The work was carried out construction of immunizing designs based on selenium colloids extracellular antigens and whole cell vaccine strain Escherichiacoli B-5 and studied the protective immunization of these drugs in laboratory animals. For immunization using nonlinear white mice and guinea pigs. Immunized intraperitoneally twice at an interval of 1 week. After the second immunization, animals were injected with LD 100 E.coli B-5 mortality rate in the Group accounts for 5 days. Previous immunization was carried out in 4 repetitions. As a result of carried out work, it was found that the selenium colloid, as an adjuvant to stimulate antibody production against the components of bacterial cells (the outer membrane lipoproteins, flagella, live E.coli cells) against hemolysin and its culture medium. Serum after immunization loses their growth properties. Immunized animals by selenium constructs show higher survival in comparison the control group vaccinated with the killed culture after infection with a lethal dose for intact animals.

It is shown that the natural activity of bacteria supports their L-form in the body of obligate hosts. If the conditions of life in their body are changing, this form transformes into pathogenic infectious agents. In this situation the disease is defined as a factor disease. With the penetration of L-form in the body of a potential host, it is transformed into S-form, and the disease is defined as classic disease.

Infections caused by the avian influenza virus are a serious problem of veterinary and medicine. It is well known that the natural reservoir of most subtypes of influenza virus are wild waterfowl. It is believed that the cause of influenza pandemics is the penetration of new subtype virus or some of its genes from the natural reservoir. In this regard, it is important to explore the insufficiently known reservoirs, such as marine mammals that are closely in contact with wild birds. In the present study, as a result of monitoring conducted by the Caspian seal population on the coast of the Caspian Sea, located in the European part of Russia, it has been allocated a new avian influenza virus strain of subtype H4N6. The biological properties of the new isolated virus was studied in mice (Balb/с). It has been shown that the strain H4N6 is capable of replicating in the lungs and cause disease in experimental mice. By light microscopy have been revealed pathological changes in lung tissues of experimental group of mice compared with controls. Thus, the most likely that avian influenza virus H4N6, has overcome the species barrier and infect the Caspian seal (Phoca caspica), has the ability to replicate in the lungs of mice and cause their pathological changes.

The article presents new data on the epizootiology and epidemiology of toxoplasmosis in the Voronezh region. Investigations revealed that of the 400 examinees cats, Toxoplasma antibodies were found in 84 animals (21%) as the results of СFT; 210 animals (52.5%) as result of IFA. In 70 animals(17.5%), the level of specific antibodies was 1: 128. Of the 120 sera samples obtained from dogs and examined by RAC, antibodies were detected in 20 cases (16.7%) in IFA - 36%. In 30% of the animals the level of antibodies was 1: 128. Retrospective analysis of the epidemiological situation revealed that 116014 people - 51516 (40.3%) were seropositive for toxoplasmosis. From them were 45.6% women and 29.7% men. Invasion was increase with age. Children up to 10 years had antibodies to Toxoplasma in 12.3% of cases, young people aged 11 to 20 years - 18.5%, from 21 to 30 years - 27.3%, those of 30 and over - in 41.9%.

The relationship between the V. cholerae with all components of the water hydrobiotite are discussing. We are considering the possibility of changing the geography of the pathogen with increasing temperature due to climate change. Furthermore, changes in plankton populations and other hosts, in relation to which the vibrio are commensals or symbionts, can also cause changes in the ecology of Vibrio. Besides the climatic factors, the article examines the effects of anthropogenic impact on the ecology of surface reservoirs. The increase of biogen inputs leads to the development of the process of anthropogenic eutrophication of water bodies. In the upper layer of water there is a concentration of nutrients that induces an active microflora development of phytoplankton and zooplankton, the increase in weight. This environmental situation may be favorable for long-term circulation of V. cholerae.