Life Cycle and Vectorial Capacity of Hyalomma anatolicum anatolicum (Acari: Ixodidae) in the Sudan

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Hagir Medani Hussien, Hussien
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Biological parameters of life cycle of Hyalomma anatolicum anatolicum collected from different geographic areas in the Sudan (Atbara, Khartoum, Kosti and Singa) were studied under laboratory conditions. Significant (P < 0.05) differences were observed among the 4 stocks in the length of feeding periods, preoviposition, and oviposition period and hatching periods. Preoviposition and oviposition periods were short at (42.05°C-23.7°C) and 75% RH for all stocks. The shortest preoviposition period was 4.9±0.39 days for Kosti stock. H. a. anatolicum for the 4 stocks underwent 2 and 3 host types of life cycle when fed on rabbits, with percentage of the 3-host type being higher in Kosti and Atbara stocks than the 2-host type feeding cycle. Direct effect of temperature was observed on hatching and moulting periods. They increased directly when room temperature ranged between 35°C to 40°C. No significant differences were detected between the stocks in the engorgement weights of females and measurement of males' scutal length and width. Experimental infection with Theileria annulata was conducted using Friesian calves. All calves showed severe theileriosis symptoms e.g. enlargement of superficial parotid lymph nodes and rise in body temperature were the most obvious signs. Assessment of the infection rate in the ticks was carried out using clean nymphs from the 3 stocks (Khartoum, Atbara and Singa). Dissection of 50 ticks from each stock reflected high percentage of infection rate, which reached 96% from ticks fed on one calf and 80% in Khartoum stock from the other calf. The low infection rate reached 3.7% in Khartoum on the second day of tick dropping. Maximum number of parasite mass per tick reached 11. The three stocks of H. a. anatolicum differed in their susceptibility to infection with T. annulata.
Life Cycle and Vectorial Capacity of Hyalomma anatolicum anatolicum (Acari: Ixodidae) in the Sudan