[Elizabeth_Zeibig]_Clinical_Parasitology__A_Practi(z-lib.org)

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APPENDIX B Answers to Case Studies: Under the Microscope
CHAPTER 10
Case 10-1: Under the Microscope
1. Hymenolepis nana.
2. No intermediate host is required.
3. Adult worm develops in humans following
ingestion of an egg.
4. Praziquantel.
Case 10-2: Under the Microscope
1. Proglottid.
2. A, Uterine branches; B, radial striations; C,
hexacanth embryo; D, hooklets.
3. Taenia solium.
4. Pork tapeworm.
5. The proglottids of T. solium differ from T.
saginata in that the latter has 15 to 30 uterine
branches, whereas the former possesses less
than 15 uterine branches. Eggs of both organisms
are identical morphologically.
6. See E. Also, the rostellum of T. solium possess
hooklets, whereas that of T. saginata possesses
no hooklets.
CHAPTER 11
Case Study 11-1: Under the Microscope
1. Clonorchis sinensis. The other trematodes
that cause infections from eating raw fish,
metagonimiasis and heterophyiasis, live in the
intestine, not the liver.
2. Human infection occurs following the ingestion
of undercooked fish contaminated with
encysted metacercariae. Maturation of the
immature flukes takes place in the liver. The
adult worms take up residence in the bile
duct. Eggs are passed in bile to the intestine,
where they can be identified in feces. On
contact with fresh water, the miracidium
emerges from each egg. Specific species of
snails serve as the first intermediate host. The
miracidium penetrates into the snail, where a
sporocyst develops. Numerous rediae result
and ultimately produce many cercariae. The
cercariae emerge from the snail and enter a
fish, where they encyst.
3. Clonorchiasis.
4. Appropriate strategies in a prevention plan
include practicing proper sanitation procedures,
especially the practice of proper human
and reservoir host feces disposal, and avoiding
the practice of consuming raw, undercooked,
or freshly pickled freshwater fish and shrimp.
Case Study 11-2: Under the Microscope
1. Eggs of Schistosoma haematobium.
2. Schistosomiasis, bilharziasis.
3. Snail.
4. Penetration of cercariae through the skin that
takes place when unsuspecting humans swim
in contaminated fresh water.
CHAPTER 13
Case Study 13-1: Under the Microscope
1. A type of hard shell tick is the most likely
suspect.
2. There are both male and female forms of
ticks, as well as hard and soft shell ticks.
3. If you must enter an area where ticks are
prevalent, you should wear clothing that
covers as much of the body as possible. Tick
repellants are also recommended.
4. Hard ticks (Ixodes spp.) are capable of transmitting
a number of bacterial, rickettsial, and
parasitic diseases.
Case Study 13-2: Under the Microscope
1. The most likely arthropod involved is the itch
mite Sarcoptes scabiei, the cause of scabies.
2. Skin scrapings should be collected from the
lesions and placed in a sterile container with
70% ethanol and 5% formalin or sterile
saline, enough to cover the sample.
3. This parasite is transmitted from person to
person through close contact. Members of the
household or other patients in an institutional
care facility are easily infected.
4. There are several prescription level topical
treatments available but it is also necessary to
treat the clothing, bedding, and close contacts
of this patient to prevent reinfection of the
patient or the spread of scabies to others in the
facility (e.g., staff, patients, family members).