Infectious hepatitis; report of an outbreak of 24 cases

In an epidemic of 24 cases of infectious hepatitis in a small lumbering community, the majority of cases occurred in children. Sixteen of them were pupils in one school. The school apparently was the focus for the spread of infection, which is thought to have been through contact between persons. Five multiple case households with eight secondary cases were observed. With one exception, gamma globulin was not used for the prophylaxis of infectious hepatitis in families in which one member had the disease.     

INFECTIOUS HEPATITIS—Report of an Outbreak of 24 Cases

In an epidemic of 24 cases of infectious hepatitis in a small lumbering community, the majority of cases occurred in children. Sixteen of them were pupils in one school. The school apparently was the focus for the spread of infection, which is thought to have been through contact between persons. Five multiple case households with eight secondary cases were observed. With one exception, gamma globulin was not used for the prophylaxis of infectious hepatitis in families in which one member had the disease.     

School’s Out: Seasonal Variation in the Movement Patterns of School Children

School children are core groups in the transmission of many common infectious diseases, and are likely to play a key role in the spatial dispersal of disease across multiple scales. However, there is currently little detailed information about the spatial movements of this epidemiologically important age group. To address this knowledge gap, we collaborated with eight secondary schools to conduct a survey of movement patterns of school pupils in primary and secondary schools in the United Kingdom. We found evidence of a significant change in behaviour between term time and holidays, with term time weekdays characterised by predominately local movements, and holidays seeing much broader variation in travel patterns. Studies that use mathematical models to examine epidemic transmission and control often use adult commuting data as a proxy for population movements. We show that while these data share some features with the movement patterns reported by school children, there are some crucial differences between the movements of children and adult commuters during both term-time and holidays.     

Epidemiological survey for the prevalence of overweight and abdominal obesity in Greek adolescents

This study was designed to provide estimates of overweight (OW), obesity (OB), and abdominal OB (AO) in a representative sample of adolescents throughout the whole of Greece. A total of 14,456 adolescents aged 13-19 years (6,677 boys and 7,779 girls) had direct measurements (height, weight, waist circumference (WC)) taken at school during 2003. The overall prevalence of OW including OB in the population studied was 29.4% in boys and 16.7% in girls. OB prevalence was also higher in boys than in girls (6.1% vs. 2.7%), whereas prevalence of AO was higher in girls than in boys (21.7% vs. 13.5%). Rates of OW, OB, and AO were significantly more prevalent in the Greek than in the foreign male population (immigrants). OW% in adolescent girls was independently associated with smoking and alcohol consumption. The prevalence of OW and OB in Greek adolescents is high, particularly in boys, comparable with that reported for most Mediterranean European countries. AO, mainly in adolescent girls, also appears high. Preventive and treatment strategies are urgently needed to combat this OB epidemic in Greece.     

Changes in anthropometrical characteristics during two years in 6 year old children

The purpose of this study was to investigate changes in anthropometrical characteristics during the last year (autumn-spring) in preschool and first year (autumn-spring) in school. Changes in anthropometrical characteristics during summer months were also studied (spring-autumn). The subjects were 130 boys and 122 girls, 6 years of age at the beginning of the investigation. The body height and mass were measured and the BMI (kg/m2) was calculated. In total, eight skinfolds, 10 girths and two bone widths were measured. In boys, the body height and mass were higher than in girls, while the skinfold thicknesses were thicker in girls. There were only very few significant differences between sexes in girth parameters. The width parameters were higher in boys. Our results indicated that there were more significant changes in skinfold thickness, girths and width parameters during winter in preschool in comparison with first year in school in boys, while there were only a very few significant changes during summer months in boys. In contrast, there were more significant changes in school in girls. The Spearman correlations between baseline and after 6, 12 and 18 months of study indicated that the tracking of body height was high in boys and girls. Body mass tracking was high in girls and moderate in boys, while BMI tracking was moderate in both groups. The tracking coefficients of skinfold thicknesses were relatively stable during the two years of study and mostly at the moderate level (r = 0.3-0.6). Tracking coefficients of girths measures were at moderate level, but lower in boys in comparison with girls. It was concluded that social changes and probably changes in the physical activity during transition from preschool to school slightly influenced the measured anthropometrical parameters.     

Stability of the Association between Birth Weight and Childhood Overweight during the Development of the Obesity Epidemic

Objective: To assess whether changes in the birth weight distribution or changes in the association of birth weight with the later risk of childhood overweight have contributed to the development of the obesity epidemic. Research Methods and Procedures: A Danish population‐based cohort study of 124,615 girls and 128,346 boys (ages 6 to 13 years), born between 1936 and 1983, were studied. Birth weight and annual measurements of height and weight were obtained from school health records. Overweight was defined by BMI in relation to internationally accepted criteria. The relative risk of being overweight by birth weight was calculated separately for each age, sex, and time period. Results: The birth weight distribution remained relatively stable over time. Compared with children with a birth weight of 3.0 to 3.5 kg, the risk of overweight increased consistently with each increase in birth weight category among girls and boys and at all ages between 6 and 13 years. Furthermore, the association between birth weight and increased risk of overweight in childhood remained stable across a 48‐year period. Discussion: The increase in the prevalence of overweight could not be explained by time trends in the distribution of birth weight or by changes in the association between birth weight and the later risk of overweight over time. This implies that, unless the prenatal environment influences the later risk of overweight without increasing birth weight, the environmental influences contributing to the obesity epidemic in children of school age operate in the early postnatal period.     

Health behaviours of school children in northwestern Poland in 2000

The 3568 final class primary school in northwestern Poland were investigated between January and June 2000. The youths fulfilled the questionnaire concerned health behaviour issues. The 56% of school children do not drink milk daily, 68% do not eat raw vegetables, and 35% do not take any food at school. Every second boy and every fourth girl brushes his/her teeth too rarely. 23% of boys and 10% of girls smoke cigarettes. About 30% of boys and 20% of girls declare that it “happens” that they drink alcohol. 15% boys and 8% of girls report that they tried to use at least one of the psychoactive substances. Physical exercises are performed by 28% of boys and 36% of girls and 45% and 28% respectively watch TV four or more hours a day.     

Psychosocial factors associated with smoking and drinking among Japanese early adolescent boys and girls: Cross-sectional study

Background  

Smoking and drinking alcohol among early adolescents are serious public health concerns, but few studies have been conducted in Japan to assess their prevalence and etiology. A regional survey was conducted in eight schools in two Japanese school districts to identify psychosocial factors associated with smoking and drinking behaviors for boys and girls.     

Estimating spatial coupling in epidemiological systems: a mechanistic approach

In recent years, ecologists and epidemiologists have paid increasing attention to the influence of spatial structure in shaping the dynamics and determining the persistence of populations. This is fundamentally affected by the concept of 'coupling'—the flux of individuals moving between separate populations. In this paper, we contrast how coupling is typically implemented in epidemic models with more detailed approaches. Our aim is to link the popular phenomenological formulations with the results of mechanistic models. By concentrating on the behaviour of simple epidemic systems, we relate explicit movement patterns with observed levels of coupling, validating the standard formulation. The analysis is then extended to include a brief study of how the correlation between stochastic populations is affected by coupling, the underlying deterministic dynamics and the relative population sizes.     

Sexual development of patients with isochromosomes for the long arm of the X chromosome

Summary The sexual development of 14 girls with non-mosaic monocentric 46,X,iXq karyotype was studied. Seven out of eight girls were found to have immature secondary sexual characteristics and amenorrhoea, a finding greatly contrasting with that in Triplo-X girls. The relative ineffectiveness of the isochromosome Xq in maintaining fertility may be due to the absence of one short arm, which probably also carries a gonadal determinant. Alternatively, the presence of two inactivation sites on one isochromosome may render the gonadal determinants inactive at an important stage in gonadal development.     

Nutritional status of adolescents in the context of the Moroccan nutritional transition: the role of parental education

In Morocco, the beginning of the nutritional transition is closely linked to social and economic transformations and changes in behaviour and traditional lifestyles. The objective of this study is to describe the current pattern of food consumption and the nutritional status of adolescents in the province of Ouarzazate and its association with parents' educational level. The sample comprises 327 high school students from Ouarzazate: 135 (41.3%) boys and 192 (58.7%) girls (age range 15-20 years). For both boys and girls, the results show lower height and BMI z-scores than the WHO reference values. Adolescents whose parents have a low educational level have lower height/age and BMI/age z-scores than those whose fathers have a high educational level. No differences are observed in total daily energy intake depending on fathers' educational level, but the energy provided by lipids is higher in adolescents whose fathers have a high educational background. The quality of fats consumed (MUFA+PUFA/SFA) is better among those boys whose fathers have low education, but no differences are observed for girls. The process of nutritional transition is not uniform in the sample, but depends on the socioeconomic characteristics of population groups, which include, among others, accessibility of certain food, differences in habits and lifestyles related to energy expenditure, and higher prevalence of overweight and obesity in more favoured groups.     

Hypoxia and the antipredator behaviours of fishes

Hypoxia is a phenomenon occurring in marine coastal areas with increasing frequency. While hypoxia has been documented to affect fish activity and metabolism, recent evidence shows that hypoxia can also have a detrimental effect on various antipredator behaviours. Here, we review such evidence with a focus on the effect of hypoxia on fish escape responses, its modulation by aquatic surface respiration (ASR) and schooling behaviour. The main effect of hypoxia on escape behaviour was found in responsiveness and directionality. Locomotor performance in escapes was expected to be relatively independent of hypoxia, since escape responses are fuelled anaerobically. However, hypoxia decreased locomotor performance in some species (Mugilidae) although only in the absence of ASR in severe hypoxia. ASR allows fish to show higher escape performance than fish staying in the water column where hypoxia occurs. This situation provides a trade-off whereby fish may perform ASR in order to avoid the detrimental effects of hypoxia, although they would be subjected to higher exposure to aerial predation. As a result of this trade-off, fishes appear to minimize surfacing behaviour in the presence of aerial predators and to surface near shelters, where possible. For many fish species, schooling can be an effective antipredator behaviour. Severe hypoxia may lead to the disruption of the school unit. At moderate levels, hypoxia can increase school volume and can change the shuffling behaviour of individuals. By altering school structure and dynamics, hypoxia may affect the well functioning of schooling in terms of synchronization and execution of antipredator manoeuvres. School structure and volume appear to be the results of numerous trade-offs, where school shape may be dictated by the presence of predators, the need for energy saving via hydrodynamic advantages and oxygen level. The effects of hypoxia on aquatic organisms can be taxon specific. While hypoxia may not necessarily increase the vulnerability of fish subject to predation by other fish (since feeding in fish also decreases in hypoxia), predators from other taxa such as birds, jellyfish or aquatic mammals may take advantage of the detrimental effects of hypoxia on fish escape ability. Therefore, the effect of hypoxia on fish antipredator behaviours may have major consequences for the composition of aquatic communities.     

The effect of risk-taking behaviour in epidemic models

We study an epidemic model that incorporates risk-taking behaviour as a response to a perceived low prevalence of infection that follows from the administration of an effective treatment or vaccine. We assume that knowledge about the number of infected, recovered and vaccinated individuals has an effect in the contact rate between susceptible and infectious individuals. We show that, whenever optimism prevails in the risk behaviour response, the fate of an epidemic may change from disease clearance to disease persistence. Moreover, under certain conditions on the parameters, increasing the efficiency of vaccine and/or treatment has the unwanted effect of increasing the epidemic reproductive number, suggesting a wider range of diseases may become endemic due to risk-taking alone. These results indicate that the manner in which treatment/vaccine effectiveness is advertised can have an important influence on how the epidemic unfolds.     

Epidemiologic and economic effectiveness of school closure during influenza epidemics and pandemics

Epidemiologic and economic effectiveness of school closure during influenza epidemics and pandemics is discussed. Optimal effect of school closure is observed when this measure is taken at the start of the epidemic or pandemic and for a sufficiently long time. School closure during high morbidity among schoolchildren, in the middle (at the peak) and by the end of epidemic or pandemic does not influence significantly the spread of influenza or morbidity. Significant economic losses and other negative consequences of school closure are noted. School closure may be the most appropriate during the emergence of influenza pandemic when the pandemic vaccine is not yet available, however timely mass immunization of schoolchildren against influenza may be a more appropriate measure than school closure for the reduction of influenza morbidity and spread during seasonal influenza epidemics.     

The relationship between violent video games,acculturation, and aggression among Latino adolescents

Multiple factors are involved in the occurrence of aggressive behavior. The purpose of this study was to evaluate the hypotheses that Latino middle school children exposed to higher levels of video game playing will exhibit a higher level of aggression and fighting compared to children exposed to lower levels and that the more acculturated middle school Latino children will play more video games and will prefer more violent video games compared to less acculturated middle school Latino children. This study involved 5,831 students attending eight public schools in Texas. A linear relationship was observed between the time spent playing video games and aggression scores. Higher aggression scores were significantly associated with heavier video playing for boys and girls (p < 0.0001). The more students played video games, the more they fought at school (p < 0.0001). As Latino middle school students were more acculturated, their preference for violent video game playing increased, as well as the amount of time they played video games. Students who reported speaking more Spanish at home and with their friends were less likely to spend large amounts of time playing video games and less likely to prefer violent video games (p < 0.05).     

Virginity Testing: Managing Sexuality in a Maturing HIV/AIDS Epidemic

KwaZulu-Natal province in South Africa is currently the site of the world's fastest growing HIV/AIDS epidemic, where it is estimated that between 30 and 40 percent of the adult population is seropositive for HIV. With support from local politicians and members of various government ministries, several self-styled guardians of tradition have emerged to form organizations that advocate and conduct regular virginity testing of girls. Reference to the current HIV/AIDS epidemic is central to calls for greater support of this practice. Drawing on original research among Zulu-speaking people in the periurban communities of Durban, this article examines the sociocultural construction of HIV/AIDS and locates the growing popularity of virginity testing within a gendered meaning-making process consistent with commonly held beliefs that the epidemic is the result of women being sexually "out of control." With the social impact of AIDS starting to take its toll in the forms of increasing AIDS-related deaths and a growing population of orphans, I argue that virginity testing is an attempt to manage the epidemic by exerting greater control over women and their sexuality. In addition, virginity testing of girls helps to draw attention away from the role of men in the maturing epidemic, consideration of which has been conspicuously absent in the popular discourse on AIDS at all levels of South African society.     

Variational data assimilation with epidemic models

Mathematical modelling is playing an increasing role in developing an understanding of the dynamics of communicable disease and assisting the construction and implementation of intervention strategies. The threat of novel emergent pathogens in human and animal hosts implies the requirement for methods that can robustly estimate epidemiological parameters and provide forecasts. Here, a technique called variational data assimilation is introduced as a means of optimally melding dynamic epidemic models with epidemiological observations and data to provide forecasts and parameter estimates. Using data from a simulated epidemic process the method is used to estimate the start time of an epidemic, to provide a forecast of future epidemic behaviour and estimate the basic reproductive ratio. A feature of the method is that it uses a basic continuous-time SIR model, which is often the first point of departure for epidemiological modelling during the early stages of an outbreak. The method is illustrated by application to data gathered during an outbreak of influenza in a school environment.     

家庭因素对女儿初潮年龄的影响

作者于1987年4月,用回亿法在医学院及护校作了七百余例女生的初潮年龄的调查并作了统计分析。结果表明,父母的职业及学历对女儿初潮年龄有极显著的影响。按职业分,农民和家庭妇女组的初潮年龄最高;按学历分,文盲组的初潮年龄最高,且初潮年龄随父母文化程度增高而递减,没有看出父母出生地对女儿初潮年龄的影响。另外,可以看到初潮年龄提前的趋势。     

Sleep patterns of day-working, evening high-schooled adolescents of São Paulo, Brazil

Children who grow up in developing countries of the world must work to help financially support their families, and they must also attend school. We investigated the impact of work on the sleep of working vs. nonworking high school students. Twenty-seven S?o Paulo, Brazil, public high school students (eight male and eight female working students plus six nonworking female and five nonworking male students) 14-18 yrs of age who attended school Monday-Friday between 19:00 to 22:30h participated. A comprehensive questionnaire about work and living conditions, health status, and diseases and their symptoms was also answered. The activity level and rest pattern (sleep at night and napping during the day) were continuously assessed by wrist actigraphy (Ambulatory Monitoring, USA). The main variables were analyzed by a two-factor ANOVA with application of the Tukey HSD test for multiple comparisons, and the length of sleep during weekdays vs. weekends was compared by Student t-test. Working students went to sleep earlier weekends [F(1,23)=6.1; p=0.02] and woke up earlier work days than nonworking students [F(1,23) = 17.3; p = 0.001]. The length of nighttime sleep during weekdays was shorter among all the working [F(1,23)= 16.7; p <0.001] than all the nonworking students. The sleep duration of boys was shorter than of girls during weekends [F(1,23)= 10.8; p <0.001]. During weekdays, the duration of napping by working and nonworking male students was shorter than nonworking female students. During weekdays working girls took the shortest naps [F(1,23)= 5.6; p = 0.03]. The most commonly reported sleep complaint during weekdays was difficulty waking up in the morning [F(1,23) = 6.5; p = 0.02]. During weekdays, the self-perceived sleep quality of working students was worse than nonworking students [F(1,23) = 6.2; p = 0.02]. The findings of this study show that work has negative effects on the sleep of adolescents, with the possible build-up of a chronic sleep debt with potential consequent impact on quality of life and school learning.     

Evidence for recent changes in sexual behaviour in homosexual men in England and Wales

Over 80% of cases of Acquired Immune Deficiency Syndrome (AIDS) in England and Wales have occurred in homosexual men. Changes in sexual behaviour in this group may have a substantial influence on the incidence of Human Immunodeficiency Virus (HIV) infection and will therefore be crucial in determining future cases of AIDS. This paper critically weighs the indirect and direct evidence for changes in behaviour in homosexual men since the advent of the AIDS epidemic. The paper reports on falling incidence of gonorrhoea, hepatitis B and syphilis in homosexual men, the changes being most marked from 1985 onwards. Data on temporal trends in HIV prevalence and incidence in homosexual men are reviewed. These suggest that the maximum incidence of HIV infection occurred in 1982-84 and may have fallen since then. Evidence for a concomitant change in sexual behaviour is reported from several sources. This points towards a recent change in sexual behaviour characterized by reduction in the numbers of partners and adoption of safer sexual practices. In some places change may have occurred as early as 1983. A change became apparent generally in 1985 and this appears to have been sustained in 1986-87. Nevertheless, a substantial proportion of homosexual men studied continue to practice high risk sexual practices, such as anal intercourse, including relationships with casual partners.