Otobius Otobius megnini: Spinose ear tick

General Description: Larvae and nymphs are found in the ears of the horse and many other animals, including cattle, sheep, and dogs. The 6–legged larva is 3 mm. long, while the more commonly seen nymph is 1 cm. long, with a spiny body that narrows posteriorly, and has 8 legs.

Life Cycle: Free–living adult females lay eggs on the ground that hatch in 3 weeks. Larvae and nymphs live and feed on one host for up to 7 months. The life cycle can be completed in 2.5 months, but may take up to a year.

Location: Adults on ground, larvae and nymphs in ears of horses.

Geographical Distribution: Otobius is found primarily in arid hot regions of the world, with none present in areas with more than 1000 mm. annual rainfall.

Significance: Heavy infestations cause great annoyance and serious blood loss.

Effect on Host: These ticks are a source of great annoyance to the horse. Ear canker can result from bacterial infections in the inflamed inner ear. Large numbers of ear tick larvae and nymphs can cause substantial blood loss. Infested horses continually shake their heads. Loss of appetite, debilitation, and anaemia may be present.

Diagnostic Information: Ticks may be found by swabbing the ear, or by direct inspection of heavily infected ears.

Control: Infested animals should be treated with organo–phosphorus compounds.

Otobius