Laboratory Activity 2
Topics: Ascaris lumbricoides and Trichuris trichiura
I. Ascaris lumbricoides is also called the giant intestinal round worm. The male measures
15-31 cm long and 2-4 mm wide, and the female, 20-35 cm long and 3-6 mm wide.
1. Examine preserved adult Ascaris worms and note the visible difference between
male and female worms. Determine the anterior and posterior ends and note the
transverse striae, literal lines, and locations of the genital openings. Draw and label
the structures noted above.
Male Ascaris lumbricoides
, 2. Examine mounted unfertilized, fertilized and embryonated Ascaris eggs. Note the
differences in appearance of these eggs. Draw and label the three types of eggs in
the space provided below.
Unfertilized Ascaris eggs Fertilized Ascaris eggs Embryonated Ascaris eggs
● Yellow to brown ● Golden brown ● Golden brown
● Egg shell is thinner ● Broadly oval / nearly ● Round / ovoidal with
● Larger, narrower, and spherical thick shell
elongated than fertilized ● Single cell separated ● With embryo / larvae
from inner shell inside
● With albuminous
mammillary coat
3. Prepare and examine a Direct Fecal Smear (DFS) as described in this manual using
your own stool specimen. Note the character of normal stool specimen. What are the
common elements of stool seen in your specimen? Draw and label in the space
provided below.
Topics: Ascaris lumbricoides and Trichuris trichiura
I. Ascaris lumbricoides is also called the giant intestinal round worm. The male measures
15-31 cm long and 2-4 mm wide, and the female, 20-35 cm long and 3-6 mm wide.
1. Examine preserved adult Ascaris worms and note the visible difference between
male and female worms. Determine the anterior and posterior ends and note the
transverse striae, literal lines, and locations of the genital openings. Draw and label
the structures noted above.
Male Ascaris lumbricoides
, 2. Examine mounted unfertilized, fertilized and embryonated Ascaris eggs. Note the
differences in appearance of these eggs. Draw and label the three types of eggs in
the space provided below.
Unfertilized Ascaris eggs Fertilized Ascaris eggs Embryonated Ascaris eggs
● Yellow to brown ● Golden brown ● Golden brown
● Egg shell is thinner ● Broadly oval / nearly ● Round / ovoidal with
● Larger, narrower, and spherical thick shell
elongated than fertilized ● Single cell separated ● With embryo / larvae
from inner shell inside
● With albuminous
mammillary coat
3. Prepare and examine a Direct Fecal Smear (DFS) as described in this manual using
your own stool specimen. Note the character of normal stool specimen. What are the
common elements of stool seen in your specimen? Draw and label in the space
provided below.
