First pandemic A (H1N1) pdm09 outbreak in a private school, Bangkok, Thailand, June 2009.

OBJECTIVE: On June 9, 2009, the Thailand Ministry of Public Health received their first report of an outbreak of the pandemic A (HIN1) pdm09 that occurred in a school. The authors conducted a study to describe the epidemiological characteristics of the outbreak and its resurgence, estimate the basic reproduction number (R) and review recommendations for prevention and control. MATERIAL AND METHOD: Active case finding in the school and reviewing reports to the national surveillance system identified 184 students infected by the new virus. A survey described the illness in the students and the prevention and control measures taken by the school. The basic reproduction number was estimated from data in the early epidemic phase. The other survey was done to assess factors contributing to the resurgence of the outbreak. RESULTS: Students with the pandemic A (HINI) pdm09 had a mild illness resembling seasonal influenza. Overcrowding in the classroom and activities that mixed students from different classes contributed to transmission in the school. The basic reproduction number for this school-based setting is 3.58. The second outbreak occurred because of poor monitoring of absenteeism and management of ill students. CONCLUSION: This was the first outbreak ofthepandemic A (HIN1) pdm09 in Thailand. The source could not be identified. Effective control measures monitoring, screening, strict personal hygiene and proper management of ill students.

Lessons from the 2006 Louisiana health and population survey.

The 2005 hurricane season caused extensive damage and induced a mass migration of approximately 1.1 million people from southern Louisiana in the United States. Current and accurate estimates of population size and demographics and an assessment of the critical needs for public services were required to guide recovery efforts. Since forecasts using pre-hurricane data may produce inaccurate estimates of the post-hurricane population, a household survey in 18 hurricane-affected parishes was conducted to provide timely and credible information on the size of these populations, their demographics and their condition. This paper describes the methods used, the challenges encountered, and the key factors for successful implementation. This post-disaster survey was unique because it identified the needs of the people in the affected parishes and quantified the number of people with these needs. Consequently, this survey established new population and health indicator baselines that otherwise would have not been available to guide the relief and recovery efforts in southern Louisiana.

Are nitrate levels in groundwater stable over time?

Epidemiologists often use a retrospective study design to examine for associations between an exposure and the occurrence of adverse health effects. Several of these studies used this approach to examine for an association between elevated levels of nitrate in drinking water and related health effects such as methemoglobinemia, cancer, neural tube effects, or spontaneous abortions. Often, data on exposures that occurred before these health outcomes were not available. Consequently, researchers use measurements of exposures at the time of the study to represent exposures that occurred before people developed these conditions. An opportunity to examine the stability of nitrate in water occurred during a survey of private water wells in nine Midwestern states. In this survey, water samples from 853 homes with drilled wells were collected in May 1994 and in September 1995 and nitrate-nitrogen (nitrate-N) was measured by the colorimetric cadmium reduction method. Nitrate-N levels from the same well over time were assessed by a mixed-effects analysis of variance. Analysis showed no significant difference in between the initial level and those measured 16 months later. Furthermore, analysis showed that most of the variance in the nitrate concentrations in well water was due to well-to-well variation (89%) rather than to residual error (12%). This observation showed that a single measurement of nitrate in water from drilled wells could represent longer periods of exposure.

Maternal exposure to polybrominated and polychlorinated biphenyls: infant birth weight and gestational age.

Understanding the influence of maternal exposures on gestational age and birth weight is essential given that pre-term and/or low birth weight infants are at risk for increased mortality and morbidity. We performed a retrospective analysis of a cohort exposed to polybrominated biphenyls (PBB) through accidental contamination of cattle feed and polychlorinated biphenyls (PCB) through residual contamination in the geographic region. Our study population consisted of 444 mothers and their 899 infants born between 1975 and 1997. Using restricted maximum likelihood estimation, no significant association was found between estimated maternal serum PBB at conception or enrollment PCB levels and gestational age or infant birth weight in unadjusted models or in models that adjusted for maternal age, smoking, parity, infant gender, and decade of birth. For enrollment maternal serum PBB, no association was observed for gestational age. However, a negative association with high levels of enrollment maternal serum PBB and birth weight was suggested. We also examined the birth weight and gestational age among offspring of women with the highest (10%) PBB or PCB exposure, and observed no significant association. Because brominated compounds are currently used in consumer products and therefore, are increasingly prevalent in the environment, additional research is needed to better understand the potential relationship between in utero exposure to brominated compounds and adverse health outcomes.

Key factors for civilian injuries and deaths from exploding landmines and ordnance.

OBJECTIVE: To identify risk factors for death or injury from landmines and ordnance in Kabul City, Afghanistan, so programs can target preventive actions. METHODS: Active surveillance in hospitals and communities for injuries and deaths from landmine and ordnance explosions in Kabul City. RESULTS: Of the 571 people the authors identified during the 25-month period, 161 suffered a traumatic amputation and 94 were killed from a landmine or ordnance explosion. Of those asked, 19% of victims had received mine awareness education before the incident, and of those, the majority was injured while handling or playing with an explosive device. Most victims were young males with a few years of education. The occupation types most at risk were students and laborers, and unemployment was common among the victims. Collecting wood or paper and playing with or handling an explosive were the most frequent activities associated with injuries and deaths. CONCLUSIONS: From May 1996 to July 1998, explosions from landmines and ordnance claimed 571 victims and were an important preventable cause of injury and death among people in Kabul City. Prevention strategies should focus on high-risk groups and changing risky behaviors, such as tampering with explosive devices.

Inorganic arsenic in cooked rice and vegetables from Bangladeshi households.

Many Bangladeshi suffer from arsenic-related health concerns. Most mitigation activities focus on identifying contaminated wells and reducing the amount of arsenic ingested from well water. Food as a source of arsenic exposure has been recently documented. The objectives of this study were to measure the main types of arsenic in commonly consumed foods in Bangladesh and estimate the average daily intake (ADI) of arsenic from food and water. Total, organic and inorganic, arsenic were measured in drinking water and in cooked rice and vegetables from Bangladeshi households. The mean total arsenic level in 46 rice samples was 358 microg/kg (range: 46 to 1,110 microg/kg dry weight) and 333 microg/kg (range: 19 to 2,334 microg/kg dry weight) in 39 vegetable samples. Inorganic arsenic calculated as arsenite and arsenate made up 87% of the total arsenic measured in rice, and 96% of the total arsenic in vegetables. Total arsenic in water ranged from 200 to 500 microg/L. Using individual, self-reported data on daily consumption of rice and drinking water the total arsenic ADI was 1,176 microg (range: 419 to 2,053 microg), 14% attributable to inorganic arsenic in cooked rice. The ADI is a conservative estimate; vegetable arsenic was not included due to limitations in self-reported daily consumption amounts. Given the arsenic levels measured in food and water and consumption of these items, cooked rice and vegetables are a substantial exposure pathway for inorganic arsenic. Intervention strategies must consider all sources of dietary arsenic intake.

Menstrual function among women exposed to polybrominated biphenyls: a follow-up prevalence study.

BACKGROUND: Alteration in menstrual cycle function is suggested among rhesus monkeys and humans exposed to polybrominated biphenyls (PBBs) and structurally similar polychlorinated biphenyls (PCBs). The feedback system for menstrual cycle function potentially allows multiple pathways for disruption directly through the hypothalamic-pituitary-ovarian axis and indirectly through alternative neuroendocrine axes. METHODS: The Michigan Female Health Study was conducted during 1997-1998 among women in a cohort exposed to PBBs in 1973. This study included 337 women with self-reported menstrual cycles of 20-35 days (age range: 24-56 years). Current PBB levels were estimated by exponential decay modeling of serum PBB levels collected from 1976-1987 during enrollment in the Michigan PBB cohort. Linear regression models for menstrual cycle length and the logarithm of bleed length used estimated current PBB exposure or enrollment PBB exposure categorized in tertiles, and for the upper decile. All models were adjusted for serum PCB levels, age, body mass index, history of at least 10% weight loss in the past year, physical activity, smoking, education, and household income. RESULTS: Higher levels of physical activity were associated with shorter bleed length, and increasing age was associated with shorter cycle length. Although no overall association was found between PBB exposure and menstrual cycle characteristics, a significant interaction between PBB exposures with past year weight loss was found. Longer bleed length and shorter cycle length were associated with higher PBB exposure among women with past year weight loss. CONCLUSION: This study suggests that PBB exposure may impact ovarian function as indicated by menstrual cycle length and bleed length. However, these associations were found among the small number of women with recent weight loss suggesting either a chance finding or that mobilization of PBBs from lipid stores may be important. These results should be replicated with larger numbers of women exposed to similar lipophilic compounds.

Tetramethylenedisulfotetramine: old agent and new terror.

Tetramethylenedisulfotetramine has accounted for numerous intentional and unintentional poisonings in China. In May 2002, the first known case of human illness in the United States caused by tetramethylenedisulfotetramine, a banned neurotoxic rodenticide from China, occurred in New York City. The clinical presentation after tetramethylenedisulfotetramine exposure is dose dependent, and the most recognized complication is status epilepticus. Poisonings may be fatal within hours. No known antidote exists, and treatment is mainly supportive. Anecdotal reports, case reports, and 2 animal studies suggest possible success with certain pharmacologic interventions, including pyridoxine and chelation therapy. Pesticide and rodenticide poisonings, whether intentional or unintentional, pose a serious threat to populations, and the availability of a banned rodenticide such as tetramethylenedisulfotetramine, with its associated morbidity and lethality, is a serious public health concern. Given the recent case report that confirms the presence of tetramethylenedisulfotetramine in the United States, the toxicity of the compound, its unique physical properties, the absence of an antidote, and the history of its use as an agent of intentional mass poisoning, public health entities have undertaken educational efforts to inform the public, health care providers, and emergency personnel of this potentially lethal rodenticide.

Time to menopause in relation to PBBs, PCBs, and smoking.

OBJECTIVES: Because halogenated biphenyl exposure is suspected to disrupt endocrine function, we assessed time to menopause in women aged 24 years and older who were exposed orally to polybrominated biphenyls (PBBs) and polychlorinated biphenyls (PCBs) (n = 874). We also examined smoking in relation to menopause. METHODS: To define menopausal status, women were interviewed in 1997 and asked whether they had had any menstrual periods in the previous year, why their menstrual periods had stopped (e.g. surgery), and age at their last menstrual period. Serum PBB and PCB taken at enrollment (1976-1978) into the Michigan PBB registry was used as the measure of halogenated biphenyl exposure. Women whose menopause occurred before their PBB exposure were excluded. Proportional hazard modeling was used to analyze the "risk" for menopause in relation to exposure. Premenopausal women contributed person-time until their interview date, at which time they were censored. RESULTS: We did not find an association between either PBB or PCB exposure and time to menopause. Women who were current smokers had a shorter time to menopause than never smokers (menopause ratio 2.02, 95% C.I. 1.21-3.37). Time to menopause was shortest among women who reported started smoking when they were <18 years of age, smoked at least 20 cigarettes per day, or had at least 10 pack-years of smoking.

Persistence of pharmaceutical compounds and other organic wastewater contaminants in a conventional drinking-water-treatment plant.

In a study conducted by the US Geological Survey and the Centers for Disease Control and Prevention, 24 water samples were collected at selected locations within a drinking-water-treatment (DWT) facility and from the two streams that serve the facility to evaluate the potential for wastewater-related organic contaminants to survive a conventional treatment process and persist in potable-water supplies. Stream-water samples as well as samples of raw, settled, filtered, and finished water were collected during low-flow conditions, when the discharge of effluent from upstream municipal sewage-treatment plants accounted for 37-67% of flow in stream 1 and 10-20% of flow in stream 2. Each sample was analyzed for 106 organic wastewater-related contaminants (OWCs) that represent a diverse group of extensively used chemicals. Forty OWCs were detected in one or more samples of stream water or raw-water supplies in the treatment plant; 34 were detected in more than 10% of these samples. Several of these compounds also were frequently detected in samples of finished water; these compounds include selected prescription and non-prescription drugs and their metabolites, fragrance compounds, flame retardants and plasticizers, cosmetic compounds, and a solvent. The detection of these compounds suggests that they resist removal through conventional water-treatment processes. Other compounds that also were frequently detected in samples of stream water and raw-water supplies were not detected in samples of finished water; these include selected prescription and non-prescription drugs and their metabolites, disinfectants, detergent metabolites, and plant and animal steroids. The non-detection of these compounds indicates that their concentrations are reduced to levels less than analytical detection limits or that they are transformed to degradates through conventional DWT processes. Concentrations of OWCs detected in finished water generally were low and did not exceed Federal drinking-water standards or lifetime health advisories, although such standards or advisories have not been established for most of these compounds. Also, at least 11 and as many as 17 OWCs were detected in samples of finished water. Drinking-water criteria currently are based on the toxicity of individual compounds and not combinations of compounds. Little is known about potential human-health effects associated with chronic exposure to trace levels of multiple OWCs through routes such as drinking water. The occurrence in drinking-water supplies of many of the OWCs analyzed for during this study is unregulated and most of these compounds have not been routinely monitored for in the Nation's source- or potable-water supplies. This study provides the first documentation that many of these compounds can survive conventional water-treatment processes and occur in potable-water supplies. It thereby provides information that can be used in setting research and regulatory priorities and in designing future monitoring programs. The results of this study also indicate that improvements in water-treatment processes may benefit from consideration of the response of OWCs and other trace organic contaminants to specific physical and chemical treatments.

The application of geographic information systems and global positioning systems in humanitarian emergencies: lessons learned, programme implications and future research.

Geographic information systems (GIS), global positioning systems and remote sensing have been increasingly used in public health settings since the 1990s, but application of these methods in humanitarian emergencies has been less documented. Recent areas of application of GIS methods in humanitarian emergencies include hazard, vulnerability, and risk assessments; rapid assessment and survey methods; disease distribution and outbreak investigations; planning and implementation of health information systems; data and programme integration; and programme monitoring and evaluation. The main use of GIS in these areas is to provide maps for decision-making and advocacy, which allow overlaying types of information that may not normally be linked. GIS is also used to improve data collection in the field (for example, for rapid health assessments or mortality surveys). Development of GIS methods requires further research. Although GIS methods may save resources and reduce error, initial investment in equipment and capacity building may be substantial. Especially in humanitarian emergencies, equipment and methodologies must be practical and appropriate for field use. Add-on software to process GIS data needs to be developed and modified. As equipment becomes more user-friendly and costs decrease, GIS will become more of a routine tool for humanitarian aid organisations in humanitarian emergencies, and new and innovative uses will evolve.

Polybrominated biphenyl exposure and benign breast disease in a cohort of US women.

PURPOSE: We examined the relation between serum polybrominated biphenyl (PBB) levels and the risk of benign breast disease in a cohort of Michigan women unintentionally exposed to PBBs in 1973 and interviewed in 1997. METHODS: We used extended Cox models to generate adjusted hazard ratios; models included polychlorinated biphenyls (PCBs) and risk factors for benign breast disease reported in the literature. RESULTS: Two hundred fourteen (23%) of 951 women reported benign breast disease diagnosed by a physician. Compared with women with low PBB exposure, benign breast disease was not reported more frequently among those with moderate (>1-12 parts per billion [ppb]), (odds ratio [OR] 1.08, 95% confidence interval [CI] = 0.80-1.45), or high (>12 ppb), (OR 0.79, 95% CI = 0.46-1.38) PBB exposure. PCB exposure was also not associated with self-reported physician-diagnosed benign breast disease. Age, smoking, and annual number of health-care provider visits were significantly associated with benign breast disease. CONCLUSIONS: Our analysis did not demonstrate an association between serum PBB level and self- reported physician-diagnosed benign breast disease. We did observe an increased risk of benign breast disease for women who smoked, an association that has not been consistently found in previous studies.

Growth in girls exposed in utero and postnatally to polybrominated biphenyls and polychlorinated biphenyls.

BACKGROUND: Accidental contamination with polybrominated biphenyls (PBBs) of the Michigan food supply in 1973 led to the exposure of more than 4000 individuals and to formation of the PBB cohort registry (1976-1979). At enrollment, measurements were taken of serum PBB and polychlorinated biphenyl (PCB), possible endocrine disrupting chemicals. METHODS: We examined the association of estimated PBB and PCB exposure during pregnancy with current height and weight in 308 daughters, 5-24 years of age (mean age 15.2 years), born to women in the cohort. We estimated prenatal PBB exposure using maternal enrollment serum PBB and a model of PBB elimination. Prenatal PCB exposure was estimated using maternal enrollment serum PCB because background-level exposure through diet was ongoing. Self-reported height and weight were obtained from a 1997-1998 health survey. RESULTS: We found no association between prenatal PBB exposure and either daughter's current height or daughter's weight adjusted for height; however, prenatal PCB exposure above 5 parts per billion was associated with reduced weight adjusted for height. Exposure through breastfeeding did not modify the association. CONCLUSIONS: Mothers with PCB levels above the median had daughters whose current weights were 11 pounds lower than that of the daughters whose mothers had levels below the median. This study provides evidence that prenatal exposure to PCBs may affect growth.