Indoor airborne infection

Airborne infection from person to person is an indoor phenomenon. The infectious organisms are atomized by coughing, sneezing, singing, and even talking. The smallest droplets evaporate to droplet nuclei and disperse rapidly and randomly throughout the air of enclosed spaces. Droplet nuclei have negligible settling velocity and travel wherever the air goes. Outdoors, dilution is so rapid that the chance of inhaling an infectious droplet nucleus is minimal. Measles and other childhood contagions, the common respiratory virus infections, pulmonary tuberculosis, and Legionnaires' Disease are typically air-borne indoors. In analyzing a measles outbreak, the probability that a susceptible person would breathe a randomly distributed quantum of airborne infection during one generation of an outbreak was expressed mathematically. Estimates of the rate of production of infectious droplet nuclei ranged between 93 and 8 per min, and the concentration in the air produced by the index case was about 1 quantum per 5 m³ of air. Infectious airborne particles are thus few and far between. Control of indoor airborne infection can be approached through immunization, therapeutic medication, and air disinfection with ultraviolet radiation.     

A review of virus and protein sorption by ion exchange resins

This paper reviews the use of ion exchange resins for adsorbing proteins and viruses and for purifying viral suspensions. The analysis of resin performance under different conditions provides some information on the fundamental nature of virus/protein-resin interaction.A variety of systems are considered and the influence of factors such as resin type, resin pretreatment, chemical characteristics of the solution and virus type on adsorption are discussed and compared. Analogies are made between virus-host and virus-resin interactions, both of which are specific to the virus-host or virus-resin pair. Consideration is given to the use of proteins as models for virus adsorption. The use of viral parameters such as iso-electric point and the amino acid content of the protein coat for predicting virus adsorption behavior is also discussed. Anion exchange resins were found to be more effective virus sorbents than cation exchange resins. Cation exchange resins were ineffective in low ionic strength media, while anion exchange resins were most effective in low ionic strength media.     

Application of enteric viruses for fecal pollution source tracking in environmental waters

Microbial source tracking (MST) tools are used to identify sources of fecal pollution for accurately assessing public health risk and implementing best management practices (BMPs). This review focuses on the potential of enteric viruses for MST applications. Following host infection, enteric viruses replicate and are excreted in high numbers in the hosts' feces and urine. Due to the specificity in host infection, enteric viruses have been considered one of the most accurate library-independent culture-independent MST tools. In an assessment of molecular viral assays based on sensitivity, specificity and the density of the target virus in fecal-impacted samples, human adenovirus and human polyomavirus were found to be the most promising human-specific viral markers. However, more research is needed to identify promising viral markers for livestock because of cross-reactions that were observed among livestock species or the limited number of samples tested for specificity. Other viral indicators of fecal origin, F+ RNA coliphage and pepper mild mottle virus, have also been proposed as potential targets for developing MST markers. Enhancing the utility of enteric viruses for MST applications through next generation sequencing (NGS) and virus concentration technology is discussed in the latter part of this review. The massive sequence databases generated by shotgun and gene-targeted metagenomics enable more efficient and reliable design of MST assays. Finally, recent studies revealed that alternative virus concentration methodologies may be more cost-effective than standard technologies such as 1MDS; however, improvements in the recovery efficiency and consistency are still needed. Overall, developments in metagenomic information combined with efficient concentration methodologies, as well as high host-specificity, make enteric viruses a promising tool in MST applications.     

Risk management of viral infectious diseases in wastewater reclamation and reuse: Review

Inappropriate usage of reclaimed wastewater has caused outbreaks of viral infectious diseases worldwide. International and domestic guidelines for wastewater reuse stipulate that virus infection risks are to be regulated by the multiple-barrier system, in which a wastewater treatment process composed of sequential treatment units is designed based on the pre-determined virus removal efficiency of each unit. The objectives of this review were to calculate representative values of virus removal efficiency in wastewater treatment units based on published datasets, and to identify research topics that should be further addressed for improving implementation of the multiple-barrier system. The removal efficiencies of human noroviruses, rotaviruses and enteroviruses in membrane bioreactor (MBR) and conventional activated sludge (CAS) processes were obtained by a systematic review protocol and a meta-analysis approach. The log₁₀ reduction (LR) of norovirus GII and enterovirus in MBR were 3.35 (95% confidence interval: 2.39, 4.30) and 2.71 (1.52, 3.89), respectively. The LR values of rotavirus, norovirus GI and GII in CAS processes were 0.87 (0.20, 1.53), 1.48 (0.96, 2.00) and 1.35 (0.52, 2.18), respectively. The systematic review process eliminated a substantial number of articles about virus removal in wastewater treatment because of the lack of information required for the meta-analysis. It is recommended that future publications should explicitly describe their treatment of left-censored datasets. Indicators, surrogates and methodologies appropriate for validating virus removal performance during daily operation of wastewater reclamation systems also need to be identified.     

Presence and behavior of organic pollutants in an aqueous environment surrounded by an industrialized area

Water and sediment samples in a bay surrounded by heavily industrialized areas were analyzed by a combined gas chromatography/mass spectrometry/computer system, and a number of aliphatic hydrocarbons, polycyclic aromatic hydrocarbons (PAH), and polar oxygenated compounds were found. Behavior of PAH in the bay and its surroundings was traced by gas chromatographic fingerprint by using a glass capillary column. Water and sediment, dust fall, and airborne particulate samples were used as environmental samples. It was emphatically suggested that the major origin of sedimentary PAH was airborne dust.     

Enhanced susceptibility to infection in mice after exposure to dilute exhaust from light duty diesel engines

A series of experiments was conducted in which groups of mice were first exposed for various durations to diluted exhaust from light duty diesel engines and then briefly to an infectious aerosol generated by nebulizing cultures of a bacterial pathogen (Streptococcus). Typically, postinfection mortality was significantly greater in groups exposed to exhaust than in their corresponding control groups exposed to purified air only. Data of recent diesel and of past diesel- and catalyst-treated gasoline engine exhaust experiments suggest a somewhat greater excess mortality from (enhanced susceptibility to) bacterial infection in mice exposed to diesel exhaust than in those exposed to catalytic gasoline exhaust. Limited data on acute tests of NO₂ and acrolein vapor alone suggest that the infectivity-enhancing effect of diesel exhaust could be accounted for in large part by these components. Exposures to diesel exhaust, NO₂, or acrolein did not enhance the mortality response to a viral pathogen (A/PR8-34).     

Variations of airborne and waterborne Rn-222 in houses in Maine

Concentrations of airborne radon ranging from 0.05 to 135 pCi/L were found in houses in Maine. Tracketch cups were placed in five positions for 100 houses to determine integrated average radon concentrations over the period October 1980–May 1981. To investigate the association between elevated radon concentrations in well water and the indoor airborne radon concentrations, the radon in the water supplies of these houses was measured by liquid scintillation. Monitors of airborne radon, recording in intervals of 10 min for periods of 5–7 days, were used for dynamic studies in 18 houses, determining the component of airborne radon associated with major water uses, such as showers, laundry, and dishwashing, which liberate radon in bursts. House residents kept logs noting the time of major water uses. For some of the houses, ventilation rates ranging from 0.3 to 2 air changes per hour were determined by analysis of the dynamic data. The component of airborne radon associated with water sources was found to vary inversely with ventilation rate and directly with waterborne radon concentration, with 0.8 ± 0.2 pCi Rn/L air per nCi Rn/L water at a ventilation rate of 1.0 air change per hour. The data are pertinent to a study which has revealed significant correlations between county averages, from the National Cancer Institute, or age-adjusted cancer mortality rates in Maine and average values of radon concentrations in water for the counties.     

Viruses in wastewater aerosols

Agricultural land application of wastewater is becoming a widely used means of dealing with water scarcity and diminishing sources of unpolluted water. One of the most common forms of land application—sprinkler irrigation—poses an environmental problems in that it created wastewater aerosols. Air sampling experiments done at distances of up to 100 meters from wastewater irrigation sprinklers have detected several airborne enteroviruses: echovirus 1, 25, 29; poliovirus II, and coxsackie B1. The levels of airborne viruses found in wastewater aerosols may be potentially hazardous at any level. Since the impact of these findings on public health is not clear, epidemiological investigations by standard techniques should be conducted. It is estimated that the number of viruses isolated in environmental samples may be smaller by one or two orders of magnitude (90%–99%) than their actual number due to the limitations of virus recovery procedures. The unvailability of a reliable indicator microorganism which fulfills all the requirements for a biological indicator also makes it difficult to determine the virus level in the aerosols. Thus the scientific knowledge available today is insufficient to determine with certainty that no public health risk is created by wastewater aerosols. A comprehensive prospective study will, in all likelihood, provide answers to most questions and make it possible to assess more reliably the extent of the health risk due to wastewater aerosols.     

Volumetric assessment of airborne fungi in two sections of a rural indoor dairy cattle shed

There is increasing concern about the exposure to fungal aerosols in occupational environments and associated respiratory allergic diseases and asthma. A large number of people work in cattle sheds around the world, pulmonary function impairments and higher frequency of respiratory symptoms have been reported in dairy farmers; however, it appears that adequate information on the fungal aerosols from the cattle sheds are largely lacking. Volumetric assessment of airborne culturable and nonculturable fungal spores was performed in two sections of a large rural indoor cattle shed of West Bengal, India for 2 consecutive years. An Andersen Two Stage Viable Sampler was used for sampling culturable fungi and a Burkard Personal Slide Sampler was used to collect the total airborne fungal spores including both the culturable and nonculturable types. A total of 31 spore types and 35 types of viable colony-forming units were recorded. Average concentration range of total fungal spores was 233-2985/m(3) and concentration of viable colony-forming units ranged between 165 and 2225 CFU/m(3). Burkard Sampler showed higher frequencies of Aspergilli/Penicilli, Cladosporium, Alternaria, and smut spores. Andersen Sampler showed the prevalence of Aspergillus niger, Aspergillus flavus and Cladosporium cladosporioides colonies. Some recorded fungi were earlier reported as allergenic, toxic, and pathogenic for occupational workers as well as cattle population. Higher concentration levels of airborne total and culturable fungal spores were recorded during the months of November through February (winter) and June through September (late summer and rainy season).     

The response of gypsy moth (<Emphasis Type="Italic">Lymantria dispar</Emphasis> L.) larvae infected with nuclear polyhedrosis virus to induced resistance in birch (<Emphasis Type="Italic">Betula pendula</Emphasis> Roth.)

The effects of birch resistance induced by its artificial defoliation on the development of gypsy moth larvae and their sensitivity to viral infection and on the state of the antioxidant and detoxification systems of the insect midgut were studied. The dynamics of larval body weight; larval mortality and its etiology; glutathione-S-transferase (GT), nonspecific esterase (NE), and catalase (CAT) activities; and the ratio between the concentrations of oxidized and reduced thiol-containing compounds (RSSR/RSH) were estimated. In larvae feeding on the leaves of a previously defoliated plant, body weight was decreased, NE was inhibited, and the RSSR/RSH ratio was increased.     

Viruses in wastewaters

Viruses of animals, plants, and bacteria abound in sewage and receiving waters. Their ecological impact has, for the most part, gone unheeded except as it relates to viruses from human sources. Viruses present at levels infective to man have been recovered from waters used for recreational or drinking purposes. Their presence in a water environment virtually always denotes prior contamination by domestic wastes. Neither conventional sewage treatment processes nor the discharge to land or water of sludges produced by these processes achieve full viral control. Many environmental virologists advocate the setting of permissible virus limits for those recreational and potable waters dominated by wastewater effluents. The initiation of regulatory pressure to restrict virus discharges into these water environments has been instituted in Montgomery County, Maryland, and in the states of California and Arizona.     

Assessing the risk of wind-borne spread of foot-and-mouth disease in Australia

The effect the environment has on the spread of animal disease depends on the particular disease and can vary from being minor to being almost the sole determinant. An assessment of the risk of a particular disease outbreak and its consequences must combine the epidemiology of the disease with the variability of the environment. Foot-and-mouth disease is a highly contagious animal disease that spreads readily by close contact with infected animals and infected product. For such spread, the environment has little consequence. However, occasionally, wind-borne viral particles can spread the disease considerable distances. This paper concentrates on the methods used in a study undertaken to assess the potential for the wind-borne spread of foot-and-mouth disease under Australian conditions. The conditions suitable for the virus to persist as an aerosol, the amount of virus produced during an outbreak, and the dose-response to wind-borne virus were determined by considering the epidemiology of the disease. Environmental components considered included an analysis of weather records and livestock distribution data to identify areas at risk, and the use of a Gaussian plume model to estimate the extent of spread.     

Photodegradation characteristics of PPCPs in water with UV treatment

The degradation characteristics of PPCPs commonly found in surface water under UV treatment were examined for 30 kinds of PPCPs using a UV/Lamp1 that emits light at a wavelength of 254 nm and a UV/Lamp2 that emits light at 254 nm and 185 nm in pure water. When a UV dose of some 230 mJ/cm² was introduced to the 30 PPCPs, photodegradation rates of about > 3% (theophylline) to 100% (diclofenac) and about > 15% (clarithromycin) to 100% (diclofenac) were observed for UV/Lamp1 and UV/Lamp2, respectively. This study also showed that UV/Lamp2, which photolyzes water molecules and generates OH radicals, is more effective for PPCP removal than UV/lamp1. It was postulated that the degradation rates of sulfamethoxazole, sulfamonomethoxine, sulfadimethoxine and sulfadimidine, all, including sulfamethoxazole, derived from sulfanilamide, under UV/Lamp1 resulted mainly from the bond-breaking reactions occurring between –SO₂– and its side atoms, the C–S bond and the N–H bond. Some PPCPs with amide bonds, such as cyclophosphamide and DEET, were highly resistant to photodegradation by UV/Lamp1. AOPs (Advanced oxidation processes) such as the UV/H₂O₂ or UV/O₃ processes should therefore be considered for their potential to remove these substances effectively.     

Radiochemical analyses for environmental radiological studies at nuclear power stations

The analytical procedures used in a program of radiological monitoring studies at nuclear power stations are discussed. Samples of in-plant and effluent liquids, gases, and airborne particles were analyzed by radiochemical methods or by gamma-ray spectrometry. These procedures were modified for environmental media, including air, airborne particles, vegetation and food, milk, animal tissue, water, soil and sediment, generally by analyzing larger samples, enhancing the purification procedures, and increasing the detection sensitivity. Emphasis was placed on analyzing special samples for effluent radionuclides not routinely monitored, such as gaseous H-3, C-14, and Kr-85, and on measuring radionuclides at very low concentrations in media of possible dosimetric significance, such as radioiodine in milk. Measurements at these low levels permitted comparisons of source terms with environmental radioactivity in terms of calculational models.     

江苏省水资源短缺风险的相似云评价方法研究

为有效的监测和评估水资源短缺风险的程度,实现水资源可持续开采和利用,提出水资源短缺风险的相似云综合评价模型。针对水资源短缺风险的影响因素同时具有模糊和随机性问题,建立基于熵权和相似云方法的综合评估模型。借鉴现有理论的基础上,综合考虑风险率、脆弱性、可恢复性等5个评价指标,采用熵权法确定各个指标的权重,利用正态云模型定量描述单指标条件下待评价城市水资源的短缺风险等级。给出一种新的计算正态云模型相似度方法——基于组合模糊贴近度的正态云相似度度量方法,通过比较待评价城市与风险等级之间的熵权正态云相似度值的大小,构建基于熵权相似云的水资源短缺风险评价模型。江苏省三大流域的实例表明,该方法简单可行,结果相对客观合理,能够克服现有方法的一些缺点。     

Social preferences towards ecosystem services provided by cloud forests in the neotropics: implications for conservation strategies

Despite the importance of neotropical cloud forests as providers of ecosystem services to society, they are one of the most threatened ecosystems in the world. We analysed the importance of three cloud forest reserves in central Colombia as providers of ecosystem services, as well as the social support to conservation actions in these ecosystems through willingness to pay (WTP) and willingness to give up time (WTT) estimates. Our results highlight the high commitment of all users of the cloud forest areas towards the conservation of the ecosystem services provided by these strategic ecosystems. We found that the most important perceived ecosystem services were water supply and habitat maintenance for species. Our findings also suggest that the respondents’ ecological knowledge (measured as the awareness of the ecosystem services supplied by cloud forests) was an important factor in determining both WTP and WTT for conserving cloud forests. Moreover, our results indicate that WTT should be a viable technique to explore individual preferences of different stakeholders towards conservation activities in cloud forests. Based on our results, we propose a conservation strategy of cloud forests that considers different users’ socio-economic and environmental characteristics, in which both experimental and experiential knowledge should be incorporated in order to promote collective action.     

Determination of parabens and benzophenone-type UV filters in human placenta. First description of the existence of benzyl paraben and benzophenone-4

UV filters and parabens (PBs) are chemicals used in daily personal care and hygiene products to protect materials and humans from the adverse effects of UV radiation and to preserve the integrity of the formulation, respectively. Several studies highlight their widespread environmental occurrence and endocrine disrupting effects. However, little is known about human exposure to these compounds. The objective of this study was to investigate the exposure of human embryos and foetuses to endocrine disrupting UV filters and PBs.Placentas from volunteer mothers in Barcelona were collected at delivery after informed, written consent by the pregnant women. UV filters and parabens were analysed by liquid chromatography-tandem mass spectrometry. The excellent performance of the method allowed measuring the target compounds in human placental tissue at low ng/g fresh weight level. The detection frequency of the selected compounds was in the range 17–100%. Benzophenone-1, methyl paraben, butyl paraben and benzyl paraben were detected in all samples. The highest measured concentration corresponded to methyl paraben, 11.77 ng/g fresh weight. Reported concentrations of benzophenone-4 and benzyl paraben constitute the first evidence about their accumulation in placenta. The results obtained corroborate that foetuses are exposed to a wide diversity of UV filters and PBs via the placenta.     

Review of bioaerosols in indoor environment with special reference to sampling,analysis and control mechanisms

Several tiny organisms of various size ranges present in air are called airborne particles or bioaerosol which mainly includes live or dead fungi and bacteria, their secondary metabolites, viruses, pollens, etc. which have been related to health issues of human beings and other life stocks. Bio-terror attacks in 2001 as well as pandemic outbreak of flue due to influenza A H1N1 virus in 2009 have alarmed us about the importance of bioaerosol research. Hence characterization i.e. identification and quantification of different airborne microorganisms in various indoor environments is necessary to identify the associated risks and to establish exposure threshold. Along with the bioaerosol sampling and their analytical techniques, various literatures revealing the concentration levels of bioaerosol have been mentioned in this review thereby contributing to the knowledge of identification and quantification of bioaerosols and their different constituents in various indoor environments (both occupational and non-occupational sections). Apart from recognition of bioaerosol, developments of their control mechanisms also play an important role. Hence several control methods have also been briefly reviewed. However, several individual levels of efforts such as periodic cleaning operations, maintenance activities and proper ventilation system also serve in their best way to improve indoor air quality.     

我国棉铃虫病毒杀虫剂的研究开发和应用

棉铃虫核型多角体病毒（ＮＰｖ），从分离开始，经过实验室研究到工厂生产商品销售，至今历经了１８个春秋。是中国生防史上第一次使一种昆虫病毒的研究，从技术上的成功转变成商业上的开发成功。从１９８８～１９９３年，总共生产棉铃虫病毒杀虫剂１００ｔ，使用面积７万ｈａ，（１００多万亩）。在防治棉花、烟叶、辣椒和蕃茄等作物上的棉铃虫和烟青虫方面，均获得了有效的控制。本文主要介绍该病毒的基本特性，生产工艺和应用效果，并展望未来的前景。     

基于正态云模型和熵权的人口发展现代化程度综合评价

为有效地监测和评估人口发展现代化程度,实现人口、经济、环境协调发展,探索和构建了人口发展程度综合评价模型。针对人口发展过程中存在的模糊性和随机性问题,建立了基于正态云模型和熵权的综合评判模型。借鉴已有理论的基础上,综合考虑人口总量、人口结构等5个方面因素构建人口综合发展现代化程度指标体系,采用熵权法确定各个指标权重,借助于正态云模型定量描述单指标条件下待评价我国人口发展的等级。云模型是表示某个定性概念与定量表示之间不确定性转换的模型,它将概念的模糊性和随机性结合在一起,对解决不确定性问题具有很强的鲁棒性。采用云模型理论实现评语与评估指标值之间的不确定映射,保留了评估过程中的随机性和模糊性。最后,以2000-2009年我国10年人口发展相关指标的时间序列数据,以及2009年全国和四个直辖市的人口综合发展截面数据为例,对人口发展现代化程度进行实证检验,结果表明,该模型比传统的模糊综合法能得到更加合理的评估结果。