Enoplids 2 Flashcards
List some of the defining characteristics of the enoplids.
Don’t have tails
Lay eggs with bi-polar plugs (except Trichinella sp.)
L1 is the infective stage (except Dioctophyme renale)
*Dioctophyme is also unique in that it requires an intermediate host. All other enoplids have direct life cycles.
What is a stichosome?
A narrow tube surrounded by large gland cells (stichocytes) arranged in a single-file column.
Each stichocyte communicates with the lumen of the esophagus with a pore.
*Stichosomes are found in members of superfamily Trichinelloidea
Which nematode clade possesses stichosomes?
Superfamily Trichinelloidea
Which whipworm species infects ruminants?
Trichuris discolor
Which whipworm species infects swine?
Trichuris suis
Which whipworm species infects canids?
Trichuris vulpis
Which whipworm species infects primates (including humans)?
Trichuris trichiura
Which whipworm species infects horses?
JK
No species known to infect horses
How common are feline whipworm infections in the US?
Rare
More common in the Caribbean
Where do whipworms typically live in the host?
Lower GI tract
Why is the common name for enoplids “whipworms?”
Shaped like a bullwhip.
Note that the skinny part of the worm is the anterior portion.
Describe how whipworms associate with the host gut mucosa.
Anterior end of the worm is stitched into the mucosa.
Posterior end is free in the lumen.
True or False
Enoplids tend to be fairly host-specific
TRUE
Describe the characteristics of the egg of Trichuris spp.
Rust brown to orange color
Thick shell with smooth surface
Bipolar plugs with ridges
Perfectly symmetrical on the longitudinal axis
One-cell stage when laid
Which species is this?
Trichuris sp.
Note the rust-brown color, bipolar plugs with ridges, and perfect symmetry.
What species is this?
Trichuris sp.
Note the ridges within the bipolar plug. This is a good way to distinguish this egg from a capillarid egg.
What species is this?
Capillarid
Note the pale color, plugs with no ridges, and asymmetrical shape.
(This egg is from Eucoleus aerophila)
What species is this?
Capillarid
Note the pale color, bipolar plug with no ridges, and asymmetry.
Which stage of Trichuris is infectious?
L1
(All enoplids except Dioctophyme renale have infections L1’s)
Can you find the L1 of Trichuris in the environment?
Nope
The L1 develops inside the egg and does not hatch until the egg is swallowed by a new host.
Describe the migration of Trichuris spp.
Mucosal migration only
L1 penetrates into large intestine mucosa, matures, and emerges into the lumen
The feeding of adult Trichuris spp. can cause intestinal bleeding. Would you expect to see frank blood or melena in the feces?
(Don’t worry, this isn’t a Goff question.)
