Norwalk virus gastroenteritis among Israeli soldiers: lack of evidence for flyborne transmission

BACKGROUND

Paired sera collected from subjects before and after a fly-control intervention trial conducted in the Israel Defense Force (IDF) were tested for seroconversion to Norwalk virus (NV) to examine the role of NV as a cause of diarrhea in this population and to ascertain whether flies might also be implicated in transmission.

MATERIALS AND METHODS

An enzyme-linked immunosorbent assay (ELISA), using recombinant NV capsid proteins (rNV) as antigen was employed to determine the seroconversion rate in a sample of 444 subjects.

RESULTS

During 11-week field training cycles, 18% of IDF soldiers who were tested had an NV infection defined as a > or = 4-fold rise in antibody, yielding a cumulative incidence of nearly one infection (0.95) per soldier per year. The rate of seroconversion was nearly twice as high among soldiers who recalled having diarrhea as among those who did not, but the rates did not differ significantly between soldiers in the fly intervention areas and those in the control areas.

CONCLUSION

NV is a common cause of enteric infections and diarrhea among Israeli soldiers who serve under field conditions, but unlike infections with Shigella and enterotoxigenic Escherichia coli, transmission of NV cannot be interrupted with an aggressive program of fly-control.

The brain decade in debate: IV. Chronobiology

The present article is the adapted version of an electronic symposium organized by the Brazilian Society of Neuroscience and Behavior (SBNeC) which took place on June 14, 2000. The text is divided into three sections: I. The main issues, II. Chronodrugs, and III. Methods. The first section is dedicated to the perspectives of chronobiology for the next decade, with opinions about the trends of future research being emitted and discussed. The second section deals mostly with drugs acting or potentially acting on the organism's timing systems. In the third section there are considerations about relevant methodological issues concerning data analysis.

Seasonality of birth in children (0-14 years) and young adults (0-29 years) with type 1 diabetes mellitus in Sardinia differs from that in the general population. The Sardinian Collaborative Group for Epidemiology of IDDM

A cohort of 1,118 children (0-14 years) and 810 adolescents and young adults (15-29 years) with type 1 diabetes mellitus (DM) diagnosed in Sardinia between 1989 and 1998 were analyzed for seasonality of month of birth, and compared to the pattern registered in 314,084 live births. Patients with DM of both age groups had a statistically significant different seasonality pattern from the general population, revealing an increased birth rate during the summer months, a mirror image of the seasonality of onset of disease.

Secular trends in the epidemiology of major infectious diseases among Israeli soldiers

BACKGROUND

Army personnel, albeit in general young and healthy, are at greater risk for infectious morbidity owing to higher crowding, compromised hygienic conditions, and exposure to new geographic and climatic factors. We describe the changing trends in the incidence of major infectious diseases of public health importance in the Israeli military: hepatitis A, measles, meningococcal disease, and diarrheal diseases.

METHODS

Departments of Epidemiology and Medical Statistics of the Israel Defense Forces Medical Corps monitor the incidence of infectious diseases within the military. Notifiable diseases are predefined and their reporting is mandatory.

RESULTS

The incidence of hepatitis has declined significantly since the introduction of prophylaxis with immune serum globulin in the 1970s, and complete control of outbreaks has been achieved. Outbreaks of diarrheal diseases have decreased, probably as a result of intensive control measures begun in the last decade. However, sporadic diarrheal morbidity continues to rise. The vaccination of recruits against Neisseria meningitidis was begun in 1994, following an increase in cases caused by serogroup C bacteria. So far, the program has proved efficacious in reducing morbidity. Measles morbidity in the military was much higher than in the civilian sector over the years. It has become negligible since 1995, when the first cohorts with 2 vaccination doses began their service.

CONCLUSION

Despite improvements in personal and environmental health measures, immunization remains the most efficient means for preventing infectious diseases in the military.

Seasonality of birth in children (0-14 years) with type 1 diabetes mellitus in Slovenia

The aim of this study was to find out whether there is seasonality of month of birth of children with diabetes in Slovenia and if so whether it differs from that of the general population. A cohort of 849 children and adolescents (0-14 years) with type 1 diabetes mellitus born between 1956 and 1998 were included in the study. Monthly and seasonal patterns of birth of the patients with diabetes were compared with the pattern of normal live births (n = 1,345,921) and the pattern of disease onset. Statistical analysis was made using Student's t-test to compare the means between the four seasons of the year, and single cosinor analysis for a period of 12 months. The children and adolescents with diabetes had a statistically significant different seasonality of month of birth compared to that of the general population, and an opposite pattern from the seasonality of month of onset of disease. The observations made are in accordance with observations made recently in other countries and support the hypothesis that a virus infection transmitted by the mother to the fetus during the annual viral epidemic induces the autoimmune process in the pancreatic beta-cells in genetically susceptible individuals who will subsequently develop clinical diabetes during childhood.

Measles epidemic in Israel-successful containment in the military

BACKGROUND

Measles vaccination at ages 12-15 months is a routine part of standard health care in developed countries. Nonetheless, the prevention and control of measles outbreaks remain a challenge, owing to incomplete or variable compliance with immunization programs and primary vaccine failure (approximately 5%). In Israel, vaccination coverage against measles is high, yet sero-epidemiological studies conducted in the early 1990s showed that 15% of 18-year-olds were unprotected.

METHODS

1994 there was a countrywide epidemic of measles, which spread to the military. The Israel Defense Forces Medical Corps immediately launched a wide-scale vaccination campaign, targeting primarily field units and training bases, where crowded living conditions are the rule.

RESULTS

The immunization campaign led to an abrupt cessation of morbidity in the military. In the civilian sector, where no intervention was undertaken, the epidemic continued for another 4 months.

CONCLUSIONS

Institutional measles outbreaks, especially in the presence of crowded conditions or high contact rates, may be effectively controlled by mass vaccination.

Rabies in Israel: decades of prevention and a human case

Animal rabies is endemic in Israel, with 50-80 laboratory-confirmed cases being diagnosed annually. Despite the high incidence among animals, human rabies has not occurred in Israel for almost four decades. This is likely due to the highly effective prevention policy implemented by the Ministry of Health, based on pre-exposure vaccination of populations at risk, post-exposure treatment, and updated rules. Notwithstanding the previous success, a human case occurred in 1996 when a soldier was bitten, while asleep, by an unidentified small animal, which according to his description was a rat or a mouse. Since injuries by these rodents do not require antirabies treatment, no antirabies post-exposure prophylaxis was administered. Five weeks later the soldier complained of fever and nausea with interchanging periods of rage and calm, confusion, and water aversion. His condition deteriorated gradually, leading to deep coma and death. Immunofluorescence examination of a skin biopsy was positive for rabies, and PCR of saliva revealed Lyssavirus genotype 1. We review the changes in the epizootiology of rabies in Israel, the trends of human exposure to animals, and the pre- and post-exposure prophylaxis guidelines, and discuss possible measures that could have been undertaken to prevent the eventuality of this case. This case of rabies, the first after a long period without human disease, accentuates the importance of strict adherence to prevention guidelines. Considerations of geography, epidemiology, and the circumstances of exposure are crucial in the treatment decision-making process.

Helicobacter pylori infection and subsequent peptic duodenal disease among young adults

BACKGROUND

Evidence for a causal relationship between presence of Helicobacter pylori (H. pylori) in gastric mucosa and development of peptic disease is based largely on intervention studies in which eradication of H. pylori led to healing of the lesion. The aim of this study was to assess the importance of H. pylori seropositivity for subsequent development of peptic disease in a prospective study design in young Israelis.

METHODS

A nested case-control serum bank study based on a systematic sample of male and female inductees to the Israel Defense Force. Twenty-nine cases of duodenal ulcer or duodenitis of moderate or higher severity, diagnosed between 1986 and 1995, were individually matched for age, sex, ethnicity, education and year of induction, with five healthy controls each. Presence of anti-H. pylori antibodies in the frozen stored sera was determined by ELISA.

RESULTS

The geometric mean titre of anti-H. pylori antibodies at baseline was significantly higher in cases (18. 3 U/ml) than controls (6.9 U/ml; P = 0.009). The matched odds ratio for peptic ulcer disease by seropositivity was 3.8 (95% CI : 1.4-10. 2). A stronger association was evident for subjects diagnosed > or =2 years after induction than those diagnosed earlier. The population attributable fraction was 56.6% (95% CI : 15.7-81.1).

CONCLUSIONS

Pre-existing infection with H. pylori, as determined by seropositivity, is an important determinant of development of duodenal ulcer or duodenitis in young Israelis, supporting the generalizability of an apparent causal association to diverse populations.

Seasonality of birth in children (0-14 years) with diabetes mellitus type 1 in Baden-Wuerttemberg, Germany

The aim of the study was to find out whether children with diabetes type 1 in Baden-Wuerttemberg present a pattern of seasonality in their month of birth. A cohort of 1,184 children and adolescents (0-14 years) diagnosed as having diabetes between January 1st, 1987 and June 30th, 1997 were included in the study. Monthly and seasonal patterns of birth of patients with diabetes were compared with the pattern of normal live births (n = 2,724,746) during the years 1972-1997 and the seasonality of onset of disease. Statistical analysis was made using Student's t-test to compare the means between four yearly seasons and single cosinor analysis for a period of 12 months. The children and adolescents with diabetes had a significantly different seasonality in month of birth pattern from that registered in the general population, demonstrating fewer births during the months April-June and July-September. This seasonality pattern also differs from those registered in Israel, Sardinia and Slovenia, in which the population with diabetes type 1 had most births during these months.

Safety and immunogenicity of two different lots of the oral, killed enterotoxigenic escherichia coli-cholera toxin B subunit vaccine in Israeli young adults

Enterotoxigenic Escherichia coli (ETEC) is one of the leading causes of diarrhea among Israeli soldiers serving in field units. Two double-blind placebo-controlled, randomized trials were performed among 155 healthy volunteers to evaluate the safety and immunogenicity of different lots of the oral, killed ETEC vaccine consisting of two doses of whole cells plus recombinantly produced cholera toxin B subunit (rCTB). The two doses of vaccine lot E005 and the first dose of vaccine lot E003 were well tolerated by the volunteers. However, 5 (17%) vaccinees reported an episode of vomiting a few hours after the second dose of lot E003; none of the placebo recipients reported similar symptoms. Both lots of vaccine stimulated a rate of significant antibody-secreting cell (ASC) response to CTB and to colonization factor antigen I (CFA/I) after one or two doses, ranging from 85 to 100% and from 81 to 100%, respectively. The rate of ASC response to CS2, CS4, and CS5 was slightly lower than the rate of ASC response induced to CTB, CFA/I, and CS1. The second vaccine dose enhanced the response to CTB but did not increase the frequencies or magnitude of ASC responses to the other antigens. The two lots of the ETEC vaccine induced similar rates of serum antibody responses to CTB and CFA/I which were less frequent than the ASC responses to the same antigens. Based on these safety and immunogenicity data, an efficacy study of the ETEC vaccine is under way in the Israel Defense Force.

Association in the seroprevalence of hepatitis A and herpes simplex-1 viruses in young adults in Israel

BACKGROUND

The rise in the standard of living of the Israeli population during recent decades has been accompanied by a significant decline in the prevalence of various viral diseases including hepatitis A (HAV). This trend is not reflected in the seroprevalence of herpes simplex (HSV) infection, which has remained stable during these years.

MATERIALS AND METHODS

The Public Health Branch of the Israel Defense Force (IDF) Medical Corps continuously draws a systematic, representative sample of male and female recruits on their 1st day of service, based on digit combinations of the military identification number. These recruits are asked to give a blood sample and to undergo a short interview. A quantitative determination of anti-HSV-1 and anti-HAV antibodies was performed.

RESULTS

In the present study that included 124 male and 98 female 18-year-old army recruits, 51.1% of the anti-HSV-positive subjects was also positive for anti-HAV, compared to 27% among anti-HSV-negative persons. Rate ratio (RR) for anti-HAV seropositivity between anti-HSV-1-positive and negative recruits was 1.86 (95% CI 1.3-2.7).

CONCLUSION

The present study suggests a strong association between the seroprevalence of both viruses.

Active versus passive immunization against hepatitis A in the Israel defence forces: a cost-benefit analysis

We compared cost-benefit and cost-effectiveness analyses of hepatitis A prevention with immune serum globulin (ISG) vs inactivated hepatitis A vaccine (iHAV) in the Israel Defence Forces. Personnel were grouped according to conditions and duration of service and analyses were performed based on maximum and minimum hepatitis A projected incidences for each group. For standing army soldiers in field units, iHAV is economically superior compared with ISG. For the five other groups studied, the reverse is true. Expected increases in production costs of ISG and expected decreases in costs of iHAV are likely to make iHAV more economical in the future.

Adverse reactions to smallpox vaccine: the Israel Defense Force experience, 1991 to 1996. A comparison with previous surveys

The aim of the present study was to assess the post-smallpox vaccination complication rate in a cohort of Israel Defense Force recruits enlisted in the calendar years 1991 to 1996 and to compare it with rates reported, in similar age groups, in large surveys during the 1960s. The overall complication rate was 0.4 per 10,000 vaccinees, and the rate of severe complications was very low, similar to previously published data. We conclude that among young healthy adults, vaccination with smallpox vaccine is relatively safe and is associated with a low rate of complications. Severe complications were very rare in this age group in our study. However, the complication rate is increasing with the increased percentage of primary vaccinees.

Differences in rhythms of enzymatic activity of maternal and fetal blood

Blood specimens were obtained at different daily times from the umbilical cord and brachial vein from 53 women within 10 minutes after delivery. Enzyme activities were measured in the white blood cells (WBCs) and serum of each sample. For each enzyme, the results were grouped according to sampling (delivery) times and arrayed to form a 24h time series. Separate time series were generated for maternal and fetal enzymes. Analysis of variance (ANOVA) and cosine best-fit analyses were applied to elucidate significant differences between enzyme activity patterns of mothers and fetuses with regard to time dependency, number of peaks, and acrophases. These and previously documented results indicate that not all mothers and fetuses have rhythms that are concordant. For some enzymes of fetuses, the activity rhythms differ in phase and shape of the time series pattern from those of the mothers; for other enzymes, the activity rhythms develop after birth.

Immunity to varicella zoster virus in young Israeli adults

BACKGROUND

Chickenpox is a highly contagious childhood infection caused by varicella zoster virus, a virus of the herpes family. Although a mild and self-limiting disease in otherwise healthy children, chickenpox can be a complicated and even life-threatening disease in adults, pregnant women and immunosuppressed individuals. Among infants whose mothers had varicella during the first trimester of pregnancy, 2-3% will develop a congenital VZV syndrome that includes a combination of scarring, limb deformation, central nervous system impairment and ocular injury. In 1974, a live attenuated virus vaccine against VZV was developed in Japan and has been thoroughly tested for safety, efficacy and long-term effects. In March 1995 the vaccine was licensed in the U.S. for use in healthy children only.

OBJECTIVES

To determine the rate of immunity to VZV in young Israeli adults.

METHODS

On the assumption that a randomly picked sample of 18-year-old army recruits in Israel is representative of the general Jewish population, 900 sera samples were taken for 3 years (1985,1988,1992). The sera were analyzed for IgG to VZV with a commercial ELISA kit using microwells coated with VZV antigens.

RESULTS

A total of 98% of the samples tested positive for VZV antibodies. The difference in serologic values between the recruitment years was not statistically significant.

CONCLUSION

The majority of the Israeli population reaches adulthood already immunized against VZV, with immigrants having slightly lower immunity rates. Nonetheless, a few dozen cases of chickenpox are diagnosed in the IDF annually. These data should be taken into account when a vaccination program is devised. Should such a program be implemented, it would be interesting to repeat the serosurvey for comparison. A shift in the peak occurrence age might necessitate the administration of a booster vaccine at an older age.

Incidence of Type 1 diabetes mellitus in children aged 0-14 in Japan, 1986-1990, including an analysis for seasonality of onset and month of birth: JDS study. The Data Committee for Childhood Diabetes of the Japan Diabetes Society (JDS)

AIMS

To detect the incidence of childhood Type 1 diabetes mellitus (DM) (0-14 years) in Japan and to find out whether there is a seasonal pattern in the onset of disease and month of birth of children with diabetes.

METHODS

Ascertained data for the period 1986-1990 could be collected in 35 out of 47 local government areas representing 69.4% of the childhood population (aged 0-14 years) of Japan.

RESULTS

A total of 1,260 children with Type 1 DM were identified (738 girls, 522 boys). With age there was a progressive increase in incidence from 0.7 to 2.1/10(5) in boys and from 0.6 to 3.5/10(5) in girls. With the exception of 1987, when a coxsackie B3 virus epidemic was registered, no seasonal variation in the month of onset was observed, nor was a seasonal pattern of the month of birth registered in this cohort.

CONCLUSIONS

Compared to European countries, the USA and Israel, the Japanese cohort of children with diabetes presents the following differences: the incidence is much lower, there is a preponderance of girls and there is (with one exception) no seasonal pattern.