Differentiating Taenia eggs found in human stools: does Ziehl-Neelsen staining help?
OBJECTIVE
To determine whether Ziehl-Neelsen staining can differentiate Taenia solium from Taenia saginata eggs.


METHODS
Tapeworm proglottids (33 specimens, 23 T. solium and 10 T. saginata) and eggs (31 specimens, 13 T. solium and 18 T. saginata) were stained. Four eggs from each sample were measured and average diameters were recorded.


RESULTS
Taenia saginata eggs stained entirely magenta in seven of 13 cases. Taenia solium eggs stained entirely blue/purple in 4/18 cases and entirely magenta in one. Eggs of T. saginata were slightly larger and always ovoid, while T. solium eggs were smaller and mostly spheric.


CONCLUSIONS
Ziehl-Neelsen staining can occasionally distinguish fully mature T. solium from T. saginata eggs, but this distinction is neither very sensitive nor completely specific. Differential staining suggests differences in embryophore components between species which become evident with egg maturation. In this small series, egg morphology (shape, maximal diameter) provided appropriate differentiation between T. solium and T. saginata eggs.
Jimenez
Juan A
JA
Department of Microbiology, School of Sciences, Universidad Peruana Cayetano Heredia, Lima, Perú.
Rodriguez
Silvia
S
Moyano
Luz M
LM
Castillo
Yesenia
Y
García
Héctor H
HH
D000818:Animals; D004396:Coloring Agents; D018509:DNA, Helminth; D005243:Feces / Q000469:parasitology*; D006652:Histological Techniques; D006801:Humans; D008018:Life Cycle Stages; D010270:Parasite Egg Count; D013194:Staining and Labeling; D041202:Taenia saginata / Q000254:growth & development / Q000302:isolation & purification*; D041201:Taenia solium / Q000254:growth & development / Q000302:isolation & purification*
D004396:Coloring Agents; D018509:DNA, Helminth