A waterborne outbreak involving hepatitis A virus genotype IA at a residential facility in the Republic of Korea in 2015

BackgroundHepatitis A virus (HAV), a major cause of acute hepatitis, has had the highest occurrence among group 1 nationally notifiable infectious diseases in Korea since 2010.Recently,the annual increase in the HAV infection rate among young adults has become a public health concern.ObjectivesThe aim of this study was to describe an outbreak of acute hepatitis in a residential facility in April 2015 and to identify potential sources of this outbreak.Study designSera from all exposed residents were tested for anti-HAV IgM or IgG antibodies by ELISA. Clinical (sera and stool) and environmental samples were screened for the presence of HAV RNA using one-step RT-PCR and nested PCR. The VP3-VP1 regions of HAV were analyzed using the BLAST database and MEGA7 software.ResultsOf the 82 persons in the facility, 12 (14.6%, including 10 residents and 2 health care workers) were diagnosed with hepatitis A. Clinical symptoms were evident in 9 individuals, one of whom died, and the remaining four patients were asymptomatic. Traceback investigation revealed that HAV-RNA (genotype IA) was detected in the patients’ stools and the groundwater used in the facility.ConclusionsWe described an HAV outbreak in a facility for the disabled due to using a water supply that was mixed with contaminated groundwater. Therefore, HAV vaccination and periodic water inspections in group facilities should be emphasized to prevent HAV infection.     

水体中隐孢子虫的检测方法

隐孢子虫(Cryptosporidium spp.)是一类顶复门肠道原虫,隐孢子虫病(cryptosporidiosis)是由隐孢子虫引起的人兽共患原虫病.由于隐孢子虫病可通过水传播,故该文对水体中隐孢子虫的常规检测包括样品收集、浓缩、卵囊分离和染色镜检等步骤,和常用分子生物学方法如多种PCR方法和基于核酸序列的扩增方法等进行综述.     

Renal responses to acute lead waterborne exposure in the freshwater rainbow trout (Oncorhynchus mykiss)

The possible nephrotoxic effects of waterborne lead exposure (as Pb(NO₃)₂) were investigated in the freshwater rainbow trout (Oncorhynchus mykiss). Kidney lead accumulation was time-dependent, increasing upon exposure to 0.57 ± 0.01 mg dissolved Pb L⁻¹ for up to 96 h with a significantly higher burden occurring in the posterior kidney compared to the anterior segment. Urine analyses in trout exposed to 1.20 ± 0.09 mg dissolved Pb L⁻¹ revealed a significant increase in urinary lead excretion rate throughout 96 h of exposure. Urine flow rate and glomerular filtration rate (GFR) were not impacted with the exception of a significant decrease in GFR from 84 to 96 h in lead-exposed trout. Urine pH decreased significantly over time in lead-exposed fish. Correspondingly, urine ammonia excretion rate showed a marked increase from 48 h onwards. In experimental fish, urine glucose excretion was significantly greater by 96 h while urine lactate, urea and protein excretion were not significantly altered by lead exposure. The urine excretion rate of Ca²⁺ increased significantly by approximately 43% after only 24 h of lead exposure, and was maintained at a higher rate than controls for up to 96 h. Magnesium excretion increased in a time-dependent fashion, reaching a two- to three-fold rise by 96 h. In contrast, rates of Na⁺ and Cl⁻ excretion were decreased in experimental fish by approximately 30% by 48 h, this trend continuing for the duration of lead-exposure. There were no changes in any of these parameters in similarly treated control fish. Clearance ratio analyses indicated progressive decreases in the net reabsorption efficiencies of the renal system for Ca²⁺, Mg²⁺, Pb, and glucose, suggesting that the active tubular transport mechanisms for these substances were inhibited by lead exposure, while Na⁺, K⁺, Cl⁻, lactate, and protein reabsorptions were unaffected. Net ammonia secretion increased. We conclude that changes in renal function both reflect and help to minimize some of the associated disturbances in systemic physiology. Lead-induced ionoregulatory toxicity in rainbow trout, particularly the disturbance of Ca²⁺ homeostasis, is not exclusively a branchial phenomenon, but is in part a result of disruption of ionoregulatory mechanisms at the kidney. This action of lead outside the gills is critical to consider when developing guidelines for water quality.     

Appropriate technology for rural India - solar decontamination of water for emergency settings and small communities

A commercial solar water heating system was evaluated for its effectiveness in decontaminating drinking water with a view to use in emergency situations. A total of 18 seeding experiments carried out over 6 months with 10(5) to 10(7)Escherichia coli/ml showed that the solar heater produced 125 l of bacteriologically safe water in 4 h when the ambient temperature was above 30 degrees C, with a holding time of at least 2 h. The solar water heating system is inexpensive, easy to transport and set up and could provide safer drinking water for 50 people a day. It would be effective in the decrease and prevention of waterborne disease in emergency situations, and is appropriate for use in small communities.     

Performance of the rural health improvement scheme in reducing the incidence of waterborne diseases in rural Sarawak, Malaysia

This study evaluates and discusses the impact of the rural health improvement scheme in reducing the incidence of dysentery, enteric fever, cholera and viral hepatitis in Sarawak, Malaysia, using data compiled from state and federal health department reports. This study suggests that from 1963 to 2002, water supply intervention contributed to a more than 200-fold decrease in dysentery and a 60-fold decrease in enteric fever. Variations in reporting of viral hepatitis during that period make it difficult to detect a trend. Cholera was still endemic in 2002. Cholera and dysentery outbreaks, occurring when rural populations relied on contaminated rivers for their water supply, suggested that sanitation intervention was not as effective in reducing waterborne diseases. Recommendations are made for successive one-component interventions focusing on catchment management to ensure protection of current and alternative water supplies.     

零陵区中小学校饮用水卫生现状及介水传染病调查

目的了解零陵区中小学校饮用水卫生现状及介水传染病的发病情况,为进一步改善饮用水质量,预防介水传染病的发生和流行提供科学依据。方法 按照国家水质分析标准方法对该区16所中小学校生活饮用水进行分析,并拟定调查表,采用现状加回顾性的流行病学调查方法对饮用该水的学生进行介水传染病发病情况的调查。结果该区中小学校饮用水的合格率仅为25.00%,不合格项目为细菌总数、总大肠菌群、游离性余氯;近1年16所学校饮水学生的肠炎、细菌性痢疾、甲型肝炎的发病率分别为5.68%、0.34%、0.09%。结论零陵区中小学校饮用水存在微生物污染,导致了介水传染病的发生。     

Viral outbreaks and communicable health hazards due to devastating floods in Pakistan

Pakistan is a developing country that has a population of 190 million people and faces a huge burden of viral diseases. Every year during monsoon season heavy rain fall and lack of disaster management skills potentially increase the transmission of waterborne diseases, vector borne diseases and viral outbreaks. Due to severe flooding, thousands of people lose their lives and millions are displaced each year. In most of the cases the children who lose their family members are forced into illegal professions of begging, child labor and prostitution which make them prone to sexually transmitted infections. Up to date, no scientific study has been conducted nationwide to illustrate epidemiological patterns of waterborne diseases, vector borne diseases and viral epidemics during flash flood. Mosquito sprays would not be a sufficient approach for dengue eradication; mass awareness, larvicide and biological control by Guppy fishes are also effective strategies to overcome dengue problem. International health bodies and non-governmental organizations must take note of this alerting situation and take adequate steps such as financial/medical aid in order to defeat the after-effects of flood.