Abnormal Helminth Egg Development, Strange Morphology, and the Identification of Intestinal Helminth Infections.

Sarah G.H Sapp,Richard S Bradbury,Michael J Yabsley

doi:10.3201/eid2408.180560

Abstract

Occasionally, abnormal forms of parasitic helminth eggs are detected during routine diagnostics. This finding can prove problematic in diagnosis because morphologic analysis based on tightly defined measurements is the primary method used to identify the infecting species and molecular confirmation of species is not always feasible. We describe instances of malformed nematode eggs (primarily from members of the superfamily Ascaridoidea) from human clinical practice and experimental trials on animals. On the basis of our observations and historical literature, we propose that unusual development and morphology of nematode and trematode eggs are associated with early infection. Further observational studies and experimentation are needed to identify additional factors that might cause abnormalities in egg morphology and production. Abnormal egg morphology can be observed early in the course of infection and can confound accurate diagnosis of intestinal helminthiases.

Highlights

Abnormal forms of parasitic helminth eggs are detected during routine diagnostics
One author (R.S.B.) had observed multiple highly abnormal forms of Ascaris lumbricoides roundworms being passed by humans during the course of human intestinal helminth surveillance studies in the eastern Solomon Islands
These forms were passed by different persons and included eggs with double morulae, giant eggs, and eggs not conforming to the traditional symmetric, ovoid morphology associated with those of A. lumbricoides

Summary

Introduction

Abnormal forms of parasitic helminth eggs are detected during routine diagnostics. Casual discussions between the authors revealed that they had each observed highly abnormal forms of helminth eggs from humans and animals during the course of their work. One author (R.S.B.) had observed multiple highly abnormal forms of Ascaris lumbricoides roundworms being passed by humans during the course of human intestinal helminth surveillance studies in the eastern Solomon Islands.

Results

Conclusion