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The  Coxiella burnetii strain NL3262 was isolated during the Q fever outbreak in the Netherlands in 2007-2010. Formal-order analysis (FOA) was used to study the similarity of the genome (chromosome and plasmid) of this strain with the genomes from other strains. Chromosomes from ten C. burnetii strains and eight plasmids were studied with FOA tools such as 'Map of genes' and 'Matrix of similarity.' The 'Map of genes' tool showed that the chromosome of strain C. burnetii str. NL3262 distanced itself by the index of average remoteness ( g ) of 1.449640 ( x -axis) from chromosomes of other strains ( g 1.448295-1.448865). The 'Matrix of similarity' was used for an advanced analysis of the obtained results. The complete similarity of the components of chromosomes and plasmids was determined by pairwise comparison and the identification of nucleotides matching with them. A total of 84.90% of the chromosomal components of C. burnetii strain NL3262 coincided completely with the chromosomal components of strain Z3055. For chromosomes of other strains, this percentage varied from 12.06% to 47.14%. The plasmid of strain NL3262 had 50.0% of the components being completely coincident with the components of the plasmid of RSA 331; with RSA 493 it was 29.89%. Thus, C. burnetii str. NL3262 is the closest to str. Z3055 by the similarity of the chromosomal components, but on the index of average remoteness of the chromosome and the similarity of the plasmids' QpH1 components, it is the closest to strain RSA 331.

This article highlights the biography and scientific accomplishments of Pavel F. Zdrodovskii and his contributions to understanding the biology, pathogenesis, treatment, prevention and epidemiology of brucellosis, rickettsioses and many other infectious diseases.

Materials, that summarize data of original research and scientific literature on epidemiology and problems of persistence during epidemic typhus, whose causative agent (Rickettsia prowazekii) is reactivated in the organism of the previously ill and is manifested as Brill-Zinser disease, are presented. A retrospective analysis was carried out with the data obtained by Russian (All-Union) Centre for Rickettsioses during study of epidemiologic examination maps of 5705 typhus nidi and results of 19 463 blood sera analysis during study of immunologic structure of population in the territories of the former USSR for the period from 1970 to 1992. A decrease of epidemic typhus morbidity and an increase of the fraction of Brill-Zinser disease took place as a result of pediculosis corporis control. In separate territories specific weight of Brill-Zinser disease was 48% in 1952, up to 80% in 1969, and from 1977 all the ill were previously ill. However, during the perestroika period and afterwards, due to a reduction of economic and hygienic living conditions, appearance of refugees, the immune structure regarding typhus began to change. Due to the buildup of the population migration process and the presence of risk groups (refugees, homeless) among population of regions, where local wars are waged, the enhancement of methods of epidemic typhus and Brill-Zinser disease diagnostics and pediculosis corporis eradication is necessary. Study of R. prowazekii by molecular-genetics methods is necessary for complete understanding of its mechanism of persistence.

Aim: Analysis of clinical cases of tick-borne spotted fever (TSF) group rickettsiosis in 2005 - 2010., Materials and Methods: General clinical, biochemical and serological parameters were determined in 10 tick-borne spotted fever group rickettsiosis patients who had visited various geographical regions of the World., Results: TSF group rickettsiosis diagnostic criteria, optimal serological diagnostics timing were determined. Possible diagnostic errors, features of serological diagnostics and antibacterial therapy of this nosologic form are discussed., Conclusion: Indication for TSF examination are primarily epidemiologic including tick attachment indication and clinical data. Serological studies are positive only in 3 - 4 weeks after the onset of the infection and thus can not be used for early diagnostics.

Questions of ecology of obligate-transmissible rickettsioses causative agents and their natural environment--organism of blood-sucking arthropoda (ixodes, gamasid ticks, harvest ticks, lices, fleas) are considered. In tick organism Rickettsia are propagated, and transphase and transovarial transmission of rickettsia maintains population in natural focuses. The relationship between Rickettsia ecology and rickettsioses epidemiology is evident. Data about new-revealed and recurrent rickettsioses and role of molecular-biological and genetical methods of Rickettsia detection are represented. Biological and social factors having influence on appearance of new and recurrent rickettsioses are determined with the aim of their prediction.

Aim: To characterize the clinical and histological features of Bartonella infection in patients asking for hematological advice and to assess the significance of serological and molecular methods for the diagnosis of this infection., Materials and Methods: The case histories of 747 patients asking for advice at the Hematology Research Cancer, Russian Academy of Medical Sciences, for lymphadenopaphy were retrospectively studied. The study included 10 patients in whom Bartonella infection could be suspected. For verification of the diagnosis, the authors conducted a serological study of the patients' sera and a molecular study of archival paraffined lymph node biopsy specimens., Results: The study showed it possible to make a retrospective diagnosis of cat-scratch disease (CSD) by polymerase chain reaction (PCR) used in the study of archival lymph node biopsy specimens and stained preparations., Conclusion: CSD should be suspected when a patient has sustained lymphadenopathy and a respective epidemiological history (feline contact). Bartonella infection should be diagnosed on the basis of a dynamic serological study and, if possible, PCR of cells from biopsy specimens of lymph nodes or the lesion developed at the site of Bartonella penetration into the human body (primary affect).

Currently, several rickettsioses are officially being reported in the Russian Federation. These are epidemic typhus and Brill-Zinsser disease, both caused by Rickettsia prowazekii which has a historic prevalence in Russia. Nowadays only single sporadic cases of R. prowazekii infection are reported. The last significant outbreak occurred in 1997 in a mental nursing home, where 29 cases were identified. Registered morbidity of typhus in Russia varies from 0 to 0.01 per thousand for the last decade. Siberian tick typhus, caused by R. sibirica, is registered on a large territory from Pacific coasts to Western Siberia, and its incidence continuously increases, varying between 2.5 and 4.0 thousand officially registered cases per year. Astrakhan spotted fever, caused by R. conorii subsp. caspia has been recognized since 1983. Recently, Far Eastern tick-borne rickettsiosis, caused by R. heilongjiangensis, has been described. Several other pathogenic spotted fever group rickettsiae have been detected and isolated from ticks in Russia; however, they have not yet been linked with clinical cases in these regions.

Thirty-one rickettsial isolates from ticks or patients in North Asian tick typhus (NATT) foci from the Ural region to the Russian Far East were obtained at the Omsk Research Institute of Natural Foci Infections between 1954 and 2001. Using citrate synthase (gltA) and outermenbrane protein a (ompA) gene sequencing, we identified these isolates as Rickettsia sibirica sensu stricto (25 isolates), R. sibirica strain BJ-90 (2 isolates), R. slovaca (1 isolate), and R. heilongjiangensis (3 isolates). We demonstrate that Ixodes persulcatus ticks should be considered potential vectors of NATT. We also demonstrate the presence of R. slovaca in Ural and R. heilongjiangensis in Siberia and Russian Far East, where they may cause human infections misdiagnosed as cases of NATT. Clinicians should be aware that several spotted fever rickettsioses with different prognoses coexist in Russia in areas where NATT was the only previously recognized rickettsiosis.

For the first time the survival of Coxiella burnetii of five types in soils has been studied. The survival of C. burnetii has been found to depend on the content of organic substances in black earth, as well as soil temperature. The method for the prevention of an epidemic outbreak of Q fever directly under the natural conditions has been proposed.

The Bank of Standard Sera created in the Gamaleya Research Institute of Epidemiology and Microbiology provide for evaluation the epidemiological situation in any separate territory and in the whole of the country. The collection of certified blood sera is divided according to different territories of the country and makes it possible to obtain the retrospective and operative information on the level of population immunity and the immune structure of the population with respect to different infective agents, and to reveal the susceptible group of the population. The analysis of the unfavorable character of the epidemiological situation in the inspected territory with due consideration of its climato-geographical and anthropogenic environmental, socio-demographic characteristics, the level of population immunity and the immune structure of the population with respect to different infective agents makes it possible to carry out the epidemiological diagnostic (an outbreak, the import of infection, the use of a bacteriological weapon), prognosis and the prophylaxis of diseases, as well as the epidemiological cartography of territory.

Information on the epidemiology, clinic and diagnostics of bartonellosis is updated. The importance of bartonellosis lies in the fact that its main risk group embraces patients with immunodeficiencies of different origin, the number of such patients constantly growing. The diagnostics of bartonellosis is insufficiently developed and the research on Bartonella organisms, except for the trunch (Volynia) fever causative agent, is insufficient in our country.

Study of reference rate in healthcare institutions in 1991 - 2001 demonstrated a steady growth of general mortality and disease incidence among the population (by 22.7% and 8.1%, respectively). The number of patients with acute and chronic diseases registered in 2001 was by 16.4% higher than that in 1991. These trends were characteristic of all disease classes, but the most intensive growth was observed in such classes as diseases of blood and hemopoetic organs (2.5 times), endocrinal and urogenital diseases (1.8 times). Disease incidence and general mortality among children aged 0 to 14 had grown by 25% and 33.2%, among adolescents--by 60% and 71.1%, among adults--by 5.2% and 20.3%, respectively. These negative trends in population health were accompanied by a constant growth of incapacitation rate in 1990 - 2000 (2.4 times, and 4.3 times among children and adolescents younger than 18). There is a correlation between mortality and traditionally used demographic parameters, which suggests that mortality should be recognized the key demographic parameter. In order to achieve a satisfactory level of population health and adequate demographic transition, and to develop general sanatory strategy, the State should undertake powerful, goal-seeking, society-oriented measures, including deep clinical and epidemiological study of human pathology.

The review updates knowledge on the taxonomy, bacteriology and genetics of Bartonella as well as pathogenesis of bartonellosis. The role of Bartonella in human pathology, formerly considered to be rather modest, causes now growing anxiety. In this connection Bartonella are now believed to be the causative agents of so-called emerging and re-emerging diseases, i.e. diseases, formerly unknown to man, and diseases, believed to be eradicated and playing at present no important role in human pathology. These microorganisms are a bright example of successes of molecular biology in the detection of microorganisms, as well as in their phylogenetics and systematics.

A new microorganism, tentatively named "Montezuma" was detected in ticks and in specimens (blood, bioptic specimens of the primary affect) taken from patients with an acute fever disease, etiologically linked with the bites of Ixodes ticks in the Far East of the Russian Federation. After sequencing the products of the amplification of DNA isolated from ticks with wide-spectrum primers new primers were developed, highly specific to the unusual sequence thus obtained. The study revealed that ticks of the species Ixodes persulcatus (97%) and Haemophysalis concinnae (5%) contained DNA of this microorganism. The same DNA was detected in materials taken from the patients. The phylogenetic analysis of the gene showed that this organism formed an independent and well defined branch within the order Rickettsiales. The nearest homology (89%) was observed with recently detected endosymbiotes Acanthamoeba. The similarity with their relatives from the families Rickettsiaceae and Anaplasmataceae of the order Rickettsiales was within 81-86%, which made it possible to infer the existence of, probably, only a new genus, but also a family. The isolated DNA belonged, supposedly, to the new microoganism which caused a tick-borne disease in humans, transmitted through bites of Ixodes ticks, and was, supposedly, widely spread in the southern area of the Khabarovsk Territory.

R. slovaca was first detected in the ticks D. marginatus gathered in the Stavropol Territory and the Voronezh Region (European Russia). The recently discovered rickettsial genotype DnS14 was first found in the ticks D. silvarum from Buryatia and D. niveus from the Karaganda Region (Central Kazakhstan). The rickettsial genotype RpA4 was most common in the ticks of the genus Dermacentor in Russia and Central Kazakhstan. An analysis of the spread of rickettsias of the STF group shows their close ecological relation to definite types of Ixodes. The rickettsias R. slovaca and RpA4 co-exist in the ticks D. marginatus and D. reticulatus (the western part of a Dermacentor area in Eurasia) and DnS14 and R. sibirica do in D. nuttalli and D. silvarum (the eastern part of the area). D. marginatus and D. reticulatus in the areas characterized by the most specific saturation of a Dermacentor area (the south of West Siberia) are carriers and reservoir of R. sibirica. The rickettsial genotype DnS28 may be now considered to be environmentally associated with one species of ticks--D. nuttalli. At least 6 genotypes of STF rickettsias--R. sibirica, R. astrahan fever (R. conorii), R. slovaca, RpA4, DnS14, DnS28--has been currently identified in Russia and Kazakhstan.

Current tendencies and problems of molecular biology and its application in infectious diseases are discussed. Basic stages of the development of molecular epidemiology as a leading tool for epidemiological studies are reviewed. More than 30 years ago, molecular epidemiology was first used to study nosocomial infections. Special attention is given to the achievements of Russian scientists, especially in the discovery of Astrakhan spotted fever Rickettsia, noncultured forms of Vibrio cholerae, and the microorganism "Montezuma." Also, the development of PCR-based methods of identification and typing of Mycobacterium tuberculosis by Russian specialists and its significant role in strategies for diagnosing and treatment of tuberculosis are discussed. Now, the most important field of application of molecular biology methods is bacterial evolution, especially with regard to pathogenic microorganisms and emerging infections. Searching for the novel pathogenic agents, establishment of the infectious nature of diseases with unclear origin, and determining the precise mechanisms of pathogenicity are most intriguing issues. So, molecular biology should play a major role both in clinical and research fields.

Twenty female imago of Haemaphysalis concinnae ticks collected from wild vegetation in May of 2001 in the Obor region near Khabarovsk in the Russian Far East were studied. DNA was extracted with commercially available kits following manufacturer's instructions. We used broad range primers SFG3 and SFG6 proposed for amplification of 16S ribosomal RNA gene's portion of spotted fever group Rickettsia. Initial amplification resulted in positive results in all 20 ticks. Direct sequencing of five randomly chosen amplicons showed that obtained sequences belong to a new species. Closest homology was found in Coxiella burnetii 16S rDNA. Using the obtained sequence as a basis, we designed internal primers highly specific for that sequence. Then we confirmed our results by nested PCR amplification with newly designed primers Cox1 and Cox2-all 20 samples also were positive. Having combined these primers with universal eubacterial primers fD1 and rP2 we retrieved a 1,043 bp portion of the 16S rRNA gene. Consecutive homology search demonstrated that the closest sequence similarity belongs to new Coxiella sp. recently found in Rhipicephalus sanguineus ticks (95.2% of homology) and Coxiella burnetii (94% of homology). So, our results suggest that a novel Coxiella-like microorganism, provisionally called here "Cenerentola," is harbored by Haemaphysalis concinnae ticks in the Russian Far East.

There have been recently reports on over 10 new and resurgent rickettsioses and bartonelloses in different countries, which reflects both socioeconomic processes in society and a higher methodological level of indication and identification of causative agents. In 1991, the author' laboratory, N. F. Gamaleya Research Institute of Experimental Medicine, Russian Academy of Medical Sciences, established the etiology of the new rickettsiosis Astrakhan spotted fever. It separated and studied 2 strains of Rickettsia sp. nov. from patients and 8 ones from the carrier the Ixodes tick Rhipicephalus pumilio. It is suggested that the natural focus has transformed to the anthropurgic one due to technogenic environmental pollution. The annual increase in morbidity rates (2000 cases in 1983 to 2000) and its area are a challenge to public health care and medical science. The paper presents data on the new bartonellosis cat-scratch disease (caused by Bartonella henselae) detected not only in Russia. There is also information on tick-borne rickettsiosis, epidemic typhus, and trench fever as resurgent infections.

The paper discusses the problems of purification of Provachek's rickettsias used to prepare typhus vaccines and diagnostic kits. The currently available agents contain many admixtures of rickettsias products, more commonly yolk and chick embryo yolk sack cell detritus, which make it impossible to determine the true antigenic properties of rickettsias in the context of protection and diagnosis. By applying the well-known principle of distribution of biological particles in the two-phase systems of water soluble polymers, investigations were made to examine the distribution of rickettsias and their infected biological mass in the system: polyethylene glycol-6600, sodium-500 dextran sulfate, potassium phosphate, sodium chloride in order to prepare agents of pure rickettsias. It has been found that rickettsias are distributed in the polymer-enriched phase, their number and the degree of purity when isolated from the infected biological mass depends on the capacity of an interphase wherein tissue detritus sorption occurs.

Ehrlichia infections are more and more common in the USA and Europe. The genetics and genome organization of Ehrlichia are little studied due to great difficulties in cultivating these bacteria. Pulse gel electrophoresis was first used to determine the sizes of a genome of 3 representatives of the genus Ehrlichia. The sizes of a genome was established for E. sennetsu (881 kb), for E. risticii (867 kb), E. chaffeensis (1,236 kb).

The analysis of the results of prolonged observations on the prophylactic immunization of employees working with R. prowazekii is presented. The necessity of the differentiated approach to the determination of the immunization schedule and the choice of vaccine is shown. The presence of specific antibodies (Ab) and the level of their titers have been found to be related to the degree of anti-infectious protection. The following characteristics indicate the presence of profound immunological transformation in vaccinees: complement-fixing Ab in titers 1:10 and more and/or immunofluorescent Ab in titers not below 1:180, Ab to protein in the hemagglutination test in titers not below 1:1000. These specific Ab and the level of their titers can be registered after the second injection of live combined typhus vaccine E and the third injection of chemical typhus vaccine. Cases of laboratory infection and their relationship to the character of immunization and the intensity of contacts with R. prowazekii virulent strains are discussed. Attention is drawn to the strict observance of professional safety rules.

The isolation of Orientia tsutsugamushi was attempted from 249 rodents and approximately 14,000 trombiculid mites captured in the Primorye region, Far East Russia in 1993 and 1994, where high infection rates were recorded in both rodents and mites in the 1960s. However, no rickettsia was isolated from the samples. Low antibody titers against O. tsutsugamushi were detected in 7.1% of the rodents. These results indicate that the prevalence of O. tsutsugamushi in the Primorye region has decreased considerably in the past 30 years.

In this article materials on obtaining rickettsial liposomal preparations on the basis of R.prowazekii phospholipid antigen and chemical typhus vaccine are presented. Electron microscopic studies revealed the formation of liposomes in this system. Liposomal preparations were not hemotoxic and produced no toxic action in experiments on guinea pigs and white mice. Phospholipid antigens incorporated into liposomal preparations were found to produce a potentiating effect on the immunogenic properties of chemical typhus vaccine. The adjuvant properties of rickettsial phospholipids incorporated into liposomes on the basis chemical typhus vaccine were registered.

Neotrombicula kanekoi n. sp. is described from Apodemus agrarius and Crocidura lasiura collected in the Primorye Territory, Russian Far East. This species is close to N. subsignata but differs in having eight setae in the first posthumeral row, whereas N. subsignata has six. The new species is the sixth known member of the bisignata group in the Far East.

Two spotted fever group rickettsia strains, A-108 and A-167, were isolated from the hemolymph of Rhipicephalus pumilio ticks collected in the Astrakhan region of Russia, which is area endemic for Astrakhan fever. These tick isolates were compared with a strain isolated from a patient suffering from Astrakhan fever and with reference spotted fever group rickettsiae strains. New tick isolates and the human strain were identical in their serologic, antigenic, and genetic characteristics by several methods: microimmunofluorescence, protein gel electrophoresis with immunoblotting, polymerase chain reaction followed by restriction endonuclease fragment length polymorphism analysis, and pulsed-field gel electrophoresis (PFGE). Astrakhan fever rickettsiae were found to be serologically and antigenically similar to Israeli spotted fever rickettsiae. Both of them probably belong to a single Rickettsia conorii pathotype complex. Only PFGE pattern analysis could clearly discriminate Astrakhan fever rickettsiae from other isolates.

It was shown that the immunization of mice by the chemical Q fever vaccine prepared with the use of the strain "Coxiella burnetii, Nine Mile", phase I did not markedly activate the oxidative metabolism of the peritoneal exudate cells and did not induce the non-specific cytotoxicity in them. However, it resulted in a significant suppression of the mitogen-induced proliferation of splenocytes on days 3-5. The immunization of mice by the combined (corpuscular/chemical) vaccine prepared with the use of the strain "Apodemus flavicollis-Luga", phase I induced a significant activation of the oxidative metabolism of the peritoneal exudate cells and the development of the nonspecific cytotoxicity in them, whereas no suppression of the mitogen-induced proliferation of splenocytes was observed. The differences are likely associated with the presence of the corpuscular component in the combined vaccine and the strain antigenic specificity.

The past ten years were characterized by the appearance of several "new" transmissible spotted fever group (SFG) rickettsioses, e.g. Israeli, Japanese and Astrakhan fevers. The factors responsible for their establishment probably include the introduction of chemicals from industry, agriculture and the timber industry into natural habitats. Such factors may influence the pathogenicity of these rickettsiae. In this case, in addition to the human influence, the mechanism of the circulation of the agents under natural conditions of both abiotic (climate, etc.) and biotic (flora and fauna) components may play a decisive role. The modern management of breeding domestic animals, indoor and outdoor maintenance, seasonal migrations, new animal foods, stress, etc., can be important factors affecting the biological properties of the Q fever agent. Nonpathogenic rickettsiae, rickettsia-like symbionts and other microorganisms circulating in nature may also influence the pathogenic rickettsiae. Studies on their interrelationships in hosts and vectors may markedly contribute to the understanding of the circulation of pathogenic rickettsiae in nature. Recognition of factors causing the appearance of new rickettsial agents or differences in pathogenicity of rickettsial strains is important not only for the prognosis of rickettsial diseases but also for the prognosis of other infectious diseases.

Methods of mathematical modelling and prediction of louse propagation processes in the natural habitation medium are presented. Theoretical and experimental data on head louse ecology served the basis for the elaboration of a mathematical model predicting the population dynamics. The model structure corresponds to 3 stages of louse development cycle (eggs, larva, lice) and parameters corresponding to natural characteristics of louse propagation process: mean lifespan of each individual during each phase of the cycle, age, fertility and so forth. The model helped to study some properties of the population, assess maximum rate of head louse population growth, detect threshold effects, establish the effects of coefficients, limiting the number of louse per unit of the body surface. The model made it possible to formulate necessary data (distribution functions) for the creation of the mathematical model of Pediculosis.

The acute febrile disease with characteristic rash seen in Astrakhan region and named as "viral exanthema of unknown etiology" was proved to be a spotted fever group rickettsiosis. Serological examination of humans from endemic areas by complement fixation test revealed antibodies to R. conorii, R. akari and strains Netsvetaev and AR-74 of R. sibirica in titres from 20 to 640 in sera from ill persons. Of 429 sera from healthy persons, 5.1% were serologically positive in a titre of 20-40. The presence of spotted fever group rickettsiae was detected in 8 of 104 Rhipicephalus sanguineus ticks removed from dogs and tested by haemocyte test with Gimenez staining and indirect immunofluorescence technique. Attempts at isolation of rickettsiae in guinea pigs and cell cultures resulted in appearance of specific spotted fever group rickettsiae antibodies in guinea pigs (4 of 8 samples examined were positive) and detection of rickettsiae by immunofluorescence technique in cell cultures (in 2 of 12 samples tested).

Electron microscopic examination revealed replication and accumulation of Rickettsia sibirica in the fat body of experimentally infected Dermacentor reticulatus ticks. Rickettsia are released from the fat body cells by budding being surrounded with cytoplasm and plasmalemma of the host cell. Eukaryotic cell structures have been detected consisting of lamella layers whirled around the intact rickettsiae. In addition to rickettsia, microorganisms morphologically resembling Francisella tularensis and an orbivirus were found in tick tissues at morphological examination. The morphology of the virus and stages of its morphogenesis are described. Mixed viral and rickettsial infection has been shown to develop in the same ticks and even in the same fat body cells in a very close association.

The ultrastructural aspects of the interaction of R. sibirica and R. slovaca with cells of mites of the species Dermacentor reticulatus, D. marginatus and Ixodes ricinus after their parenteral infection, as well as in the organs of D. marginatus infected naturally in the environment, have been studied. Both rickettsial species have similar morphology in different organs of the vector. These rickettsiae not only multiply, their populations are also partly destroyed in phagolysosomes. The natural mixed infection of R. sibirica and orbivirus in cells of D. reticulatus is described. As shown in this study, both associates pass through the complete ontogenetic cycle of development on the level of the host body and also on the level of an individual cell.

The authors review a newly formed focus of Marseilles [correction of Marsel] fever in Astrakhan Province marked by the epidemiological characteristics related to the disturbance of the ecological balance. While analyzing the clinical picture of the disease in 251 patients, emphasis is laid on the typical signs of the given disease.

The results of this investigation indicate that preparations obtained on the basis of monoclonal antibodies have proved to be suitable for the detection of R. prowazekii antigens in the natural carrier of typhus when used in all types of the enzyme immunoassay; of these, the assay made by the capture method has been found to possess the highest sensitivity. The testing of the sensitivity limits has shown that this method known as ELISA-mu-capture, i.e. ELISA carried out with the use of antibodies to the mu chain of human immunoglobulin, is capable of detecting the antigen in a dose of 0.5-1 ng. Preparations based on monoclonal antibodies to species-specific R. prowazekii antigen permit the identification of the causative agent of typhus in its natural carrier within 24 hours.

R. prowazekii antigens have been tested with the use of monoclonal antibodies (McAb) to different epitopes of the microorganism. As revealed in these tests, McAb B4/4 and A-3/D, active against species-specific thermolabile antigen, interact with protein having a molecular weight of 90-120 KD. McAb C5/2, active against thermostable group antigen common with that of Rickettsia typhi, interact with LPS-like antigen having a molecular weight of 30 KD. Ultrastructural immunochemical studies have revealed that both R. prowazekii antigens are located on surface structures of rickettsiae, such as the microcapsule and cell wall.

A number of hybridomas to different R. prowazekii determinants were obtained by the hybridization of spleen cells of BALB/c mice immunized with R. prowazekii corpuscular and soluble antigens. Some of the monoclonal antibodies (McAb) reacted with R. prowazekii thermolabile species-specific protein and did not react with R. typhi antigens (McAb of batches B4/4 and A-D3). McAb C5/2 and A3/2 reacted with the group thermostable antigen, common for R. prowazekii and R. typhi. McAb to the species-specific thermolabile antigen belonged to IgG2a. The McAb thus obtained permit the identification of R. prowazekii and R. typhi and the solution of the problem of the intragroup differentiation of rickettsiae belonging to the typhus group.

As the result of immunization of BALB/c mice with the commercial preparation of typhus vaccine and R. prowazekii corpuscular antigen, in 29.2% and 40.3% of cases (respectively) the appearance of hybridomas synthesizing monoclonal antibodies (McAb) to different autologous structures (skin and thymic epithelium, cell nuclei, conjunctive tissue structures and vascular endothelium) has been revealed. The McAb under test have proved to be IgM-autoantibodies. McAb M-6, active against the basal membrane of human skin and thymic epithelium, produce quite a definite picture of disturbances in the differentiation of epithelium and can be used for the diagnosis of dyskeratosis.

Q fever as one of infections with natural foci is characterized by epidemic outbreaks. Biologic plasticity and ecologic peculiarities of Coxiella determine its wide distribution and development of Q fever infections which are disseminated almost every-where. They occur in two, i. e. natural and agricultural types of foci. Present paper characterizes their structures, maintenance and peculiarities if their existence. It should be emphasized that single cases of disease as well as outbreaks of Q fever originate usually from agricultural foci, where the source of the infection are livestock, sheep and goats. Data are presented on the involvement of these animals into circulation of coxiellae in various countries of the world. It was shown that agricultural foci of Q fever depending upon close connection with domestic animals are determined in many aspects by basic factors of an epidemic process of the infection, i. e. seasonal occurrence, social conditions, professional relations, etc. which also enhance the course of the infection. Principles on prophylaxis complete the given paper.

Experimental parenteral inoculation of Dermacentor reticulatus ticks with the rickettsia Coxiella burnetii (C.b.) and tick-borne encephalitis (TBE) virus resulted in a generalized rickettsial and viral infection, irrespective of whether the agents were given simultaneously or by a 7 days interval apart. Both agents multiplied intensively in ticks, C.b. being detectable predominantly in cytoplasmic vacuoles and TBE virus mostly in the endoplasmic reticulum.