Loiasis (African Eye Worm) Guidelines

Updated: Jun 03, 2020
  • Author: Darvin Scott Smith, MD, MSc, DTM&H, FIDSA; Chief Editor: Pranatharthi Haran Chandrasekar, MBBS, MD  more...
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Guidelines Summary

Prevalence Estimation

RAPLOA (Rapid Assessment Procedure for L loa) is a WHO procedure to assess the endemicity and prevalence of L loa in communities with suspected L loa infection. It consists of a questionnaire designed to take advantage of the observation that, in communities with high prevalence of L loa infection, the characteristic symptoms of loiasis are well-known and often have local names, whereas this is often not the case where the prevalence of infection is low or nonexistent. The proportion of interviewees reporting a history of eye worm has also been shown to correlate with parasitological indicators of disease prevalence. A threshold of 40% of respondents reporting a history of eye worm adequately identifies communities where the prevalence of L loa and the risk of severe adverse reactions is predicted to be too high for routine ivermectin treatment.

The steps of the RAPLOA procedure are as follows:

  • Step 1: Identification of local names for eye worm and the typical symptoms of L loa infection
  • Step 2: A survey of 80 adults on the history of eye worm
  • Step 3: Calculation of percentage of adults reporting a history of eye worm; used to predict infection prevalence [44]