In 2007 further increase of Crimean haemorrhagic fever (CHF) morbidity was registered in the territory of the Southern federal district. The cause of this is primarily the increase of the population level of H. marginatum. In the light of present epidemic situation we inclined to believe the prognosis for CHF in 2008 is unfavorable. The necessary measures to assure epidemiologic well-being for CHF are stated in the article. Acaricidal treatment of cattle carried out before mass activity of ticks and registration of the first patients is considered to be the primary one.

The questions of spreading of West Nile fever in the territory of theRussian Federationand abroad are considered. The information on the main carriers and vectors of this infection and their interaction with virus population is presented. The tendency of spreading of the West Nile fever virus in theRussian Federationand the possibilities of its maintenance during the inter-epidemic period are shown. Recommendations are given on the organization of serologic monitoring ofWest Nilefever in natural and anthropurgic biocenoses.

A short-term prognosis of plague epizootic activity in 11 natural foci in the Russian Federation for 2008 is substantiated by the authors. The present situation with the numbers of the main carriers and vectors of plague infection in diverse types of natural foci was analyzed. Some modern tendencies were noted in the dynamics of epizootic activity of the natural plague foci varying in their biocenotic structures.

 

Analysis of the situation with Lassa fever (LF) in accordance with the previously offered signs and characters, criteria and categories, actual for sanitary protection of territories from particularly dangerous viral infections (PDVI), showed LF to be a contagious PDVI classified as pathogenicity group I, capable of epidemic expansion. In case of LF import to a non-endemic territory, the maximal volume of anti-epidemic measures is recommended to be accomplished because epidemiologic complications may emerge even with the advent of an individual case of the disease.

The major trends were denned in the dynamics of cholera incidence over the world: in Africa, Asia, Americas (1997-2006). The tendency towards the increase in the dynamics of cholera morbidity in the world (rate of growth +12.817%) was found to be dependent on the incidence trends in Africa (+7.886 %). Formation of stable endemic foci in Africa is nowadays a prognostically important unfavorable index of the 7^th cholera pandemic evolution. According to WHO's formal information, 728 imported cases of cholera were reported worldwide from the countries of Asia (62.4%), Europe (22.1 %), Americas, from the USA and Canada (11 %), Australia and Oceania (4.1 %), as well as from Africa (0.4 %). The imported character of cholera outbreaks in different countries of Asia and Africa was confirmed by molecular studies of V. cholerae Ol strains. Currently, Bengal cholera is not only registered to be imported to different continents from endemic foci of India and Bangladesh, but also there is a tendency to annually detect cholera infection with no reported importation cases (China). The current trends in the evolution of the seventh cholera epidemics in CIS states and Russia during the analyzed period are determined by the importation of the infection with or without its subsequent spread. The seventh cholera pandemic is still going on. Cholera forecast worldwide remains unfavorable.

The level of fluctuating asymmetry (FA) of bilateral signs in fleas was shown to reflect a certain character of their interrelations with Yersinia pestis. Flea imagoes that had bacterial aggregations in their proventriculi demonstrated greater signs of FA chaetotaxy. Besides, in the experiments with groups of fleas originally differing in the intensity of FA expression, increased vector capacity was characteristic of individual fleas with higher levels of this index or those caught in the areas of the natural foci where epizootics had been registered. These peculiar interrelations manifested themselves both at intra- and inter-population levels in several species of Siphonaptera order, as well as in the imago hybrids originating from crosses between C.tesquorum altaicus and C.t.sungaris.

The development of two deep depressions in the numbers of small sousliks, observed in the 50ths - 60ths and 80ths - 90ths of the twentieth century, was shown to be significantly contributed to by the climatic factors in the North-Western Pre-Caspian region. The important role of the present-day climate warming upon the evolution of the inter-epidemic period in the North-Western Pre-Caspian steppe natural plague focus was ascertained, too. Search for Yersinia pestis strains in the rodent burrows soil in the areas of stable plague manifestations was recognized as a perspective surveillance measure to be practiced.

 

The technique of site-directed mutagenesis of psa operon encoding the synthesis of pH6 antigen (adhesion pili), followed by the trans-complementation procedure were used to construct two sets of isogenic Yersinia pestis strains including wild type strains 231 and I-1996, their non-polar pH6^- mutants containing deletions in the structural psA gene or in the entire operon, as well as the strains which could recover their capability for temperature- and pH-dependent synthesis of the adhesion pili or the constitutive pH6 antigen production. The loss of the ability to synthesize the pH6 antigen and its constitutive production was shown to affect neither their virulence characteristics nor mean lifetime assessments for the subcutaneously infected mice.

The review presents the data covered during the Second International Conference on the Biology of Vibrios "Vibrio 2007" (Paris, from November, 28^th to December, 1^st, 2007). Set forth are main trends of state-of-the-art vibrios research concerning their biodiversity, the peculiarities of genome arrangement, pathogenicity, epidemiology and ecology.

The results of the second phase of the experiments are presented in the paper, where β-propiolactone was used to decontaminate materials from Yersinia pestis. Both slurries and suspensions of the internal organs were decontaminated of Y. pestis 231 with 0.1 % concentrations of the preparation after 18 to 24 hours' exposition in the refrigerator, as well as at 37 °C for as long as 6 hours or more. Optimal schedules for immunologic examination are offered to prepare the samples taken in the combined foci of plague and arboviral infections.

Analysis of the recent domestic and foreign publications concerning the problems of anthrax immunodiagnosis is presented in the current review. The major achievements in the development of the procedures to detect Bacillus anthracis and its antigens using various immunodiagnostic assays are briefly characterized. The most important problems are discussed in connection with the efforts to increase the efficacy of the modern immunodiagnostic kits and their introduction into practice.

The following technique is offered for restoration of viability of Yersinia pestis cultures lyophilized at -(20±2) °C and stored for a long time (7-16 months): 10 cm³ melted culture in a 120 cm³ glass bottle under cotton stoppers is aerated by rocking in a shaker at (27±1) °C. The process of reparation of the injured bacteria was shown to depend on the presence of the oxygen and energetic sources. Viability reparation was prevented in the atmosphere of argon, when cells' breath was inhibited by cyanide (KCN), and in the case of uncoupling of the oxidative phosphorylation process by 2,4-dinitriphenol (2,4-DNF). Reparation capability was manifested by the bacterial cultures that had retained energy-dependent autoregulation of the breathing activity, estimated according to the respiration parameters, and especially by the magnitude of the metabolic breathing control (MBC).

Described in the work are the major biokinetic criteria of the submerged growth process of V. cholerae Ol strains (classical and eltor biovars), O139, non-Ol and non-O139 serogroups, capable of overproducing the main protective antigens (Ol and O139 antigens, type I and II cholera toxin, cholera toxin type II В subunit, toxin-coregulated adhesion pili). The optimal parameters were defined for each strain (nutritional media, pH indices, cultivation time, application of an additional carbohydrate source) facilitating the maximal yield of the protective antigens under the production conditions, thus making it possible to use them as a basis for manufacturing more efficient vaccinal preparations as well as to obtain the main V. cholerae protective antigens as purified drugs for constructing diagnostic preparations.

Introduction of Tn5-Mob (Km^R) transposon into the chromosome of the toxinogenic V. cholerae strain MAK757 El Tor biovar was shown to result in the emergence of insertion mutants containing an altered genome of CTXφ prophage. The reorganization ofthe latter was expressed in the deletion of four genes, zot, асе, сер, orfU, however,its ctxAB operon coding for the synthesis of type II cholera toxin being still retained. This change in the CTXφ prophage has lead to as high as 200 fold greater levels of production of this protein by MAK757clones chr::Tn5-Mob (Km') Tox⁺⁺. A single clone with the highest cholera toxin biosynthesis levels (42.0-45.0 |xg/ml) was selected among the insertion mutants Km" Tox⁺and designated as KM234. The optimal conditions for culturing the KM234 construct were fitted to provide for the highest cholera toxin elaboration by the cells. The El Tor biovar V. cholerae strain KM234 thus constructed was shown to be a stable and efficient type II cholera toxin overproducing strain promising to be applied in the industrial production of this protein routinely used to manufacture the preparations for cholera diagnosis and prophylaxis.

The system for forecasting of the incidence of the enteric infections with water-borne transmission for Saratov city was created. It is based on analytical methods of estimation of sanitary indicators of water quality in the central water supply.