Outbreak In Israel Research Articles

Israel's Silent Polio Epidemic Breaks All the Rules

A polio outbreak in Israel has had researchers scratching their heads.

Postexposure Prophylaxis of Tick-Borne Relapsing Fever: Lessons Learned from Recent Outbreaks in Israel

Tick-borne relapsing fever (TBRF) is endemic in Israel. Military activities pose a particular risk for TBRF, and its prevention is based on heightened awareness and risk stratification by active surveillance of tick bites and selective postexposure prophylaxis (PEP) with doxycycline for tick-bitten individuals. We report three outbreaks of TBRF affecting 35 exposed military personnel, with an average recognized tick bite rate of approximately 50% and an attack rate of 25-50%. Of 10 TBRF cases, 20% had no evidence of tick bites and thus restriction of PEP administration to individuals with recognized tick bites contributed to TBRF occurrence. As a result of a revised policy, 24 soldiers (including eight with recognized and 16 with unrecognized tick bites) received antimicrobials following the diagnosis of TBRF among their cohorts, and none of these individuals subsequently developed TBRF. The probability for TBRF among exposed individuals associated with well-established cases of TBRF warrants that prompt doxycycline administration be considered in all individuals who share risk factors, regardless of tick bite status.

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.

Mumps outbreak in Israel's highly vaccinated society: are two doses enough?

Mumps outbreaks in recent years have given rise to questions about the effectiveness of the mumps vaccine. This study examined the epidemiological data from a recent mumps outbreak in Israel and from outbreaks in other countries with high vaccination coverage, and considered whether long-established vaccination policies designed to protect against mumps are in need of revision. Of over 5000 case patients in the Israeli outbreak, half of whom were in the Jerusalem health district, nearly 40% were aged ≥15 years and, of those whose vaccination status was known, 78% had been fully vaccinated for their age - features similar to those in recent mumps outbreaks in Europe and North America. The epidemiological and laboratory evidence suggests that many previously vaccinated adolescents and young adults are now susceptible to mumps because their vaccine-based immunity has waned. Booster vaccination programmes for those at high risk of infection during mumps outbreaks - particularly those in congregate living environments - merit priority consideration.

Sub-optimal prevalence of mumps antibodies in a population based study of young adults in Israel after 20 years of two dose universal vaccination policy

Background A recent mumps outbreak in Israel despite an ongoing national program of a 2-dose universal childhood vaccination policy since 1988, raised questions regarding population immunity among young adults. Objective To assess the seroprevalence of mumps antibodies among young Israeli adults born after 1987 in order to determine evidence based vaccination policy. Methods We conducted a seroprevalence study of mumps IgG antibodies among 441 Israeli adults born in 1988–9, based on a representative sample of sera collected upon recruitment to mandatory military service in 2007. Results The overall seroprevalence of IgG antibody to mumps virus among 1988–9 born was 83.7%, 82.1% among males and 85.7% among females. Seroprevalence among 2007 recruits was similar to 1999 recruits (83.3%, P = 0.89) and significantly lower than 1987 recruits (94.1%, P < 0.0001). The absolute decrease between 2007 and 1987 for males was 13.1% ( P < 0.0001) and for females 7.0% ( P = 0.02). Seroprevalence was not significantly higher among native Israelis (84.9%) than among young adults born in the Commonwealth of Independent States (81.1%, P = 0.46) and significantly higher compared to young adults born in Western Europe or North America (68.2%, P = 0.045). Conclusions Our findings indicate sub-optimal population seroprevalence despite a 2-dose universal childhood vaccination policy. This study allows better understanding of current mumps outbreaks in Israel and elsewhere following periods of low circulation of wild virus. These findings support mumps vaccination, even for populations and individuals that received two doses during childhood, as means for outbreak containment among young adults, especially in crowded settings, and serve as a reminder to the need for dynamic vaccination policy, supported by health promotion activities.

Modelling the initial phase of an epidemic using incidence and infection network data: 2009 H1N1 pandemic in Israel as a case study.

This paper presents new computational and modelling tools for studying the dynamics of an epidemic in its initial stages that use both available incidence time series and data describing the population's infection network structure. The work is motivated by data collected at the beginning of the H1N1 pandemic outbreak in Israel in the summer of 2009. We formulated a new discrete-time stochastic epidemic SIR (susceptible-infected-recovered) model that explicitly takes into account the disease's specific generation-time distribution and the intrinsic demographic stochasticity inherent to the infection process. Moreover, in contrast with many other modelling approaches, the model allows direct analytical derivation of estimates for the effective reproductive number (R(e)) and of their credible intervals, by maximum likelihood and Bayesian methods. The basic model can be extended to include age-class structure, and a maximum likelihood methodology allows us to estimate the model's next-generation matrix by combining two types of data: (i) the incidence series of each age group, and (ii) infection network data that provide partial information of 'who-infected-who'. Unlike other approaches for estimating the next-generation matrix, the method developed here does not require making a priori assumptions about the structure of the next-generation matrix. We show, using a simulation study, that even a relatively small amount of information about the infection network greatly improves the accuracy of estimation of the next-generation matrix. The method is applied in practice to estimate the next-generation matrix from the Israeli H1N1 pandemic data. The tools developed here should be of practical importance for future investigations of epidemics during their initial stages. However, they require the availability of data which represent a random sample of the real epidemic process. We discuss the conditions under which reporting rates may or may not influence our estimated quantities and the effects of bias.

Hospitalization of Children With Influenza A(H1N1) Virus in Israel During the 2009 Outbreak in Israel

To describe the clinical characteristics of children hospitalized with 2009 influenza A(H1N1) infection in Israel and the risk factors associated with this infection. Prospective collection of data on children hospitalized with 2009 influenza A(H1N1) infection. Seven medical centers around Israel. Patients From July 12, 2009, to December 24, 2009, all patients 18 years or younger hospitalized with acute respiratory or acute unspecified febrile illness were screened for 2009 influenza A(H1N1) virus by reverse transcription-polymerase chain reaction. Prospective data collection for patients with confirmed infection. Clinical characteristics of patients and hospitalization rates. The mean age of 478 patients studied was 6.1 years. Forty-two patients (8.8%) were admitted to the pediatric intensive care unit; 3 patients (0.6%) died. The most frequent clinical presentations were pneumonia, influenza-like illness, wheezing exacerbation, and convulsions. Predisposing underlying illnesses were detected in 48.7% of patients. Patients with metabolic and neurologic disorders were at highest risk for severe complications (relative risk, 6.5 and 2.9, respectively). In addition, patients with cyanotic heart lesions and infants 3 months or younger who were born at 33 weeks' gestation or earlier tended to require higher rates of mechanical ventilation. The hospitalization rate for 2009 influenza A(H1N1) was 0.7 per 1000 children. The mortality rate was 3.6 per 1 000 000 children. The severity variables for 2009 influenza A(H1N1) were similar to the figures reported for seasonal influenza. Patients with underlying metabolic and neurologic metabolic disorders and presumably patients with cyanotic heart lesions and infants born prematurely are at highest risk for severe complications following 2009 influenza A(H1N1) infection.

Description of the first acute bovine diarrhea virus-2 outbreak in Israel

This is the first report of an acute and fatal outbreak of bovine diarrhea virus (BVDV)-2 infection in Israel. The clinical presentation varied with the age of the affected animals with a bovine–respiratory–complex–like syndrome in young stock, and diarrhea and dysentery only in the lactating stock. Enteritis first appeared in one shed of post-parturient cows; it spread for 6 weeks, until at least 30% of the lactating stock contracted enteritis or dysentery. At the same time, dairy calves aged 10–90 days exhibited severe respiratory disease. Of 79 animals that died, 13/350 (3.7%) were adult lactating cows, and 66/1100 (6%) were young feedlot calves. Phylogenetic analysis of the isolated virus revealed a 95% identity with the corresponding genome parts of various BVDV type 2 sequences. The route of introduction of BVDV-2 into Israel could not be elucidated.

The association of winds with the spread of EHDV in dairy cattle in Israel during an outbreak in 2006

Winds may play a major role in spread of arthropod-borne viruses (arboviruses). Arboviruses like epizootic hemorrhagic disease virus (EHDV), bluetongue virus and bovine ephemeral fever virus (BEFV) frequently cause major outbreaks in Israel with a unique pattern of spread. Most of these outbreaks begin in the Jordan valley, near the Sea of Galilee and then spread to the north, south and west through the major valleys of Israel. The aim of this study was to describe the spread pattern in such an outbreak and to find if this pattern can be explained by winds. Herein, we compared the spread rate to each direction and used Cox proportional hazards model to test factors associated with the spread of EHDV, which emerged in diary cattle in Israel during the summer of 2006. Documented, clinical and serological data on spread of the outbreak were then compared with wind data collected by meteorological stations along the trail of virus spread and with modeled winds at high altitude (>500 m). The analysis revealed that both the hazard and the rate of outbreak spread to the south and to the north were significantly higher than to the west. Average rate of outbreak spread during periods in which at least 3 h of winds to spread direction were recorded was 20,880 m/week (SD = 13,230) vs. 7486 m/week (SD = 4936) in periods during which no such winds were recorded. Serological evidence demonstrated exposure to the virus up to 166 km away from the location of the initial outbreak center. Modeled wind data showed that this spread may be explained by winds at high altitudes. Animal movements due to shipments of feedlot calves and slaughters could not explain the spread pattern observed during the outbreak. This study therefore shows that winds are probably a major contributory factor for long and medium distance spread of Culicoides borne viruses in this region.

Measles in a highly vaccinated society: The 2007–08 outbreak in Israel

Despite success in controlling measles through a national immunization program, Israel recently experienced its largest measles outbreak since 1994. Using data reported by health district offices to the Ministry of Health, an epidemiological analysis of the 2007-08 measles outbreak was performed. 1467 measles cases were reported in Israel, primarily among ultra-orthodox Jewish communities in the Jerusalem Health District and to a lesser extent in other areas. The highest age-specific incidence rate (122.5 per 100,000) occurred among infants. 38.6% of all measles patients were under the age of five, and 53.4% were under the age of ten. 186 patients (12.7%) were hospitalized; there were no fatalities. Only 4.6% of measles patients had been fully vaccinated for their age. To minimize the risk of future outbreaks in Israel, successful marketing of the MMR vaccine to under-vaccinated sub-groups is essential.

Genetic characterization of H5N1 influenza virus that caused new outbreak in Israel at the beginning of 2008

Our aim was to characterize the A/ck/Israeli/1055/2008 (H5N1) avian influenza virus that was isolated at the beginning of 2008, and to establish the phylogenetic relationship of this isolate to other H5N1 viruses that were recently isolated in adjacent countries. In light of a study of complete nucleotide sequences of all the genes we found that the isolate (year 2008) was closely related to the H5N1 viruses isolated in Egypt, Israel and Gaza in 2006. The Israeli isolate had the hemagglutinin-connecting peptide with a polybasic amino acid insertion. The most host-restriction sites of the 2008 isolate were typical of avian hosts, with one exception: K627 at the PB2 protein. As compared with previous local H5N1 isolates, a high mutation rate was found at the HA gene, which antigenic sites were under positive selection pressure.

What Parameters Correlate with the Sense of Knowledge During the Early Phase of a Bird Flu Outbreak in Israel?

Introduction: On March 2006, 298,000 cases of birds infected with bird flu were destroyed in nine rural settle- ments in Israel, out of a total of 1.2 million birds that were destroyed within these settlements and in a radius of 3 km. The population was instructed to take precautionary measures to prevent a disease outbreak. The sense of knowledge of the population concerning the disease correlated with compliance with authorities' instructions. Objectives: To analyze the relationships between the sources of information, and public emotions and interest in avian in- fluenza with the sense of knowledge concerning the disease in the affected area and the nationwide population, during the first phase of a bird flu outbreak in Israel. Methods: We conducted a telephone survey among two randomly selected, representative samples of adults, during the first phase of a bird flu outbreak. One sample involved 500 adult residents of the nationwide area; and the other sample involved 103 adult residents of the affected area. We measured the use of mass media, emotions, interest, and sense of knowledge of the population concerning avian influenza. We analyzed the relationships between the sources of informa- tion and public emotions with the sense of knowledge using chi-square and t-tests. A P value of < 0.05 was considered to be statistically significant. Results: TV viewers in the affected area had a significantly lower sense of knowledge concerning avian influenza (P<0.05). Internet users in the nationwide population had a significantly higher sense of knowledge (P<0.05). People in the affected area with higher levels of stress had a significantly lower sense of knowledge (P<0.05). People in the nation- wide population with a higher level of interest had a significantly higher sense of knowledge (P<0.05). Conclusion: The use of the internet as a source of information, combined with a high level of interest and low levels of stress correlated with a high sense of knowledge concerning avian influenza during the early phase of an avian influenza outbreak in Israel. Authorities should consider these findings when planning the strategy of mass media use, in order to increase the public's sense of knowledge concerning the disease and to enhance control of the disease outbreak by im- proving the compliance of the population with the authorities' instructions.

Differences in Sources of Information Used by the Population between the Affected Area and the General Population during the First Phase of a Bird Flu Outbreak

In March 2006, a few cases of bird flu were discovered in approximately 10 rural settlements in Israel. As a result, approximately one million birds were destroyed within a three kilometer radius of the settlements. The Israeli population was instructed to take preventive measures against the spread of the infection. The objective of this study was to compare the frequency of use of different sources of information by the population in the affected area with the general population during the first phase of a bird flu outbreak in Israel. A telephone survey among two randomly selected, representative samples of adults was conducted. One sample involved 500 adult Israeli residents; the other sample involved 103 adult residents from the affected area during the first phase of the outbreak. The use of different sources of information by the population concerning the disease was assessed. The differences in these parameters between the affected area and the nationwide population were analyzed using a chi-square and t-test analysis. A p-value of < 0.05 was considered statistically significant. Television was a significantly more common source of information in Israel as a whole (p < 0.05), whereas friends (p < 0.05) and local authorities (p < 0.05) were significantly more common sources of information in the affected area. The frequency of use of the sources of information by the population during the early phase of a bird flu outbreak is different in the affected area compared with the general population in the same country. Authorities must pay attention to this phenomenon and use the correct sources of information in each area in order to achieve better exposure of the population to the recommended behaviors during an outbreak.

The NSP immune response of vaccinated animals after in-field exposure to FMDV

The aim was to examine the immune response (IR) to non-structural proteins (NSPs), in order to assess the validity of the detection of antibodies to NSPs as a means of diagnosing foot and mouth disease (FMD infection) infection when vaccinated populations are in close contact with clinically sick animals. The study was performed during FMD outbreaks in Israel in January 2004; the IR was examined in vaccinated dairy and feedlot cattle herds under natural field exposure to FMDV, and in vaccinated and unvaccinated sheep flocks. During the 2004 outbreaks, clinical signs were age-related and were noted only among imported calves, although they had been vaccinated; such signs were not found among the local dairy cattle populations. The NSP IR among the feedlot cattle that had been vaccinated more than 4 months prior to the in-field exposure was 86%, compared with only 30% among those feedlot cattle that had received one dose of vaccine less than 4 months before the field exposure. The prevalence of NSP IR indicates that animals vaccinated once, less than 4 months prior to exposure, were clinically resistant to FMDV infection, although possibly still susceptible to subclinical infections, whereas those vaccinated more than 4 months prior to the in-field exposure presented clinical manifestations. This situation is unlikely to occur among repeatedly vaccinated livestock; these remained refractory to FMD exposure, as reflected in the absence of clinical manifestations and a relatively low prevalence of NSP IR compared with that in imported calves.

Differences in public emotions, interest, sense of knowledge and compliance between the affected area and the nationwide general population during the first phase of a bird flu outbreak in Israel

In March 2006, 298,000 cases of birds infected with bird flu were destroyed in nine rural settlements in Israel, out of around 1.2 million birds that were destroyed within these settlements and in a radius of 3 km. The nationwide population was instructed to take preventive measures against the spread of infection. This study aims to compare the emotions, interest, sense of knowledge and compliance, of the population in the affected area with the nationwide general population, during the first phase of a bird flu outbreak in Israel. We conducted a telephone survey among two randomly selected, representative samples of adults. One sample involved 500 adult residents of the nationwide area; and the other sample involved 103 adult residents of the affected area during the first phase of the outbreak. We measured perceived emotions, interest, sense of knowledge and compliance. We analyzed the differences in these parameters between the affected area and the nationwide population using chi-square and t-test analysis. A p value of less than 0.05 was considered to be statistically significant. The compliance for using measures of precaution was high and not significantly different between the affected area and the nationwide population. The interest in bird flue and the sense of knowledge were significantly higher in the affected area compared to the nationwide population (p<0.05). A misconception of a high human to human transmission was significantly higher in the nationwide population compared with the affected area (p<0.05). The levels of stress and fear perception were significantly lower in the affected area compared to the nationwide population (p<0.05). Interest, sense of knowledge and emotions of the population are different in the affected area during the early phase of bird flu outbreak compared with the general population in the same country. Authorities must consider these differences while planning the strategy of population education during the early phase of a bird flu outbreak.

The evolution of genetic structure in the marine pathogen, Vibrio vulnificus

Multi-locus sequence types (MLST) from a global collection of Vibrio vulnificus isolates were analysed for the contribution of recombination to the evolution of two divergent clusters of strains and a human-pathogenic hybrid genotype, which caused a disease outbreak in Israel. Recombination contributes more substantially than mutation to generating strain diversity. For allelic diversity within loci, the ratio of recombination to mutation events is approximately 2:1. The role of recombination relative to mutation in the generation of new MLST variants of V. vulnificus within the clusters is comparable to that of other highly recombining bacteria such as Neisseria meningitidis. However, across the divide between the two major clusters of V. vulnificus strains, there is substantial linkage disequilibrium, lower estimates for recombination rates and shorter estimates of recombination tract length. We account for these differences between V. vulnificus and N. meningitidis by attributing them to the presence of the unusual genetic structure within V. vulnificus. The reason for the presence of distinct and divergent genomes remains unresolved. Two possible explanations put forward for future study are first, ecologically based population structure within V. vulnificus and second, a recombination donor from a phenotypically differentiated species.

The west nile virus outbreak in Israel (2000) from a new perspective: The regional impact of climate change

The West Nile Virus (WNV) outbreak in Israel in 2000 appeared after medical and climatic warning signs. Re-analysis of the epidemic from a new viewpoint, the regional impact of global warming, especially the worsening in the summers' heat conditions, is presented. The disease appeared averagely at a lag of 3–9 weeks (strongest correlation = lag of 7 weeks). The minimum temperature was found as the most important climatic factor that encourages the disease earlier appearance. Extreme heat is more significant than high air humidity for increasing WNV cases. An early extreme rise in the summer temperature could be a good indicator of increased vector populations. While 93.5% of cases were in the metropolitan areas, the disease was not reported in the sub-arid regions. The outbreak development was comparable to the cases from Romania (1996) and NYC (1999). Each of those epidemics appeared after a long heatwave.

Use ofmgc2-Polymerase Chain Reaction–Restriction Fragment Length Polymorphism for Rapid Differentiation Between Field Isolates and Vaccine Strains of Mycoplasma gallisepticum in Israel

Increasing use of Mycoplasma gallisepticum (MG) live vaccines has led to a need for a rapid test for differentiation of MG field strains from the live vaccine strains ts-11 and 6/85. We examined the differentiating potential of diagnostic polymerase chain reaction (PCR) primers targeted to the gene mgc2, encoding a cytadherence-related surface protein uniquely present in MG. The mgc2-PCR diagnostic primers are specific for MG in tests of all avian mycoplasmas or bacteria present in the chicken trachea and are sensitive enough to readily detect MG in tracheal swabs from field outbreaks. Differentiation of vaccine strain ts-11 was based on identification of restriction enzyme sites in the 300-base-pair (bp) mgc2-PCR amplicon present in ts-11 and missing in MG isolates from field outbreaks in Israel. Restriction sites for the enzymes HaeII and SfaN1 were identified in the amplified region in strain ts-11 and were not found in 28 field isolates of MG, comprising a representative cross section of all the MG isolates from the period 1997-2003. In practice, differential diagnosis of MG is achieved within 1 day of submission of tracheal swab samples by mgc2-PCR amplification and restriction of the amplicon with HaeII, giving a 270-bp fragment for ts-11 or no restriction for other MG strains tested. Application of the mgc2-PCR-restriction fragment length polymorphism (mgc2-PCR-RFLP) assay enabled differential diagnosis of both components of a mixture of ts-11 and non-ts-11 DNA, detecting the field strain in the presence of a large excess of ts-11. The test was successfully applied in vivo for monitoring vaccinates in a ts-11 vaccine trial. In principle, the test may also be used to identify the 6/85 vaccine strain, which yields a 237-bp product, readily differentiated from the approximately 300-bp PCR product of all other strains tested. Further testing of field isolates will be necessary to determine the applicability of this test in the United States and other countries.

Electroencephalography findings in adult patients with West Nile virus-associated meningitis and meningoencephalitis.

Eighteen adult patients with serologically confirmed West Nile virus (WNV)-associated meningitis or meningoencephalitis were admitted to our hospital during the 2000 West Nile fever outbreak in Israel. Thirteen of the patients had a more severe and prolonged clinical course, and an electroencephalogram (EEG) was, therefore, requested. A specific EEG pattern was seen in 8 patients, consisting of generalized slowing, which was more prominent over the anterior regions. Generalized slowing that was prominent over the temporal area was seen in 2 patients, and intermittent slowing over the temporal region was seen in 1 patient. Two patients had normal EEG findings. We suggest that WNV meningoencephalitis should be considered in the differential diagnosis of meningitis or meningoencephalitis with a prolonged clinical course and anteriorly predominant slowing on an EEG.

Clinical signs of West Nile virus encephalomyelitis in horses during the outbreak in Israel in 2000

Between August and October 2000, 76 horses were reported by veterinary practitioners as having signs of a neurological disorder, varying from an involvement of the spinal cord alone to the...