猪戊型肝炎病毒检测技术的研究进展

猪戊型肝炎是一种新的人畜共患病,其病原戊型肝炎病毒(hepatitis E virus,HEV)是无囊膜的RNA病毒,主要通过消化道进行传播。研究发现,世界上许多国家的猪群中普遍存在HEV抗体及猪戊型肝炎病毒RNA携带。与患病猪群密切接触、食用未煮熟的猪肉或猪肉制品、被污染的水源及水产品,这些因素都可增加戊型肝炎的患病风险。猪作为戊型肝炎病毒的宿主,不仅对公共卫生和食品安全构成威胁,同时对人类戊型肝炎流行病学有很大的影响。本文简要介绍了HEV的病原学以及抗原抗体检测方法,包括血清学、免疫学及分子生物学方法等,并对国内外开展的戊型肝炎检测技术的研究进展进行综述。     

戊型肝炎病毒食源性传播研究进展

戊型肝炎病毒（HEV）是一种全球性食源性病原体,猪、牛、兔、骆驼等多种动物均可成为其宿主。人类直接接触受HEV感染的猪和其他动物,或食用受污染的食物（未加工或未煮熟）均有感染该病毒的风险。本文综述了HEV的病原学、流行病学特征和在动物中的流行情况,以及对肉类及其制品、水生环境、水产品和蔬菜等作物的污染情况,可进一步了解HEV食源性传播风险,为预防和控制戊型肝炎的流行提供科学依据。     

Presence of hepatitis E virus in a naturally infected swine herd from nursery to slaughter

Hepatitis E virus has recently been recognized as having zoonotic potential and could be transmitted from pig to human. Pigs are identified as a potential animal reservoir and HEV is highly prevalent in the swine population around the world. In this study, the presence of HEV was investigated in 51 subjects reared on a simulated commercial farm setting from the age of 2 weeks up to slaughter. Samples were collected on four occasions: at 2, 8, and 18 weeks and between 22-29 weeks of age. Anti-HEV IgG in plasma samples, presence of HEV RNA in plasma samples and feces were monitored. At 2 weeks of age, HEV RNA was detected in feces of 6 subjects (11.8%) but not in their plasma. At 8 weeks, HEV was detected in feces of 27 subjects (52.9%) and in plasma of one subject. At 18 weeks, HEV was detected in feces of 44 subjects (86.2%) and in plasma of 24 subjects (47.1%). At slaughter time (22-29 weeks), HEV was present in plasma of 6 subjects (11.8%) and in stools of 21 subjects (41.2%). Spread of the virus inside the population was evaluated by comparison of means (paired t-test, P<0.05) of anti-HEV IgG ELISA results from the 4 bleedings. Significant differences were noted between the results of populations at 8 and 18 weeks and also between 18 and 22 to 29 weeks indicating an immune response to the virus. Based on the comparison of a 304 nucleotides sequence of the 5' ORF 2 gene, all amplified fragments clustered in genotype 3a.     

固废填埋厂对环境的影响及治理措施探析

本文从固废的概念出发,结合固废污染现状和目前国内垃圾填埋厂的现状分析,对垃圾分类、全过程全寿命管理、加强填埋场运行管理和污染控制、做好填埋的绿化覆盖等治理措施进行了初步探析,希望对相关的工作者有所帮助.     

热环境下人体局部皮肤湿敏感性的分布特征

为研究在热环境下人体局部皮肤湿敏感性的分布特征,以及客观物理湿度与人体主观湿感觉之间的关系,采用弹性针织面料制作贴体连身实验服,在人工气候舱(温度为(30±1) ℃,相对湿度为(35±1)%)内,6位女性受试者穿着实验服以5 km/h的速度在跑步机上步行运动,记录受试者在实验过程中的客观生理数据和主观评价数据。结果表明:热环境中人体皮肤湿敏感性呈现局部分布特征,高敏感区为上额、前胸、下背,中敏感区为上臂、前腹、上背、小臂、臀部,低敏感区为小腿和大腿;实验证实了皮肤的湿度感知随着物理湿润度的提高而增强,湿度感知与物理湿润度存在正相关关系。     

The distribution of lactococcal bacteriophage in the environment of a cheese manufacturing plant

Survival of starter bacteria and their bacteriophages following spray irrigation of whey in the vicinity of a cheese plant was investigated. Phage in environmental samples that attacked starter strains used in the plant were detected infrequently in water, but persisted for up to six weeks in the soil. Enrichment of cow dung, grass and trough water samples was required to detect phage, indicating their presence at low levels. No starter bacteria could be re-isolated from grass samples from whey irrigated pasture. Inside the plant, whey contained the largest numbers of phage and when released into the environment (via irrigation practices) contributed to the recycling of phages through the plant. It did not, however, appear to be the initial source for starter infection by ‘new’ phage. The detection of phages in the bulk raw milk that were not active on starter strains that were being used in the plant, reemphasized raw milk as a potential source of new phage.     

Distribution and trophic transfer of short-chain chlorinated paraffins in an aquatic ecosystem receiving effluents from a sewage treatment plant

Short-chain chlorinated paraffins (SCCPs) are an extremely complex group of industrial chemicals and found to be potential persistent organic pollutants (POPs), and thus have attracted extensive concern worldwide. In this study, influent, effluent, and sludge were collected from a large sewage treatment plant (STP) in Beijing, China. Water, sediment, and aquatic species were also collected from a recipient lake that receives effluents discharged from the STP. These samples were then analyzed to investigate the effect of STP effluent on distribution and trophic transfer of SCCPs in the local aquatic ecosystem. Concentrations of total SCCPs (ΣSCCPs) in lake water and surface sediments were found in the range 162-176 ng/L and 1.1-8.7 μg/g (dry weight, dw), respectively. Vertical concentration profiles of sediment cores showed ΣSCCPs decreased exponentially with increasing depth. Specific congener composition analysis in sediment layers indicated possible in situ biodegradation might be occurring. High bioaccumulation of SCCPs was observed in the sampled aquatic species. The bioaccumulation factor (BAF) generally increased with the number of chlorines in the SCCP congeners. A significantly positive correlation between lipid-normalized ΣSCCPs concentration and trophic levels (R(2) = 0.65, p < 0.05) indicate that SCCPs can biomagnify through the food chain in the effluent-receiving aquatic ecosystem.     

High pressure processing inactivates human cytomegalovirus and hepatitis A virus while preserving macronutrients and native lactoferrin in human milk

The effect of high pressure processing (HPP) compared to Holder pasteurization (HoP) (62.5 °C, 30 min), on the inactivation of cytomegalovirus (CMV) and hepatitis A virus (HAV) inoculated human milk pools (n = 10) and culture media (n = 3) was studied. Samples were retained as untreated controls, treated by HoP (62.5 °C, 30 min) or with one of six different HPP protocols (350 MPa, 500 MPa, 600 MPa for 8- or 10-min at <10 °C). Macronutrient concentration and lactoferrin were measured to confirm milk quality. Both HPP and HoP reduced CMV by >4.8-log PFU/mL and >0.9-log PFU/mL in culture medium and human milk, respectively. HoP reduced HAV by 3.4-log PFU/mL and 3.1-log PFU/mL in culture medium and human milk, respectively. HPP treatments of 500 or 600 MPa reduced HAV by >5.7-log PFU/mL and >4-log PFU/mL in culture medium and in human milk, respectively. Macronutrients (fat, total protein, carbohydrate) and energy composition was not affected by any treatment. Lactoferrin concentration decreased by 35% ± 21% (SD) after HoP, but not HPP.Industrial relevanceThis study confirms that HPP is effective in inactivating representative enveloped and non-enveloped viruses in human milk and reducing bacterial load, with no adverse effect on macronutrient and energy composition. For these reasons, evidence it reduces bacteria, and increased efficiency in which milk can be processed, HPP shows great promise in replacing HoP in human milk banking.     

Inactivation of infectious hepatitis E virus present in commercial pig livers sold in local grocery stores in the United States

Hepatitis E virus (HEV) is a zoonotic pathogen and pigs are a known reservoir. Recently we showed that approximately 11% of commercial pig livers sold in local U.S. grocery stores for food consumptions are contaminated by infectious HEV. In this study, a swine bioassay was used to determine if the infectious HEV in contaminated commercial pig livers could be inactivated by traditional cooking methods. Group 1 pigs (n=5) were each inoculated intravenously (i.v.) with a HEV-negative liver homogenate as negative controls, group 2 pigs (n=5) were each inoculated i.v. with a pool of two HEV-positive pig liver homogenates as positive controls, groups 3, 4 and 5 pigs (n=5, each group) were each inoculated i.v. with a pool of homogenates of two HEV-positive livers incubated at 56 degrees C for 1 h, stir-fried at 191 degrees C (internal temperature of 71 degrees C) for 5 min or boiled in water for 5 min, respectively. As expected, the group 2 positive control pigs all became infected whereas the group 1 negative control pigs remained negative. Four of the five pigs inoculated with HEV-positive liver homogenates incubated at 56 degrees C for 1 h also became infected. However, pigs in groups 4 and 5 did not become infected. The results indicated that HEV in contaminated commercial pig livers can be effectively inactivated if cooked properly, although incubation at 56 degrees C for 1 h cannot inactivate the virus. Thus, to reduce the risk of food-borne HEV transmission, pig livers must be thoroughly cooked.     

Inactivation of hepatitis A virus,poliovirus and a norovirus surrogate by high pressure processing

Hepatitis A virus (HAV), feline calicivirus (FCV, a surrogate for non-culturable norovirus), and poliovirus (PV), suspended in buffered cell culture media, were treated with pressures ranging from 200 to 600 MPa at ambient temperature for between 30 and 600 s. HAV was inactivated by > 1-log₁₀ tissue culture infectious dose 50% mL^− 1 (TCID₅₀ mL^− 1) and > 2-log₁₀ TCID₅₀ mL^− 1 after 600 s treatment with 300 and 400 MPa, respectively, and was undetectable (> 3.5-log₁₀ TCID₅₀ mL^− 1 reduction) within 300 s treatment with 500 MPa. FCV was inactivated by 3.6-log₁₀ TCID₅₀ mL^− 1 after 120 s treatment with 300 MPa, and was undetectable after 180 s treatment with 300 MPa. PV was the most resistant with little or no substantial reduction in titre after 300 s treatment with 600 MPa. The studies were designed to determine the efficacy of using high pressure to inactivate enteric viruses and generate inactivation data to assist in determining appropriate process criteria for safe shellfish production.Industrial relevanceThe high pressure treatment of raw oysters has proved commercially successful, due in part to a marked increase in the product’s shelf life, yet little alteration of its organoleptic properties. Illnesses from human enteric viruses such as hepatitis A virus and norovirus have traditionally been associated with shellfish consumption, and for this reason, studies have examined the stability of enteric viruses under high pressure. However, kinetic data on enteric virus stability under pressure is needed by processors to better understand the response of viruses throughout the entire treatment time. The kinetic data obtained in this study may be useful for processors wishing to alter high pressure processing conditions to ensure a high quality product in terms of organoleptic and microbiological properties.     

2014~2016年景洪市食品、公共场所 从业人员甲、戊肝调查分析

目的 分析景洪市2014~2016年食品、公共场所从业人员健康体检中甲肝、戊肝的结果, 为食品、公共场所从业人员健康体检工作的可持续发展提供数据支持。方法 对景洪市2014~2016食品、公共场所从业人员健康体检中戊型肝炎、甲型肝炎的检出率进行分析, 采用SPSS17.0进行?2检验。结果 2014~2016年食品、公共场所从业人员健康体检共检15897人, 总合格率99%。景洪市食品、公共场所从业人员甲型肝炎、戊型肝炎总体发病率呈下降趋势。其中, 甲型肝炎男性高发于女性; 戊型肝炎女性高发于男性; 甲型肝炎在公共场所行业高发于食品行业; 戊型肝炎阳性率无差异。结论 本市对于食品、公共场所从业人员的监管力度加强, 能够对感染源形成有效控制。     

UV light inactivation of hepatitis A virus, Aichi virus, and feline calicivirus on strawberries, green onions, and lettuce

A majority of illnesses caused by foodborne viruses are associated with fresh produce. Fruits and vegetables may be considered high-risk foods, as they are often consumed raw without a specific inactivation step. Therefore, there is a need to evaluate nonthermal treatments for the inactivation of foodborne pathogens. This study investigates the UV inactivation of three viruses: feline calicivirus (a surrogate for norovirus), and two picornaviruses, hepatitis A virus and Aichi virus. Three produce types were selected for their different surface topographies and association with outbreaks. Green onions, lettuce, and strawberries were individually spot inoculated with 10(7) to 10(9) 50% tissue culture infective doses (TCID50) of each virus per ml and exposed to UV light at various doses (< or = 240 mW s/cm2), and viruses were eluted using an optimized recovery strategy. Virus infection was quantified by TCID50 in mammalian cell culture and compared with untreated recovered virus. UV light applied to contaminated lettuce resulted in inactivation of 4.5 to 4.6 log TCID50/ml; for contaminated green onions, inactivation ranged from 2.5 to 5.6 log TCID50/ml; and for contaminated strawberries, inactivation ranged from 1.9 to 2.6 log TCID50/ml for the three viruses tested. UV light inactivation on the surface of lettuce is more effective than inactivation on the other two produce items. Consistently, the lowest results were observed in the inactivation of viruses on strawberries. No significant differences (P > 0.05) for virus inactivation were observed among the three doses applied (40, 120, and 240 mW s/cm2) on the produce, with the exception of hepatitis A virus and Aichi virus inactivation on green onions, where inactivation continued at 120 mW s/cm2 (P < 0.05).     

Distribution of perfluorooctane sulfonate and other perfluorochemicals in the ambient environment around a manufacturing facility in China

Perfluorinated compounds (PFCs) can be released to the surrounding environment during manufacturing and usage of PFC containing products, which are considered as main direct sources of PFCs in the environment. This study evaluates the release of perfluorooctane sulfonate (PFOS) and other PFCs to the ambient environment around a manufacturing plant. Among the nine PFCs analyzed, only PFOS, perfluorooctanoic acid (PFOA), and perfluorohexane sulfonate (PFHxS) were found in dust, water, soil, and chicken eggs. Very high concentrations of PFOS and PFOA were found in dust from the production storage, raw material stock room, and sulfonation workshop in the manufacturing facility, with the highest value at 4962 μg/g (dry weight) for PFOS and 160 μg/g for PFOA. A decreasing trend of the three PFCs concentrations in soils, water, and chicken eggs with increasing distance from the plant was found, indicating the production site to be the primary source of PFCs in this region. Risk quotients (RQs) assessment for surface water >500 m away from the plant were less than unity. Risk assessment of PFOS using predicted no-effect concentration (PNEC, 3.23 ng/g on a logarithmic scale) indicated no immediate ecological risk of a reduction in offspring survival. PFOS concentrations in most egg samples did not exceed the benchmark concentration derived in setting a reference dose for noncancer health effects (0.025 μg/(kgxd)).     

Fate of estrogens in a municipal sewage treatment plant

The fate of the highly potent endocrine disrupters estrone (E1), 17beta-estradiol (E2), and 17alpha-ethinylestradiol (EE2) was investigated in mechanical and biological sewage treatment as well as in sewage-sludge treatment at a municipal German sewage treatment plant (STP). The main outcome of the study was that a common municipal STP with an activated sludge system for nitrification and denitrification including sludge recirculation can appreciably eliminate natural and synthetic estrogens. As a consequence, the endocrine effects of biota in the receiving waters should be significantly reduced. All estrogen concentrations decreased gradually along the treatment train. In the STP effluent, the steroid estrogen concentrations were always below the quantification limit of 1 ng/L. The elimination efficiency of the natural estrogens (E1 and E2) exceeded 98%, and EE2 was reduced by more than 90%. The natural estrogens were largely degraded biologically in the denitrifying and aerated nitrifying tanks of the activated sludge system, whereas EE2 was only degraded in the nitrifying tank. Only about 5% of the estrogens are sorbed onto digested sewage sludge. It is very likely that conjugates (glucuronides and sulfates) of the estrogens were cleaved into the parent compounds mainly in the first denitrification tank.     

Inactivation of hepatitis A virus and a calicivirus by high hydrostatic pressure

Potential application of high hydrostatic pressure processing (HPP) as a method for virus inactivation was evaluated. A 7-log10 PFU/ml hepatitis A virus (HAV) stock, in tissue culture medium, was reduced to nondetectable levels after exposure to more than 450 MPa of pressure for 5 min. Titers of HAV were reduced in a time- and pressure-dependent manner between 300 and 450 MPa. In contrast, poliovirus titer was unaffected by a 5-min treatment at 600 MPa. Dilution of HAV in seawater increased the pressure resistance of HAV, suggesting a protective effect of salts on virus inactivation. RNase protection experiments indicated that viral capsids may remain intact during pressure treatment, suggesting that inactivation was due to subtle alterations of viral capsid proteins. A 7-log10 tissue culture infectious dose for 50% of the cultures per ml of feline calicivirus, a Norwalk virus surrogate, was completely inactivated after 5-min treatments with 275 MPa or more. These data show that HAV and a Norwalk virus surrogate can be inactivated by HPP and suggest that HPP may be capable of rendering potentially contaminated raw shellfish free of infectious viruses.     

Tracking polybrominated diphenyl ether releases in a wastewater treatment plant effluent, Palo Alto, California

Polybrominated diphenyl ethers (PBDEs) are commonly used flame-retardants that are now ubiquitous environmental contaminants. Wastewater treatment plants are one source of PBDEs to the environment through their discharge of treated effluent and land application of sewage sludge. Effluent and sludge were collected and analyzed for PBDEs at a wastewater treatment plant in California. The total concentration of PBDEs ranged from 61 to 1440 microg/kg dry wt in the sludge and from 4 to 29,000 pg/L in discharged effluent. The congeners with the highest abundance in sludge were BDE-47, BDE-99, and BDE-209, while in treated effluent BDE-47 and BDE-99 were the most abundant. BDE-47 and BDE-99 are major congeners of the penta-formulation, while BDE-209 composes the deca-formulation. The sum of the major congeners in the penta-formulation (BDE-47, 99, 100, 153, and 154) comprises 88% of the total PBDEs in the effluent, while BDE-209 is only 6%. Based on the loading analysis, the total PBDE concentrations loaded to the San Francisco Estuary through effluent discharge from this wastewater treatment plant is 2 lb/year (0.9 kg/year).