Ophthalmologic Manifestations of Onchocerciasis Treatment & Management

Updated: Jun 22, 2018
  • Author: Debora E Garcia-Zalisnak, MD; Chief Editor: Hampton Roy, Sr, MD  more...
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Treatment

Medical Care

Traditionally, DEC was used to kill microfilariae. It is not in wide use now because of the severe reactions mentioned above in the Mazzotti test.

The standard treatment now includes ivermectin given as a single dose and repeated every 6-12 months for 10 years. Ivermectin works by paralyzing the microfilariae over 6 months. It has no effect on adult worms. [10, 11]

Ivermectin has been shown to delay the development of optic atrophy, reduce the visual field loss, and decrease the severity of keratitis. More advanced chorioretinal and keratitis lesions and angle-closure glaucoma are not treated with ivermectin. Iridocyclitis can result from ivermectin therapy and can be treated with steroids and cycloplegic drops. In addition, some ivermectin-resistant strains of O volvulus have recently appeared. [12]

Moxidectin is an antiparasitic drug that was approved by the FDA in June 2018 to treat onchocerciasis in patients aged 12 years or older. The WHO initiated clinical trials for use in onchocerciasis treatment in 2009. Moxidectin is closely related to ivermectin but yields a more sustained reduction in microfilarial levels. FDA approval was based on a double-blind, parallel group, superiority trial (n=1472) that compared moxidectin (8 mg PO once) with ivermectin (150 mcg/kg PO once). The trial took place in Ghana, Liberia, and the Democratic Republic of the Congo. Results showed skin microfilarial loads (ie, parasite transmission reservoir) were lower from month 1 to month 18 after moxidectin treatment than after ivermectin treatment, with an 86% difference at month 12. Moxidectin would therefore be expected to reduce parasite transmission between treatment rounds more than ivermectin could, thus accelerating progress toward elimination. [13]

Doxycycline has been used against Wolbachia and has been shown to decrease microfilarial loads. [14] Animal models treated with doxycycline have had a decrease in posttreatment corneal thickness and stromal haze. [14]

Other drugs currently under investigation include rifampin and azithromycin.

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Surgical Care

Surgical treatments are usually directed against preventing the loss of vision caused by Ovolvulus. These include the following:

  • Cataract extraction for visually significant cataracts

  • Trabeculectomy or drainage implants for glaucoma management

  • Penetrating keratoplasty for corneal pathology

  • Vitrectomies or laser photocoagulation for chorioretinal lesions

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Consultations

Infectious disease physicians and ophthalmologists should be involved in the care of all patients with onchocerciasis.

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Diet

There are no dietary restrictions for affected patients.

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Activity

Depending on the severity of disease, patients with severe vision loss may need assistance with activities of daily living. Otherwise, patients should have as much activity as tolerated.

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