Africa Wild Arachnid Book: Ixodida (Ticks)
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Ticks are small arachnids in the order Ixodida. Along with mites, they constitute the subclass Acarina. Ticks are ectoparasites (external parasites), living by hematophagy on the blood of mammals, birds, and sometimes reptiles and amphibians.
Morphology of ticks
Ticks are closely related in general body structure to parasitic mites. The separationof ticks from mites is based on two useful morphologic characteristics: firstly the occurrence of a hypostome (ventral mouthpart) that has been modified into a piercing organ (usually with recurved teeth) and secondly the presence of a distinct sensory apparatus (Haller’s organ) on the dorsal aspect of the tarsus of the first leg.
The conscutum covers nearly the entire dorsal surface of male ixodid ticks and so limits the amount of blood that can be ingested. Female ticks and larvae and nymphs also have a scutum, but it covers only the anterior third of the dorsum, thus allowing the tick to expand when engorging.
Life cycle of ticks
There are four stages in the life cycle of an ixodid tick, namely the egg, the larva, the nymph, and the adult. The three instars (larva, nymph and
adult) climb on to the vegetation in order to attach to a passing host or quest for a host from the soil surface. Once on the host, the tick crawls to a predilected feeding site where it cuts the skin with its chelicerae and inserts its hypostome that together with cement secreted by the salivary glands, anchors the tick firmly in place. The tick remains in place for several days (larva, 3–6 days; nymph, 4–7 days; adult female, 7–9 days) during which time active growth of gut and cuticle occurs in order to accommodate the blood meal, most of which will be acquired in the final 24 hours of engorgement. During feeding the blood meal is concentrated by the extraction of water, which is then secreted back into the host by specialised salivary gland cells and is an important means by which tick-borne pathogens invade their hosts. Once fully engorged the tick withdraws its hypostome and falls to the ground where it begins digesting the blood meal and developing to the next instar.
Digestion is slow, and development of the new instars takes several months in temperate regions. The newly moulted (or hatched) unfed tick may remain quiescent for a time, but will eventually ascend the vegetation to quest for a host and a blood meal. After the engorged female detaches from a host digestion of the blood meal and oogenesis take place followed by oviposition. The incubation period of the eggs varies with the species and ambient temperature. Embryogenesis usually lasts 20 – 50 days.
Ixodid ticks have substantial capability to swallow and concentrate a large volume of host blood, their rapid metabolism and body development can explain the on-host intervals. During off-host periods, ticks experience some environmental distress such as climate and temperature. High temperatures and body-water homeostasis are of importance in processes that influence off-host survival. Ticks as a group have this capability to survive without food and/or water longer than most other arthropods. Ixodid species usually spend an annual total of 12-21 days on the host
compared to the off-host period.
Off-host fasting is characterized by slow metabolism with lengthy intervals of immobility, interrupted by movement within the microhabitat to increase water uptake, or to seek a position for detection of a passing blood-meal source. Spending a long period off the host gives the tick an opportunity to find a suitable species of animal to which to attac.
Ticks as gorging and fasting creatures, are considered to be two exceptionally different animals. A creature that is adapted for existing on a host body as a blood feeder, the other as a conservative one that can survive off the host and has the ability to expand its life strategies to adjust to the availability of water and energy resources to increase its chances of obtaining a blood meal. Diversity in daily and seasonal behaviour influences both physiological ageing and the balance of energy and water resources.
Ticks may have one, two or three-host life cycles, depending on the species:
One-host ticks
Larvae hatch from eggs, climb on to a host, attach, engorge and moult on the host to nymphs. The nymphs re-attach, engorge and moult to males and females on the same host. The adult ticks re-attach to the same host, partially engorge and mate and the females engorge fully. After detaching from the host, the females drop to the ground and deposit eggs and eventually die.
With the elimination of the waiting period for a host and shortening of metamorphosis, the monoxenic cycle on the host is shortened to possibly 3-4 weeks. There are not many one-host species, but some are important from the veterinary point of view. One-host ticks include Rhipicephalus (Boophilus) decoloratus, R. (B.) microplus, and Margaropus species.
Two-host ticks
After the new generation of larvae hatch from eggs laid by females, they climb on to the first host, engorge and moult to nymphs. The nymphs reattach, engorge, detach, drop to the ground and moult to females and males. The adult ticks climb on to the second host, attach, partially engorge and mate. The females engorge fully, detach and drop to the ground and eventually lay eggs that give rise to the next generation. In the dixenic host life cycle, the three stages develop on two different individuals that may or may not belong to the same species. In the first, the engorged larva moults on the host and the nymph reattaches close by. At the end of the blood meal the nymph detaches and metamorphoses on the ground. There are only two searches for a host, which eliminate the risks linked with the need for nymphal host searching and attachment. Hyalomma species and some Rhipicephalus species belong to this group.
Three-host ticks
Briefly, each stage of the parasitic cycle takes place on a different host. The fully engorged females detach from the third host, lay eggs in a sheltered locality and then die. Amblyomma species and the majority of Rhipicephalus species belong to this group. In the life cycle of a three-host tick, which is common to most ticks, host finding occurs three times. The tick requires three hosts (irrespective of the host species) for development and completion of its life cycle. There are three parasitic phases separated by two phases on the ground, when metamorphosis occurs.
Host specificity
Host specificity is defined as an association between tick species and one or a group of vertebrate species for the continuation of ticks` life cycles. Ticks have conventionally been observed as comparatively host-specific and it has generally been believed that their geographic distributions can be determined by that of their host/hosts. The strict or limited degree of host specificity of the majority of tick species (at least 700 out of 800 ixodid species) have been determined.
Host-finding of ambushing tick larvae is achieved by a sequence of behavioural processes. Under natural conditions this behaviour pattern constitutes localization, identification and invasion of the tick’s host.
Hard ticks seek hosts by an interesting behaviour called "questing." Questing ticks crawl up the stems of grass or perch on the edges of leaves on the ground in a typical posture with the front legs extended, especially in response to a host passing by. Subsequently, these ticks climb on to a potential host, which has brushed against their extended front legs. Certain bio-chemicals such as carbon dioxide as well as heat and movement serve as stimuli for host seeking behaviour.
Stage and site specificity
One of the factors limiting the distribution of ticks on the host’s body is the restriction of many tick species to certain parts of the body. This characteristic leads to reduction of the area available for attachment of any particular species.
At the site of attachment, ticks cause skin irritation, which stimulates the animal to groom itself with the tongue. This act successfully limits the number of ticks feeding and engorging on these areas. The common phenomenon of limitation of ticks to certain parts of the host body is thus either due to the host or characteristics of the environment and climate which are considered as evolutionary forces.
AW Arachnid Book: Ticks (Ixodida) - Photos & Descriptions
Moderator: Klipspringer
Index to Ticks (Order Ixodida)
Index to Ticks (Order Ixodida)
Ixodidae (Hard Ticks)
Amblyomma hebraeum African Bont Tick
Hyalomma rufipes Coarse Bont-legged Tick
Hyalomma truncatum Small Bont-legged Tick
Ixodidae (Hard Ticks)
Amblyomma hebraeum African Bont Tick
Hyalomma rufipes Coarse Bont-legged Tick
Hyalomma truncatum Small Bont-legged Tick
Re: AW Arachnid Book: Ticks (Ixodida) - Photos & Description
African Bont Tick Amblyomma hebraeum
Family: Ixodidae (Hard ticks)
Male © mposthumus
Male © mposthumus
Female © mposthumus
Female © mposthumus
Kruger National Park, Transport dam
Description
A hebraeum males are 4.2–5.7 mm long and A. hebraeum females are 5 mm long.
A. hebraeum has a variety of colours.
Hard ticks have a dorsal shield (scutum) and their mouthparts (capitulum) protrude forward when they are seen from above. Amblyomma ticks are large variegated ticks with long, strong mouthparts. The palps are long; the second segment is twice as long as it is wide. Eyes are present and the festoons are well developed. The males have no adanal shields, accessory shields or sub anal shield. A. hebraeum males are 4.2–5.7 mm long, oval ticks. The capitulum is long, with a rectangular basis; the lateral margins are rounded and the posterolateral angles are rounded and slightly salient. Palpal segment 2 is approximately three times as long as palpal segment 3. The scutum is smooth and convex, with fine black or brown spots and stripes on a pale greenish-white back-ground. The posteromedian stripe is narrow and is knobbed anteriorly; it rarely reaches the falciform stripe. The poster–accessory stripes are short and well separated from the third lateral spots.
The festoons, with the exception of the external festoons, are pale. The scutal eyes are small, slightly convex and circular. The ventral surface is dull greenish-yellow, with distinct ventral plaques and festoons with dark brown scutes (obsolete on the external one). The spiracular plate is moderately large and triangular, with rounded angles. The legs are dark brown, moderately stout, and have apical yellow banding at the distal end of each segment. Coxa I has two unequal spurs, coxae II and III contain salient ridges, and coxa IV has a short stout spur. The tarsi are short and abruptly attenuated.
Unfed A. hebraeum females are 5 mm long; engorged females can be up as long as 20 mm. The dorsum is dark greenish–brown or black, punctate and striate. The capitulum is 2 mm long, with a rectangular basis, convex lateral margins and slightly salient posterolateral angles. The palpi are slender; segment 2 is slightly curved and is approximately 2.5 times as long as segment 3.
The cervical stripe ex-tends posteriorly to the limiting spots and is generally connected to a small frontal spot by the thin line. The scapulae are dark and the punctuations are fine. The eyes are pale, circular and bugging.
Adult A. hebraeum are large, conspicuous ticks with long mouthparts, brightly coloured patterns on the scutum of both males and females, flat eyes, and brown and white banded legs. The males have yellow-coloured festoons.
Hosts
The preferred hosts of the adults are the larger domestic and wild ungulates to which they attach in clusters in the groin and axillae as well as on the dewlap, belly, perineum and peri-anal region. The larvae and nymphs feed on a wide variety of large and small mammals, birds and tortoises. On domestic livestock nymphs attach most commonly to the feet, and larvae to the face, the dewlap, neck and legs. On the larger ground-frequenting birds the nymphs and larvae attach mainly on the head and neck.
Geographic Distribution
A. hebraeum is found in the tropics and subtropics. It is endemic in African countries including South Africa, Zimbabwe, Botswana, Namibia, Malawi, Mozambique and Angola.
Habitat
Amblyomma hebraeum is often found in moderately humid, warm environment. Unfed nymphs of A. hebraeum are found sheltered under debris of the soil
Lifecycle
3-host, female produces up to 20000 eggs that hatch between 4-13 weeks, depending on the circumstances. The larvae engorge 4-20 days and moult in 2-7 weeks. The nymphs engorge in 5-20 days and moult in 14- 60 days. Adult females engorge in 10-20 days.
Amblyomma hebraeum has a three-host life cycle, with larvae, nymphs and adults feeding on separate hosts. On completion of feeding, engorged female ticks leave the host and seek sheltered microhabitats in which to moult or to lay eggs. The developmental periods off the host can be long. In the Eastern Cape Province of South Africa, larvae may take five months to hatch from eggs laid by female ticks that detached from hosts during March or April, and nymphs may remain inactive for two to three months after moulting. However, the life cycle usually lasts one year under field conditions, but may for the above reasons extend for longer. The pattern of seasonal occurrence is dependent on climate and varies considerably throughout the distribution range of the tick. In general, adults tend to be most numerous during the warm, wet summer months, larvae during the colder, dry, late autumn and winter months, and nymphs during the winter and spring months. However, varying numbers of all stages of development can often be found on hosts throughout the year. In the warmer, moist, lowveld regions of the KwaZulu-Natal, Mpumalanga and Limpopo provinces in the north-east of South Africa as well as in southern Zimbabwe, the life cycle seems to be continuous with little indication of a definite seasonal pattern of abundance for the various life stages.
Diet
Immature A. hebraeum ticks feed on small mammals, ground-feeding birds and reptiles. Adult ticks can be found on livestock and wildlife including antelope.
Disease Transmitted
African Tick-Bite fever caused by Rickettsia africae transmitted by A. hebraeum.
Links:
https://www.anipedia.org/resources/vect ... #amblyomma
Family: Ixodidae (Hard ticks)
Male © mposthumus Male © mposthumus Female © mposthumus Female © mposthumusKruger National Park, Transport dam
Description
A hebraeum males are 4.2–5.7 mm long and A. hebraeum females are 5 mm long.
A. hebraeum has a variety of colours.
Hard ticks have a dorsal shield (scutum) and their mouthparts (capitulum) protrude forward when they are seen from above. Amblyomma ticks are large variegated ticks with long, strong mouthparts. The palps are long; the second segment is twice as long as it is wide. Eyes are present and the festoons are well developed. The males have no adanal shields, accessory shields or sub anal shield. A. hebraeum males are 4.2–5.7 mm long, oval ticks. The capitulum is long, with a rectangular basis; the lateral margins are rounded and the posterolateral angles are rounded and slightly salient. Palpal segment 2 is approximately three times as long as palpal segment 3. The scutum is smooth and convex, with fine black or brown spots and stripes on a pale greenish-white back-ground. The posteromedian stripe is narrow and is knobbed anteriorly; it rarely reaches the falciform stripe. The poster–accessory stripes are short and well separated from the third lateral spots.
The festoons, with the exception of the external festoons, are pale. The scutal eyes are small, slightly convex and circular. The ventral surface is dull greenish-yellow, with distinct ventral plaques and festoons with dark brown scutes (obsolete on the external one). The spiracular plate is moderately large and triangular, with rounded angles. The legs are dark brown, moderately stout, and have apical yellow banding at the distal end of each segment. Coxa I has two unequal spurs, coxae II and III contain salient ridges, and coxa IV has a short stout spur. The tarsi are short and abruptly attenuated.
Unfed A. hebraeum females are 5 mm long; engorged females can be up as long as 20 mm. The dorsum is dark greenish–brown or black, punctate and striate. The capitulum is 2 mm long, with a rectangular basis, convex lateral margins and slightly salient posterolateral angles. The palpi are slender; segment 2 is slightly curved and is approximately 2.5 times as long as segment 3.
The cervical stripe ex-tends posteriorly to the limiting spots and is generally connected to a small frontal spot by the thin line. The scapulae are dark and the punctuations are fine. The eyes are pale, circular and bugging.
- Amblyomma hebraeum.jpg (43.22 KiB) Viewed 884 times
Adult A. hebraeum are large, conspicuous ticks with long mouthparts, brightly coloured patterns on the scutum of both males and females, flat eyes, and brown and white banded legs. The males have yellow-coloured festoons.
Hosts
The preferred hosts of the adults are the larger domestic and wild ungulates to which they attach in clusters in the groin and axillae as well as on the dewlap, belly, perineum and peri-anal region. The larvae and nymphs feed on a wide variety of large and small mammals, birds and tortoises. On domestic livestock nymphs attach most commonly to the feet, and larvae to the face, the dewlap, neck and legs. On the larger ground-frequenting birds the nymphs and larvae attach mainly on the head and neck.
Geographic Distribution
A. hebraeum is found in the tropics and subtropics. It is endemic in African countries including South Africa, Zimbabwe, Botswana, Namibia, Malawi, Mozambique and Angola.
Habitat
Amblyomma hebraeum is often found in moderately humid, warm environment. Unfed nymphs of A. hebraeum are found sheltered under debris of the soil
Lifecycle
3-host, female produces up to 20000 eggs that hatch between 4-13 weeks, depending on the circumstances. The larvae engorge 4-20 days and moult in 2-7 weeks. The nymphs engorge in 5-20 days and moult in 14- 60 days. Adult females engorge in 10-20 days.
Amblyomma hebraeum has a three-host life cycle, with larvae, nymphs and adults feeding on separate hosts. On completion of feeding, engorged female ticks leave the host and seek sheltered microhabitats in which to moult or to lay eggs. The developmental periods off the host can be long. In the Eastern Cape Province of South Africa, larvae may take five months to hatch from eggs laid by female ticks that detached from hosts during March or April, and nymphs may remain inactive for two to three months after moulting. However, the life cycle usually lasts one year under field conditions, but may for the above reasons extend for longer. The pattern of seasonal occurrence is dependent on climate and varies considerably throughout the distribution range of the tick. In general, adults tend to be most numerous during the warm, wet summer months, larvae during the colder, dry, late autumn and winter months, and nymphs during the winter and spring months. However, varying numbers of all stages of development can often be found on hosts throughout the year. In the warmer, moist, lowveld regions of the KwaZulu-Natal, Mpumalanga and Limpopo provinces in the north-east of South Africa as well as in southern Zimbabwe, the life cycle seems to be continuous with little indication of a definite seasonal pattern of abundance for the various life stages.
Diet
Immature A. hebraeum ticks feed on small mammals, ground-feeding birds and reptiles. Adult ticks can be found on livestock and wildlife including antelope.
Disease Transmitted
African Tick-Bite fever caused by Rickettsia africae transmitted by A. hebraeum.
Links:
https://www.anipedia.org/resources/vect ... #amblyomma
Re: Index to Africa Wild Insect & Invertebratae Books
Coarse Bont-legged Tick Hyalomma rufipes , formerly Hyalomma marginatum rufipes
Family: Ixodidae (Hard ticks)
KTP
Distribution
There are about 30 species of Hyalomma, known in South Africa as bont-legged ticks (Afrikaans: bontpootbosluise), which are found in Asia, Europe and Africa.
H. m. rufipes has been recorded from a wide range of habitats and climatic regions from desert to rain forest. The wide distribution probably results from the dispersal of birds infested with the immature stages of this tick. H. m. rufipes is the most widespread species of the genus in Africa.
Identification
Unfed Hyalomma ticks are large at 5 to 6mm including mouthparts. The integument texture has striations. The mouthparts are anterior and palp article 2 are longer than articles 1 and 3. The basis capituli has medium angular lateral margins. Eyes are always very convex. The scutum /conscutum are coloured brown. Enamel is usually absent. The slender legs usually have pale rings and pulvilli pulvilli are always present. Festoons(ridges on the edge of the lower abdomen) are present in both sexes but are unclear in females when fed. Spiracular plates are large and posterior to legs, and ventral plates are present in males only. The anal groove is posterior to the anus. Coxae 4 are of normal size and coxae 1 have large and equal paired spurs.
Adult H. rufipes are large ticks with dark-brown bodies, long mouthparts, a scutum that is heavily punctate, beady eyes, and long, red and white banded legs. They differ from those of H. truncatum in that the whole scutum is punctate and in the males it is more circular than the rather elongate shape of the latter tick.
Dorsal region: scutum rugged with dense large punctuations; short lateral grooves; presence of paracentral festoons.
Ventral region: adanal plates, length twice the width and the distance separating the pates is less compared to the width of their ends.
Life Cycle
All ticks have an incomplete metamorphosis: after hatching from the egg a series of similar stages (instars) develop from a six legged larva, to eight legged nymph and then a sexually developed eight legged adult. Between each stage there is a molt which enables the developing tick to expand within a new external skeleton.
H. m. rufipes is a two host tick. The larva attaches to the first host (a bird), feeds, and then moults to a nymph while on the host. After engorgement at the nymphal stage, the ticks drop off from the bird and moult on the ground before attaching to their second and final host which is usually a large mammal.
Hosts
The main host of adult H. m. rufipes is cattle, but wild ungulates are also frequently infested.
Disease Vector
This tick is the most important vector in southern Africa of the virus causing Crimean-Congo haemorrhagic fever (CCHF) in humans. Human beings become infected through tick bites, by crushing infected ticks, after contact with a patient with CCHF during the acute phase of infection, or by contact with blood or tissues from viraemic livestock.
The disease now occurs sporadically throughout much of Africa, Asia, and Europe and results in an approximately 30% fatality rate. After a short incubation period, CCHF is characterized by a sudden onset of high fever, chills, severe headache, dizziness, back, and abdominal pains. Additional symptoms can include nausea, vomiting, diarrhea, neuropsychiatric, and cardiovascular changes. In severe cases, hemorrhagic manifestations, ranging from petechiae to large areas of ecchymosis, develop. Treatment options for CCHF are limited. Immunotherapy and ribavirin have been tried with varying degrees of success during sporadic outbreaks of disease.
It also transmits the bacterium Anaplasma marginale to cattle causing bovine anaplasmosis, the bacterium Rickettsia conorii causing tick typhus in humans and the protozoan Babesia occultans to cattle. The feeding of adults on cattle causes large lesions at the attachment sites, leading to the formation of severe abscesses.
Links:
https://www.anipedia.org/resources/vect ... 4#hyalomma
https://www.researchgate.net/publicatio ... 2/download
http://www.nicd.ac.za/assets/files/CCHF ... Public.pdf
http://ecdc.europa.eu/en/healthtopics/v ... atum-.aspx
http://www.parasitesandvectors.com/content/5/1/170
http://www.sciencedirect.com/science/ar ... 4204001639
http://www.thelancet.com/journals/lanin ... 2/fulltext
http://www.afrivet.co.za/downloads/arti ... Cattle.pdf
Family: Ixodidae (Hard ticks)
KTPDistribution
There are about 30 species of Hyalomma, known in South Africa as bont-legged ticks (Afrikaans: bontpootbosluise), which are found in Asia, Europe and Africa.
H. m. rufipes has been recorded from a wide range of habitats and climatic regions from desert to rain forest. The wide distribution probably results from the dispersal of birds infested with the immature stages of this tick. H. m. rufipes is the most widespread species of the genus in Africa.
Identification
Unfed Hyalomma ticks are large at 5 to 6mm including mouthparts. The integument texture has striations. The mouthparts are anterior and palp article 2 are longer than articles 1 and 3. The basis capituli has medium angular lateral margins. Eyes are always very convex. The scutum /conscutum are coloured brown. Enamel is usually absent. The slender legs usually have pale rings and pulvilli pulvilli are always present. Festoons(ridges on the edge of the lower abdomen) are present in both sexes but are unclear in females when fed. Spiracular plates are large and posterior to legs, and ventral plates are present in males only. The anal groove is posterior to the anus. Coxae 4 are of normal size and coxae 1 have large and equal paired spurs.
Adult H. rufipes are large ticks with dark-brown bodies, long mouthparts, a scutum that is heavily punctate, beady eyes, and long, red and white banded legs. They differ from those of H. truncatum in that the whole scutum is punctate and in the males it is more circular than the rather elongate shape of the latter tick.
Dorsal region: scutum rugged with dense large punctuations; short lateral grooves; presence of paracentral festoons.
Ventral region: adanal plates, length twice the width and the distance separating the pates is less compared to the width of their ends.
Life Cycle
All ticks have an incomplete metamorphosis: after hatching from the egg a series of similar stages (instars) develop from a six legged larva, to eight legged nymph and then a sexually developed eight legged adult. Between each stage there is a molt which enables the developing tick to expand within a new external skeleton.
H. m. rufipes is a two host tick. The larva attaches to the first host (a bird), feeds, and then moults to a nymph while on the host. After engorgement at the nymphal stage, the ticks drop off from the bird and moult on the ground before attaching to their second and final host which is usually a large mammal.
Hosts
The main host of adult H. m. rufipes is cattle, but wild ungulates are also frequently infested.
Disease Vector
This tick is the most important vector in southern Africa of the virus causing Crimean-Congo haemorrhagic fever (CCHF) in humans. Human beings become infected through tick bites, by crushing infected ticks, after contact with a patient with CCHF during the acute phase of infection, or by contact with blood or tissues from viraemic livestock.
The disease now occurs sporadically throughout much of Africa, Asia, and Europe and results in an approximately 30% fatality rate. After a short incubation period, CCHF is characterized by a sudden onset of high fever, chills, severe headache, dizziness, back, and abdominal pains. Additional symptoms can include nausea, vomiting, diarrhea, neuropsychiatric, and cardiovascular changes. In severe cases, hemorrhagic manifestations, ranging from petechiae to large areas of ecchymosis, develop. Treatment options for CCHF are limited. Immunotherapy and ribavirin have been tried with varying degrees of success during sporadic outbreaks of disease.
It also transmits the bacterium Anaplasma marginale to cattle causing bovine anaplasmosis, the bacterium Rickettsia conorii causing tick typhus in humans and the protozoan Babesia occultans to cattle. The feeding of adults on cattle causes large lesions at the attachment sites, leading to the formation of severe abscesses.
Links:
https://www.anipedia.org/resources/vect ... 4#hyalomma
https://www.researchgate.net/publicatio ... 2/download
http://www.nicd.ac.za/assets/files/CCHF ... Public.pdf
http://ecdc.europa.eu/en/healthtopics/v ... atum-.aspx
http://www.parasitesandvectors.com/content/5/1/170
http://www.sciencedirect.com/science/ar ... 4204001639
http://www.thelancet.com/journals/lanin ... 2/fulltext
http://www.afrivet.co.za/downloads/arti ... Cattle.pdf
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Re: Index to Africa Wild Insect & Invertebratae Books
Small Bont-legged Tick Hyalomma truncatum
Family: Ixodidae (Hard ticks)
Male, Kieliekrankie Wilderness Camp, Kgalagadi Transfrontier National Park © ExFmem
Distribution
This tick is adapted to dry climates and is absent in Lesotho and, with the exception of the Eastern Cape, the eastern half of the Free State, south-eastern Gauteng and Mpumalanga, and southern KwaZulu-Natal, it is present throughout South Africa, Zimbabwe and much of Mozambique. It is also present in south-eastern and north-western Botswana; central and northern Namibia; southern Angola; western, southern, central and eastern Zambia; central and southern Malawi; south-western and north-eastern Tanzania; southern, central and western Kenya; and eastern Uganda.54, 149 It also occurs in many countries in north-eastern, Central and West Africa.
H. truncatum is usually found in lower rainfall areas. At a local level the abundance of H. truncatum is influenced by the abundance of hares, which are the preferred hosts of the immature stages.
Identification
Adults of H. truncatum are medium-sized ticks with long mouthparts and dark-brown bodies, beady eyes, and long, red and white banded legs. The posterior surface of the scutum in males is characterized by a depression containing numerous large punctations, otherwise it is comparatively smooth.
Dorsal region: Dark and shiny conscutum; festoons present; caudal depression.
Ventral region: Adanal plates with squared-ends
Life Cycle
Hyalomma truncatum has a two-host life cycle, which normally takes a year to complete under field conditions in South Africa.
This tick completes only one life cycle per year and the adults are present on large ungulates in summer and the immature stages on hares from autumn to spring.
Hosts
The preferred hosts of the adults are large ungulates, both domestic and wild. They attach in the tail switch, around the anus, on the lower perineum, and on the legs, including around the feet. The immature stages feed on hares and on certain rodents, particularly gerbils.
It has been recovered from a wide range of ungulates of various sizes, but it usually parasitizes the larger species. A substantial and strong predilection for Cape hares and scrub hares by the immature stages has been stated.
In the Kgalagadi Transfrontier Park H. truncatum, is present on gemsbok, eland and black wildebeest.
Disease Vector
Babesia caballi, the cause of equine piroplasmosis. Because the immature stages of H. truncatum do not feed on horses the transmission of B. caballi by this tick has of necessity to take place transovarially. Hyalomma truncatum also transmits the virus causing Crimean-Congo haemorrhagic fever (CCHF) in humans, and the toxin causing sweating sickness in cattle and especially in young calves. Only certain strains of H. truncatum produce this toxin and then it is only female ticks that do so. The long mouthparts of the ticks, as well as their tendency to form clusters, can cause tissue damage resulting in secondary bacterial infections and abscess formation. The attachment of adult ticks to the interdigital clefts and fetlocks of lambs almost always causes lameness.
Links:
https://www.anipedia.org/resources/vect ... 4#hyalomma
https://www.researchgate.net/publicatio ... 2/download
https://repository.up.ac.za/bitstream/h ... sequence=1
Family: Ixodidae (Hard ticks)
Male, Kieliekrankie Wilderness Camp, Kgalagadi Transfrontier National Park © ExFmem
Distribution
This tick is adapted to dry climates and is absent in Lesotho and, with the exception of the Eastern Cape, the eastern half of the Free State, south-eastern Gauteng and Mpumalanga, and southern KwaZulu-Natal, it is present throughout South Africa, Zimbabwe and much of Mozambique. It is also present in south-eastern and north-western Botswana; central and northern Namibia; southern Angola; western, southern, central and eastern Zambia; central and southern Malawi; south-western and north-eastern Tanzania; southern, central and western Kenya; and eastern Uganda.54, 149 It also occurs in many countries in north-eastern, Central and West Africa.
H. truncatum is usually found in lower rainfall areas. At a local level the abundance of H. truncatum is influenced by the abundance of hares, which are the preferred hosts of the immature stages.
Identification
Adults of H. truncatum are medium-sized ticks with long mouthparts and dark-brown bodies, beady eyes, and long, red and white banded legs. The posterior surface of the scutum in males is characterized by a depression containing numerous large punctations, otherwise it is comparatively smooth.
Dorsal region: Dark and shiny conscutum; festoons present; caudal depression.
Ventral region: Adanal plates with squared-ends
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Life Cycle
Hyalomma truncatum has a two-host life cycle, which normally takes a year to complete under field conditions in South Africa.
This tick completes only one life cycle per year and the adults are present on large ungulates in summer and the immature stages on hares from autumn to spring.
Hosts
The preferred hosts of the adults are large ungulates, both domestic and wild. They attach in the tail switch, around the anus, on the lower perineum, and on the legs, including around the feet. The immature stages feed on hares and on certain rodents, particularly gerbils.
It has been recovered from a wide range of ungulates of various sizes, but it usually parasitizes the larger species. A substantial and strong predilection for Cape hares and scrub hares by the immature stages has been stated.
In the Kgalagadi Transfrontier Park H. truncatum, is present on gemsbok, eland and black wildebeest.
Disease Vector
Babesia caballi, the cause of equine piroplasmosis. Because the immature stages of H. truncatum do not feed on horses the transmission of B. caballi by this tick has of necessity to take place transovarially. Hyalomma truncatum also transmits the virus causing Crimean-Congo haemorrhagic fever (CCHF) in humans, and the toxin causing sweating sickness in cattle and especially in young calves. Only certain strains of H. truncatum produce this toxin and then it is only female ticks that do so. The long mouthparts of the ticks, as well as their tendency to form clusters, can cause tissue damage resulting in secondary bacterial infections and abscess formation. The attachment of adult ticks to the interdigital clefts and fetlocks of lambs almost always causes lameness.
Links:
https://www.anipedia.org/resources/vect ... 4#hyalomma
https://www.researchgate.net/publicatio ... 2/download
https://repository.up.ac.za/bitstream/h ... sequence=1