Onchocerciasis (River Blindness) Guidelines

Updated: Oct 06, 2017
  • Author: Darvin Scott Smith, MD, MSc, DTM&H; Chief Editor: Mark R Wallace, MD, FACP, FIDSA  more...
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Guidelines

Guidelines Summary

Control and Elimination

The World Health Organization (WHO) maintains and issues guidelines for the control of onchocerciasis and the certification of its elimination from endemic regions. Historically, nodulectomy and vector control were used to decrease the frequency and intensity of filarial infections in areas endemic for onchocerciasis. Current strategy centers on the mass drug administration (MDA) of ivermectin. In Africa, this distribution is managed through community-directed treatment with ivermectin on an annual or semiannual basis. In the Americas, semi-annual ivermectin treatment is generally used, although quarterly administration has been undertaken.

Three phases are used to control onchocerciasis using MDA programs with ivermectin.

Phase 1 - Treatment

Features include the following:

  • Regular ivermectin treatment with at least 80% therapeutic coverage to the population at risk
  • Campaigns typically last 12-15 years
  • Supplemented with vector control in three countries (equatorial Guinea, Uganda, and Tanzania)

The following recommendation are used to demonstrate the interruption of O volvulus transmission to stop MDA and to move to the Post-Treatment Surveillance phase (phase 2):

  • O-150 PCR (Poolscreen) testing in blackflies should be used to demonstrate the interruption of O volvulus transmission  (strong recommendation with high certainty of evidence).
  • The Ov-16 serology test in children younger than 10 years to demonstrate the interruption of O volvulus transmission (strong recommendation with low certainty of evidence)
  • Skin snip microscopy should not be used to demonstrate the interruption of O volvulus transmission but may be used in a transition to using Ov-16 serology, during which skin snip microscopy and Ov-16 serology should be used in parallel. Skin snip microscopy, if used, should be applied with a sample size providing adequate statistical certainty that programmatic goals have been reached (conditional recommendation with low certainty of evidence).
  • Assessment of ocular infection should not be used to demonstrate the interruption of O volvulus transmission (strong recommendation, low certainty of evidence).

Phase 2 - Post-Treatment Surveillance

Features include the following:

  • Lasts 3-5 years
  • Surveillance for new infections

The following methods are used to confirm the interruption of O volvulus transmission at the end of the post-treatment surveillance period, leading to the elimination of human onchocerciasis, and to move to the Post-Elimination Surveillance phase (phase 3):

  • O-150 PCR (Poolscreen) testing in black flies should be used to confirm the interruption of O volvulus transmission (strong recommendation with high certainty of evidence).
  • The Ov-16 serology test should be used in children to confirm the interruption O volvulus transmission when O-150 PCR (Poolscreen) results in blackflies are at or near the threshold (<1 infected blackfly in 2000 total flies) (conditional recommendation with low certainty of evidence).
  • Assessment of ocular infection should not be used to confirm the interruption of O volvulus transmission (strong recommendation with low certainty of evidence). [53]

Phase 3 - Post-Elimination Surveillance

Features include the following:

  • Starts after 3-5 years of post-treatment surveillance
  • Follows confirmation of phase 2 assessments
  • Provides strong evidence of permanent interruption (elimination) in a defined geographic area