunting bag statistics from Spain and Portugal. Density was estimated assigning the wild boar population size to the “potential resources” or suitable habitats categorized by their importance to provide food and/or shelter to wild boars. Land uses were selected from CORINE, the EU database for land cover, using scientific literature and statistical significance for wild boar presence from published data. The hunting bag was 176245 and 15167 in Spain and Portugal, respectively. The average density was 0.373/km2 (min 0.014-max 2.22) in Spain and 0.13/km2 (min 0.00048-max 1.99) in Portugal, being 0.31/km2 (0.00048-2.22) over the entire Peninsula. Statistical analysis showed that wild boar presence was significantly (p < 0.05) associated to thirteen of the seventeen CORINE land uses selected. Agro-forestry, moors and heathland land use were not statistically significant but were included in the model due to their biological importance. Suitable habitats and distribution of wild boar were mapped for the Iberian Peninsula. This approach is a preliminary step intended to be useful in environmental management and animal health.

5-HT loss in rat brain by type II pyrethroid insecticides

Study objective: Type II pyrethroids are a group of insecticides largely used in agriculture and public health. The nervous system is the main target for pyrethroids in insects and mammals. One notable form of toxicity associated with over exposure has been a facial cutaneous paraesthesia and irritation-related respiration symptoms including behavioural excitation mainly observed in workers spraying pyrethroids or in occupational settings. In acutely exposed rats, type II pyrethroids produce a severe syndrome characterized by salivation and choreoathetosis. Because many of the acute functional effects of type II pyrethoids can be associated with the neurotoxic effect on 5-hydroxytryptamine (5-HT) neurones, the objective of the present study was to examine whether deltamethrin, cyfluthrin and l-cyhalothrin administration results in changes of 5-HT content in rat brain. Characterizing this target will help us to better understand the toxicological effects of type II pyrethroids. Design: Rats were injected with either corn oil or pyrethroids (deltamethrin, 20 mg/kg per day, i.p., for 6 days; cyfluthrin, 14 mg/kg per day, i.p., for 6 days; l-cyhalothrin, 8 mg/kg per day, i.p., for 6 days). The frontal cortex, hippocampus, midbrain and striatum were removed at 24 hours post treatment and were analysed for content of 5-HT and 5-HIAA using a HPLC method with electrochemical detection. Results: A serotonin depleting effect was produced by these type II pyrethroids. The concentration of 5-HT and its metabolite 5-HIAA decreased in the brain regions from pyrethroid treated animals. Pyrethroids accelerated the turnover of 5-HT in midbrain and striatum areas. It is concluded that pyrethroids affect serotonin neurotransmission.

Mycotoxins modify the barrier function of Caco-2 cells through differential gene expression of specific claudin isoforms: Protective effect of illite mineral clay.

Aflatoxin B1 (AFB1), fumonisin B1 (FB1), ochratoxin A (OTA) and T-2 toxin (T2) are mycotoxins that commonly contaminate the food chain and cause various toxicological effects. Their global occurrence is regarded as an important risk factor for human and animal health. In this study, the results demonstrate that, in human Caco-2 cells, AFB1, FB1, OTA and T2 origin cytotoxic effects, determining cell viability through MTT assay and LDH leakage, and decrease trans-epithelial electrical resistance (TEER). The decrease in barrier properties is concomitant with a reduction in the expression levels of the tight junction constituents claudin-3, claudin-4 and occludin. The protective effect of mineral clays (diosmectite, montmorillonite and illite) on alterations in cell viability and epithelial barrier function induced by the mycotoxins was also evaluated. Illite was the best clay to prevent the mycotoxin effects. Illite plus mycotoxin co-treatment completely abolished AFB1 and FB1-induced cytotoxicity. Also, the decreases in the gene expression of claudins and the reduction of TEER induced by mycotoxins were reversed by the illite plus mycotoxin co-treatment. In conclusion, these results demonstrated that mycotoxins AFB1, FB1, T2 and OTA disrupt the intestinal barrier permeability by a mechanism involving reduction of claudin isoform expressions, and illite counteracts this disruption.

Plasma disposition and tissue depletion of difloxacin and its metabolite sarafloxacin in the food producing animals, chickens for fattening.

Chickens were used to investigate plasma disposition of difloxacin after single intravenous (IV) and oral dose (10 mg/kg body weight (BW)) and to study residue depletion of difloxacin and its major metabolite sarafloxacin after multiple oral doses (10 mg difloxacin/kg BW, daily for 5 days). Plasma and tissue samples were analyzed using a HPLC method. After IV and oral administration, plasma drug concentration-time curves were best described by a two-compartment open model. Mean (± SD) elimination half-lives (t(½)β) of difloxacin were 9.53±1.00 and 12.23±1.81 h after IV and oral administration. Maximum plasma concentration was 2.34±0.50 μg/ml and interval from oral administration until maximal concentration was 1.34±0.03 h. Oral bioavailability was found to be 68.89±15.21%. Difloxacin was converted to sarafloxacin. After multiple oral dose (10mg difloxacin/kg BW, daily for 5 days), mean kidney, liver, muscle and skin + fat tissue concentrations of difloxacin and sarafloxacin ranging between 604.8±132.5 and 368.1±52.5 μg/kg and 136.4±18.3 and 10.4±1.2 μg/kg, respectively, were measured 1 day after administration of the final dose of difloxacin. A withdrawal time of 5 days was necessary to ensure that the residues of difloxacin were less than the maximal residue limits (MRL) or tolerance established by the European Union.

Modular framework to assess the risk of African swine fever virus entry into the European Union

BackgroundThe recent occurrence and spread of African swine fever (ASF) in Eastern Europe is perceived as a serious risk for the pig industry in the European Union (EU). In order to estimate the potential risk of ASF virus (ASFV) entering the EU, several pathways of introduction were previously assessed separately. The present work aimed to integrate five of these assessments (legal imports of pigs, legal imports of products, illegal imports of products, fomites associated with transport and wild boar movements) into a modular tool that facilitates the visualization and comprehension of the relative risk of ASFV introduction into the EU by each analyzed pathway.ResultsThe framework’s results indicate that 48% of EU countries are at relatively high risk (risk score 4 or 5 out of 5) for ASFV entry for at least one analyzed pathway. Four of these countries obtained the maximum risk score for one pathway: Bulgaria for legally imported products during the high risk period (HRP); Finland for wild boar; Slovenia and Sweden for legally imported pigs during the HRP. Distribution of risk considerably differed from one pathway to another; for some pathways, the risk was concentrated in a few countries (e.g., transport fomites), whereas other pathways incurred a high risk for 4 or 5 countries (legal pigs, illegal imports and wild boar).ConclusionsThe modular framework, developed to estimate the risk of ASFV entry into the EU, is available in a public domain, and is a transparent, easy-to-interpret tool that can be updated and adapted if required. The model’s results determine the EU countries at higher risk for each ASFV introduction route, and provide a useful basis to develop a global coordinated program to improve ASFV prevention in the EU.

Environmental Risk Factors Associated with H5N1 HPAI in Ramsar Wetlands of Europe

Abstract The objective of this study was to identify environmental characteristics of European Ramsar wetlands, which are natural habitats for waterbirds, that could have contributed as risk factors for H5N1 HPAI (highly pathogenic avian influenza) in water birds (2006–2009). Ramsar wetlands in which H5N1 outbreaks were reported were considered infected (positive), and a case-control study was conducted using a logistic regression model in order to identify environmental risk factors associated with disease. Forestry (odds ratio, OR  =  6.90) and important area for water birds with mixosaline water (OR  =  6.31), as well as distance to the nearest positive wetland (OR  =  0.66), which was included into the model to adjust for spatial dependence, were associated with status of the wetlands. The model was used to estimate the risk for H5N1 HPAI on each European Ramsar wetland. Results will help to identify wetlands at high risk for H5N1 HPAI infection, wetlands that could be selectively targeted as part of a surveillance program aimed at early detection and prevention of future H5N1 HPAI epidemics.

Plasma disposition and tissue depletion of chlortetracycline in the food producing animals, chickens for fattening.

Chickens were used to investigate plasma disposition of chlortetracycline after single IV (15 mg/kg) and multiple oral administration (60 mg/kg, 5 days) and residue depletion of chlortetracycline after multiple oral doses (60 mg/kg, 5 days). Plasma and tissue samples were analyzed by HPLC. Mean elimination half-lives in plasma were 7.96 and 13.15 h after IV and multiple oral administration. Maximum plasma concentration was 4.33 μg/ml and the interval from oral administration until maximal concentration was 1.79 h. Oral bioavailability was 17.76%. After multiple oral dose, mean kidney, liver and muscle tissue concentrations of chlortetracycline+4-epi-chlortetracycline of 835.3, 192.7, and 126.3 μg/kg, respectively, were measured 1 day after administration of the final dose of chlortetracycline. Chlortetracycline residues were detected in kidney and liver (205.4 and 81.7 μg/kg, respectively), but not in muscle, 3 days after the end of chlortetracycline treatment. The mean chlortetracycline+4-epi-chlortetracycline concentrations were below LOQ at 3 and 5 days after cessation of medication in muscle and liver, respectively. A withdrawal time of 3 days was necessary to ensure that the chlortetracycline residues were less than the maximal residue limits (MRLs) established by the European Union (100, 300, and 600 μg/kg in muscle, liver, and kidney, respectively).