Common trematode eggs seen on easily recognized on microscopy (wet mount with iodine) include:
(A) Schistosoma mansoni
(B) Schistosoma haematobium
(C) Schistosoma japonicum
(D) Clonorchis
(E) Fasciola
(F) Paragonimus
Schistosoma eggs are the largest of the helminths and can be distinguished by their spines which are lateral (S. mansoni, A), terminal (S. haematobium and S. intercalatum, B), or vestigial (S. japonicum or S. mekongi, C). Clonorchis and Opisthorchis eggs have an operculum and small remnant at the opposite end (D). Fasciola and Fasciolopsis are also operculated but smooth (E). Paragonimus eggs are also operculated but have a thick, almost pointed opposite end (F).
The measurements given represent the length of the eggs along the long axis for each organism.
Panels A-C reproduced from: Centers for Disease Control and Prevention. Public Health Image Library (PHIL). Available at:
http://phil.cdc.gov/phil/home.asp (Accessed on March 18, 2014).
Panels D-F reproduced from: Centers for Disease Control and Prevention. DPDx - Laboratory Identification of Parasitic Diseases of Public Health Concern. Available at:
http://www.cdc.gov/dpdx/ (Accessed on March 18, 2014).
