Diagnostic Findings [Last Modified: ]
Taeniasis
[Taenia saginata] [Taenia solium]

Causal Agent Life Cycle Geographic Distribution Clinical Features Laboratory Diagnosis Treatment

Microscopy
TAKE EXTREME CARE IN PROCESSING THE SAMPLES!
INGESTION OF EGGS CAN RESULT IN CYSTICERCOSIS!

Taenia egg Taenia egg
A B

A, B: Taeniid eggs.  The eggs of Taenia saginata and Taenia solium are indistinguishable morphologically (morphologic species identification will have to rely on the proglottids or scolices).  The eggs are rounded, diameter 31 to 43 µm, with a thick radially striated brown shell.  Inside each shell is an embryonated oncosphere with 6 hooks.  The egg in Figure B still has the primary membrane that surrounds eggs in the proglottids.

Pollen artifact
C

C: Pollen artifact that could be mistaken for a taeniid egg; however, the shell is thinner, of nonuniform thickness, and no hooks are visible.

T. saginata gravid proglottid T. saginata gravid proglottid
D E

T. solium gravid proglottid T. solium gravid proglottid
F G

D, E, F, G: Gravid proglottids of Taenia saginata (Figures D and E) and Taenia solium (Figures F and G).  Injection of India ink in the uterus allows visualization of the primary lateral branches.  Their number allows differentiation between the two species: T. saginata has 15 to 20 branches on each side (Figure D and E), while Taenia solium has 7 to 13 (Figures F and G).  Note the genital pores in mid-lateral position.

T. saginata scolex T. solium scolex T. solium scolex
H I J

H, I, J: Scoleces of Taenia saginata (Figure H) and Taenia solium (Figures I and J).  Scolex of T. saginata has 4 suckers and no hooks.  T. solium has 4 suckers in addition to a double row of hooks.

T. saginata adult worm T. saginata adult worm
K L

K, L: Taenia saginata adult worm.  The adult in Figure K is 12 feet long.

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