| Abstract [eng] |
The links between the frequency of the respiratory tract diseases and the meteorological conditions in Lithuania Summary Main goal of the study is the assessment of the respiratory tract diseases dependence on meteorological conditions in Lithuania for 1995-2005 period. The research includes following tasks: a) an assessment the links between climatic indices and the frequency of the respiratory tract diseases; b) an assessment of the prevalent atmospheric circulation in the European Atlantic region – advection, flow direction and the position of the Centers of Action – during epidemic periods in 1995-2004. The paper concerns the impact of the complex of meteorological parameters (minimal, maximal and daily mean air temperatures, relative humidity and wind speed) on respiratory diseases such as the flu and the acute respiratory tract infections in the largest Lithuanian towns – Vilnius, Kaunas, Klaipeda, Siauliai and Panevezys. The study also includes the assessment of the relationship between climatic indices (comfortability, discomfort and wind chill) and the frequency of respiratory diseases (cases). An epidemic flu index was used in the research because it reflects cases best of all. As a rule it is calculated for 10 thousand habitants and the epidemic threshold is treated to be exceeded when the cases of flu and acute respiratory tract disease was determined to 100 patients for 10 thousand habitants or number of cases increases twice for a week. Referring to the P. Hess and H. Berezowsky classification technique and catalog there were studied atmospheric circulation patterns favorable for reoccurrence of epidemic spells in Lithuania. Correlation analysis and analysis of variance reveals the dependence between growth rate of cases and total effect of meteorological parameters because of the individual parameters have the different sign of the forcing. For instance, the wind speed is in relevance with the number of cases while the temperature parameters and the relative humidity are in inverse ratio with cases. Also there was determined that the maximal values of the flu index fall to the minimal air temperature interval lying between 4.2 and 5.7 °C, the maximal air temperature interval – 0.2-1.2 °C and the daily mean temperature interval - -1.6 --2.9 °C. The most favorable humidity range is 81-85 % and the wind speed – 3.5 – 4.5 m/s. The indices of comfortability and discomfort have different impact on the number of cases of respiratory diseases. Largest number of cases was determined for comfortability index oscillating between 1045 and1107 W/m2 (it is so called sub-comfortable or dicomfortable cold), for discomfort index values 0.0 - -1.2 °C and wind chill index - -6.7- -10.2 °C. According the large scale atmospheric circulation catalog by P. Hess and H. Berezowsky the high pressure field related to the cut off low circulation southward from Lithuania and the weak easterly flow under higher surface pressure field were determined as the most favorable for the formation of the flu epidemic. More detailed relationship between the weather conditions and the frequency of diseases requires further research applying more state of the art techniques such as modeling or artificial intelligence. |
