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Biomedical subjects

E I Korenberg

Publications and source records attributed to E I Korenberg.

At least 19 recordsLinked to original sources
PubMed2006

[Allele variants of Borrelia afzelii found by sequencing of the chromosome gene p66].

Sequencing of gene p66 fragments of 246-337 p.b. was performed in 45 isolates of Aorrelia afzelii isolated from different transmitting agents and reservoir hosts within the habitation area of the spirochaeta. At least seven allele variants of the pathogenic agent were found indifferent natural foci of the disease. The extent of similarity between the nucleotide sequences of the isolates of the same allele variant was 99.9-100%; the extent of similarity between different allele variants was 98.9-99.7%. It was found that the majority of genovariants of A. afzelii (with respect to 5S-23S) incorporated several different allele variants of gene p66, all allele variants being found in the two genogroups (VS461 and NT28) of the pathogenic agent.

Alleles↗
PubMed2005

[Climate changes and health of population in Russia in XXI century].

Warming seen in Russia is a real danger to health of population. The authors consider influence of warming on prevalence of some infectious and parasitic diseases. At present, the most reliable proof are obtained for West Nile fever and Crimean fever. To obtain reliable data on other infectious diseases we need prolonged followup in inpatient departments. Abnormally high temperatures in cities result in higher mortality rate withcardiovascular diseases including myocardial infarction, increased drowning and suicides numbers.

Bacterial Infections↗
PubMed2005

[Genetic variants of Borrelia afzelii, a pathogen of the ixodes tick borrelioses].

Borrelia afzelii is one of two most important pathogens of the ixodes tick borrelioses (ITB) in Russia and neighboring countries. This pathogen circulates in various ecosystems and has a wide range of reservoir hosts and transmitters. The results of studies of genetic heterogeneity of the spirochaetae B. afzelii are considered. A total of 139 primary isolates were studied. The isolates were isolated from three species of Ixodes ticks at different stages of development and obtained from the laboratory of infection transmitters, Gamaleya Scientific Research Institute of Epidemiology and Microbiology, Russran Academy of Medical Sciences, Moscow. The transmitters and reservoir hosts of borrelias were caught in natural foci of Russia (from Kaliningrad region irk the west to south Sakhalin in the east), Czechia, Lithuania, Estonia, Ukraine, and Moldavia. Analysis of genotype sequence similarity obtained by sequencing of the rrf(SS)-rrl(23S) spacer demonstrated that the B. afzelii genospecies incorporated no less than 10 genetic variants of spirochaetae, most variants being geographically widespread.

Animals↗
PubMed2005

[Evaluation of the effect of climatic warming on population health is a new task of preventive medicine].

Climatic warming in Russia presents a real hazard to population health. The authors consider effects of warming on prevalence of a range of infectious and parasitic diseases and stress that nowadays the most sufficient evedence has been obtained for West Nil fever and Crimea fever. Long-term dynamic stationary observations are necessary to obtain sufficient data on other infectious diseses. In cities abnormally high temperatures cause elevation of cardiovascular mortality, including myocardial infarction mortality, as well as growth of drowning and suicide rate.

Climate↗
PubMed2001

The prevalence of Borrelia burgdorferi sensu lato in Ixodes persulcatus and I. ricinus ticks in the zone of their sympatry.

A total of 7210 unfed adult Ixodes persulcatus Schulze, 1930 and I. ricinus (L., 1758) ticks were collected from the vegetation by flagging in 35 study sites located in the zone of their sympatry (mainly in Leningrad region, Russia). Borrelia infection in ticks was estimated by the dark-field microscopic analysis of gut contents in standard vital preparations at a magnification of x600. No correlation was revealed between the series of parameters characterising the abundance of each tick species (tau = -0.13) and between the series of these parameters and the prevalence of Borrelia in each vector. It is concluded that in the broad zone of I. persulcatus and I. ricinus sympatry, the presence and proportion of one vector in the ecosystem does not have any significant effect on the extensity of infection and on the epizootic and epidemic significance of the other vector. Each tick species has its independent (of the other species) and relatively original functional role in the focal ecosystem.

Animals↗
PubMed2001

[Study and prevention of mixed infections, transmitted by Ixodes ticks].

The paper deals with the main aspects of mixed infections transmitted by Ixodes ticks: the biocenotic bases of existence of natural focal mixed infections, the magnitude of their spread, the indices of mixed infestation and the relationships of different causative organisms with Ixodes ticks and reservoir hosts, the spatial relations of mixed parasitic systems, the incidence of tick-borne mixed infections, the problems of their diagnosis and clinical manifestations, as well as the tasks of complex prevention. It is concluded that there is a necessity of applying the comprehensive synecological approach in studying the processes occurring in the focal ecosystems, which requires a definite methodological and structural rearrangement in science organization.

Animals↗
PubMed2000

Seasonal population dynamics of ixodes ticks and tick-borne encephalitis virus.

Seasonality of the epidemic and epizootic processes of tick-borne encephalitis (TBE) depend on the period of activity of ixodid ticks Ixodes persulcatus Schulze and I. ricinus Linnaeus, which are the main reservoirs and vectors of TBE virus, and also on the process of their activation. The period of activity is the period during which the ticks occur in the active state. Activation is the transition into this state of ticks that moulted from the preceding stage and completed post-moulting development. For I. persulcatus, the first adult ticks generally emerge between April 10 and May 9. Under a variety of natural conditions, activation of adult I. persulcatus after wintering lasts for 45-86 days and this period may be even longer in certain areas of the Far East. The period during which one-half of the entire tick population becomes activated (AT50) comprises no more than 10-20 days. In adult I. ricinus ticks the activation period may last even longer than in I. persulcatus. The data on duration of the period of activity and on activation of larval and nymphal stages of both tick species were considered. Ticks exhausting their nutrient reserves and failing to find a host die quickly. The period during which 50% of the entire tick population die under natural conditions is designated LT50. The main types of I. persulcatus and I. ricinus seasonal activity within their species ranges were reviewed. Data on the relationship between TBE virus reproduction in a natural focus and physiological age, pattern of activation, and seasonal changes in age structure of the tick population were analyzed. Seasonal changes in the prevalence of infection among active unfed adult ticks in a natural population are determined by virus content in individual ticks at the moment of their activation and also by the duration of subsequent virus persistence (the rate of virus loss) in ticks. Apparently, the opportunity and frequency of horizontal TBE virus transmission under natural conditions, change during the season of tick activity.

Animals↗
PubMed1999

Main features of tick-borne encephalitis eco-epidemiology in Russia.

Tick-borne encephalitis (TBE) is a classic obligatorily transmissible viral infection with natural focality, which is widespread mainly in Eurasian forests of the temperate zone. Virus was discovered in the Russian Far East in 1937. Its main long-term reservoirs and vectors in natural foci are Ixodes persulcatus and I. ricinus ticks. Boundaries of the virus range and the location of natural foci within it are closely associated with the distribution pattern of these ticks. The largest categories of TBE range zoning are described. Each natural focus functions as a relatively autonomous parasitic system. The principal scheme of TBE virus circulation related to the development of three successive generations of the main vector is presented. The main parameter of epizootic activity and epidemic manifestation of natural foci and their long-term fluctuations in different regions are discussed. TBE morbidity in Russian and its dynamics during approximately 45 years are analysed.

Animals↗
PubMed1999

Mixed infection by tick-borne encephalitis virus and Borrelia in ticks.

To investigate the relationships between tick-borne encephalitis (TBE) virus and the bacterial spirochaete Borrelia burgdorferi sensu lato in vectors with mixed infections, unfed adult Ixodes persulcatus ticks were collected by flagging from vegetation in southern-taiga forests of the Pre-Urals region of Russia where both infections circulate sympatrically. Prevalences of TBE and Borrelia infections in a total of 4234 ticks were compared over 5 years. No significant differences were revealed between the prevalence of Borrelia infection in ticks with and without TBE virus (29.4+/-7.8% vs 23+/-3.6%), or between the prevalence of TBE virus infection in ticks with and without Borrelia (24.0+/-6.6% vs 18.4+/-3.4%). In ticks with mixed infection (40/689 = 5.8%), concentrations of TBE virus and Borrelia were not significantly correlated with one another. Field observations showed parallel trends in the prevalence of these pathogens in tick populations from year to year (1993-1997) indicating that, in I. persulcatus with mixed infection, Borrelia and TBE virus do not seem to interfere with each other and are apparently not involved in any antagonistic relationships.

Animals↗
PubMed1997

Genetic diversity of Borrelia burgdorferi sensu lato isolated in far eastern Russia.

One-hundred and fifty-seven Borrelia isolated from adult ticks, Ixodes persulcatus, and wild rodents, Clethrionomys rufocanus and Apodemus peninsulae, in the far eastern part of Russia were characterized and identified by restriction fragment length polymorphism (RFLP) of the 5S-23S rRNA intergenic spacer. Some isolates showed unique RFLP patterns and were determined as Borrelia garinii on the basis of a sequence analysis of the intergenic spacer amplicon and reactivity with species-specific monoclonal antibodies (MAbs). 86.5 and 12.7% of the tick isolates, and 74.2 and 12.9% of the rodent isolates were determined as Borrelia garinii and Borrelia afzelii, respectively, but not Borrelia burgdorferi sensu stricto was detected. This finding is similar to the results obtained from Borrelia surveys of I. persulcatus and wild rodents in Hokkaido, Japan.

Animals↗
PubMed1996

Prevalence of Lyme disease spirochetes in Ixodes persulcatus and wild rodents in far eastern Russia.

Borrelia spirochetes were isolated from the adult ixodid tick (Ixodes persulcatus) in three areas of far eastern Russia, namely, Khabarovsk, Vladivostok, and Yuzhno-Sakhalinsk. Borrelia infective rates of ticks in those areas were 24.5, 41.4, and 25.1%, respectively (total rate was 26.6%). Spirochetes were also isolated from the tissues of small mammals captured at Khabarovsk (infective rate was 20.8%). Samples were classified by rRNA gene restriction fragment length polymorphism (RFLP) analysis. The isolated spirochetes from ticks were classified mainly RFLP ribotype group IV (B. garinii), followed by groups II (B. garinii), III (B. afzelii), and V (B. garinii), showing that B. garinii is a dominant species among them. Both B. garinii and B. afzelii were also found in rodents, and multiple infections with those two species were observed in some rodents. B. burgdorferi sensu stricto (group I) was not isolated from either ticks or rodents.

Animals↗
PubMed1995

Differences in Borrelia infections in adult Ixodes persulcatus and Ixodes ricinus ticks (Acari: Ixodidae) in populations of north-western Russia.

Dark-field microscopy was used to determine the number of Borrelia spirochetes in 630 standard preparations obtained from adult ixodid ticks (344 Ixodes persulcatus and 286 I. ricinus) collected in 1989-92 in the Leningrad region of Russia. The average numbers of Borrelia in I. persulcatus and I. ricinus preparations were 34.7 and 23.3 per 100 microscopic fields, respectively. The maximal individual values registered each year for ticks of both species were several hundred times greater than the minimal values. Ticks carrying relatively small numbers of Borrelia generally predominated. Proportions of more heavily infected ticks varied considerably from year to year. These parameters were significantly higher in foci with predominance of I. persulcatus ticks. As a consequence, risk to acquire Lyme borreliosis in such foci is considered greater than in foci where I. ricinus predominates.

Animals↗
PubMed1995

Small mammals as reservoir hosts for Borrelia in Russia.

In 1992-1993, a total of 29 isolates of Borrelia were obtained from small mammals captured in taiga forests of the Perm' region: 26 isolates were obtained from Clethrionomus glareolus and one each from C. rufocanus, Microtus oeconomus, and Apodemus sylvaticus. Isolation of Borrelia was performed by plating the animal material on BSK-II medium. Most isolates (86.2%) were obtained from the urinary bladder, the rest from the heart and spleen. According to the results of IFA with a set of monoclonal antibodies, isolates did not contain Borrelia burgdorferi sensu stricto. Preliminary data suggest that they can belong to B. garinii and B. afzelii. On the basis of the abundance of animals, it is suggested that C. glareolus, a background species among small mammals inhabiting the study region, is the main reservoir host for Borrelia.

Animals↗
PubMed1995

Variation in parameters affecting risk of human disease due to TBE virus.

To rank variables affecting risk of human disease due to tick-borne encephalitis (TBE) virus in the Russian Far East, we compared annual changes in (1) frequency of human contact with vector ticks, (2) prevalence of infection in the tick population and (3) quantity of virus present infected ticks. Sites were sampled uniformly over a 4-year period in a forested region where Ixodes persulcatus serves as the principle vector. The questing density of ticks on vegetation remained relatively constant during the course of this study. The frequency of contacts of the local human population with ticks carrying different doses of the TBE virus was changeable. The rate of TBE infection of humans in the study site corresponded to that of human contacts with highly infected ticks. The density of highly infected ticks represents the principal parameter for determining potential epidemiological significance of a natural TBE focus.

Animals↗
PubMed1994

Comparative ecology and epidemiology of lyme disease and tick-borne encephalitis in the former Soviet Union.

The recently defined range of human Lyme disease in Russia coincides with that of the intensively studied agent of tick-borne encephalitis (TBE). Although identical vectors transmit both infections during the same seasons and in the same locations, more than twice as many people suffer from Lyme disease as from TBE. Edward Korenberg here describes characteristic features of vectors with respect to their seasonal activity, abundance, rates of infection by TBE and Lyme disease agents, as well as incidence of human-tick contact, and how these factors determine the incidence of TBE and Lyme disease in different regions.

Journal Article↗
PubMed1993

Advances in investigations of Lyme borreliosis in the territory of the former USSR.

Whereas late manifestations of Lyme borreliosis were described in Russia more than 100 years ago, early manifestations were described as different disease entities such as tick-borne erythema, etc. In 1985 Lyme borreliosis was first verified serologically and the agent was first identified in 1986. By the beginning of 1992 Lyme borreliosis was serologically confirmed in patients from the Baltics to the Far East. Their geographical patterns in Russia are closely related to areas of the hard ticks Ixodes persulcatus and Ixodes ricinus which are also the main vectors of tick-borne encephalitis virus. As in the case of this infection, in the west of Russia there are "ricinus" natural foci of Lyme borreliosis, and to the east there are similar "persulcatus" foci; through large territories in the East Europe there are common foci for both species. Many Borrelia burgdorferi strains of tick origin have been isolated from various regions of Russia and neighbouring republics. Adult tick infection rates vary from several per cent to 30% in I. ricinus and up to 50-60% in I. persulcatus. Double infections of Lyme borreliosis spirochetes and tick-borne encephalitis virus have been recorded for ticks as well as for humans. Lyme borreliosis morbidity and its importance for the Russia territory are discussed.

Animals↗
PubMed1992

Probability models of the rate of infection with tick-borne encephalitis virus in Ixodes persulcatus ticks.

A total of 3,254 adults of Ixodes persulcatus tick were collected in a taiga forest habitat situated in the Amgun river basin (Khabarovsk region, the Far East, USSR) and examined individually for the presence and amount of tick-borne encephalitis virus. The over-all proportion of infected ticks was 6.6% and it varied between 3.4% and 9.4% in the years 1982 to 1985. The amount of virus per tick was approximated by the gamma distribution determining a probability that the number of plaque-forming units (PFU) per tick is not greater than a selected value. The frequency distribution of infected ticks followed a model of the negative binomial distribution, enabling the estimation of probability of the occurrence of a given number of infected ticks in the area. However, the parameters of both probability models (i.e., the PFU content per tick, and the frequency of infected ticks) varied for particular years.

Animals↗