Public Health Vectors and Pests

African Bont Tick


Male: Amblyomma hebraeum
Male: Amblyomma hebraeum
Female: Amblyomma hebraeum
Female: Amblyomma hebraeum
Common Name African Bont Tick
Scientific Name Amblyomma hebraeum
Size A hebraeum males are 4.2–5.7 mm long and A. hebraeum females are 5 mm long
Colour A.hebraeum has a variety of colours
Description A.hebraeum belongs in the family of Ixodidae (hard tick). 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 palps1 are long; the second segment is twice as long as it is wide. Eyes are present and the festoons2 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 capitulum3 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.
 
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
Disease Transmitted African Tick-Bite fever caused by Rickettsia africae transmitted by a hebraeum.
Control Measures used to exclude ticks of foreign origin from a country include pre-export inspection and certification that the animals are free of ectoparasites, quarantines during entry, and animals should be treated with acaricides. In countries where A. hebraeum is already present, acaricides can remove the ticks from the animal, but it does not prevent reinfestation. Three-host ticks spend at least 90% of their life cycle in the environment rather than on the host animal; ticks must be controlled in the environment to prevent their wide spread in the community.
If ticks are already widespread in the community, extirpation can be almost impossible. Extirpation programs are based on animal identification and periodic acaricide treatment of livestock, as well as public education, surveillance, quarantines and movement restrictions
 

1An elongated, often segmented appendage usually found near the mouth in invertebrate organisms such as mollusks, crustaceans, and insects, the functions of which include sensation, locomotion, and feeding.
2Ridges on the edge of the lower abdomen
3Head or mouthpart
 

 

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