[THE EPIZOOTIC AND EPIDEMIC ACTIVITY OF NATURAL TULAREMIA FOCI OF DIFFERENT LANDSCAPE EPIDEMIOLOGICAL TYPES IN 2009-2014].

OBJECTIVE: to assess the present state of the natural tularemia foci of different landscape epidemiological types, by using individual focal areas as an example. MATERIALS AND METHODS: Epizootological monitoring and epidemiological analysis were conducted in the areas of natural tularemia foci of tundra (Wrangel Island), meadow-field (Central Federal District of the Russian Federation), flood-swamp (Arkhangelsk Region, Khanty-Mansi Autonomous District), and steppe (Mongolii) types. Small mammals (organs, blood), tularemia patients' sera, and environniental objects were examined. Molecular genetic and immune serological diagnostic assays were used. The incidence of tularemia in the past decade was analyzed using the maps for the epidemiological examinations of tularemia cases and medical reports. RESULTS: The natural foci of tularemia were established to continue to actively operate. There were 2913 cases of tularemia in the Russian Federation in 2001 to 2014. The flood-swamp natural foci, in which there were summer transmissive tularemia outbreaks, the largest of high occurred in Khanti-Mansiysk in 2013 when a total of 1005 people fell ill, are a special epidemic hazard. Analysis of the tularemia outbreaks suggests that there is a need for continuous epizootological monitoring of the areas of natural tularemia foci for the timely prediction and prevention of epidemic complications. It is noted that there is an unfounded reduction in the scope of preventive measures, and immunoprevention in particular, and a weaker control of the antitularemia immune status in the population residing in the area of active natural foci of tularemia.

[Epizootic and epidemic manifestation of natural foci of tularemia in Moscow region (1965-2013)].

AIM: Detection of contemporary features of tularemia focimanifestations, determination of territories of high epidemic risk in various landscape zones and creation of a map of foci territories of Moscow Region for isolation of tularemia infectious agent cultures and registered human morbidity for justified planning of prophylaxis measures. MATERIALS AND METHODS: Report materials of epizootologic examinations of natural foci for 1965-2013, 156 maps of epidemiologic examination of cases of human infection with tularemia, results of studies of casting of predatory birds and dung of predatory mammals were used. Registered morbidity and isolation of tularemia infectious agent cultures from 1965 to date were applied to an electronic map of Moscow Region by sign method using modern. GIS-technologies (MapInfo 10.5 program). Electronic maps Ingit at 1:200,000 scale, as well as Google Earth program were used to search for base points. RESULTS: Analysis of morbidity has revealed structure change in human tularemia morbidity--an increase of the fraction of urban population and a decrease of the fraction of patients among rural inhabitants, unimmunized against this infection are mostly ill. The presence of DNA of tularemia causative agent in biological objects in the complex with serologic and bacteriological studies was shown to allow to detect flaccid epizootics even at low numbers of rodents. CONCLUSION: Cartographic reflection of registered morbidity and isolation of tularemia infectious agent cultures allowed to show territories with various degrees of epizootic activity and epidemic manifestation. Positive results of serologic and molecular-genetic studies of environmental objects gives evident on epizootic activity and constant risk of aggravation of epidemic situation for this infection.

[Evaluation of modern epizootic activity of natural tularemia foci in Voronezh region using immune-serological and molecular-genetic study of main carriers of the disease].

AIM: Improvement of monitoring and prognosis of epidemic manifestations of natural foci of tularemia on the territory of Voronezh region using immune-serological and molecular-genetic study of main carriers of the disease. MATERIALS AND METHODS: 539 small mammals captured during summer period of 2011 in 4 districts of North-Eastern part of Voronezh region were studied. Animal organs were studied by serologic (search for Francisella tularensis antigens) and molecular-biologic (detection of F. tularensis DNA) methods. Tularemia antigen was detected using passive hemagglutination reaction (PHAR) with erythrocytic tularemia immunoglobulin diagnosticum. Real-time polymerase chain reaction (RT-PCR) was applied for detection of tularemia causative agent DNA. RESULTS: Complex study revealed epizootic activity of natural foci of tularemia in the examined territory. F. tularensis antigen and/or DNA were detected in 82 objects (15.2%). Use of RT-PCR allowed to additionally detect samples with relatively low content of F. tularensis DNA substrate, when antigen was not detected in samples. High sensitivity and specificity of the RT-PCR was ensured by inclusion of specific probes (tu14-PR2 and ISFTu2P). CONCLUSION: The results obtained give evidence on functioning and epizootic activity of natural foci of tularemia in Voronezh region that requires constant monitoring of the territory and prophylaxis measures, first of all vaccination of risk groups by live tularemia vaccine.

[Monitoring the natural foci of tularemia on Wrangel Island].

Long-term annual monitoring of the natural foci of tularemia was first made on Wrangel Island. The objects of the investigation were pellets of birds-myophages, blood samples from rodents, and excrements from carnivorous mammals. A total of 2626 biological samples were examined in the period 2002 to 2011. A serological test was ascertained to be the most effective method for the detection of tularemia epizooties; polymerase chain reaction should be used as an additional technique to examine blood samples, as well as rodent tubular bone debris taken from the pellets. Tularemia epizooties were registered in the populations of two species of lemmings every year, except in 2003. An intensive diffuse tularemia epizooty was first detected in this area, which emerged in 2019, peaked by spring 2011, and covered most of the island. The antigen of tularemia pathogen was identified in 43.46% of the samples under examination,which is a high quantitative indicator of the intensity of an epizootic process. The fact that positive samples are annually found in the same areas of the island suggests that the causative agent is steadily and long preserved in the parasitic system. The availability of stable and active natural tularemia foci on Wrangel Island calls for preventive measures, particularly vaccination of risk groups coming to the island to conduct researches.

[Detection of natural tularemia foci in Mongolia].

AIM: Study of the current spread of natural tularemia foci in Mongolia and its epizootic activity evaluation for consequent substantiation of the recommendations for prophylaxis of this disease. MATERIALS AND METHODS: Study of 1119 pellet specimens from predatory birds obtained in 6 aimag in Mongolia in 2008--2010 was performed. Tularemia antigen was detected by using antibody neutralization reaction (ANR) and passive hemagglutination reaction (PHR) with tularemia diagnosticums. Tularemia DNA was detected by PCR by using strain specific primers. Presence of plague antigen in PHR with plague immunoglobulin diagnosticum was also studied in all the samples. RESULTS: Epizootologic monitoring allowed the detection of natural tularemia foci in 5 of the 6 studied aimags in Mongolia. PHR was the most effective study method that allowed to detect tularemia antigen in the environmental objects in high quantities (up to 9.2% of positive samples) and high titers (up to 1:1600). PCR was less effective. Plague antigen was detected in 9 samples in 2010 for the first time, and in 3 cases together with tularemia antigen, which indicates a presence of combined natural foci of tularemia and plague in this territory. CONCLUSION: In the studied regions of Mongolia natural tularemia foci were detected, their epizootic activity was determined and recommendations for future study tactics of natural tularemia foci were given.

[Natural foci of tularemia on the Wrangel island].

The subjects of the study were snowy owl castings (611 samples), polar fox litters (148 samples), and water samples of outdoor tundra water reservoirs. Tularemia antigen was sought in the castings and litters by the antibody neutralization test. The water was examined by bioassays. Tularemia antigen was annually detected in the study samples. Epizootically active autonomous natural foci of tundra-type tularemia were ascertained to continue to exist on the Wrangel island. The major vectors of the causative agent of tularemia were two types of lemmings (Siberian lemming and Vinogradov's one). The availability of epizootically active natural foci determines the need for vaccination against tularemia of persons who are long engaged in researches who are epidemiologically a risk group.

Photodynamic therapy targeted to pathogens.

Photodynamic therapy (PDT) employs a non-toxic dye termed a photosensitizer (PS) together with low intensity visible light, which, in the presence of oxygen, produce cytotoxic species. PS can be targeted to its destination cell or tissue and, in addition, the irradiation can be spatially confined to the lesion giving PDT the advantage of dual selectivity. This promising approach can be used for various applications including microbial inactivation and the treatment of infections. Resistance to PDT has not been shown and multiantibiotic-resistant strains are as easily killed as naive strains. It is known that Gram (+) bacteria are more sensitive to PDT as compared to Gram (-) species. However, the use of cationic PS or agents that increase the permeability of the outer membrane allows for the effective killing of Gram (-) organisms. Some PS have an innate positive charge, but our approach is to link PS to a cationic molecular vehicle such as poly-L-lysine. This modification dramatically increases PS binding to and penetrating through the negatively charged bacterial permeability barrier. Due to focused light delivery the use of PDT is possible only for localized infections. Nonetheless numerous diseases can be treated. Selectivity of the PS for microbes over host cells, accurate delivery of the PS into the infected area, and PDT dose adjustment help minimize side effects and give PDT an advantage over conventional therapy. There are only a few reports about the use of antimicrobial PDT in animal models and clinical trials. We have used genetically modified bioluminescent bacteria to follow the effect of PDT in infected wounds, burns, and soft tissue infections in mice. Not only were bacteria infecting wounds, burns, and abscesses killed, but mice were saved from death due to sepsis and wound healing was improved.

Macrophage-targeted photodynamic therapy.

Photodynamic therapy (PDT) uses light activatable molecules that after illumination produce reactive oxygen species and unwanted tissue destruction. PDT has dual selectivity due to control of light delivery and to some extent selective photosensitizer (PS) accumulation in tumors or other diseased tissue, additional targeted selectivity of PS for disease is necessary. The delivery of drugs to selected lesions can be enhanced by the preparation of targeted macromolecular conjugates that employ cell type specific targeting by ligand-receptor recognition. Macrophages and monocytes express a scavenger-receptor that is a high-capacity route for delivering molecules into endocytic compartments in a cell-type specific manner. We have shown that by attaching PS to scavenger-receptor ligands it is possible to get three logs of selective cell killing in macrophages while leaving non-macrophage cells unharmed. The capability to selectively kill macrophages has applications in treating cancer and in the detection and therapy of vulnerable atherosclerotic plaque and possibly for autoimmune disease and some infections.

[Results of the study of bird droppings collected in the Lithuanian SSR for the purpose of searching out tularemia epizootics]. / Rezul'taty issledovaniia pogadok ptits, sobrannykh na territorii Litovskoi SSR s tsel'iu poiska épizootii tuliaremii.

There are practically no records of cases of tularemia among humans in the Lithuanian SSR. Nevertheless, the mass sero-allergic survey of the population for tularemia, carried out 10-12 years ago, showed that 2.3% of the adult population in the Republic had had contacts with the causative agent of this infection. The work was aimed at the determination of the present activity of the foci of tularemia. During 6 years in 22 rural districts 2582 samples of avian excrements, containing bones and wool of small animals, were collected and studied by means of the antibody neutralization test (ANT). In 132 (5.1 +/- 0.4%) excrement samples collected on the territory of 12 districts Francisella tularensis antigen was detected. The average ANT titer was 45.2, the maximum titer (10 excrement samples) reached 1: 160. The study revealed the existence of the natural foci of tularemia in Lithuania at present, but their activity proved to be low. The most unfavorable situation was found to exist in western districts of the Republic.