CC BY
4UDC 576.895.42.1
BIOLOGICAL CHARACTERISTICS OF THE FAUNA OF THE TICKS OF THE GENUS RHIPICEPHALUS IN THE NORTH-EAST REGION OF UZBEKISTAN
R.K. SHAPAOTOV1, I.O. ERKINOV2, O.T. TO'RAEVA3
1Doctoral student, 2teacher, 3student institute of Zoology Academy of Sciences of the Republic of Uzbekistan 2Namangan State University 3National University of Uzbekistan named after Mirzo Ulugbek
Аннотация. Отмечено, что виды клещей Rhipicephalus sanguineus, R. turanicus, R. bursa, R. annulatus рода Rhipicephalus обнаружены у сельскохозяйственных животных в Ташкентской и Сырдарьинской областях. В частности, уровень инфицированности домашних животных составил 31,8% у крупного рогатого скота, 36,3% у лошадей, 61,3% у овец, 47,6% у коз и 41,4% у собак. Было отмечено, что Rhipicephalus sanguineus преобладал по численности и составлял 67,9% от общего числа собранных клещей. Изучены биологические особенности этих клещей.
Ключевые слова: Rhipicephalus, клещ, личинка, нимфа, имаго, инвазия, доминант.
The practical importance of the Ixodidae ticks is that they are ectoparasites of agricultural and hunted animals, and as carriers of many infectious and parasitic diseases, they attract the attention of zoologists, parasitologists, entomologists, veterinary and medical specialists. The main content of a large number of works carried out by researchers of several scientific and educational institutions of the world is the development of various aspects of the participation of blood-sucking Ixodidae ticks in the spread of pathogens of transmissible diseases in animals and humans and the development of ways to protect against their attack. Ticks are the main reason for the transmission of infectious diseases such as rickettsiosis and CCHF to humans, these diseases are currently considered one of the major health problems, and ticks belonging to the genus Rhipicephalus are defined as carriers of rickettsioses in our country [11]. Currently, Rhipicephalus ticks are widely distributed throughout the world and have been found to parasitize many farm animals and cause significant economic losses every year [8]. In recent years, 82 species of ticks of the genus Rhipicephalus Koch., 1844 have been recorded in the world fauna (Ixodidae) [4]. In the fauna of Uzbekistan, Rhipicephalus sanguineus, R. turanicus, R bursa, R rossicum, R pumilio, R. leporis and R schulzei ticks belonging to the genus Rhipicephalus Koch., 1844 were found [5].
Materials and methods. Research work was carried out in the spring, summer and autumn seasons in 2022-2023 in the territory of Tashkent and Syrdarya regions. Specimens of ticks in 1,149 animals from 6 state farms and 24 personal farms located in the districts of Tashkent region, including Yuqorichirchiq, Quyichirchiq, Parkent, Chinoz, Buka, Bostonlik, Bekabad and in the districts of Syrdarya region, including Boyavut, Saikhunabad were examined. In particular, 2761 specimens of ticks, belonging to the genus Rhipicephalus were collected from 157 Bos taurus (cattle), 22 Equus caballus (horse), 628 Ovis aries (sheep), 313 Capra hircus (goat) and 29 Canis lupus familiaris (dog) based on route and stationary methods. During the research, 801 tick specimens were collected from 9 landscapes in the flatland, mountain and foothill areas based on the method of A.D.Reshetnikov and A.I.Barashkova (2020) [7]. Species composition and biological characteristics of ticks were carried out based on the method of Walker et al (2003), Estrada-Peña et al (2004) [9, 3].
Research results. In the studied areas, species of ticks belonging to the genus Rhipicephalus, such as Rhipicephalus sanguineus (Latreille 1806), Rhipicephalus turanicus (Pomerantsev 1936), Rhipicephalus bursa (Canestrini & Fanzago 1878), Rhipicephalus annulatus (Say 1821) were recorded in the agricultural animals (cattle, horses, sheep, goats, dogs). Infestation rate of domestic animals (IR) showed Bos taurus 31.8%, Equus caballus 36.3%, Ovis aries 61.3%, Capra hircus 47.6%, Canis lupus familiaris 41.4%
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Based on the number of tick specimens collected from animals during the research, it was observed that the species R. sanguineus is superior in numbers, which is 67.9% of the total ticks collected. Respectively, the rates for the species R Turanicus made up 28.4%, R. Annulatus -2.5% and R. bursa -1.2%
When 801 specimens of the Rhipicephalus ticks were collected from landscapes, according to their vertical distribution, 49.7% of them belonged to the flatland regions, 42% to foothill areas, and 8.2% mountain areas.
The occurrence of R sanguineus and R turanicus species was observed in the flatland and mountain areas. Only one female species was recorded in the mountain area where R. bursa species was studied. The species R. annulatus was not observed in mountain and foothill areas.
According to the sex ratio of female and male individuals of total tick species collected from the landscapes, the amount of females was high and made up 53.9%
In our experiments, it was observed that the air temperature of 26-30°C is favorable for the development of tick species Rhipicephalus. It was observed that female ticks in the imago stage feed for 3-7 days and then leave the body of their host. In particular, it was noted that these ticks parasitize the ears and eyes of domestic animals in large numbers.
The biological characteristics of Rhipicephalus sanguineus species were studied. In particular, after R. sanguineus female individuals were separated from the host's body, egg-laying processes began 5 days later in laboratory conditions, and the duration was 9-14 days. It was observed that a female tick lays an average of 1400 eggs. It was noted that the eggs were spherical and brown, and the hatching of the larvae took place between 23-27 days. Hatched larvae were separated into male and female individuals under a microscope based on the chitin coating. It was noted that female larvae are more numerous in terms of sex ratio. It was observed that the length of the body size of the larvae is 0.5-0.8 mm and the snout is clearly visible from the shoulder
According to the results of the observations, it was observed that the fed larvae pass to the first stage of nymphs. This can be explained by the fact that their body size is small, on average 1.3 - 2.5 mm, and their genitals are underdeveloped, which differs from the adult stage. The nymph also passed through the night on stage 2-3 and it was observed that the length of the imago stage female ticks averaged 4.5 - 10 mm. It was found that male ticks are smaller than females, the average body size is 3-4 mm, the body is brown, and the upper part is covered with a chitin.
This chitin covers the entire body surface of the male and is called the dorsal shield. In females, the shield covers only the front (shoulder) part of the body. This ensures that male ticks are different from females
According to the results of the study, the shape of the adanal plates of R. sanguineus male individuals was studied, and it was found that the front end was sharpened and the front part of the body was extended to the side. It was observed that the back end of the adanal plates became blunt and thickened (Fig. 5). It was found that there is an additional adanal plate on the side where the left and right adanal plates form a blunt [2].
In addition, the appearance of the breathing holes (tracheas) in males is diverted to the dorsal area, and in females it is oval, wider and larger than that of males
Discussion. In the conducted studies, it was observed that adult female R. sanguineus ticks feed from 5 to 21 days, and then leave the body of the host. After that, the pre-period of egg laying began and lasted from 3 to 14 days. In the literature, it is stated that female ticks lay eggs for an average of 16-18 days and lay 1500-4000 eggs [2, 6].
It was noted that the average body size of the hatched larvae is from 0.54 to 0.39 mm. The length of the body of nymphs is from 1.14 to 1.30 mm, and differs from adults in that the genitals are not developed. Adult male ticks have a body length of 3 mm. Females are slightly larger than males, reaching a length of 11.5 mm [9, 10].
The results of our research are generally consistent with the scientific data presented in the literature. Partial differences in some biological indicators, the duration of egg-laying, the number of
eggs, morphometric measurements of larvae and nymph, can be explained by the natural and climatic conditions of the researched areas.
Conclusion. Species belonging to the Rhipicephalus genus, including R sanguineus, R turanicus, R bursa, R. annulatus were found in the northeastern region of Uzbekistan, and it was noted that they parasitize cattle, horses, sheep, goats, and domestic dogs.
A total of 2,761 ticks belonging to the genus Rhipicephalus were collected from domestic animals, of which 67.9% were R. sanguineus, 28.4%- R. turanicus, 1.2%- R. bursa, and 2.5%- R. annulatus species. It was noted that R. sanguineus is the dominant species, and it is found that it makes up 67.9% of the total infected ticks.
According to the distribution of the total ticks collected from the landscapes, it was noted that 49.7% correspond to the flatland region, 42% to the foothill areas and 8.2% to the mountain regions.
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