Home hygiene: a risk approach

The need to place "prevention through hygiene" at the core of strategies for infection prevention has been emphasised by recent events. Indications are that re-evaluation of current practice and the promotion of improved hygiene in the domestic setting could have a significant impact in reducing infectious disease. If the public are to play a part however they must be properly informed. Encouraging the concept of the home as a setting in which the whole range of activities occur, including food hygiene, personal hygiene and hygiene related to medical care, provides the opportunity for a rational approach to home hygiene based on risk assessment. In the home surfaces (including hand surfaces) and other sites play an important part in the transmission of infection, especially food-borne infections. From an assessment of the frequency of occurrence of pathogens and potential pathogens at reservoirs, disseminators and hand and food contact sites together with the potential for transfer within the home, the risks of exposure can be assessed. This can be used to develop a rational approach in which effective hygiene procedures involving cleaning and disinfection as appropriate are targeted at these sites to reduce risks of cross contamination. This approach is consistent with the view that good home hygiene is not about "getting rid of household germs" but about targeting hygiene measures appropriately to reduce exposure to germs and thereby prevent cross infection. In motivating change, education programmes must take account of concerns related to antimicrobial resistance, the environment and the "health" of the immune system.     

Home hygiene and environmental sanitation: a country situation analysis for India

Problems of the environment and of domestic hygiene are always related to poverty of population and the sanitation of settlements. Most cities and towns in developing countries, like India, are characterised by over-crowding, congestion, inadequate water supply and inadequate facilities of disposal of human excreta, waste water and solid wastes. Inadequacy of housing for most urban poor invariably leads to poor home hygiene. Personal and domestic hygiene practices cannot be improved without improving basic amenities, such as water supply, waste water disposal, solid waste management and the problems of human settlements. But even under the prevailing conditions, there is significant scope of improving hygiene practices at home to prevent infection and cross-infection. Unfortunately, in developing countries, public health concerns are usually raised on the institutional setting, such as municipal services, hospitals, environmental sanitation, etc. There is a reluctance to acknowledge the home as a setting of equal importance along with the public institutions in the chain of disease transmission in the community. Managers of home hygiene and community hygiene must act in unison to optimise return from efforts to promote public health. Current practices and perceptions of domestic and personal hygiene in Indian communities, the existing levels of environmental and peri-domestic sanitation and the 'health risk' these pose will be outlined, as well as the need for an integrated action for improving hygiene behaviour and access to safe water and sanitation.     

Pathogens transmitted in animal feces in low- and middle-income countries

Animals found in close proximity to humans in low-and middle-income countries (LMICs) harbor many pathogens capable of infecting humans, transmissible via their feces. Contact with animal feces poses a currently unquantified—though likely substantial—risk to human health. In LMIC settings, human exposure to animal feces may explain some of the limited success of recent water, sanitation, and hygiene interventions that have focused on limiting exposure to human excreta, with less attention to containing animal feces.We conducted a review to identify pathogens that may substantially contribute to the global burden of disease in humans through their spread in animal feces in the domestic environment in LMICs. Of the 65 potentially pathogenic organisms considered, 15 were deemed relevant, based on burden of disease and potential for zoonotic transmission. Of these, five were considered of highest concern based on a substantial burden of disease for which transmission in animal feces is potentially important: Campylobacter, non-typhoidal Salmonella (NTS), Lassa virus, Cryptosporidium, and Toxoplasma gondii. Most of these have a wide range of animal hosts, except Lassa virus, which is spread through the feces of rats indigenous to sub-Saharan Africa. Combined, these five pathogens cause close to one million deaths annually. More than half of these deaths are attributed to invasive NTS. We do not estimate an overall burden of disease from improperly managed animal feces in LMICs, because it is unknown what proportion of illnesses caused by these pathogens can be attributed to contact with animal feces.Typical water quantity, water quality, and handwashing interventions promoted in public health and development address transmission routes for both human and animal feces; however, sanitation interventions typically focus on containing human waste, often neglecting the residual burden of disease from pathogens transmitted via animal feces. This review compiles evidence on which pathogens may contribute to the burden of disease through transmission in animal feces; these data will help prioritize intervention types and regions that could most benefit from interventions aimed at reducing human contact with animal feces.     

Risk factor analysis of diarrhoeal diseases in the Aral Sea area (Khorezm, Uzbekistan)

In the Aral Sea basin, human activities have resulted in the severe degradation of water and soil, which is considered to cause serious human health problems. This study investigated the risk factors: water, sanitation and related hygiene issues for diarrhoeal disease in Khorezm province, Uzbekistan. The risk factors were studied using a combination of quantitative and qualitative methods including water quality monitoring, standardised questionnaires and spot checks. Multiple linear regression analysis revealed that visible contamination of drinking water during storage and the absence of anal cleansing materials were significantly associated with the number of diarrhoeal episodes per household. Overall, the findings of the study show that the domestic domain plays a major role with regard to faecal-oral disease transmission in Khorezm, Uzbekistan. Unhealthy excreta disposal habits and unsafe drinking water storage practices have to be urgently tackled in order to break the faecal-oral transmission route.     

Risk factors for transmission of foodborne illness in restaurants and street vendors in Jakarta, Indonesia

In a previous risk factor study in Jakarta we identified purchasing street food as an independent risk factor for paratyphoid. Eating from restaurants, however, was not associated with disease. To explain these findings we compared 128 street food-vendors with 74 food handlers from restaurants in a cross-sectional study in the same study area. Poor hand-washing hygiene and direct hand contact with foods, male sex and low educational level were independent characteristics of street vendors in a logistic regression analysis. Faecal contamination of drinking water (in 65 % of samples), dishwater (in 91 %) and ice cubes (in 100 %) was frequent. Directly transmittable pathogens including S. typhi (n = 1) and non-typhoidal Salmonella spp. (n = 6) were isolated in faecal samples in 13 (7 %) vendors; the groups did not differ, however, in contamination rates of drinking water and Salmonella isolation rates in stools. Poor hygiene of street vendors compared to restaurant vendors, in combination with faecal carriage of enteric pathogens including S. typhi, may help explain the association found between purchasing street food and foodborne illness, in particular Salmonella infections. Public health interventions to reduce transmission of foodborne illness should focus on general hygienic measures in street food trade, i.e. hand washing with soap, adequate food-handling hygiene, and frequent renewal of dishwater.     

Microbial risk assessment framework for exposure to amended sludge projects

BACKGROUND: Although the U.S. Environmental Protection Agency has a long history of using risk-based approaches for regulatory purposes, pollutant limits for pathogens in biosolids are not currently based on quantitative risk assessments. OBJECTIVES: We developed and demonstrated a risk-based methodology for assessing the risk to human health from exposure to pathogens via biosolids. MATERIALS: Four models were developed, incorporating direct ingestion, groundwater, and aerosol exposure pathways. Three sources of environmental data were used to estimate risk: pathogen monitoring of sludge, efficacy of sludge treatment, and pathogen monitoring of biosolids. RESULTS: Risk estimates were obtainable even for Class A biosolids, where posttreatment monitoring data are below detectable levels, demonstrating that risk assessments for biosolids exposure are practical. Model analyses suggest that: a) a two-digester design decreases the probability of risks >10(-4) compared with one-digester designs, b) risks associated with exposures to groundwater and aerosol pathways were, in general, lower than exposures to the direct ingestion pathway, and c) secondary transmission can be an important factor in risk estimation. CONCLUSIONS: The risk-based approach presented here provides a tool to a) help biosolids producers interpret the results of biosolids monitoring data in terms of its health implications, b) help treatment plant engineers evaluate the risk-based benefits of operational changes to existing or projected treatment processes, and c) help environmental managers evaluate potential capital improvements and/or land application site placement issues. Regulation of pathogens can now be based on human health risk in a manner parallel to other water-related risks.     

Flies and water as reservoirs for bacterial enteropathogens in urban and rural areas in and around Lahore, Pakistan.

The study was conducted to isolate and characterize campylobacter, enterotoxigenic Escherichia coli-labile toxin (ETEC-LT), shigella and salmonella in flies and water. The material for the study, flies (n = 300) and water samples (n = 148), was collected from different localities in and around Lahore, Pakistan. Cultivation of the samples was performed on conventional standard media. Membrane filtration technique was used for water prior to culture. Determination of ETEC-LT was done by GM1 ELISA. Results of our study showed that flies and water were reservoirs for all the four pathogens, campylobacter, ETEC-LT, shigella and salmonella. Flies from the village were carrying fewer enteropathogens, while water from the village was found to be more contaminated as compared to the city. Campylobacter and ETEC-LT were the most frequently isolated pathogens in both flies and water. Thus the incidence of diarrhoeal disease in children of developing countries may be decreased by providing plenty of safe drinking water, improving excreta disposal, toilet facilities and giving education in personal hygiene.     

广西少数民族农村地区肠道寄生虫感染因素的多水平多因素模型分析

目的 探讨广西少数民族农村地区肠道寄生虫感染的影响因素。方法 采用自制问卷进行横断面入户调查,收集资料和居民粪便标本;用改良加藤厚涂片法检查寄生虫卵;采用多水平多因素Logistic回归模型分析人口学特征、饮食和生活卫生习惯、家庭水平因素以及自然村水平因素对广西少数民族地区肠道寄生虫感染情况的影响。结果 多水平多因素Logistic回归模型显示:性别、受教育年限、个人饮食与生活卫生习惯、家庭人均年收入、家庭是否存在人畜混居现象、家庭是否有厕所与卫生橱柜等变量与肠道寄生虫感染有统计学关联（均有P<0.05）。控制个人和家庭水平因素后,自然村的自来水供应情况、公共厕所有无和环境卫生状况等社区环境水平变量均对肠道寄生虫感染具有独立效应（均有P<0.05）。结论 受教育程度较高和具有良好个人饮食与生活卫生习惯者肠道寄生虫感染机会较低,家庭经济条件好、拥有自家厕所和卫生橱柜均可降低肠道寄生虫的感染。自然村供应自来水、建有公共厕所和改善自然村环境卫生状况等社区社会经济环境因素也能降低肠道寄生虫感染。     

Sharps injuries in healthcare waste handlers

Clinical waste disposal carries with it a risk of serious and possibly life-threatening infection. Combining confidential questionnaires and structured interviews with discrete observation, the attitudes and approach to safe handling of bulk clinical wastes by staff in a specialist waste treatment facility were assessed. With particular attention to glove use and hand hygiene, observations were supplemented by review of group-wide accident and incident records, with emphasis on sharps injuries and related blood and bloodstained body fluid exposures. Deficiencies in glove selection and use, and in hand hygiene, were noted despite extensive and on-going training and supervision of waste handlers. Though ballistic puncture-resistant gloves protect against sharps injury, these were uncomfortable in use and were sometimes rejected by waste handlers who preferred thin-walled nitrile gloves that were more comfortable in use though provide no resistance to penetrating injury. Among the waste handlers working for a single specialist waste disposal company, sharps injuries (n = 40) occurred at a rate of approximately 1 per 29 000 man hours. Injuries were caused by hypodermic needles from improperly closed or overfilled sharps boxes (n = 6) or from sharps incorrectly discarded into thin-walled plastic sacks intended only for soft wastes (n = 34). Most injuries occurred to the fingers or hands. No seroconversions occurred, though two individuals suffered anxiety/stress disorder necessitating prolonged leave of absence with professional counselling and support. Glove use and hand hygiene must feature prominently in the on-going training of waste handlers. Though ballistic gloves afford protection against sharps injury, the initial segregation and safe disposal of clinical wastes by healthcare professionals must provide the primary control measure. Despite robust and unambiguous legislation and good practice guidelines, serious errors by healthcare staff that result in the disposal of hypodermic needles and other sharps to thin-walled plastic waste sacks places waste handlers at risk of bloodborne virus infection. Further improvement in the standards of waste segregation and disposal by healthcare professionals are still required to protect ancillary and support staff and waste handlers working in the disposal sector.     

The infection potential in the home and the role of hygiene: historical and current perspectives

The control of infection through hygiene has a long erratic history. Personal hygiene and handwashing was less appreciated in the past, since it was not known that invisible organisms could spread from apparently clean hands and surfaces. The role of a hygienic home environment received little attention until the 19th century. Since then, the modern tradition of hygiene has served us well, with improved water and drainage developing alongside vaccination, antibiotics, water purification, improved food production and hygienic food preparation and storage. Two major epidemiological trends are relevant to hygiene perspectives: the decline in the morbidity and mortality from infection, and the transition towards higher levels of chronic or debilitating disease. While mortality from some infections has decreased, communicable disease is no less prevalent. Infectious intestinal disease is still unacceptably high in both developed and developing countries. The control of infection within the home needs to take account of changing epidemiological trends, emphasis on evidence-based approaches and loss of public awareness of the role of hygiene. In earlier eras lack of research on the home environment prevented sufficient attention to infection transmission in the domestic setting. Recent research has demonstrated how microbial contamination can be transmitted by activities in the home. Application of this knowledge could significantly reduce the continuing impact of infectious diseases in our communities.     

Interventions for the control of diarrhoeal diseases among young children: improving water supplies and excreta disposal facilities

A theoretical model is proposed that relates the level of ingestion of diarrhoea-causing pathogens to the frequency of diarrhoea in the community. The implications of this model are that, in poor communities with inadequate water supply and excreta disposal, reducing the level of enteric pathogen ingestion by a given amount will have a greater impact on diarrhoea mortality rates than on morbidity rates, a greater impact on the incidence rate of severe diarrhoea than on that of mild diarrhoea, and a greater impact on diarrhoea caused by pathogens having high infectious doses than on diarrhoea caused by pathogens of a low infectious dose. The impact of water supply and sanitation on diarrhoea, related infections, nutritional status, and mortality is analysed by reviewing 67 studies from 28 countries. The median reductions in diarrhoea morbidity rates are 22% from all studies and 27% from a few better-designed studies. All studies of the impact on total mortality rates show a median reduction of 21%, while the few better-designed studies give a median reduction of 30%. Improvements in water quality have less of an impact than improvements in water availability or excreta disposal.     

Environmental health conditions and cholera vulnerability in Latin America and the Caribbean.

Epidemic cholera reached South America in January 1991 and later spread to Central America and the United States. It afflicted 312,000 people and claimed 3200 lives. Since cholera had not been in Latin America for almost 70 years, health authorities allowed environmental health barriers to cholera collapse. For example, the Governments of the Region agreed in 1961 to abide by the Charter of Punta del Este to provide water and sewerage to 70% of the urban population and 50% f the rural population by 1971. They did not achieve their goals for the rural population. In fact, at the end of 1988, water was piped to 79% of the urban households and an additional 11% of the urban population had access to a public water source. Sewerage services served 49% of the urban population and, with other methods of excreta disposal, 80% of the population had adequate excreta disposal. On the other hand, only 55% of rural inhabitants had access to either piped water or public standpipes. Further sanitary excreta disposal services only covered 32%. Besides the water quality of existing water supply systems was poor. Since feces of infected people have as many as 1 billion Vibrio cholerae and , in some of Vibrio, up to 80% of carriers exhibit only mild symptoms or no symptoms at all, it is easy to understand how cholera took hold in Latin America. Researchers identified the points of contamination responsible for the cholera outbreak in Piura and Trujillo, Peru to be wells, distribution systems, and house. Annual population growth in Latin America at 2.6% poses specific problems to providing enough water and sanitation services to all in need, especially those in marginal areas around the cities (who will make up 40% of the population by 2000).     

Avian influenza and oseltamivir; a retrospective view

The outbreak of avian influenza A due to an H7N7 virus in Dutch poultry farms turned out to have public-health effects for those who were involved in the management of the epidemic and who were thus extensively exposed to contaminated excreta and dust. An outbreak-management team (OMT) of experts in virology, infectious diseases and public health advised the Dutch government with respect to the potential health effects on humans. Strict hygiene measures were advised. Moreover, vaccination against human influenza was advised to prevent emergence of a new pandemic virus in humans. Since the human influenza virus H3N2 circulated at the same time, a double infection and emergence of a new human virus was the main fear on which prevention was focused. Conjunctivitis was observed in about 10% of the people involved. The conjunctivitis was sometimes accompanied by mild flu-like symptoms and incidental transmission between humans occurred as well. Because of the unexpected high incidence of symptomatic infections, proven to be caused by the H7N7 strain, oseltamivir was advised as an additional control measure, both for the treatment of symptoms and prophylactically for those with prolonged occupational exposure. After the unfortunate death of a veterinarian due to pneumonia caused by the avian virus, the preventive policy was further extended to people with short and incidental exposure to infected flocks. It is concluded that the policy was adequate, in spite of the unforeseen victim.     

How to treat a patient with indications for an infectious viral hemorrhagic fever

Lassa, Ebola, Marburg and Crimean-Congo haemorrhagic fever viruses are the most important causes of viral haemorrhagic fever which is transmitted from person to person through contact with blood or excreta. A non-specific fever may be the initial symptom of viral haemorrhagic fever. By means of carefully noting where the patient has travelled, possible exposure to ill persons, vectors or an animal reservoir, and the incubation period (< or = 21 days versus longer), it is possible to estimate the risk of infection with one of these viruses. Using this approach it is possible to diagnose high-risk patients in good time and to take appropriate measures.     

Assessment of source water pathogen contamination

During the last decade, the source to tap risk-based approach to pathogens in drinking water has been largely promoted. This paper addresses the issue of source water pathogen contamination, which is the first step of quantitative microbial risk assessment. It is focused on a selection of pathogens considered to be a major risk to human health. Source water quality is highly variable and understanding the reasons for this variability is important as it will influence the requirements for treatment, treatment efficiency and the resulting health risk associated with the finished water. A framework for source water microbial quality assessment based on catchment surveys and monitoring programmes was set and tested on ten water sources. The monitoring programmes included faecal indicators and pathogens, during both baseline and hazardous event conditions. Concentrations varied greatly within and between systems. Faecal indicators were shown to be poor surrogates for pathogen presence and concentrations. There was no recurring evidence that the pathogens correlated together and links between microbial parameters appeared to be very site specific. Such variability between systems shows the importance of running local monitoring programs for use in risk assessment. Finally, pathogen detection methods are not yet optimal due to their sensitivity and to the lack of knowledge on viability and infectivity of pathogens. A great effort needs to be made in the future to ensure better quality data as this may have large implications in the statistical risk assessment calculations.     

Food handlers' beliefs and self-reported practices

Despite an increase in the number of food handlers receiving food hygiene training, a high proportion of food poisoning outbreaks still occur as a result of poor food handling practices. This paper uses elements of social cognitive theory to examine the beliefs of food handlers towards food safety and to determine food handlers' self-reported practices. Questionnaires were completed by 137 food handlers from 52 small to medium-sized food businesses in Wales. Generally, food handlers were aware of the food safety actions they should be carrying out but identified a number of barriers which would prevent them from implementing these practices. These barriers included lack of time, lack of staff and a lack of resources. Despite 95% of respondents receiving food hygiene training, 63% admitted to sometimes not carrying out food safety behaviours. All the food handlers also perceived their business to be of relatively low risk and yet all businesses prepared high risk foods. This research highlights the need for training to be based around a risk-based approach and demonstrates that behavioural change will not occur merely as a result of training. Food safety practices will only be implemented given adequate resources and an appropriate management culture.     

Application of microbial risk assessment on a residentially-operated bio-toilet

The Sustainable Sanitation System is a new wastewater treatment system that incorporates a non-flushing toilet (Bio-toilet) that converts excreta into a reusable resource (as fertilizer or humus for organic agriculture) and reduces the pollution load to environments of the rivers, the lakes, and the sea. However, the risk of exposure to pathogens should be considered, because excrement is stored in the Bio-toilet. The aim of the present work is to analyze the health risk of dealing with the matrix (excreta and urine mixed with sawdust) of the Bio-toilet. Therefore, the fate of pathogenic viruses was investigated using coliphages as a virus index, and the modeling of the die-off rate in matrix was introduced. Then the microbial risk assessment was applied to a Bio-toilet that was actually used in a residential house; the infection risks of rotavirus and enterovirus as reference pathogens were calculated. According to the lab-scale experiment using coliphages for investing the die-off rate of viruses in the Bio-toilet, Qbeta had a higher die-off, which was greatly influenced by the water content and temperature. On the other hand, T4 showed a lower rate and was independent of water content. Therefore, these two phages' data were used as critical examples, such as viruses having high or low possibilities of remaining in the Bio-toilet during the risk assessment analysis. As the result of the risk assessment, the storage time required for an acceptable infectious risk level has wide variations in both rotavirus and enterovirus cases depending on the phage that was used. These were 0-260 days' and 0-160 days' difference, respectively.     

Sorbitol-fermenting Bifidobacteria are indicators of very recent human faecal pollution in streams and groundwater habitats in urban tropical lowlands

Sorbitol-fermenting Bifidobacteria (SFB) proved to be an excellent indicator of very recent human faecal pollution (hours to days) in the investigated tropical stream and groundwater habitats. SFB were recovered from human faeces and sources potentially contaminated with human excreta. SFB were undetectable in animal faeces and environmental samples not contaminated with human faeces. Microcosm studies demonstrated a rapid die-off rate in groundwater (T₉₀ value 0.6 days) and stream water (T₉₀ value 0.9–1.7 days). Discrimination sensitivity analysis, including E. coli, faecal coliforms, total coliforms and Clostridium perfringens spores, revealed high ability of SFB to distinguish differing levels of faecal pollution especially for streams although high background levels of interfering bacteria can complicate its recovery on the used medium. Due to its faster die-off, as compared to many waterborne pathogens, SFB cannot replace microbiological standard parameters for routine water quality monitoring but it is highly recommendable as a specific and complementary tool when human faecal pollution has to be localized or verified. Because of its exclusive faecal origin and human specificity it seems also worthwhile to include SFB in future risk evaluation studies at tropical water resources in order to evaluate under which situations risks of infection may be indicated.     

手部卫生与医院感染的研究进展

医疗机构中医务人员手上携带的细菌已成为医院感染的主要致病源,这些病原体不仅可从已感染伤口或引流伤口处获得,还可从正常、完整的皮肤区域获得。手的清洗和消毒是防止医院感染的最重要措施之一。论文概述了手清洗、卫生手消毒和外科手消毒的分类定义。并对目前使用的酒精、洗必泰葡萄糖酸盐、碘伏、六氯酚、三氯生等各类手卫生产品的作用机理、效果对比及其特点进行了讨论。总结了手卫生存在的一些问题,包括医护人员手卫生遵守率低下,医疗机构对手卫生的重视不足,细菌对消毒剂敏感度的降低和消毒剂使用中发生的接触性皮炎等。并就如何降低接触性皮炎的发生率、减少杀菌剂不利效果的方法、提高手卫生遵守率等一些最新的旨在改进手卫生状况的策略和对策进行阐述。