Michal Bromberg

A Large Q Fever Outbreak in an Urban School in Central Israel

BACKGROUND. On 28 June 2005, numerous cases of febrile illness were reported among 322 students and employees of a boarding high school located in an urban area in central Israel. Subsequent investigation identified a large outbreak of Q fever which started 2 weeks earlier. We describe the investigation of this outbreak and its possible implications. METHODS. We conducted a case-control study to identify risk factors for Q fever disease. Environmental sampling was conducted to identify the source and the mode of transmission of Coxiella burnetii, the infectious agent. RESULTS. Of 303 individuals, 187 (62%) reported being ill between 15 June and 13 July 2005. Serological evidence for C. burnetii infection was evident in 144 (88%) of the 164 tested individuals. Being a student, dining regularly at the school dining room, and boarding at school during a June religious holiday and the preceding weekend were all significant risk factors for contracting Q fever. C. burnetii DNA was detected using polymerase chain reaction on samples from the school dining rooms air conditioning system, supporting contribution of the air conditioning system to the aerosol transmission of the infectious agent. CONCLUSIONS. We report a large outbreak of Q fever in an urban school, possibly transmitted through an air conditioning system. A high level of suspicion for C. burnetii infection should be maintained when investigating point source outbreaks of influenza-like disease, especially outside the influenza season.

Invasive Bacterial Infections in Relation to Influenza Outbreaks, 2006–2010

BACKGROUND We aimed to define the excess morbidity associated with bloodstream infections (BSIs), imposed by pandemic H1N1 influenza during 2009-2010 (pH1N1/2009-2010) and seasonal influenza. METHODS Eight hospitals, accounting for 33% of hospitalizations in Israel, provided data on BSI during 2006-2010. The age-specific incidence of BSI due to Streptococcus pneumoniae, Staphylococcus aureus, and Streptococcus pyogenes was determined. BSI incidence rate ratios (IRRs) during seasonal and pH1N1 influenza seasons were assessed. RESULTS Regular influenza seasons were characterized by increased rates of S. pneumoniae BSI but with no increase in S. aureus and S. pyogenes BSI rates. The pH1N1/2009-2010 influenza outbreak was characterized by (1) higher rates of S. pneumoniae bacteremia among children but not among adults (IRRs for S. pneumoniae BSI among children aged 0-4 years during the summer and winter of 2009-2010 were 14.8 [95% confidence interval {CI}, 5-43.7] and 6.5 [95% CI, 3.6-11.8], compared with 2006-2009 summers and influenza-active winter weeks, respectively [P < .0001]), higher rates of S. aureus BSI in all age groups (IRRs during the summer and winter of 2009-2010 were 1.6 [95% CI, 1.4-1.9] and 1.5 [95% CI, 1.2-1.7], compared with 2006-2009 summers and influenza-active weeks, respectively [P < .0001]), higher rates of S. pyogenes BSI during 2009-2010 influenza season (IRR 2.7 [95% CI, 1.6-4.6] and 3.3 [95% CI, 1.9-5.8] during the summer and winter of 2009-2010, compared with 2006-2009 summers and influenza-active weeks, respectively [P < .0001]). CONCLUSIONS pH1N1 influenza seasons were characterized by marked increases in invasive S. aureus and S. pyogenes infections among children and adults, with the highest increase in S. pneumoniae BSI among children.

Adenovirus Infections in Hospitalized Patients in Israel: Epidemiology and Molecular Characterization

ABSTRACT Adenoviruses can cause a broad spectrum of clinical diseases, most of which are self-limited. However, adenovirus infection can occasionally result in severe or lethal infection. Fifty-five adenovirus serotypes are known today, and they are classified into 7 subgroups (subgroups A to G). Here we examined 282 samples derived from hospitalized patients in Israel (September 2006 to August 2008) who were diagnosed as suffering from adenovirus infections. We used a recently described PCR amplification method and subsequent sequencing to identify the adenovirus. In addition, we studied the medical charts of 106 hospitalized patients from Sheba Medical Center in Israel. The most prevalent adenovirus serotypes found were serotypes 1 (22.8%), 2 (19.2%), 7 (18%), and 3 (14%). In addition, we identified several serotypes that have not been identified previously in Israel. Overall, serotypes of subgroup B were found to be approximately 4 times more prevalent among immunocompromised children than among generally healthy children (52.6%; P < 0.007). The realization that the virus subtypes are different among healthy and immunocompromised patients may lead to more efficient treatment of adenovirus infections among immunocompromised children in the future.

Increased Extent of and Risk Factors for Pandemic (H1N1) 2009 and Seasonal Influenza among Children, Israel

During the pandemic (H1N1) 2009 outbreak in Israel, incidence rates among children were 2× higher than that of the previous 4 influenza seasons; hospitalization rates were 5× higher. Children hospitalized for pandemic (H1N1) 2009 were older and had more underlying chronic diseases than those hospitalized for seasonal influenza.

Micro-inflammatory changes in asymptomatic healthy adults during bouts of respiratory tract infections in the community: Potential triggers for atherothrombotic events

OBJECTIVE To explore the possibility that mild inflammatory changes exist in asymptomatic adults during bouts of acute respiratory tract infections in the general population, and may mediate atherothrombotic events. METHODS An epidemiological study that enrolled 5315 males and 2795 females attending a routine screening health program between the years 2003 and 2007. We correlated the concentrations of high sensitivity C-reactive protein (hs-CRP) and quantitative fibrinogen in completely asymptomatic and non-inflamed adults to the weekly epidemiological data for the incidence of acute respiratory tract infections in the community. RESULTS Significant seasonal variations in the inflammatory variables were found for both genders. The populations weekly rates of acute respiratory tract infection had a significant epidemiological influence on the inflammatory biomarkers in the asymptomatic cohort. The magnitude of this influence could reach as much as 12% (3-22%) in hs-CRP concentrations in women and 0.30 micromol/L (0.20-0.41) in fibrinogen concentrations in men, for the change between the mean August and the mean January populations respiratory illness burden. CONCLUSION Increase in the concentrations of two inflammation-sensitive biomarkers can occur in completely asymptomatic adults at times of increased burden of acute respiratory tract infection in the general population. The possibility exists that these inflammatory changes represent occult and asymptomatic infections that could by themselves trigger acute atherothrombotic events.

Significant cross reactive antibodies to influenza virus in adults and children during a period of marked antigenic drift.

BackgroundLittle is known about the development of cross-reactive antibodies following natural exposure to pathogens. Such knowledge is critical in the development of new universal influenza vaccines.MethodsTo study the possibility of the presence of cross-reactive antibodies to influenza viruses which underwent a major antigenic drift between the years 1999 and 2007 sera from samples of 80 children and 400 adults were selected at random from the Israeli national serum bank. The sera was obtained in 2002 and in 2007, two time points that followed a major drift in the infectious H3N2 influenza virus strain (A/Panama/2007/99 to A/Wisconsin/67/2005).ResultsIn the summer of 2002, 13% of the children had Hemagglutination Inhibition (HI) antibody titers of at least 40 and these antibodies recognized both A/Panama/2007/99 and A/Wisconsin/67/2005, where the latter strain only began to circulate in Israel in 2006. In 2007, 29% of the children had HI antibody titers of at least 40 directed against both A/Wisconsin/67/2005 and A/Panama/2007/99, even though they had never been exposed to the latter virus. Anti-A/Panama/2007/99 antibodies were detected in 58% and 68% of the 2002 and 2007 adult samples, respectively, while 8% and 39% had antibodies against A/Wisconsin/67/2005, respectively.ConclusionsThe presence of naturally occurring cross-reactive influenza virus antibodies in a significant percentage of children has important implications for the development of a universal influenza vaccine.

Herpes zoster in a partially vaccinated pediatric population in central Israel.

Background: This study was performed during an era of partial vaccination with varicella vaccine in Israel to characterize ambulatory pediatric herpes zoster (HZ) cases in a population with partial varicella vaccination coverage. Methods: Data were collected from computerized databases of a population of 114,000 children. Records of children aged 0–18 years, diagnosed with HZ during 2006 to 2008 were reviewed by pediatric infectious diseases experts. Telephone interviews were done with a sample of the parents to get further clinical details. Results: Of 692 medical records reviewed, 450 cases were approved for analysis, and 77 interviews were conducted. Incidence of HZ was 130 of 100,000 person life-years. Peak incidence was detected in children aged 9–11 years (222/100,000 person life-years). Pain and fever accompanied 52% and 13% of episodes, respectively. Higher risk for HZ was found in children who had varicella during their first year of life (relative risk and 95% confidence interval: 13.5[9.6–18.8]; P < 0.001), and in children who had varicella during the second year of life (relative risk = 2 [1.5–2.6]; P < 0.001). Vaccination was found to be protective against HZ (relative risk = 0.42 [0.33–0.55]; P < 0.001). Conclusions: The epidemiology of HZ seems to be changing in a population with partial varicella vaccination rate. Our results may suggest that children who contracted chicken pox in their first year of life may benefit from varicella vaccination.

Comparing three basic models for seasonal influenza

In this paper we report the use of the open source Spatiotemporal Epidemiological Modeler (STEM, www.eclipse.org/stem) to compare three basic models for seasonal influenza transmission. The models are designed to test for possible differences between the seasonal transmission of influenza A and B. Model 1 assumes that the seasonality and magnitude of transmission do not vary between influenza A and B. Model 2 assumes that the magnitude of seasonal forcing (i.e., the maximum transmissibility), but not the background transmission or flu season length, differs between influenza A and B. Model 3 assumes that the magnitude of seasonal forcing, the background transmission, and flu season length all differ between strains. The models are all optimized using 10 years of surveillance data from 49 of 50 administrative divisions in Israel. Using a cross-validation technique, we compare the relative accuracy of the models and discuss the potential for prediction. We find that accounting for variation in transmission amplitude increases the predictive ability compared to the base. However, little improvement is obtained by allowing for further variation in the shape of the seasonal forcing function.

The dynamics of infection and the persistence of immunity to A(H1N1)pdm09 virus in Israel

Influenza virus A(H1N1)pdm09 first appeared in Israel in late April 2009, disappeared in mid‐March 2010, and reappeared in late October 2010. Symptoms were mostly mild without need for medical care.

Seasonality of Bacillus species isolated from blood cultures and its potential implications

BACKGROUND Because they are rarely associated with actual infections, Bacillus species are usually defined as contaminants. However, when isolated, they require precise laboratory identification and may influence treatment. METHODS Our aims were to examine the seasonality of Bacillus spp isolates cultured from clinical blood specimens. Blood culture results of several hospitals between December 1, 2003, and October 31, 2007, were analyzed. The data were aggregated by month of isolation and were also studied by age. Spectral and Cosinor analyses were used to examine the periodicity of the bacillus isolates. RESULTS Of 931,331 blood cultures analyzed, 2487 (1.7%) yielded Bacillus spp isolates. There was a 2.5-fold increase in the number of bacillus isolates during August to October, compared with the other months (P < .01). This finding was consistent over hospitals and in all age groups. Spectral and Cosinor analyses confirmed this pattern. CONCLUSION Isolation of Bacillus spp from blood cultures has a seasonal pattern. This observation needs to be taken into account in surveillance systems for early detection of anthrax and in investigating nosocomial outbreaks. Elucidating the cause of this seasonality may enable future reduction in contamination rates.