A retrospective analysis was conducted of human cases and outbreaks of tularemia in the Republic of Armenia from 1996 to 2012 utilizing geographic information system software. A total of 266 human cases of tularemia were recorded in Armenia from 1996 to 2012, with yearly incidence ranging from 0 to 5.5 cases per 100,000 people. Cases predominantly affected the male population (62.8%), 11-20 year age group (37.2%), agricultural workers (49.6%), and persons residing in rural areas (93.6%). In 2003, a waterborne outbreak involving 158 cases occurred in Kotayk Marz, and in 2007, a foodborne outbreak with 17 cases occurred in Gegharkunik Marz, attributed to exposure of food products to contaminated hay. Geospatial analysis of all cases showed that the majority were associated with the steppe vegetation zone, elevations between 1,400 and 2,300 m, and the climate zone associated with dry, warm summers, and cold winters. Characterization of these environmental factors were used to develop a predictive risk model to improve surveillance and outbreak response for tularemia in Armenia.

Silicon is one of the most common elements in the earth’s crust. It is always present in water and food in varying amounts. Higher amounts of Si are found in plant-based foods. About 20% of the total amount of silicon ingested with food and water comes with drinking water and drinks (including beer, which contains in average 20–25 mg/l of silicon)․ For higher animals and humans, silicon is generally not considered to be an essential nutrient. However, the importance of this element for human health is now supported by increasing research evidence. The biological role of silicon in human organism is still not clear, but it assumed to be necessary for processes of bone mineralization, collagen synthesis. It has a positive effect on the skin, hair, and nails, contributes to the prevention of atherosclerosis and Alzheimer disease. In the population of most Western countries, dietary Si intakes range from 20 to 50 mg/day. In addition to the beneficial effect of Si on health, questions regarding the adverse effect of this element on the body are also discussed in the literature. First of all, we are talking about the Russian authors’ researches in the field of drinking water hygiene. At present, the adequate and maximum admissible levels of Si consumption have not yet been established. Taking into account the results of research on humans and animals, some scientists have suggested a dietary intake of Si of about 25 mg/day. As for the standards of silicon content in drinking water, it is not regulated in the drinking water quality guidelines of the WHO and the European Union, as well as in the national normative documents of different countries. In the Russian Federation, as well as in the Republic of Armenia, in the hygienic requirements for water quality, Si is normalized according to the sanitary-toxicological index, with the value of the maximum admissible concentrations in drinking water amounting to 10 mg/l.