[The multiyear changes in the epidemic activity of the foci of zoonotic cutaneous leishmaniasis at the Murgab oasis. I. An analysis of the relations of morbidity to heliogeophysical factors].
Attempts were made to analyse the relationships of changes in the pattern of zoonotic cutaneous leishmaniasis (ZCL) morbidity by the 1951-1993 statistics of the Turkmenistan Ministry of Health by the areas of Maryĭskiĭ velaiat with heliogeophysical factors. For quantitative characterization of solar activity changes, various indices were used; among them there was the Wolf number, radio radiation flux at a wavelength of 10.7 cm. and the geomagnetic Aa-index. In some many-year observations, vague cyclic variations were detected on a personal computer by spectral and periodogram analyses proved to be effective in other diseases. Correlation and cross-correlation analyses were used to evaluate the possible relationships between the morbidity rates and the changes in heliogeophysical factors. The study has revealed that the epidemic activity of ZCL foci is characterized by cyclicity with variations of about 2.4, 3.6, 6.9, and 11.2 years. The changes in ZCL morbidity in the areas, including the natural ZCL foci of Murgab delta landscapes, slightly differ from those in the areas with valley foci in the south part of the velayat in the duration and expression of cycles. At the same time sun-caused 11-year cycles are observed in all groups of the areas, though they are slightly more pronounced in the north than in the south. The greatest epidemic outbreaks (1956-1957, 1965, 1977, and 1986-1988) occurred in various areas of the Murgab oasis on an average of 1-3 years after the minimum of 11-year solar cycles. Noteworthy, they are greatly marked in odd solar activity cycles (the 1957 and 1977 outbreaks) in many areas. Among the parameters chosen, the radio flux of solar radiation at a wavelenght of 10.7 cm and the Wolf number (the correlation coefficients are as high as 0.30-0.50 at P = 0.95) are closely related with ZCL morbidity changes when the plot is shifted. At the same time the values of the geomagnetic Aa-index are unlikely to greatly affect changes in the epidemiological situation. The regularities revealed are of particular significance for long-term prediction of the greatest rises of ZCL morbidity rates. Taking into account the estimated solar activity changes within the next years, one may expect activation of natural ZCL foci and, in case of untimely use of prophylactic measures, the following rise in the population's morbidity in 1998-1999.
Neronov
V V
VV
Malkhazova
S M
SM
Ponirovskiĭ
E N
EN
Charyev
B Ch
BCh
D004196:Disease Outbreaks / Q000706:statistics & numerical data*; D004197:Disease Reservoirs / Q000706:statistics & numerical data*; D004574:Electromagnetic Fields; D006801:Humans; D015994:Incidence; D016773:Leishmaniasis, Cutaneous / Q000453:epidemiology*; D009017:Morbidity / Q000639:trends; D010507:Periodicity; D019445:Solar Activity; D013997:Time Factors; D014423:Turkmenistan / Q000453:epidemiology