Helminths

1
Helminths
2
Schistosomiasis

• Tissue damage (granulomas) in response to eggs
  lodging in tissues

3
Schistosomiasis
(a) Male and female schitosomes.
Figure 23.27a
4
Schistosomiasis
Figure 23.27b
5
Helminthic Diseases of the Digestive System
Figure 25.21
6
Tapeworms

• Taenia spp.
• Transmitted as cysticerci in undercooked meat
• Cysticerci may develop in humans
• Diagnosed by observing proglottids and eggs in
  feces
• Treatment with praziquantel
• Neurocysticercosis may require surgery

Figure 12.27
7
Echinococcus granulosus
Figure 12.28
8
Pinworms

• Enterobius vermicularis
• Definitive host Humans
• Transmitted by ingesting Enterobius eggs
• Treatment with pyrantel pamoate or mebendazole

9
Pinworms
Figure 12.29
10
Hookworms

• Larvae in soil hatched from eggs shed in feces
• Larvae bore through skin migrate to intestine
• Treated with mebendazole

11
Hookworms
Figure 25.24
12
Hookworms
Figure 12.30
13
Ascariasis

• Ascaris lumbricoides
• Lives in human intestines
• Transmitted by ingesting Ascaris eggs
• Treated with mebendazole

Figure 25.25
14
Trichinosis

• Trichinella spiralis
• Larvae encyst in muscles of humans and other
  mammals
• Transmitted by ingesting larvae in undercooked
  meat
• Treated with mebendazole to kill adults worms

Figure 25.26
15
Trichinosis
1
Adult Trichinella spiralis develop, invade
intestinal wall of pig, and produce larvae that
invade muscles.
Capsule
Garbage, including undercooked or raw pork
2
Section showing T. spiralis larvae encysted in
pigs muscle tissue (capsule is 0.25 to 0.5 in
length).
5
Meanwhile, other animals are infected by eating
infected meat that has been dumped.
Section of T. spiralis
3
Human eats undercooked pork containing cysts.
Undercooked pork
4
In human intestine, cyst walls are removed, and
T. spiralis adults develop. Adults produce larvae
that encyst in muscles.
T. spiralis adult
Figure 25.26
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