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Invasive Tissue Parasites 203

Source: Centers for Disease Control and Prevention (CDC) General Classification—Nematode
MICROSCOPIC DIAGNOSTIC
FEATURE

(roundworm)

Trichinella spiralis
Organism
Specimen Required Muscle biopsy; hard
to recover adults
or larvae from fecal
sample
FIGURE 9-2 Trichinella cysts develop within human Stage Larvae in muscles;
muscle tissue adults in stool
samples
Source: Centers for Disease Control and Prevention (CDC) Shape Worm-shaped
Size
In adults, F 5 4.0 mm
3 150 μm; M 5 1.4–1.6
mm 3 40–60 μm
Motility
Migration through
walls of intestine,
circulation in blood
to muscle tissue
Calcified larvae are
Other Features
graphic exam; stained
with hematoxylin and
eosin
FIGURE 9-3 Splinter hemorrhages under fingernails found by radio-
in trichinosis
T. spiralis
Encysted larvae form
Source: Centers for Disease Control and Prevention (CDC) Delmar/Cengage Learning

near the orbital bones of the eyes, muscular pain, and
tenderness, accompanied by generalized weakness
FIGURE 9-4 Clinical appearance of eyes, periorbital
swelling, muscle pain, diarrhea, and increased (Figure 9-4).
eosinophil count
Treatment and Prevention
period. Increased allergic responses to parasitic
infections and hemorrhages beneath the fingernails For heavy and symptomatic infections, anti-parasite
may be evident (Figure 9-3). Other symptoms and medication is recommended. Anti-parasite (anti-
signs may occur including headaches and edema helminthic) medication is the first line of treatment