The Relationship between the Population of Ixodid Ticks and Climate Change in Stavropol Region

The Relationship between the Population of Ixodid Ticks and Climate Change in Stavropol Region

Robert Gurgenovich Zakinyan¹, Galina Khamzatovna Badakhova¹, Maria Sergeevna Lopteva², Natalya Anatolyevna Koshkina², Vasiliy Petrovich Tolokonnikov³, Sergey Nikolaevich Povetkin^4*

¹Department of Theoretical and Mathematical Physics, Faculty of Physics and Technology, North Caucasus Federal University, Stavropol, Russia.

²Laboratory of Veterinary Medicine, Department of Animal Husbandry and Veterinary Medicine, Federal State Budgetary Scientific Institution "North Caucasus Federal Scientific Agrarian Center", Mikhaylovsk, Russia.

³Department of Parasitology and Veterinary Examination, Anatomy, and Pathanatomy named after Professor S.N.Nikolsky, Faculty of Veterinary, Stavropol State Agrarian University, Stavropol, Russia.

⁴Laboratory of Food and Industrial Biotechnology, Faculty of Food Engineering and Biotechnology, North Caucasus Federal University, Stavropol, Russia.

ABSTRACT

One of the main factors hindering the development and causing damage to animal husbandry is the parasitism of animals of ixodid ticks - carriers of pathogens of blood parasitic diseases. In the course of this scientific work, a study was made of the influence of changes in climatic conditions on the species composition of ixoid ticks. In the course of the work, for the meteorological station in Kislovodsk, the average winter temperature was calculated, as the average winter wind speed, and the variability, and trend of the Bodman index, characterizing the severity of the climate. The distribution of ixodid tick species largely depends on climatic zones. On the territory of the Stavropol Region, parasitism of 16 species of ixodid ticks belonging to 6 genera was established. Monitoring of ixodid ticks on the territory of the Stavropol Region since 1999 has shown a trend toward an increase in the species composition of ixodid. During the period of climate warming in the territory of the region, there is a weakening of the severity of bioclimatic conditions, especially in winter, which entails the spread and increase in the number of biotopes of ixodid ticks.

Keywords: Insects, Parasites, Climate change, Stavropol.

Assessment of bioclimatic conditions based on the Bodman index, moisture coefficient, and other coefficients and indices based on typical climatic parameters will trace the relationship between climatic conditions, landscape appearance, and the spread of ixodid ticks (Figure 2) [14].

MATERIALS AND METHODS

Having been engaged in the monitoring of ixodid ticks on the territory of the Stavropol Region since 1999, we found a tendency to increase the species composition of ixodids and unfavorable points for the spread of blood parasitic diseases [15, 16].

The information base for the research work was the materials of meteorological observations of the ground network of the Stavropol Center for Hydrometeorology and Environmental Monitoring over the past 20 years, as well as reference data on the temperature regime and wind speed in the area of the station location for two long-term periods of the year of the twentieth century.

During the research work for the Kislovodsk weather station, the following indicators were calculated:

• average winter temperature;
• average winter wind speed;
• variability and trend of the Bodman index in the resort of Kislovodsk, characterizing the severity of the climate.

To monitor the ixodofauna, we investigated four areas of the zone of sufficient moisture: Mineralovodsk, Predgornyy, Georgievsk, and Kirovsk districts, as well as the species composition of the ixodids ticks of the city of Kislovodsk. The collection of ticks was carried out using a standard flag – a piece of light-colored flannel with a length of 1 m and a width of 0.6–0.7 m, as well as by collecting directly from animals. The collection of ticks was carried out in March–May, July, and August - October 2016 - 2022.

Typing of ixodid ticks was carried out in the laboratory of veterinary medicine of the All-Russian Research Institute of Sheep and Goat Breeding - Branch of the Federal State Budgetary Scientific Institution North Caucasus Federal Scientific Agrarian Center under a binocular magnifying glass (MBS-2 binocular microscope) using the Methodological guide for accounting and distribution of ixodid ticks in Stavropol Region [17].

RESULTS AND DISCUSSION

On the territory of the Stavropol Region, parasitization of 16 species of ixodid ticks belonging to 6 genera has been established [18]. All ixodids are highly specialized parasites of terrestrial vertebrates, especially mammals and birds [19, 20]. The epizootological and epidemiological significance of ixodid ticks is determined by their participation in the transmission of pathogens of many dangerous vector-borne infections to humans and animals (bacteria, rickettsias, viruses, protozoa, spirochaetes) [21].

The distribution of ixodid ticks species depends more on climatic zones. There are four agricultural zones in the Region: extremely arid, arid, unstable humidification zone, and a zone of sufficient humidification [22, 23]. The zone of sufficient moisture, which includes the Mineralovodsk, Predgornyy, Georgievsk, and Kirovsk districts, covers the sloping plains of the foothills of the Caucasus. The humidification conditions in this zone correspond to the forest steppe, i.e. the evaporation rate is not much higher than the amount of precipitation, and 500-700 mm can evaporate. The humidification coefficient ranges from 0.7–1.0. In the zone of sufficient moisture, winter usually begins in late November-early December and ends in the first decade of March.

The ixodofauna of the zone of sufficient moisture for the period 2016-2022 is presented in Table 1.

The dynamics towards an increase in the species composition of ixodids is traced. If in the period 1999 – 2006, the ixodofauna of the areas of the zone of sufficient moisture was represented by 6 species belonging to 5 genera, then already in the period 2016-2022 12 species of ixodid ticks belonging to 6 genera parasitize in these territories.

In the city of Kislovodsk itself in 2022 appeared in the biotope of 9 species belonging to 5 genera (Hyalomma, Dermacento, Rhipicephalus, Ixodes ricinus, Haemaphisalis).

Table 1. Ixodofauna of the zone of sufficient humidification of the Stavropol Territory in the period from 1999 – 2006 to the period 2016 - 2022.

One of the factors of such a spread of ixodid ticks is certainly an increase in the average winter temperature, which contributes to the spread and increase in the number of biotopes favorable for the hatch of ixodids.

CONCLUSION

Analysis of the data obtained showed that both for Kislovodsk and for the entire territory of the Region, frosts are a characteristic feature of the spring and autumn periods.

For a day with frost, a day is taken on which at least one of the dates the minimum air temperature was below 0 °C, while the average daily temperature is positive. The date of the last spring frost marks the beginning of the frost–free period, and the date of the first autumn frost marks its end. In accordance with the general trend of climate warming, the duration of the frost-free period in the territory of the Region should increase. However, due to increased climate instability, both late frosts in spring and early frosts in autumn can be expected, which may lead to a reduction in the frost-free period.

The growing season of crops and natural vegetation has been lengthened by about one to four days per decade over the past 50 years in the northern hemisphere, especially in high latitudes. The boundaries of plant growth and animal habitat have shifted towards the pole and up in absolute height. There is an earlier flowering, an earlier arrival of birds, and an earlier time of the appearance of insects in the northern hemisphere. There is also an increase in average annual temperatures in the Region, largely due to the warming of the cold period of the year. During the warm period, despite the general increase in the temperature background, in some months there is a tendency for cooling in almost all landscape zones.

These studies show that during the period of climate warming in the territory of the Region, there is a weakening of the severity of bioclimatic conditions, especially in winter, which entails the spread and increase in the number of biotopes of ixodid ticks.

ACKNOWLEDGMENTS: The authors are thankful to Dr. Sergey Pushkin for assistance in conceptualization and methodology.

CONFLICT OF INTEREST: None

FINANCIAL SUPPORT: The study was funded by a grant from the Ministry of Science and Higher Education of the Russian Federation "Study of the mechanisms of interaction of lactic acid microorganisms, lactose-fermenting yeast and biologically active substances during micro capsulation of various fractions of microbiota" by Decree of the Government of the Russian Federation No. 220 in the form of a subsidy from the federal budget for state support of scientific research conducted under the leadership of leading scientists of Russian educational institutions of higher education, scientific institutions and state scientific centers of the Russian Federation (IX stage), Agreement No. 075-15-2022-1129 01.07.2022.

ETHICS STATEMENT: None