Baseline survey of Ixodid Ticks Infesting Cattle in Northern State, Sudan

Received Date: Sep 26, 2019 / Accepted Date: Oct 03, 2019/ Published Date: Oct 05, 2019 Abstract Background and objective: Ixodid ticks are serious obstacle to development and utilization of animal resource in tropical countries like Sudan. Over 70 species of tick are prevalent in the Sudan in diverse ecological zones. The aim of this study was to provide a baseline data on tick species infesting cattle in the Northern State, Sudan as a prerequisite to design tick control policy in the state as well as the whole country. Materials and Methods: This study was conducted in April 2017 and included seven provinces of the state. Total body tick collection (n=1,098) was carried out from 365 heads of cattle. Tick identification to the genus and species level was carried out as well as statistical analysis using twoway ANOVA. Results: Nine tick species of two genera, Hyalomma and Rhipicephalus, were identified. The genus Hyalomma represented 82% of the collected ticks. Hyalomma rufipes was the most common tick species (48.5%) followed by Rhipicephalus praetextatus (14.9%), H. anatolicum (14.4%), H. excavatum (12.8%), H. dromedarii and R. sanguineus (3.4% each), H. impeltatum (2.2%), H. marginatum (0.46%) and the least prevalent tick species was R. evertsi evertsi (0.09%). The prevalence of tick infestation significantly varied within the age groups for H. anatolicum, H. rufipes and H. excavatum. The mean tick infestation was found to be independent on breed and sex of the animals. Conclusion: It is concluded that there were nine ticks species distributed in the State. Among these species is H. anatolicum, which is the vector of two vital diseases, bovine tropical theileriosis and malignant ovine theileriosis. Thus, tick control strategy, and creation of awareness among animal breeders on the problem associated with tick infestation are recommended.


Introduction
Ticks are destructive and obligatory blood sucking parasites, found in most if not all the countries of the world. They parasitize reptiles, birds and mammals [1]. Ticks cause blood loss, inflammation and irritation of the skin, stimulate hypersensitive allergic reactions; and they may cause a toxic reaction in the host, complicated by paralysis (called "tick paralysis"). They are important vectors of diseases affecting both humans and animals [2]. This is the second study on the distribution of tick infesting livestock in the Northern State of Sudan since the 1950s. The first study on ticks in the Northern State of the Sudan [5].
The most significant cattle tick in the country (above 10 latitude) is Hyalomma anatolicum, the vector of Theileria annulata and T. lestoquardi the causatives of tropical theileriosis in cattle and malignant ovine theileriosis in sheep, respectively [6][7][8]. Ticks of Amblyomma variegatum and A. lepidum transmit Ehrlichia ruminantium, among sheep, goats and cattle [9,10], while Rhipicephalus decoloratus and R. annulatus are the main vectors of bovine babesiosis [11]. This study was conducted with the objective of elucidating tick species infesting cattle in Northern State of the Sudan.  [12]. This study was conducted in seven provinces of the Northern State: Halfa, Dalgo, Borgig, Dongola, Golid, Deba, and Marawi ( Figure 1).

Tick collection
The survey was conducted during April 2017. The surveyed infested animals were mostly present in the agricultural areas of the River Nile banks in both east and west side of the river, in addition to the islands. A total body tick collection was made on 365 infested cattle. The collected ticks were transferred into a glass bottle containing 70% ethyl alcohol for preservation and brought to the laboratory for identification. Information such as date and place of collection, age, sex and breed of the host were recorded at the time of collection [13].

Tick identification
The ticks were identified morphologically under a dissecting microscope at Department of Entomology and Ticks, Central Veterinary Page: 39 www.raftpubs.com Research Laboratory, Khartoum, Sudan [12,14].

Statistical analysis
Data collected on ticks were subjected to an appropriate general linear model (GLM) procedure using the Statistical Analysis System (SAS) package. These data include the number of ticks collected, the county where collection was carried out, as well as breed, age groups and sex of cattle from which ticks was collected. The SAS was used to perform twoway analysis of variance (ANOVA) while mean separations were performed using the Ryan-Einot-Gabriel-Welsch (REGW) multiple range test [15].

Prevalence of tick species in the Northern State
A total of 1,098 ticks were collected from the infested cattle. Generally, two tick genera, Hyalomma and Rhipicephalus, and nine species were identified from the seven study areas (Figure 2-4). The genus Hyalomma (82%) was more prevalent than the genus Rhipicephalus (18%) in the State. Hyalomma rufipes was the most common tick species (48.5%) followed by R. praetextatus ( Page: 40 www.raftpubs.com   Page: 41 www.raftpubs.com

Distribution of tick species in the seven provinces
The mean total numbers of ticks per head of cattle at the different location are summarized in Table 2. The highest mean (4.08±0.38) of the number of ticks identified was recorded at Dongola Province, while the lowest mean (1.70±0.17) was recorded at Deba ( Page: 42 www.raftpubs.com  Page: 43 www.raftpubs.com  [21]. In study, similar tick species to those found in the above-mentioned states was found (Khartoum, River Nile State, Kordofan, and North Darfur). This may be due to the fact that these states share boundaries with the Northern State, and that animals move freely among these States.
The ticks identified in this study are known to be xerophilic species that can survive well in the arid and harsh environment of Northern State [22]. Immature H. rufipes ticks do not feed on cattle but on birds, while adults feed on larger animals including cattle. The high prevalence and wide distribution of this tick species in the present study is indicative of the availability of immature host species throughout the Northern State [23]. On the other hand, H. anatolicum are well adapted to manmade environment and this may explain its high prevalence and wide distribution in the State [24]. The differences noted in the geographical distribution of ticks and the infestation rates in this study may be related to local ecological differences such as abundance and species of domestic and wild animals, climate and the vegetation cover that exist in a particular area. Other tick spp might have been absent or were present numbers below the detection limit of the current study.
Finally, we recommend that a large scale longitudinal seasonal survey must be carried out in the whole country with emphasize on Northern State, to update the information concerning the prevalence and distribution of ticks among the livestock.

Conclusion
It is concluded that there were nine ticks species distributed in the State. Among these species is H. anatolicum, which is the vector of two vital diseases, bovine tropical theileriosis and malignant ovine theileriosis. Thus, tick control strategy, and creation of awareness among animal breeders on the problem associated with tick infestation are recommended.