Anthropurgic foci of pseudotuberculosis and the mechanisms of their formation in groups of servicemen

At the period of 1982 - 2003, morbidity rate in pseudotuberculosis and the Yersinia pseudotuberculosis culture rates in groups of servicemen (from different abiotic objects, from humans and small rodents) in different geographic zones were studied. The cases of the isolation of Y. pseudotuberculosis were most frequently registered in groups of servicemen in the Far East and the Kola Peninsula. In these regions the highest morbidity rate in pseudotuberculosis was registered among servicemen. The contamination rate of vegetables during the year was always greater than in other objects under study, including small rodents. The study demonstrated that in the Armed Forces could appear, temporary and relatively constant anthropurgic foci of pseudotuberculosis even in non endemic regions. They were formed in the objects of the food supply service due to the supply of contaminated vegetables. Synanthropic rodents played a secondary role, though they too facilitated the formation of new anthropurgic foci. Under definite conditions anthropurgic foci could exist autonomously, independently of natural foci.     

Environmental pollution with soil-transmitted helminths in Sanliurfa, Turkey.

Soil transmitted helminth (STH) infection are endemic in developing countries. A study was carried out of sewage farms, streams and vegetables to determine the sources and routes of STH infection in Sanliurfa, Turkey. Stool samples from farmhouse inhabitants as well as soil and vegetable samples from the gardens were collected and examined. In addition, water samples from streams and vegetable samples from the city market were collected and examined. One hundred and eighty-seven (59.5%) of a total of 314 samples, including 88.4% of the stool samples, 60.8% of the water samples, 84.4% of the soil samples and 14% of the vegetable samples, were found to be positive for STH eggs. These results indicate that the water, soil and vegetables are heavily contaminated, and suggest a vicious circle between humans and the environment. Improving environmental sanitation is imperative for the control of soil-transmitted helminthiasis in Sanliurfa.     

Effect of common Brassica vegetables (Brussels sprouts and red cabbage) on the development of preneoplastic lesions induced by 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) in liver and colon of Fischer 344 rats

Aim of the present study was the investigation of effects of juices from commonly consumed Brassica vegetables (two cultivars of Brussels sprouts and two cultivars of red cabbage) on formation and development of preneoplastic lesions in colons (aberrant crypt foci, ACF) and livers (glutathione-S-transferase placental form, GST-P+) in male F344 rats. The foci were induced by 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), a widespread carcinogenic heterocyclic aromatic amine which is found in fried meats. Recently, we reported on pronounced protective effects in the two-organ foci model when the vegetable juices were given during the carcinogen treatment but several findings by other groups indicated that breakdown products of glucosinolates contained in Brassica vegetables cause tumour promotion in various organs of laboratory rodents. In the present study, the animals received the juices in the drinking water (5%) over a period of 20 days after treatment with IQ (100 mg/kg bw on 10 alternate days). To increase the foci yield (which facilitates the detection of modifying effects), the animals were fed with a modified (high fat, fibre free) AIN-76 diet. With exception of the sprout variety "Cyrus", all juices lowered the number of GST-P+ foci as well as the foci area in the liver, but none of these effects was statistically significant. In the colon, none of the juices had an impact on crypt multiplicity (number of crypts/focus), whereas the number of ACF was decreased; only with the sprout variety Maximus the protective effect was significant (reduction 49%). The present findings show that administration of vegetable juices to the animals after the carcinogen does not increase the number and size of IQ-induced preneoplastic lesions in liver and colon.     

福建省土壤－蔬菜系统中铬转移规律研究

调查福建省28个蔬菜品种及其土壤铬含量,研究铬在土壤－蔬菜系统中的转移规律。结果表明,供试土壤全铬含量平均值为53.61 mg·kg-1,未超过国家土壤环境质量标准中铬的限量(pH<6.5,农田旱地 <150 mg·kg-1)。供试土壤有效铬含量平均值为0.92 mg·kg-1。蔬菜可食部分铬含量0.001～0.321 mg·kg-1,调查区蔬菜样品铬含量均低于食品安全国家标准。其中,萝卜、空心菜铬含量与土壤全铬呈显著正相关。采样区大部分蔬菜铬含量与土壤有效铬之间相关性不显著。利用DPS统计软件,将蔬菜对土壤全铬和有效铬的转移能力分为高、中、低三等进行分析。根据土壤-蔬菜高、中、低转移规律可指导蔬菜的区域规划种植。     

日光温室蔬菜栽培对土壤物理质量的影响

以陕西省泾阳县云阳镇不同蔬菜种植年限日光温室的重壤质土壤为对象,以相邻露地菜田土壤为对照进行系统采样,测定了日光温室土壤的主要物理性状,研究了土壤物理质量的演变趋势.结果表明:日光温室蔬菜栽培对0～30cm土层容重的影响较大,使0～10cm土层容重增加,10～30cm土层容重减小,对30～40cm土层容重的影响甚微.日光温室土壤中<0.01mm物理性粘粒含量和<0.001mm粘粒含量在0～40cm剖面呈现上低下高的特征,两种粘粒均发生下移现象,这种现象随日光温室蔬菜栽培时间的延长而加强.日光温室蔬菜栽培的最初5年内土壤的田间持水量下降明显,降幅达13.8%,之后变化较小,相对稳定.     

Salmonella enterica serovar Typhimurium and Escherichia coli contamination of root and leaf vegetables grown in soils with incorporated bovine manure

Bovine manure, with or without added Salmonella enterica serovar Typhimurium (three strains), was incorporated into silty clay loam (SCL) and loamy sand (LS) soil beds (53- by 114-cm surface area, 17.5 cm deep) and maintained in two controlled-environment chambers. The S. enterica serovar Typhimurium inoculum was 4 to 5 log CFU/g in manure-fertilized soil. The conditions in the two environmental chambers, each containing inoculated and uninoculated beds of manure-fertilized soil, simulated daily average Madison, Wis., weather conditions (hourly temperatures, rainfall, daylight, and humidity) for a 1 March or a 1 June manure application and subsequent vegetable growing seasons ending 9 August or 28 September, respectively. Core soil samples were taken biweekly from both inoculated and uninoculated soil beds in each chamber. Radishes, arugula, and carrots were planted in soil beds, thinned, and harvested. Soils, thinned vegetables, and harvested vegetables were analyzed for S. enterica serovar Typhimurium and Escherichia coli (indigenous in manure). After the 1 March manure application, S. enterica serovar Typhimurium was detected at low levels in both soils on 31 May, but not on vegetables planted 1 May and harvested 12 July from either soil. After the 1 June manure application, S. enterica serovar Typhimurium was detected in SCL soil on 7 September and on radishes and arugula planted in SCL soil on 15 August and harvested on 27 September. In LS soil, S. enterica serovar Typhimurium died at a similar rate (P >or= 0.05) after the 1 June manure application and was less often detected on arugula and radishes harvested from this soil compared to the SCL soil. Pathogen levels on vegetables were decreased by washing. Manure application in cool (daily average maximum temperature of <10 degrees C) spring conditions is recommended to ensure that harvested vegetables are not contaminated with S. enterica serovar Typhimurium. Manure application under warmer (daily average maximum temperature >20 degrees C) summer conditions is not recommended when vegetable planting is done between the time of manure application and late summer. A late fall manure application will not increase the risk of contaminating vegetables planted the next spring, since further experiments showed that repeated freeze-thaw cycles were detrimental to the survival of S. enterica serovar Typhimurium and E. coli in manure-fertilized soil. The number of indigenous E. coli in soil was never significantly lower (P < 0.05) than that of S. enterica serovar Typhimurium, suggesting its usefulness as an indicator organism for evaluating the risk of vegetable contamination with manure-borne S. enterica serovar Typhimurium.     

Health Risk Assessment of Heavy Metals in Soils and Vegetables from a Typical Greenhouse Vegetable Production System in China

There is growing concern about food safety and environmental contamination due to potential health risks to consumers. The aims of this study are to elucidate the accumulation status, influencing factors, and potential risk of selected heavy metals in soils and vegetables from a typical greenhouse vegetable production system in China. The potential health risks of heavy metals through soil contact and vegetable consumption were evaluated for greenhouse and corresponding open field production. The results indicated that the mean concentrations of Hg, Pb, Cu, and Zn in greenhouse vegetable soils were greater than those in open field soils. Leaf vegetables had relatively higher concentrations and transfer factors of heavy metals than root and fruit vegetables, especially for Cd. The target hazard quotient of heavy metals through vegetable consumption was greater than 1 for leaf vegetables, and was also higher for greenhouse vegetables than those from open field. The risk of exposure to heavy metals through direct contact with soil and vegetable consumption was higher for children than for adults and seniors. Planting patterns with different vegetable types and soil properties can affect bioavailability and crop accumulation of heavy metals.     

Arsenic in vegetables poses a health risk in the vicinity of a mining area in the southern Hunan Province,China

The main objectives of the present study were to investigate the levels of arsenic (As) in 23 vegetable species planted on As-polluted soil and assess the human health risks of contaminated vegetable consumption. The target hazard quotient (THQ) and target cancer risk (TR) methods were employed to evaluate the human health risks posed by exposure to As through vegetable consumption. Our results indicate substantial As contamination of the experimental soil. Significant differences were detected in the concentrations of total and inorganic As in the edible parts of the various vegetables grown on contaminated soil, which were generally in the following order: leafy vegetables > stem vegetables > root vegetables > melon and fruit vegetables. The total THQ value for As due to vegetable consumption for children (4.81) was higher than that for adults (3.66), the TR values for As due to vegetable ingestion for adults (1.65 × 10^?3) and children (2.17 × 10^?3) were significantly beyond the range of acceptable risk (10-6–10-4) recommended by the US Environmental Protection Agency and the maximum acceptable risk value (5.0 × 10^?5) recommended by the International Commission on Radiation Protection, which clearly poses a dangerous health risk for residents consuming vegetables in the long-term in the study area.     

Immunologic monitoring of leptospirosis in the Maritime Territory

The epidemiological and epizootic situation in Leptospira infections at the Maritime [correction of Primorski] Territory is evaluated on the basis of complex studies carried out in 1984-1989. As revealed in these studies, cases of leptospirosis among humans have a sporadic character and are mainly registered among professional high risk groups of the population. In the immunological structure of persons covered by the survey L. hebdomadis, L. pomona and L. javanica prevail. The anthropourgic foci of leptospirosis caused by L. pomona are of the leading epidemiological importance. Swine serves as the main source of infection in these foci. The study revealed the epidemic danger of the natural foci of leptospirosis caused by L. grippotyphosa and L. javanica in rice fields where the decisive factors of leptospirosis proved to be reed voles and striped field mice serving as reservoirs of this infection, as well as the synanthropic foci of leptospirosis caused by L. hebdomadis with house mice serving as the main carriers.     

Ecological risk assessment of toxic elements,microbial loads,parasites and antinutritional factors in Telfairia occidentalis grown on sewage contaminated soil

The aim of this study was to evaluate the ecological health risk assessment of toxic elements, microbial load, and anti-nutrient constituent build-up in vegetables, Talfairia occidentalis, grown on sewage contaminated soil. Samples of soil and vegetables were taken from farms near the dumpsites (sites A). As a control, samples were taken from an area with no dump sites (sites B). Atomic Absorption Spectrophotometry was used to determine the potentially toxic elements. The basic titrimetric method was used to estimate Phytate and Oxalate in the vegetables in order to assess anti-nutrient constituents. The content of cyanogenic glycosides, tannins, and alkaloids in vegetable samples was determine using a standard method. Total heterotrophic bacteria, E. coli, total coliform, faecal coliform, Staphylococcus aureus, Salmonella, and intestinal parasites were all determined using APHA standard methods. For all samples analyzed, the concentrations of metals – Cr, Zn, Pb, Cu, and Ni in site A were higher than those in site B. The soil and vegetable samples differed from the controls by a significant amount (P <0.05). Vegetable samples from site A were mainly infected with faecal coliform TO (9.7 × 10⁵cfu/g) and other bacteria at levels higher than the recommended levels. In contrast to samples from site B, which were not infected with human intestinal helminth parasites, Ascaris lumbricoides ova and Entamoeba histolytica cryst were present in vegetables in site A samples. The majority of the values obtained for the sewage dumpsite were significantly higher than the values recorded by the World Health Organization (WHO). However, sewage wastes, anthropogenic sources, and atmospheric depositions cause higher concentrations of heavy metals, anti-nutrients, and microbial load around dumpsites, which bioaccumulate in vegetables through uptake from the soil and eventual entry into the food chain. The overall evaluation found that consumption of vegetables grown on sewage soil poses a risk of heavy metals, microbial loads, and anti-nutrients adversely affecting human health.     

Grigor'ev-Shiga dysentery: a new epidemic threat. Its global tendencies and features of its spread

In this article, based on the data contained in literature, the development of the pandemic of Grigor'ev-Shiga dysentery, which began in 1960-ies, is followed. The stages of the formation of three powerful hyperpandemic foci in Central America, South-East Asia and Central Africa are characterized. The characterization of the epidemiological features of the spread of this disease and its clinical distinction are presented. The biological properties of the causative agent, and in particular its multiple medicinal resistance facilitating the spread of the disease throughout the world, is considered. The stable character of the foci of infection in developing countries, which actually present a threat also for this country, is pointed out. For this reason, the epidemiological surveillance on Grigor'ev-Shiga dysentery should be drastically strengthened.     

大气和土壤对蔬菜汞的贡献

通过田间观测和盆栽试验 ,研究了蔬菜富集Hg的特性及土壤、大气对蔬菜Hg的贡献 .对田间 11种蔬菜的研究发现 ,蔬菜根和叶的含Hg浓度高于茎和果 ;在自然条件下 ,蔬菜所吸收的Hg 6 0 %以上分布于地上部的可食部分 .盆栽试验结果表明 ,在气Hg浓度为 5 7 6± 14 7ng·m-3 条件下 ,红萝卜、莴苣叶 (可食部分 )的含Hg浓度超过了食品卫生标准 ;气Hg、土壤Hg对蔬菜Hg的贡献率分别为 70 4 %～ 90 7%和9 3%～ 2 9 6 % ,气Hg较土壤Hg是蔬菜更为重要的Hg源     

基于转移方程的蔬菜镉累积预测和土壤风险阈值推导

重金属镉(Cd)在土壤-蔬菜系统中转移方程的建立是农田Cd污染控制和风险评估的关键.本研究通过调查湖南省攸县745个土壤-蔬菜样品Cd含量,应用转移方程、敏感性分布曲线(SSD)和多元回归方法分析不同类别蔬菜Cd累积特征和影响因素,预测不同土壤条件下蔬菜Cd含量并推导相应土壤Cd风险阈值.结果表明: 叶菜对Cd胁迫较根菜敏感;土壤pH、土壤总Cd和土壤有机质(SOM)是影响蔬菜Cd富集的3个主要因子;转移方程对叶菜和根菜的解释程度分别为54.2%和69.1%.土壤Cd风险阈值随土壤pH和SOM的增加而增加,根菜在严重酸化土壤区Cd累积风险较高.当前国家土壤环境质量标准对于严重酸化、有机质含量较低的土壤过于宽泛.     

Salmonella enterica Serovar Typhimurium and Escherichia coli Contamination of Root and Leaf Vegetables Grown in Soils with Incorporated Bovine Manure

Bovine manure, with or without added Salmonella enterica serovar Typhimurium (three strains), was incorporated into silty clay loam (SCL) and loamy sand (LS) soil beds (53- by 114-cm surface area, 17.5 cm deep) and maintained in two controlled-environment chambers. The S. enterica serovar Typhimurium inoculum was 4 to 5 log CFU/g in manure-fertilized soil. The conditions in the two environmental chambers, each containing inoculated and uninoculated beds of manure-fertilized soil, simulated daily average Madison, Wis., weather conditions (hourly temperatures, rainfall, daylight, and humidity) for a 1 March or a 1 June manure application and subsequent vegetable growing seasons ending 9 August or 28 September, respectively. Core soil samples were taken biweekly from both inoculated and uninoculated soil beds in each chamber. Radishes, arugula, and carrots were planted in soil beds, thinned, and harvested. Soils, thinned vegetables, and harvested vegetables were analyzed for S. enterica serovar Typhimurium and Escherichia coli (indigenous in manure). After the 1 March manure application, S. enterica serovar Typhimurium was detected at low levels in both soils on 31 May, but not on vegetables planted 1 May and harvested 12 July from either soil. After the 1 June manure application, S. enterica serovar Typhimurium was detected in SCL soil on 7 September and on radishes and arugula planted in SCL soil on 15 August and harvested on 27 September. In LS soil, S. enterica serovar Typhimurium died at a similar rate (P ≥ 0.05) after the 1 June manure application and was less often detected on arugula and radishes harvested from this soil compared to the SCL soil. Pathogen levels on vegetables were decreased by washing. Manure application in cool (daily average maximum temperature of <10°C) spring conditions is recommended to ensure that harvested vegetables are not contaminated with S. enterica serovar Typhimurium. Manure application under warmer (daily average maximum temperature >20°C) summer conditions is not recommended when vegetable planting is done between the time of manure application and late summer. A late fall manure application will not increase the risk of contaminating vegetables planted the next spring, since further experiments showed that repeated freeze-thaw cycles were detrimental to the survival of S. enterica serovar Typhimurium and E. coli in manure-fertilized soil. The number of indigenous E. coli in soil was never significantly lower (P < 0.05) than that of S. enterica serovar Typhimurium, suggesting its usefulness as an indicator organism for evaluating the risk of vegetable contamination with manure-borne S. enterica serovar Typhimurium.     

Complex method for epizootiological and epidemiological surveillance

A complex method for the epizootological and epidemiological surveillance of a number of bacterial and viral infections on the territories inside and outside their natural foci has been developed. The investigation techniques are described and the data on the isolation rate of each causative agent in different geographical zones are presented. In the natural foci of plague and tularemia, as well as on the territories outside such foci, the causative agents of intestinal yersiniosis, pseudotuberculosis, salmonellosis, erysipeloid, staphylococci and streptococci, arena- and arboviruses have been isolated from the rodents and ectoparasites under study. The results of this investigation suggest that the method may be recommended for use in medical institutions dealing with the problems of infections originating from natural foci.     

Prevalence of <Emphasis Type="Italic">Borrelia burgdorferi</Emphasis> sensu lato in rodents from Gansu,northwestern China

Background  

Lyme disease is a multi-organ infection disease caused by Borrelia burgdorferi sensu lato. Lyme disease was first documented in north-east China in 1986. Since then more than 20 provinces in China were confirmed the existence of nature foci of Lyme disease. In the present study, a molecular epidemiological survey was conducted to investigate the presence of Borrelia burgdorferi sensu lato in rodents from Gansu Province for the first time.     

Transfer of Cadmium from Soil to Vegetable in the Pearl River Delta area,South China

The purpose of this study was to investigate the regional Cadmium (Cd) concentration levels in soils and in leaf vegetables across the Pearl River Delta (PRD) area; and reveal the transfer characteristics of Cadmium (Cd) from soils to leaf vegetable species on a regional scale. 170 paired vegetables and corresponding surface soil samples in the study area were collected for calculating the transfer factors of Cadmium (Cd) from soils to vegetables. This investigation revealed that in the study area Cd concentration in soils was lower (mean value 0.158 mg kg⁻¹) compared with other countries or regions. The Cd-contaminated areas are mainly located in west areas of the Pearl River Delta. Cd concentrations in all vegetables were lower than the national standard of Safe vegetables (0.2 mg kg⁻¹). 88% of vegetable samples met the standard of No-Polluted vegetables (0.05 mg kg⁻¹). The Cd concentration in vegetables was mainly influenced by the interactions of total Cd concentration in soils, soil pH and vegetable species. The fit lines of soil-to-plant transfer factors and total Cd concentration in soils for various vegetable species were best described by the exponential equation (), and these fit lines can be divided into two parts, including the sharply decrease part with a large error range, and the slowly decrease part with a low error range, according to the gradual increasing of total Cd concentrations in soils.     

Everyday contact spread of viral hepatitis B

The results obtained in the study of the characteristic features of the spread of viral hepatitis B under the conditions of family foci are presented. Children with viral hepatitis B have been found to infect 4-5 persons per 1,000 contacts, while adults infect not more than 1 person per 1,000 contacts. The results of the study have led to the conclusion that the idea of the potential danger of hepatitis B patients as the source of infection depends on the forms of the infectious process taken into account in evaluating its epidemiological significance. Latent cases of hepatitis B virus infection appear more frequently among the contacts of sick children than among those of sick adults, but the manifest forms of the disease are more frequently caused by infection contacted from sick adults.     

Cadmium Pollution and its Transfer in Agricultural Systems in the Suburbs of Tianjin,China

Cadmium (Cd) pollution in the suburbs of Tianjin, China, was monitored over a period of several years. During this period, 193 soil, 120 vegetable, and 71 rice samples from four suburban districts were analyzed. The Cd content of the soil samples was considerably higher than the background level. Some soil samples from the Dongli and Xiqing districts were even in the S5 (Heavy) and S6 (Severe) pollution levels, with a maximum concentration of 5.20 mg kg^?1. The Cd contents of vegetable and rice samples were found to be in the F3 (Intermediate) and F4 (Heavy) pollution levels. Vegetables showed differing abilities to accumulate Cd and can be ranked in the following order: leaf vegetables > rootstalk vegetables > fruit vegetables. The average Cd level in different vegetables ranged from 0.0064 to 0.132 mg kg^?1, and a positive relationship (p < 0.05) was found between soil and plant Cd contents. Chinese cabbage and celery were more likely to pose risks to human health, as shown by their higher hazardous quotient (HQ) values. The soil Cd pollution in Tianjin seemed primarily to be caused by wastewater irrigation and the application of sewage sludge to farmlands. Other possible sources include the use of phosphate fertilizer and atmospheric deposition.     

Epidemiological significance of carriers of hyaluronidase-active meningococci

To find out the epidemiological role of the carriers of hyaluronidase-positive meningococcal strains, their spread in the foci of meningococcal infection, as well as outside these foci, was studied. For this purpose, altogether 5059 persons from 40 family foci of infection and 40 organized groups were examined. The number of carriers of hyaluronidase-active meningococci, detected among those of them who had contacts with sick persons, was 13 times greater than among the persons having no such contacts. In preschool institutions with unfavorable morbidity situation this number was 16 times greater than in those with favorable situation. In the family foci carriers of hyaluronidase-active meningococci constituted 80-88 %. The percentage of the carriers of hyaluronidase-active meningococci causing cases of the generalized form of meningococcal infection varied in different groups. According to the results obtained in this study, the threshold percentage of such carriers constituted 30 in preschool institutions, 36 in boarding schools and 50 in common school and in hostels for adults.