Tick Diversity and Distribution of Hard (Ixodidae) Cattle Ticks in South Africa

: Ticks are amongst the important ectoparasites where livestock are concerned, as they adversely affect the animals through bloodsucking. In tropical and subtropical countries, they transmit pathogens such as babesiosis, theileriosis, ehrlichiosis


Introduction
Ticks, which are arachnids, are of primary importance in veterinary and human health due to the role they play in transmitting pathogens such as rickettsia, protozoan (Babesia spp.), spirochaetes, and viruses [1]. They are ectoparasites of different terrestrial vertebrates, amongst which are birds, amphibians, reptiles, and mammals [2]. Approximately 900 tick species have been described globally, of which more than 700 are hard ticks (Ixodidae) and approximately 200 are soft ticks (Argasidae), with only one species belonging to the Nuttalliellidae family [3]. Nuttalliella namaqua Bedford, 1931 (from the Nuttalliellidae family) have features found in both hard and soft ticks [4,5]. Hard ticks (Acari: Ixodida) are divided into two morphological and phylogenetic groups, namely the Prostriata and the Metastriata [6]. The subfamily Prostriata has one genus known as Ixodes (240 species), while the subfamily Metastriata is further subdivided into five subfamilies: the Amblyomminae (129 Figure 1. Geographical distribution of Amblyoma hebraeum across the provinces of South Africa. The red color represents the localities where the species has been found. This tick species has been previously recovered in Limpopo, North-West, Gauteng, Free State, Mpumalanga, and the coastal regions of KwaZulu-Natal and the west of the Eastern Cape. The localities in this map were adapted [30].

Hyalomma
Twenty-seven species of the genus Hyalomma are known worldwide [8]. Reported to have originated in Iran, they are distributed beyond that region and are prevalent in The red color represents the localities where the species has been found. This tick species has been previously recovered in Limpopo, North-West, Gauteng, Free State, Mpumalanga, and the coastal regions of KwaZulu-Natal and the west of the Eastern Cape. The localities in this map were adapted [30].

Amblyomma hebraeum Koch, 1844
Amblomma hebraeum Koch, 1844 is a huge and conspicuous tick, with long mouthparts, brightly colored shapes on both the male and female scutum, smooth eyes, and brown and white banded legs. Males are adorned with yellow festoons. This three-host tick is found in wooded and bushed grassland but cannot survive in open grassland. The tick species is predominantly found in the savanna biome in the eastern provinces of South Africa (Figure 1), namely KwaZulu-Natal, the west of the Eastern Cape province, Gauteng, Mpumalanga, and the east of the North-West province of South Africa [30,31]. The occurrence of this species varies from region to region in South Africa; in the Eastern Cape province, larvae were recorded to be abundant on vegetation in late summer (Febuary-March) to early winter (May-June), and least abundant in spring to mid-summer [32]. Conversely, larvae were recorded to be abundant during summer and lowest in winter and early spring at Kruger National Park in Limpopo province [33]. Overall, this species is more prevalent in cattle during spring and summer in South Africa. Amblyomma hebraeum adult ticks prefer to attach to less hairy regions including the axillae, belly, groin, sternum, and upper-lower perineum on cattle. Larvae are found on vegetation as they quest for a host [33], while nymphs and adults are found on soil surfaces and leaf litter [34]. This species is a vector of a disease caused by Ehrlichia ruminantium, which is responsible for heartwater disease which causes considerable mortality in ruminants. In South Africa, this tick species has been reported to be the main vector of Rickettsia africae, which belongs to the spotted fever group Rickettsiae [35]. However, there is little information regarding the diversity of R. africae on isolates from A. hebraeum, compared to isolates on A. variegatum in localities of South Africa [36].

Hyalomma
Twenty-seven species of the genus Hyalomma are known worldwide [8]. Reported to have originated in Iran, they are distributed beyond that region and are prevalent in Southern Africa, Europe, and Asia [37]. They include H. dromedarrii, H. glabrum, Hy. truncatum, and Hy. rufipes. Hy. truncatum and Hy. rufipes are predominant in South Africa.

Hyalomma truncatum Koch, 1844
Hyalomma truncatum are intermediate ticks with long mouthparts, dark brown bodies, beady eyes, and lengthy, red and white ringed legs. In males, the posterior outer layer of the scutum is described by a depression with multiple big punctations; alternatively, it is comparatively smooth. Adult ticks of this genus prefer both cattle and wild animals [38], attaching to areas such as the legs, lower perineum, tail switch, and anus. They are a twohost tick species but may occasionally have the character of three-host ticks; completion of the life cycle takes approximately 12 months [30]. Adults have peak activities later in wet summer (October-April), and immature stages have their peak activity in autumn (April-May) and spring (September). These ticks are found throughout South Africa, as reported in Figure 2, except for the following areas: the northeast of the Eastern Cape, southern KwaZulu-Natal, the eastern half of the Free State, and the south-eastern Gauteng provinces of South Africa, respectively [39]. Hyalomma truncatum transmits Babesia caballi, the causative agent of equine piroplasmosis, and the female ticks produce toxins that induce sweating in cattle.
provinces of South Africa, respectively [39]. Hyalomma truncatum transmits Babesia caballi, the causative agent of equine piroplasmosis, and the female ticks produce toxins that induce sweating in cattle. The red color represents the localities where the species has been found. Hyalomma truncatum is distributed across the western and northern parts of South Africa but is absent from moist areas such as the northern part of the Eastern Cape, the eastern Free State, and southern KwaZulu-Natal. The localities in this map were adapted [30].

Hyalomma rufipes Koch, 1844
Hyalomma rufipes ticks have dark brown bodies, long mouthparts, an extensively punctate scutum, beady eyes, and long, red and white banded legs. They vary from Hyalomma truncatum in that the entire scutum is punctate and in males it is much more spherical than the latter tick's elongated shape. The adult Hyalomma rufipes prefers larger animals, both domestic and wild [40]. They have been collected from cattle in four countries, namely Namibia, Botswana, South Africa, and Mozambique [41]. This tick species takes a year to complete its life cycle and is a two-host tick [30]. It prefers the upper and lower perineum [42]. Adult ticks are found in the ground, questing for passing hosts [30]. Hyalomma rufipes is present throughout South Africa, as reported in Figure 3, especially in moist and winter rainfall regions such as the Western Cape, the northeast of KwaZulu-Natal, the North-West, Limpopo, Mpumalanga, and the Free State provinces of South Africa, respectively, including Swaziland and the mountainous areas of Lesotho [30]. The peak season of adult ticks on cattle was recorded in summer (December-February) [43]. Hy. rufipes is the vector of Babesia occultans, which is responsible for causing bovine babesiosis, and Anaplasma marginale, which causes bovine anaplasmosis in South Africa. This tick species causes tissue lesions in cattle, resulting in secondary bacterial infections that lead to abscess formation [30]. The red color represents the localities where the species has been found. Hyalomma truncatum is distributed across the western and northern parts of South Africa but is absent from moist areas such as the northern part of the Eastern Cape, the eastern Free State, and southern KwaZulu-Natal. The localities in this map were adapted [30].

Hyalomma rufipes Koch, 1844
Hyalomma rufipes ticks have dark brown bodies, long mouthparts, an extensively punctate scutum, beady eyes, and long, red and white banded legs. They vary from Hyalomma truncatum in that the entire scutum is punctate and in males it is much more spherical than the latter tick's elongated shape. The adult Hyalomma rufipes prefers larger animals, both domestic and wild [40]. They have been collected from cattle in four countries, namely Namibia, Botswana, South Africa, and Mozambique [41]. This tick species takes a year to complete its life cycle and is a two-host tick [30]. It prefers the upper and lower perineum [42]. Adult ticks are found in the ground, questing for passing hosts [30]. Hyalomma rufipes is present throughout South Africa, as reported in Figure 3, especially in moist and winter rainfall regions such as the Western Cape, the northeast of KwaZulu-Natal, the North-West, Limpopo, Mpumalanga, and the Free State provinces of South Africa, respectively, including Swaziland and the mountainous areas of Lesotho [30]. The peak season of adult ticks on cattle was recorded in summer (December-February) [43]. Hy. rufipes is the vector of Babesia occultans, which is responsible for causing bovine babesiosis, and Anaplasma marginale, which causes bovine anaplasmosis in South Africa. This tick species causes tissue lesions in cattle, resulting in secondary bacterial infections that lead to abscess formation [30].

Rhipicephalus
Of the seventy species belonging to this genus [8], thirty-two are found in Southern African countries. Rhipicephalus (Bo.) decoloratus and Rh. evertsi are common in all Southern African countries, whereas the other five species of the Rhipicephalus group, namely Rh. capensis Neumann, 1904, Rh. follis Dönitz, 1910, Rh. glabroscutatum, Rh. nitens, and Rh. Warburtoni, are only restricted to South Africa [46]. Below we discuss those which are prevalent in cattle in South Africa.

Rhipicephalus appendiculatus Neumann, 1901
Rh. appendiculatus are medium-sized brown ticks with short mouthparts. Male legs grow significantly larger between the first and fourth pair, and engorged males even have a slim caudal process [47]. The common name of this tick species is derived from its uniformly brown color. It is distinguished from the other species by its short mouthparts, flat eyes, and the hexagonal shape of the adult female. This three-host tick species has a wide host range preference, which includes domestic animals and, most importantly, cattle [48]. Exogenous and endogenous factors such as animal activity and environmental change (temperature and humidity) determine questing activities [49]. Rhipicephalus appendiculatus prefers the savanna biome and areas that are temperate, and are not present in open savanna [50]. In South Africa, they are widely distributed along the south-eastern coasts, as well as Limpopo, Gauteng, the North-West, the northern part of the Free State, Mpumalanga, and the coastal areas of KwaZulu-Natal and the Eastern Cape provinces in South Africa, respectively, as reported in Figure 4. Moreover, this species has been collected in eastern Botswana across the Limpopo River, the Soutpansberg, the southern end of Kruger National Park, and the northern end of the National Park at Pafuri, near to the borders

Rhipicephalus
Of the seventy species belonging to this genus [8], thirty-two are found in Southern African countries. Rhipicephalus (Bo.) decoloratus and Rh. evertsi are common in all Southern African countries, whereas the other five species of the Rhipicephalus group, namely Rh. capensis Neumann, 1904, Rh. follis Dönitz, 1910, Rh. glabroscutatum, Rh. nitens, and Rh. Warburtoni, are only restricted to South Africa [46]. Below we discuss those which are prevalent in cattle in South Africa.

Rhipicephalus appendiculatus Neumann, 1901
Rh. appendiculatus are medium-sized brown ticks with short mouthparts. Male legs grow significantly larger between the first and fourth pair, and engorged males even have a slim caudal process [47]. The common name of this tick species is derived from its uniformly brown color. It is distinguished from the other species by its short mouthparts, flat eyes, and the hexagonal shape of the adult female. This three-host tick species has a wide host range preference, which includes domestic animals and, most importantly, cattle [48]. Exogenous and endogenous factors such as animal activity and environmental change (temperature and humidity) determine questing activities [49]. Rhipicephalus appendiculatus prefers the savanna biome and areas that are temperate, and are not present in open savanna [50]. In South Africa, they are widely distributed along the south-eastern coasts, as well as Limpopo, Gauteng, the North-West, the northern part of the Free State, Mpumalanga, and the coastal areas of KwaZulu-Natal and the Eastern Cape provinces in South Africa, respectively, as reported in Figure 4. Moreover, this species has been collected in eastern Botswana across the Limpopo River, the Soutpansberg, the southern end of Kruger National Park, and the northern end of the National Park at Pafuri, near to the borders with Zimbabwe and Mozambique. Rhipicephalus appendiculatus carry the pathogen Theileria parva, which causes East Coast Fever, Corridor Disease, and January Disease (Theileriosis) in cattle [38].
with Zimbabwe and Mozambique. Rhipicephalus appendiculatus carry the pathogen Theileria parva, which causes East Coast Fever, Corridor Disease, and January Disease (Theileriosis) in cattle [38].

Rhipicephalus (Bo.) decoloratus (Koch, 1844)
Rhipicephalus (Bo.) decoloratus are small, inconspicuous ticks with thin legs and short mouthparts. The males are brownish-yellow, and the darker gut may be seen through the moderately sclerotized scutum of the females. Males are always encountered in pairs with females. Engorged females are bluish-brown and can be observed adhering to the face, neck, shoulders, and escutcheon of cattle. This tick is indigenous to Africa and is of veterinary importance, as it imposes a burden on cattle by virtue of the tick-borne pathogens it transmits to domestic animals [45]. It is characterized by short mouthparts and teeth arrangement, which is divided into two columns, with three denticles in each row. The scutum of males and the conscutum of females have setae on the surfaces of scutum, and they do not have festoons [52]. This species has been successfully collected in the savanna, fynbos biomes, and grasslands of South Africa [30]. Rhipicephalus (Bo.) decoloratus is dominant in South Africa and has adapted to arid regions [53]. Rhipicephalus (Bo.) decoloratus is more dominant in the east and north of the Free State, KwaZulu-Natal, east of the Eastern Cape, Mpumalanga, North-West, Gauteng, and west of the Western Cape, Northern Cape, and Limpopo provinces of South Africa, respectively, as shown in Figure 5 [54]. Rhipicephalus (Bo.) decoloratus are one-host ticks whose larvae detach from vegetation, attach to the host, and complete all other life cycle stages on the host [32]. Cattle are the preferred host of Rh. (Bo.) decoloratus adult ticks [55]. In cattle, Rh. (Bo.) decoloratus attaches to the whole body of the host [56]. The activities of Rh. (Bo.) decoloratus on cattle were recorded in the spring Rhipicephalus (Bo.) decoloratus are small, inconspicuous ticks with thin legs and short mouthparts. The males are brownish-yellow, and the darker gut may be seen through the moderately sclerotized scutum of the females. Males are always encountered in pairs with females. Engorged females are bluish-brown and can be observed adhering to the face, neck, shoulders, and escutcheon of cattle. This tick is indigenous to Africa and is of veterinary importance, as it imposes a burden on cattle by virtue of the tick-borne pathogens it transmits to domestic animals [45]. It is characterized by short mouthparts and teeth arrangement, which is divided into two columns, with three denticles in each row. The scutum of males and the conscutum of females have setae on the surfaces of scutum, and they do not have festoons [52]. This species has been successfully collected in the savanna, fynbos biomes, and grasslands of South Africa [30]. Rhipicephalus (Bo.) decoloratus is dominant in South Africa and has adapted to arid regions [53]. Rhipicephalus (Bo.) decoloratus is more dominant in the east and north of the Free State, KwaZulu-Natal, east of the Eastern Cape, Mpumalanga, North-West, Gauteng, and west of the Western Cape, Northern Cape, and Limpopo provinces of South Africa, respectively, as shown in Figure 5 [54]. Rhipicephalus (Bo.) decoloratus are one-host ticks whose larvae detach from vegetation, attach to the host, and complete all other life cycle stages on the host [32]. Cattle are the preferred host of Rh. (Bo.) decoloratus adult ticks [55]. In cattle, Rh. (Bo.) decoloratus attaches to the whole body of the host [56]. The activities of Rh. (Bo.) decoloratus on cattle were recorded in the spring [57]. Unlike Rh. (Bo.) microplus, this tick species transmits African babesiosis [58] and anaplasmosis. [57]. Unlike Rh. (Bo.) microplus, this tick species transmits African babesiosis [58] and anaplasmosis.

Rhipicephalus (Bo.) microplus (Canestrini, 1888)
Rhipicephalus (Bo.) microplus adults are bigger and slightly redder in color than Rh. (Bo.) decoloratus adults, however they are almost practically identical with external structures [52]. In addition, this species' dentition is divided into two columns, with four denticles in each row. The species, which has imposed risk on cattle worldwide (including in African countries), originated in Asia [60]. Cattle transported from Asia in the 19th century carried Rh. (Bo.) microplus to other countries in eastern and Southern Africa, the Comoro Islands, and the Mascarene Islands [61]. About 13 decades ago, this species was recorded in South Africa [62] and has recently been established in West African countries such as Burkina Faso, Mali, Togo, the Ivory Coast, and Benin (Madder, Thys et al., 2011). In South Africa, Rh. (Bo.) microplus tick species have been recorded across the country, with high abundance in North-West, Limpopo, KwaZulu-Natal, Mpumalanga, Gauteng, and the coastal regions of the Western and Eastern Cape provinces, as reported in Figure  6. The preferred attachment site is not well documented; however, it is said to be similar to that of Rh. (Bo.) decoloratus [63]. Cattle are the most susceptible hosts of Rh. (Bo.) microplus [64] and, while goats play a significant role, it is to a lesser extent [65]. Rhipicephalus (Bo.) microplus is a one-host tick species, and the immature are more abundant in spring, with a slight decline towards summer, and a peak season in late summer (January-April) [57]. This tick transmits babesiosis which is caused by Babesia bigemina and Babesia bovis [66]. In addition, it also transmits A. marginale [67]. Rhipicephalus (Bo.) microplus adults are bigger and slightly redder in color than Rh. (Bo.) decoloratus adults, however they are almost practically identical with external structures [52]. In addition, this species' dentition is divided into two columns, with four denticles in each row. The species, which has imposed risk on cattle worldwide (including in African countries), originated in Asia [60]. Cattle transported from Asia in the 19th century carried Rh. (Bo.) microplus to other countries in eastern and Southern Africa, the Comoro Islands, and the Mascarene Islands [61]. About 13 decades ago, this species was recorded in South Africa [62] and has recently been established in West African countries such as Burkina Faso, Mali, Togo, the Ivory Coast, and Benin (Madder, Thys et al., 2011). In South Africa, Rh. (Bo.) microplus tick species have been recorded across the country, with high abundance in North-West, Limpopo, KwaZulu-Natal, Mpumalanga, Gauteng, and the coastal regions of the Western and Eastern Cape provinces, as reported in Figure 6. The preferred attachment site is not well documented; however, it is said to be similar to that of Rh. (Bo.) decoloratus [63]. Cattle are the most susceptible hosts of Rh. (Bo.) microplus [64] and, while goats play a significant role, it is to a lesser extent [65]. Rhipicephalus (Bo.) microplus is a one-host tick species, and the immature are more abundant in spring, with a slight decline towards summer, and a peak season in late summer (January-April) [57]. This tick transmits babesiosis which is caused by Babesia bigemina and Babesia bovis [66]. In addition, it also transmits A. marginale [67].

Rhipicephalus evertsi evertsi Neumann, 1897
Rhipicephalus evertsi evertsi ticks are medium-sized ticks, with dark brown highly punctate scuta (conscutum and scutum), beady eyes, and legs with an orange to red color [52]. This tick species, which is broadly distributed in the Central and Southern regions of Africa, is known to be a vector of tick-borne pathogens in livestock. It transmits the bacterium A. marginale, the agent responsible for bovine anaplasmosis in cattle [45]. With records of being an important and common tick species in Africa, Rh. Evertsi evertsi occur year-round, however, they are commonly active in summer (December-January), with minor fluctuations in winter [69]. Rhipicephalus evertsi evertsi are two-host tick species, the larvae and nymphs feed and grow on one host, then the nymphs leave the host to the vegetation and turn into adults that quest for a second host [70]. Their seasonal activities and distribution dynamics on the host are determined by the infestation of females attached to the host [71]. They occur throughout South Africa, as reported in Figure 7, and are notably in high abundance in Limpopo, Gauteng, the North-West, Mpumalanga, the Free State, and the Eastern and Western Cape provinces of South Africa, respectively [72]. Bovine anaplasmosis is caused by this tick infecting cattle with the bacteria A. marginale, and their saliva contains toxins that paralyze sheep and calves in cattle [45].

Rhipicephalus evertsi evertsi Neumann, 1897
Rhipicephalus evertsi evertsi ticks are medium-sized ticks, with dark brown highly punctate scuta (conscutum and scutum), beady eyes, and legs with an orange to red color [52]. This tick species, which is broadly distributed in the Central and Southern regions of Africa, is known to be a vector of tick-borne pathogens in livestock. It transmits the bacterium A. marginale, the agent responsible for bovine anaplasmosis in cattle [45]. With records of being an important and common tick species in Africa, Rh. Evertsi evertsi occur year-round, however, they are commonly active in summer (December-January), with minor fluctuations in winter [69]. Rhipicephalus evertsi evertsi are two-host tick species, the larvae and nymphs feed and grow on one host, then the nymphs leave the host to the vegetation and turn into adults that quest for a second host [70]. Their seasonal activities and distribution dynamics on the host are determined by the infestation of females attached to the host [71]. They occur throughout South Africa, as reported in Figure 7, and are notably in high abundance in Limpopo, Gauteng, the North-West, Mpumalanga, the Free State, and the Eastern and Western Cape provinces of South Africa, respectively [72]. Bovine anaplasmosis is caused by this tick infecting cattle with the bacteria A. marginale, and their saliva contains toxins that paralyze sheep and calves in cattle [45].

Ixodes rubicundus Neumann, 1904
Ixodes rubicundus ticks are small, reddish-brown, with extended mouth parts and no eyes. Their legs are assembled in front of them. This tick species plays a significant role in economic losses, as it causes paralysis in infected cattle [74]. Ixodes rubicundus were initially dominant in the Eastern, Western, and Northern Cape [75]. Their broad distribution in South Africa, as reported in Figure 8, includes the Free State, Western Cape, Eastern Cape, Northern Cape, Gauteng, Mpumalanga, and KwaZulu-Natal provinces of South Africa, in different abundances [38]. This three-host-preference tick species takes 24 months to complete all developmental stages [76]. The peak activities of adult ticks differ across regions where the nymphs and larvae feed on small animals, and the adults feed on large mammals. They are found in mountainous areas [77]. Adult females contain toxins in their saliva that cause paralysis in young mammals such as calves, sheep, and goats [45]. Importantly, most tick species can be found in all the provinces, except for I. rubicundus, which was found in six provinces, as shown in Figure 8. This knowledge is important when designing and planning methods to control ticks in the South African livestock production system. From the review materials, different tick species are widely distributed in different abundances across South Africa and thus can be attributed to different ecological regions and seasons. This has a different impact on the economic aspects within the livestock industry. The following sections will summarize the economic impact of ticks and tick-borne diseases in South Africa. The red color represents the localities where the species has been found. It occurs throughout the country but is less dominant in the Northern Cape. The localities in this map were adapted [27,28,30,73].

Ixodes rubicundus Neumann, 1904
Ixodes rubicundus ticks are small, reddish-brown, with extended mouth parts and no eyes. Their legs are assembled in front of them. This tick species plays a significant role in economic losses, as it causes paralysis in infected cattle [74]. Ixodes rubicundus were initially dominant in the Eastern, Western, and Northern Cape [75]. Their broad distribution in South Africa, as reported in Figure 8, includes the Free State, Western Cape, Eastern Cape, Northern Cape, Gauteng, Mpumalanga, and KwaZulu-Natal provinces of South Africa, in different abundances [38]. This three-host-preference tick species takes 24 months to complete all developmental stages [76]. The peak activities of adult ticks differ across regions where the nymphs and larvae feed on small animals, and the adults feed on large mammals. They are found in mountainous areas [77]. Adult females contain toxins in their saliva that cause paralysis in young mammals such as calves, sheep, and goats [45]. Importantly, most tick species can be found in all the provinces, except for I. rubicundus, which was found in six provinces, as shown in Figure 8. This knowledge is important when designing and planning methods to control ticks in the South African livestock production system. From the review materials, different tick species are widely distributed in different abundances across South Africa and thus can be attributed to different ecological regions and seasons. This has a different impact on the economic aspects within the livestock industry. The following sections will summarize the economic impact of ticks and tick-borne diseases in South Africa.

The Economic Impact of Ticks and Tick-Borne Diseases on Cattle Production
Cattle production systems are crucial to the establishment of a country's economy, and sustained production ensures that there is enough food and food security [78]. However, certain factors threaten the sustainability of cattle production, including tick infestation. It is known that livestock farmers in tropical and subtropical areas have a significant problem as a result of the economic effects of ticks and tick-borne diseases on livestock productivity [79,80]. Methods used for tick control, such as chemical acaricide, have not been widely efficient due to factors such as resistance, chemical residues, and associated costs [81].
The effects of tick-borne disease result in cattle suffering from minor to severe illnesses, and eventually dying [24]. These diseases in animals include anaplasmosis, ehrlichiosis, and babesiosis [82]. When some ticks feed on the host's blood, they bite their host and cause injury to the tissue at the feeding site, leaving irritation, inflammation, or hypersensitivity [83], which results in paralysis and allergic reaction [84]. Infestations of ticks in high numbers can result in anaemia due to blood loss and lesions in the infested areas [85]. Also, the damaged skin of cattle due to tick infestation results in wounds that expose the cattle to secondary bacterial infection, which leads to diseases [86]. Moreover, tick infestation on cattle may result in reduced milk production, weight loss, lower pregnancy and birth rates, and increased mortality rates [87]. Tick-borne diseases affect the economy of developing countries in a more adverse way. There have not been sufficient studies conducted to evaluate an economic value associated with tick-borne diseases in South Africa. This has made it difficult to ascertain the true economic impact of ticks and tick-borne diseases in South Africa.

The Economic Impact of Ticks and Tick-Borne Diseases on Cattle Production
Cattle production systems are crucial to the establishment of a country's economy, and sustained production ensures that there is enough food and food security [78]. However, certain factors threaten the sustainability of cattle production, including tick infestation. It is known that livestock farmers in tropical and subtropical areas have a significant problem as a result of the economic effects of ticks and tick-borne diseases on livestock productivity [79,80]. Methods used for tick control, such as chemical acaricide, have not been widely efficient due to factors such as resistance, chemical residues, and associated costs [81].
The effects of tick-borne disease result in cattle suffering from minor to severe illnesses, and eventually dying [24]. These diseases in animals include anaplasmosis, ehrlichiosis, and babesiosis [82]. When some ticks feed on the host's blood, they bite their host and cause injury to the tissue at the feeding site, leaving irritation, inflammation, or hypersensitivity [83], which results in paralysis and allergic reaction [84]. Infestations of ticks in high numbers can result in anaemia due to blood loss and lesions in the infested areas [85]. Also, the damaged skin of cattle due to tick infestation results in wounds that expose the cattle to secondary bacterial infection, which leads to diseases [86]. Moreover, tick infestation on cattle may result in reduced milk production, weight loss, lower pregnancy and birth rates, and increased mortality rates [87]. Tick-borne diseases affect the economy of developing countries in a more adverse way. There have not been sufficient studies conducted to evaluate an economic value associated with tick-borne diseases in South Africa. This has made it difficult to ascertain the true economic impact of ticks and tick-borne diseases in South Africa.

Control of Ticks and Tick-Borne Diseases
There are different methods used to control ticks. The most common method used to control ticks is through a chemical approach such as acaricides. However, this method loses its efficiency when the ticks selected are resistant to acaricides [88]. The sections which follow detail traditional and innovative approaches associated with the control of ticks and tick-borne diseases in South Africa.

Control of Ticks in South Africa
Common methods that have been utilized for tick control include chemicals known as acaricides; however, these have limitations because of their residue which remains present in the environment and meat, the high costs involved, and the selection of cattle breeds which are resistant to ticks [89]. Multiple types of resistance to acaricides occur [90]. For instance, the Rh. (Bo.) microplus species have shown significant multi-resistance: the species was reported to be resistant to OP (organophosphates), SP (synthetic pyrethroids), and Am (amidines) [91]. Additional chemicals used in the acaricides include organochloridespyrethroids, amitraz, macrocyclic lactones, insect grown regulators (IGRs), and phenilpirazolons (fipronil) [92]. Currently, chemicals are applied to livestock using systems such as spraying, dipping, or pouring [93]. Uncontrolled usage of chemical acaracides in many countries has resulted in tick species such as Rh. (Bo.) microplus developing resistance [94]. The mechanism that the acaricides use to control ticks on the host is either by direct contact with the specific parasites after external application or absorption of the substance from host tissues [95]. These acaricides are neurotoxins that affect the tick's nervous system [96]. Conversely, tick resistance to acaricides has become a major driver of the need for new products and strategies to successfully reduce ticks and tick-borne diseases in South Africa, and worldwide. Ranchers of dairy and beef cattle in South Africa most frequently employ the class of synthetic pyrethroid acaricides. Common acaricides used in South Africa are summarized in Table 2. Every week in the summer and every two weeks in the winter, the government offers a dipping service in which the acaricide Triatix 500 TR ® (Amitraz 50 percent) is supplied enough to be used in communal dip tanks [82]. Alternative tick-control techniques used by farmers in South Africa include using old motor oil, having hens peck at the calves, manually removing ticks by cutting and pulling them, applying Jeyes Fluid, and using medicinal plants such as Aloe ferox and Ptaeroxylon obliquum [97]. These methods have been used commonly in South Africa with sufficient impact. However, the development of resistance and chemical residues have recently rendered these methods not efficient enough. This has motivated the need for other alternative methods such as developing breeding programs which will be used to breed animals that are resistant to ticks. The other method that can be applied is using vaccines. Vector vaccines have made it possible to lessen the effects of ticks and tick-borne diseases, by (a) reducing tick abundance and, consequently, the likelihood that hosts will contract vector-borne diseases, (b) reducing the ticks' capacity to transmit pathogens, and, preferably (c), a combination of the two factors [98]. Since its invention at Onderstepoort in 1945, vaccination has been widely employed in Southern Africa [99]. The first vaccine to be used on cattle against heartwater was an attenuated vaccine using E. ruminantium [100]. The vaccine was administered through the intravenous (IV) route. The vaccine showed 83% protection against heartwater on Friesian cattle [101]. Acaricides and vaccines methods do not completely eradicate ticks; they are also not sustainable and are shaping the use of acaracides due to the costs involved in South Africa and globally, respectively, and environmental health concerns [102]. Other methods that have been employed to control ticks and tick-borne diseases are summarized below.

Other Methods of Tick Control Manual Removal
This technique involves removing ticks from cattle and is mainly done on small-scale farms where the infestation of ticks on cattle is low [87]. Engorged ticks, ranging from 5 to 10 mm in length, are removed from cattle in the morning, and this method can reduce the tick population by approximately 21% [103]. Approximately 10% of farmers have been documented to make use of blades or scissors to pull and cut ticks off animals [104]; some lowveld smallholders and highveld farmers in Zimbabwe have been reported to use their hands to remove ticks from cattle [105]. This technique has limits, in that the inappropriate removal of ticks manually may cause more damage to the cattle's tissue, particularly with tick species that have long mouthparts [82].

Husbandry Practices That Support Tick Control
Ticks and tick-borne diseases can also be controlled using their habitat through controls that include growing plants that are not tick friendly, grazing management, pasture burning, animal nutrition, plant extracts, essential oils, vaccination, and biological control [87]. Certain plant species such as Stylosanthes scabra (a tropical legume) attract and trap ticks at the larval stage in their sticky exudate [106]. Rotating cattle to clean fields is used to starve ticks, as it interrupts their life cycle [107]; however, this technique has limitations due to managerial complexity and the costs involved in fencing paddocks [108]. Another tick control strategy is the burning of pasture.
Burning pasture exposes ticks (at different stages) to high temperatures and also destroys vegetation that serves as tick habitat [94]. The burning of pasture is applied globally, particularly in countries such as South Africa, Zambia and Australia, and in North and South America [107]. This method, however, has effects on the environment such as the decrease in soil nutrients leading to leaching and/or erosion [109]. Animal nutrition also plays a part in controlling ticks, as nutrition mediates host resistance to ticks [110]. Plant species from the Poaceae, Fabaceae, Lamiaceae, Verbenaceae, Piperaceae, and Asteraceae families have been reported to contain acaricidal properties [111]. Their secondary metabolites have been used against ticks of the Amblyomma, Rhipicephalus, Hyalomma, Dermacentor, Argas, and Ixodes genera [112].

Host Resistance
Animals that are resistant to tick infestation terminate the life stage of ticks as a result of the latter's inability to feed on the host, thus reducing engorgement weights, egg production, and larval development, all of which reduce the tick population [113]. Host resistance of cattle to ticks varies across breeds, including cattle breeds such as Bos indicus, which display the strongest innate tick resistance [114]. In South Africa, Nguni cattle are known to be more tick-resistant than other, exotic cattle breeds. Variation in tick resistance within the Nguni cattle population has been reported by Mapholi and Maiwashe [51]. As a result, exotic breeds have been cross bred with South African indigenous breeds with the aim to improve cattle's tick resistance and other local adaptive traits (heat and humidity stress). For example, Bonsmara cattle are a composite breed developed for tick resistance, especially for cowdriosis, and to endure heat stress [115]. Host resistance to ticks is assessed by counting and scoring the number of ticks on the cattle [116]. It is increasingly possible to use genomics tools in combination with phenotyping information to achieve a genomic selection of tick-resistant cattle and it was revealed that utilizing genomic predictions, a joint genetic assessment of the Angus, Hereford, Brangus, Braford, and Brahman breeds may be easily adopted to increase tick resistance within those populations [83]. Their selection is based on the ability to transmit resistant genes from one generation to the next [117]. Currently, the breeding of tick-resistant cattle currently ensures that the animals can still produce in hostile environments and during tick challenges.

Conclusions
In this manuscript, we presented a comprehensive overview of ticks, their distribution, and control strategies commonly employed for tick identification and characterization in South Africa. In contrast to conventional approaches that have been used to identify ticks, the molecular characterization approaches using mtDNA markers for the proper classification of ticks within the Ixodidae are very consistent and can provide a foundation for future research of the taxonomy and evolution of Ixodidae ticks. Most of the provinces in South Africa such as Limpopo, Gauteng, Mpumalanga, Northwest, KwaZulu Natal, and the Eastern Cape Province appear to be highly endemic. Apart from this, the impact of ticks and the disease they transmit is not well documented in South Africa, and this needs to be addressed by the authorities in order to plan ahead for control strategies. Future climate change will have an impact on South Africa's habitats and climatic patterns, and it can be predicted that new tick species and diseases carried by ticks will invade the country and spread to other parts of the country where cattle ticks are non-endemic.