1.A total of 3,310 cutaneous biopsies performed on 16 onchocercal patients revealed a distribution of microfilarias which confirmed previous observations of the author (2), namely that the shoulder and neighboring areas give a greater percentage of positive results than any other regions of the body.
2.In biopsies on patients with a single nodule, more microfilarias were found at the shoulder than at the site of the nodule, in 66% of the cases. This would seem to indicate that the microfilarias distribute themselves over the entire upper part of the body, a finding which does not support the common practice of taking skin from the vicinity of the nodule.
3.Although it has been recognized that the density of microfilarias may vary from time to time, the data here given show that negative biopsies may frequently alternate with positive ones on the same patient over a period of time, and hence repeated biopsies are important to reach a diagnosis or evaluate the results of therapy.
Institute of Health and Tropical Diseases, Mexico, D.F.