Abundance of adult ticks (Acari: Ixodidae) in the Chernobyl nuclear power plant exclusion zone.

The Chernobyl nuclear disaster resulted in contamination of vast areas in Europe. To date, there is little knowledge about the effects of radioactive contamination on tick species. We sampled ticks from vegetation and large-sized wild mammals belonging to orders Carnivora and Artiodactyla at sites with 0.76, 1.91, and 4.50 mSv/hr ionizing radiation background values in the Polesky State Radio-Ecological Reserve of the Chernobyl nuclear disaster zone in spring 2010. Altogether, 122 questing ticks were collected from vegetation. Among collected ticks, Dermacentor reticulatus (Fabricius) was, by far, the most abundant species (99.2%), followed by Ixodes ricnus (L.) (0.8%), which was collected only at the 0.76 mSv/hr site. The average sex ratio female∶male was 2.9∶1.0. In parallel with the present study, we examined 3 Sus scrofa (L.), 2 Nyctereutes procyonoides (Gray), and 1 Alces alces (L.) at the 4.50 mSv/hr site; 96 D. reticulatus ticks were found on 2 N. procyonoides specimens. The mean density and the intensity of infestation were 16 ticks per animal and 48 ticks per infested animal, respectively. Future investigations are warranted to further characterize the role of various tick vectors, vertebrate reservoirs, and diversity of tick-borne pathogens in the Chernobyl exclusion zone.

[Comparison of the ability to fertilize females by Hyalomma anatolicum anatolicum males irradiated with gamma radiation from caesium 137 with non-irradiated males]. / Caesium-137 Kaynakli Gamma Radyasyonla Isinlanmis Hyalomma anatolicum anatolicum Erkeklerinin Bir Arada Bulunduklari Isinlanmamis Erkekler ile Disileri Dölleme Yetilerinin Karsilastirilmasi.

In this study, Hyalomma anatolicum anatolicum male ticks were subjected to gamma radiation with a dose of 10 Gy emitted by a gamma-ray source of Caesium 137. Female ticks were divided into 3 groups and placed in rabbit ears to feed. In the first group, the females fed with normal and irradiated males, in the second group females fed only with irradiated males and in last group females fed with normal males. Biological parameters such as the feeding period, weights, period of time from dropping until egg-laying began, the number of eggs and the number of larva hatching from eggs were recorded. With the results of statistical analysis it was found that the average egg laying period of females in the second group was clearly less (22.77 days) than other groups and the difference between these groups was statistically important (P < 0.05). After evaluation of numbers of larva, also there was a statistically important difference between the groups and the average number of larva was clearly higher (2519.30) in third group than other groups. In conclusion, in this study it was found that irradiated males could not compete with normal males in mating with females and because of this they couldn't affect the feeding and reproductivity of females.

[The importance of gamma irradiations with caesium-137 for Hyalomma anatolicum anatolicum (Metastigmata, Ixodidae) control]. / Hyalomma anatolicum anatolicum (Metastigmata, Ixodidae) mücadelesinde Caesium-137 kaynakli gamma radyasyon uygulamalarinin önemi.

In this study, male ticks belonging to the Hyalomma anatolicum anatolicum species were subjected to gamma radiation doses of 5, 10, 15, 20 and 50 Gy, emitted by a gamma-ray source of Caesium 137. In females that fed with these male ticks, proportional to the increase in radiation dose, the period of feeding was found to shorten. A decrease was demonstrated in the number of engorged female ticks, engorgement weights, number of laying ticks and number of eggs. The hatching period of larvae from eggs was found to increase despite the decrease in the number of hatched larvae. Moreover no larvae were observed to hatch from any of the eggs of female ticks treated with a radiation dose of 50 Gy. Similarly, proportional to the applied dose of radiation, rates of viability and activity were observed to decrease in male ticks. In conclusion, taking into consideration the feeding periods and fertility rates of female ticks as indicators of male activity, this study has demonstrated that in combating with H. anatolicum anatolicum, radiation may be successful and a radiation dose of 10 Gy is most favorable.