The changing global distribution and prevalence of canine transmissible venereal tumour.

BACKGROUND: The canine transmissible venereal tumour (CTVT) is a contagious cancer that is naturally transmitted between dogs by the allogeneic transfer of living cancer cells during coitus. CTVT first arose several thousand years ago and has been reported in dog populations worldwide; however, its precise distribution patterns and prevalence remain unclear. RESULTS: We analysed historical literature and obtained CTVT prevalence information from 645 veterinarians and animal health workers in 109 countries in order to estimate CTVT's former and current global distribution and prevalence. This analysis confirmed that CTVT is endemic in at least 90 countries worldwide across all inhabited continents. CTVT is estimated to be present at a prevalence of one percent or more in dogs in at least 13 countries in South and Central America as well as in at least 11 countries in Africa and 8 countries in Asia. In the United States and Australia, CTVT was reported to be endemic only in remote indigenous communities. Comparison of current and historical reports of CTVT indicated that its prevalence has declined in Northern Europe, possibly due to changes in dog control laws during the nineteenth and twentieth centuries. Analysis of factors influencing CTVT prevalence showed that presence of free-roaming dogs was associated with increased CTVT prevalence, while dog spaying and neutering were associated with reduced CTVT prevalence. Our analysis indicated no gender bias for CTVT and we found no evidence that animals with CTVT frequently harbour concurrent infectious diseases. Vincristine was widely reported to be the most effective therapy for CTVT. CONCLUSIONS: Our results provide a survey of the current global distribution of CTVT, confirming that CTVT is endemic in at least 90 countries worldwide. Additionally, our analysis highlights factors that continue to modify CTVT's prevalence around the world and implicates free-roaming dogs as a reservoir for the disease. Our analysis also documents the disappearance of the disease from the United Kingdom during the twentieth century, which appears to have been an unintentional result of the introduction of dog control policies.This is the author's accepted manuscript. The final version of this article has been published by BioMed Central: http://www.biomedcentral.com/1746-6148/10/168

Impact analysis of the toxic metals emitted to agricultural soil from industrial activities in Fez area, in the frame of Life Cycle Assessment

Contamination by trace metals in agricultural soils in the Fez region are linked to irrigation water used from the Oued Fez. This one is the direct receiving environment of industrial and urban effluents that have a high pollution load in spite of treatment and risk minimization efforts. Several reports and studies in this region confirmed a state of high metallic pollution at the Oued Fez and its confluence with the Oued Sebou. The effluents of the tannery and textile industries as well as those of the metal finishing industry, present the greatest risk in this type of pollution, because of the use of some metals in their processes. This work aims to translate the metals quantities which are emitted during the industrial activities life cycle in potential impacts on water, soil and human health. The life Cycle Assessment (LCA) was adopted as multi-criteria methodology for identifying and quantifying the majority contributions related to various local industries metal emissions. In particular, there is question to analyzing the aquatic and terrestrial ecotoxicity and human toxicity. The characterization of these impacts takes into account the fate of trace metal emissions from industrial sources until their presence in water/sediment and agricultural soil through irrigation water; and their toxic effects on aquatic species and human health.The fate of metals emissions were determined by a geochemical study in the areas with different pollution states. The analysis of total concentrations and bioavailable fractions was conducted on the industrial effluents and the three environmental compartments: water, sediments and soils. The effect factor is based on the effect concentrations HC50 of the Impact2002 + database and by specifying some parameters such as the partition coefficient of trace elements, the density and the moisture content of the soil. At this stage analysis, the trace elements Cr, Ni, Cu and Zn are the major contributors to the terrestrial ecotoxicity. This is due to several causes combined or separated: high total concentrations in the soil, a greater mobility with higher bioavailable fractions and lower concentrations of toxic effect

Behavior of enzyme activities exposed to contamination by heavy metals and dissolved organic carbon in calcareous agricultural soils

To investigate the relevance of biochemical parameters in biogeochemical mechanisms of the soil, it is important to gather data related to different soil types under different pedogeoclimatic conditions. In this study, we investigated on the calcareous agricultural soils in the Saiss plain (North Morocco). Four agricultural soils exposed to multi-metal (Cr, Cu, Zn and Ni) and organic matter contamination as a result of irrigation with Oued Fez and Oued Sebou waters that are affected by urban and industrial activities around the city of Fez, were studied and compared to a reference site irrigated with uncontaminated water.The study concerned soil physicochemical proprieties and the activity of a range of enzymes (phosphatase (PHOS), arylsulfatase (SULF), urease (UREA), arylamidase (AMID), β-galactosidase (GALA), glucosidase (GLUC) and laccase (LACA)) related to nutrients cycles. Pearson's correlations between these parameters showed that soil enzymatic activities (PHOS, SULF, UREA, GALA, GLUC and LACA) were correlated positively with heavy metals (Cu, Zn and Cr) concentrations in the soil and also with dissolved organic carbon (DOC) and negatively with the aromaticity (AROM) of these compounds. Interestingly, analysis of intra-site correlations showed strong relationships among enzyme activities in the reference soil, while in contaminated soils these activities were largely unrelated to each other.It was concluded that soil irrigation with heavy metal and organic matter contaminated watercourses over decades has resulted in soils with high enzymatic activities function and nutrient turnover but altered relationships among geochemical cycles

Evaluation of the environmental and human health risk related to metallic contamination in agricultural soils in the Mediterranean semi arid area (Saiss plain, Morocco)

International audienceIn the plain of Saiss, the most agricultural region of Morocco, the studies concerning the assessment of environmental and human risks related to metal contamination of agricultural soils are severely missing. To overcome the lack of such studies, trace-element analyses were carried out on six sampling sites of agricultural surface soils (66 sampling points), irrigated by superficial watercourses with high heavy metal contents. The average trace-element contents were 78, 55, 33, and 119 (mg kg−1), respectively, for Cr, Cu, Ni, and Zn. These values are above average worldwide soil and geochemical background levels. Multivariate statistical analyses, principal component, and cluster analyses suggest that soil contamination by Cr, Cu, and Zn is mainly due to wastewater irrigation, with the exception of Ni, which is probably of pedo-lithogenic origin. To provide further information on contamination transmission, the bioavailability and distribution of the four heavy metals in the soils were studied by sequential and single extractions. The results indicate that Cu and Zn are potentially available and can constitute a potential risk to the environment. The risk assessment of soil contamination was also carried out using risk assessment code, enrichment factor, contamination factor, degree of contamination, pollution lead index, geoaccumulation index, and potential ecological risk factors. The health risk evaluation by the Hazard Index was used to derive a combined risk of soil ingestion, dermal contact, and inhalation for adults and children. According to these indices, the soils present a moderate-to-high contamination for Cu and Zn elements, respectively. Hazard Index values indicate the relative absence of health risks associated to heavy metals for both adults and children