Incidence of and risk factors for skin ailments among farmers working with wastewater-fed agriculture in Hanoi, Vietnam

The use of wastewater in agriculture and aquaculture is widespread in many developing countries, but limited information is available about the health hazards associated with this practice. To study the occurrence of skin ailments in relation to wastewater use in agriculture and aquaculture, an open cohort of 636 adults aged 15-70 years living in a wastewater-irrigated area in Hanoi, Vietnam, was followed by weekly visits for 12 months. A nested case-control study with 108 case/control pairs was conducted to investigate possible risk factors for skin ailments. The incidence rate of skin ailments was 32.5 episodes per 100 person-years at risk. Independent determinants of skin ailments included wastewater contact in the past 7 days (odds ratio (OR=2.74, 95% confidence interval (CI) 1.29-5.82), female gender (OR=2.48, 95% CI 1.06-5.76), fish farming-related jobs (OR=3.47, 95% CI 1.27-9.50) and lack of protective measures (OR=2.24, 95% CI 1.21-4.12). It is likely that effective promotion of personal protective measures and improved hygiene practices amongst wastewater users will mitigate the risk of dermatological problems and will thus be of benefit to public health in communities that rely on the use of wastewater for agricultural and aquacultural productions.     

Microbiological quality of fish grown in wastewater-fed and non-wastewater-fed fishponds in Hanoi, Vietnam: influence of hygiene practices in local retail markets

Mean water quality in two wastewater-fed ponds and one non-wastewater-fed pond in Hanoi, Vietnam was approximately 10(6) and approximately 10(4) presumptive thermotolerant coliforms (pThC) per 100 ml, respectively. Fish (common carp, silver carp and Nile tilapia) grown in these ponds were sampled at harvest and in local retail markets. Bacteriological examination of the fish sampled at harvest from both types of pond showed that they were of very good quality (2 - 3 pThC g(-1) fresh muscle weight), despite the skin and gut contents being very contaminated (10(2) - 10(3) pThC g(-1) fresh weight and 10(4) - 10(6) pThC g(-1) fresh weight, respectively). These results indicate that the WHO guideline quality of < or = 1000 faecal coliforms per 100 ml of pond water in wastewater-fed aquaculture is quite restrictive and represents a safety factor of approximately 3 orders of magnitude. However, when the fish from both types of pond were sampled at the point of retail sale, quality deteriorated to 10(2) - 10(5) pThC g(-1) of chopped fresh fish (mainly flesh and skin contaminated with gut contents); this was due to the practice of the local fishmongers in descaling and chopping up the fish from both types of pond with the same knife and on the same chopping block. Fishmonger education is required to improve their hygienic practices; this should be followed by regular hygiene inspections.     

Microbiological quality of fish grown in wastewater-fed and non-wastewater-fed fishponds in Hanoi, Vietnam: influence of hygiene practices in local retail markets

Mean water quality in two wastewater-fed ponds and one non-wastewater-fed pond in Hanoi, Vietnam was ~10⁶ and ~10⁴ presumptive thermotolerant coliforms (pThC) per 100 ml, respectively. Fish (common carp, silver carp and Nile tilapia) grown in these ponds were sampled at harvest and in local retail markets. Bacteriological examination of the fish sampled at harvest from both types of pond showed that they were of very good quality (2-3 pThC g^-1 fresh muscle weight), despite the skin and gut contents being very contaminated (10²-10³ pThC g^-1 fresh weight and 10⁴-10⁶ pThC g^-1 fresh weight, respectively). These results indicate that the WHO guideline quality of 1000 faecal coliforms per 100 ml of pond water in wastewater-fed aquaculture is quite restrictive and represents a safety factor of ~3 orders of magnitude. However, when the fish from both types of pond were sampled at the point of retail sale, quality deteriorated to 10²-10⁵ pThC g^-1 of chopped fresh fish (mainly flesh and skin contaminated with gut contents); this was due to the practice of the local fishmongers in descaling and chopping up the fish from both types of pond with the same knife and on the same chopping block. Fishmonger education is required to improve their hygienic practices; this should be followed by regular hygiene inspections.     

Prevalence and risk factors for soil-transmitted helminth infection in mothers and their infants in Butajira,Ethiopia: a population based study

Background  

Soil-transmitted helminths (STHs) are widespread in underdeveloped countries. In Ethiopia, the prevalence and distribution of helminth infection varies by place and with age. We therefore investigated the prevalence of and risk factors for STH infection in mothers and their one year-old children living in Butajira town and surrounding rural areas in southern Ethiopia.     

Women in rice cultivation: some research tools

To further understand the agricultural, rural social structure, and development process in South India, an extensive study using local women to help collect data is being undertaken. Literate women of landowning households are instructed to keep diaries of all pertinent agricultural activities. In addition, the women keep records of how much each household member brings home using a simple pictorial chart with each member of the family depicted. The chart allows for 4 adults and 3 children which accommodates 95% of the households. Also using an agricultural chart with agricultural tasks depicted, the women record all activities they perform both in the morning as well as afternoon and evening. The charts are to be kept for 5-6 months with the charts collected weekly by 1 woman in each village who also keeps a diary on each household to serve as a check.     

Low risk of TT virus (TTV) infection in medical workers.

The rate of infection with TT virus (TTV), a novel single-strand DNA virus was evaluated and the clinical and laboratory features in affected Japanese medical workers were analysed. TTV DNA was measured in 356 medical workers and in 150 age-matched controls using a seminested polymerase chain reaction. TTV DNA was detected in 62 of 356 medical workers (17.4%). There were no differences in the prevalence of TTV infection between medical workers and controls (18.9%) and in the characteristics of medical workers with TTV infection and medical workers without it, except that the mean age of patients with TTV infection was higher than that of patients without TTV. The medical workers were drawn from three groups: medical doctors, nurses and clinical laboratory technicians. There was no statistically significant difference between the rate of TTV infection in the three groups. These findings suggest that the risk of TTV infection in medical workers is low and not related to liver dysfunction.     

南宁市小学生肠道蠕虫感染情况调查

目的:了解南宁市小学生肠道蠕虫感染现状,为儿童保健及寄生虫病防治工作提供科学依据。方法:按照自愿受检的原则,对南宁市12所小学的5 769名学生进行肠道蠕虫的病原学检查,并分析阳性者的感染情况。结果:肠道蠕虫总感染率为6.74%(389/5 769),均为单一虫种和轻度感染;蛔虫、鞭虫和钩虫的总感染率为2.84%(164/5 769),感染率城乡差异明显,男女生感染率差异无统计学意义,低年级组学生感染率最高;华支睾吸虫感染率为3.90%(225/5 769),感染率城乡差异明显,男女生感染率差异有统计学意义,高年级组学生感染率最高;感染者大多有不良饮食习惯和或卫生习惯。结论:只有全面推进和落实健康教育工作,才能降低肠道蠕虫感染,切实保护儿童身体健康。     

学龄前儿童肠道蠕虫感染现状分析

目的:了解杭州市学龄前儿童肠道常见蠕虫感染现状,为进一步防治提供参考依据。方法:选择杭州市不同区域、不同等级的14所幼儿园和一家医院儿科门诊就诊的1 932例3~6岁学龄前儿童作为调查对象,对每个被调查的幼儿采用生理盐水直接涂片法和饱和盐水浮聚法粪检蛔虫卵、钩虫卵、鞭虫卵;用透明胶纸肛拭法检查蛲虫卵。结果:1 932例受检者中,寄生虫感染249例,总感染率12.89%,其中蛲虫占4.35%,蛔虫8.07%,鞭虫0.62%,钩虫0.31%,感染两种虫种者占总感染人数的3.61%;不同级别幼儿园儿童肠道常见蠕虫感染率分别为甲级幼儿园7.31%、乙级12.60%、丙级21.47%,差异有显著性(P<0.001)。结论:杭州市学龄前儿童肠道常见蠕虫感染率为12.89%,寄生虫感染率高低与幼儿园环境卫生、教学设施等因素密切相关。     

土源性线虫感染对儿童生活质量影响因素分析

目的:探讨土源性线虫(STH)感染对儿童生活质量的影响,为提高儿童尤其是STH感染儿童生活质量提供依据。方法:采用Kato-Katz法,对小学5～6年级儿童进行粪便病原学检查,一送三检查蛔虫、钩虫、鞭虫等土源性线虫虫卵,并按WHO标准感染度分级为轻、中、重度感染;应用SF-12量表对参与粪检的507例儿童进行问卷调查。结果:回收合格问卷472份。STH感染175例,感染率37.1%。中重度以上感染79例,感染率16.7%;中重度STH感染儿童生理评分(PCS)和心理评分(MCS)(14.32±3.69和16.08±4.17),低于轻度感染儿童PCS和MCS(15.54±3.37和17.30±4.39)及未受感染儿童PCS和MCS(16.86±3.37和18.68±3.84),差异有统计学意义(P<0.001);逐步回归分析显示,影响儿童生活质量的主要因素:土源性线虫感染、母亲文化、过去1个月经常腹痛、饭前便后不洗手、过去1个月是否患病等。结论:STH感染影响儿童生活质量。做好学龄儿童卫生保健,养成良好卫生习惯,重视儿童慢性疾病的预防与控制,提高父母文化是改善STH感染儿童生活质量的重要途径。     

Malaria transmission and rice cultivation in Lagdo, northern Cameroon

Cross-sectional entomological surveys were carried out during the 2006 dry and rainy seasons in Lagdo, Cameroon to measure the impact of rice cultivation on malaria transmission and to monitor vector susceptibility to insecticides. Adult anopheline mosquitoes were captured on human volunteers and by pyrethrum spray collections. A total of 4740 mosquitoes was collected during the study. Anopheles arabiensis was the major species and the main malaria vector in all study sites, followed by A. funestus. Malaria transmission was high in the non-irrigated zone of Mayo Mbocki, whereas in the irrigated area of Gounougou it was below detection level during the dry season and high during the rainy season. Insecticide susceptibility tests performed on A. gambiae s.l. populations detected resistance to lambdacyhalothrin and to a lower extent to deltamethrin. All survivors were A. arabiensis. None of the surviving mosquitoes carried the kdr mutation, suggesting an alternative resistance mechanism.     

Sociometric risk networks and risk for HIV infection.

OBJECTIVES: This study examined whether networks of drug-injecting and sexual relationships among drug injectors are associated with individual human immunodeficiency virus (HIV) serostatus and with behavioral likelihood of future infection. METHODS: A cross-sectional survey of 767 drug injectors in New York City was performed with chain-referral and linking procedures to measure large-scale (sociometric) risk networks. Graph-theoretic algebraic techniques were used to detect 92 connected components (drug injectors linked to each other directly or through others) and a 105-member 2-core within a large connected component of 230 members. RESULTS: Drug injectors in the 2-core of the large component were more likely than others to be infected with HIV. Seronegative 2-core members engaged in a wide range of high-risk behaviors, including engaging in risk behaviors with infected drug injectors. CONCLUSIONS: Sociometric risk networks seem to be pathways along which HIV travels in drug-injecting peer groups. The cores of large components can be centers of high-risk behaviors and can become pockets of HIV infection. Preventing HIV from reaching the cores of large components may be crucial in preventing widespread HIV epidemics.     

Anemia and intestinal parasite infection in school children in rural Vietnam

OBJECTIVES: This study hypothesized that besides iron deficiency, intestinal parasites infection is also a determinant of anemia in schoolchildren in rural Vietnam. METHODS: 400 primary schoolchildren from 20 primary schools in Tam Nong district, a poor rural area in Vietnam, were randomly selected from enrollment lists. Venous blood (5ml) was collected in a cross sectional study and analyzed for hemoglobin (Hb), serum ferritin (SF), serum transferrin receptor (TfR), serum C-reactive protein (CRP) and total immunoglobulin E (IgE). Stools samples were examined for hookworm, Trichuris, and Ascaris infection. Logistic regression was used to assess the effect of intestinal parasites on anemia. RESULTS: The prevalence of anemia (Hb < 115g/l) was 25%. Iron deficiency (TfR > 8.5mg/L) occurred in 2% of the children. The prevalence of intestinal parasites was 92% with the highest prevalence for Trichuris (76%) and Ascaris (71%). More than 30% and 80% of the children showed an elevated CRP (> or = 8 mg/L) and IgE (> 90 IU/ml) concentration. Anemia status was borderline significantly associated with SF and not associated with TfR and CRP. The prevalence odds ratio for Trichuris infection was 1.96 (95% CI 1.07-3.59) and 2.00 (95% CI 1.08-3.65) with iron deficiency reflected by TfR and SF, respectively. CONCLUSION: Anemia is highly prevalent among schoolchildren in Vietnam but may not be associated with iron deficiency. Trichuris infection is associated with a doubled risk of anemia, not mediated through iron deficiency. Chronic infection may play a role in anemia, but needs further investigation.     

Malarial vectors in an irrigated rice cultivation area in southern Sri Lanka

Entomological surveys were carried out from March 1998 to December 1999 to study the prevalence, distribution and abundance of malarial vectors in relation to selected environmental factors and potential mosquito breeding sites in irrigation channels in 15 villages in the Lunugamvehera Irrigation and Settlement Project, a malaria-endemic area of southern Sri Lanka. Mosquito collections were made at monthly intervals using four sampling methods. Thirteen anopheline species were collected. Following monsoonal rains, anopheline breeding took place primarily in rainwater accumulations. During the inter-monsoonal period, pools formed in the irrigation system, semi-permanent pools formed as a result of rainfall and permanent ground pools were the major breeding sites of anophelines. Very little anopheline breeding took place within the irrigation channels. Amongst the seven anopheline species collected from human dwellings, Anopheles subpictus was the most prevalent, followed by A. culicifacies; together these two species comprised more than 99% of the indoor resting population. The number of days of rain was an important macro-epidemiological factor influencing the density of malarial vectors. There was no consistent trend between the amount of water released or the number of days of water release from the reservoir and the outdoor or indoor resting densities of anophelines.     

广州市1998-2010年肠道蠕虫感染流行病学分析

目的研究广东省广州市肠道蠕虫的感染状况及流行特点,为防治蠕虫感染提供理论依据。方法根据广州市各区的地理分布,从1998-2010年的资料中分期分批选择不同职业不同年龄不同性别的人群作为研究对象,采用改良加藤氏厚涂片法粪检蠕虫卵。结果粪检共41 280人,阳性感染者6 211人,总肠道寄生虫感染率为15.0%,其中肝吸虫感染率为7.3%,钩虫感染率为3.3%,蛔虫感染率为3.4%,鞭虫感染率为1.1%。1998-2009广州市区肠道蠕虫感染率不断增高,2010年有所下降。职业中以工商人员的感染率最高,其次是农民、干部及医务人员;男性感染率明显高于女性。结论肝吸虫及农村土源性线虫仍是目前重点防治的寄生虫。应采取有效的综合防治措施,降低人群的肠道蠕虫感染率。     

Impact of a national helminth control programme on infection and morbidity in Ugandan schoolchildren

OBJECTIVE: We aimed to assess the health impact of a national control programme targeting schistosomiasis and intestinal nematodes in Uganda, which has provided population-based anthelmintic chemotherapy since 2003. METHODS: We conducted longitudinal surveys on infection status, haemoglobin concentration and clinical morbidity in 1871 randomly selected schoolchildren from 37 schools in eight districts across Uganda at three time points - before chemotherapy and after one year and two years of annual mass chemotherapy. FINDINGS: Mass treatment with praziquantel and albendazole led to a significant decrease in the intensity of Schistosoma mansoni - 70% (95% confidence interval (CI): 66-73%) after one year and 82% (95% CI: 80-85%) after two years of treatment. Intensity of hookworm infection also decreased (75% and 93%; unadjusted). There was a significant increase in haemoglobin concentration after one (0.135 g/dL (95% CI: 0.126-0.144)) and two years (0.303 g/dL (95% CI: 0.293-0.312)) of treatment, and a significant decrease in signs of early clinical morbidity. The impact of intervention on S. mansoni prevalence and intensity was similar to that predicted by mathematical models of the impact of chemotherapy on human schistosomiasis. Improvements in haemoglobin concentration were greatest among children who were anaemic or harbouring heavy S. mansoni infection at baseline. CONCLUSION: Anthelmintic treatment delivered as part of a national helminth control programme can decrease infection and morbidity among schoolchildren and improve haemoglobin concentration.     

Hepatitis B infection in Vietnam: current issues and future challenges

Hepatitis B virus (HBV) infection remains a major public health problem in Vietnam. Recent studies have found that prevalence of current HBV infection (HBsAg+) ranges from 10% to 20% in the general population and 20% to 40% among injecting drug users and HIV+ patients. However, HBV prevention and control in Vietnam relies heavily on universal infant vaccination program and HBsAg screening for blood donors. Currently, HBV prevention and control is underfunded by the government and receives little support from international agencies. HBV-related liver disease will continue to create a heavy burden for public health in Vietnam in the next several decades unless appropriate interventions are undertaken urgently. Establishment of a national strategy for HBV prevention and control is crucial to develop and implement effective interventions.     

Mycobacterium tuberculosis Beijing genotype and risk for treatment failure and relapse, Vietnam

Among 2,901 new smear-positive tuberculosis cases in Ho Chi Minh City, Vietnam, 40 cases of treatment failure and 39 relapsing cases were diagnosed. All initial and follow-up Mycobacterium tuberculosis isolates of these case-patients had (nearly) identical restriction fragment length polymorphism patterns, and the Beijing genotype was a significant risk factor for treatment failure and relapse (odds ratio 2.8, 95% confidence interval 1.5 to 5.2).