Exam3Lec6GITractandTissueDwellingHelminthInfections

Question 1

Classification of Helminths

Answer 1

Roundworms (Nematodes)
-Tissue dwelling: Trichinella, filarial worms (river blindness, elephantiasis)
-GI tract/tissue: Hookworm, Strongyloides
-GI tract: Pinworm, Ascaris

**Tapeworms **(Cestodes):
Taenia tapeworms (pork, beef)
Echinococcus (dog)

Flukes, Flatworms (Trematodes):
Schistosoma (blood flukes)

Question 2

What is trichinosis?

what is the parasite and transmission?

Answer 2

Parasite: Trichinella spiralis
Worldwide in all climates

Transmission:
Oral (consumption of infected undercooked meat, pork, or ham)

Question 3

What is the life cycle trichinosis?

Answer 3

When you ingest undercooked meat, the larvae from parasite infect striated muscles.

Question 4

What are the sx of trichinosis?

Answer 4

Adult worms phase of life cycle can cause:
Intestinal inflammation
Diarrhea
Nausea
High eosinophilia

Encysted larvae phase of life cycle in muscle can cause:
Muscle and joint pain
Fever
Edema of the eyes
Hemorrhages under nails (petechia)

Question 5

What is Elephantiasis (Lymphatic Filariasis)

What is the parasite and tranmission?

Answer 5

Parasite: Wuchereria bancrofti

Transmission: mosquito
Transmit infective microfilariae
Adult worm causes disease

Adult worms produce microfilariae that migrate into lymph and blood channels.

adults cause disease

Question 6

What are the sx of Elephantiasis (Lymphatic Filariasis)?

Answer 6

Adult worms block lymphatic organs causing:
Proliferation of the lining of the endothelium leading to granulation
Obstruction and secondary infection of the lymphatic system

Late symptoms:
Elephantiasis
Lymphangitis
Lymphadenopathy
Filarial Abscess

Elephantiasis is a condition characterized by gross enlargement of an area of the body, especially the limbs.

Question 7

What is River Blindness (Onchocerciasis)?

What is the parasite and transmission?

Answer 7

Parasite: Onchocerca volvulus

Transmission: Blackfly
Transmit infective microfilariae
Microfilaria larvae causes disease

Adult filariae produce **thousands of infective microfilariae **that migrate in the circulation.

Question 8

What are the sx of River Blindness (Onchocerciasis)?

Answer 8

Adult worms cause subcutaneous fibrous nodules and produce thousands of microfilaria larvae

Microfilaria Larvae invade the eyes causing:
Sclerosing Keratitis
Blindness

Question 9

What is hookworm?

parasite and transmission

Answer 9

Parasite: Necator americanus & Ancylostoma duodenale
Direct parasitic cycle AND indirect free-living cycle

Transmission: Infective (3rd stage) Larvae
Found worldwide in warm climates
Mature in soil and penetrate the skin

Question 10

What are the 2 life cycles of hookworm?

Answer 10

indirect free living and parasitic cycle

These parasites have two life cycles. During the parasitic cycle they penetrate the skin, travel up to the lung (due to the high oxygenation). The infected person then coughs up the parasite and swallows it which leads to infection of the GI tract. In the free living cycle, these parasites thrive on their own whilst feeding on bacteria in the soil.

Question 11

What are the sx and diagnosis of hookworm>

Answer 11

Larvae can cause pneumonitis (larvae migrate through the lungs)

Adult worms (in jejunum) ingest blood causing:
Gastrointestinal bleeding fangs!!1
Iron deficiency
Anemia

Diagnosis: hookworm eggs recovered from stool samples

Question 12

What are Strongyloides?

parasite and transmission

Answer 12

Parasite: Strongyloides stercoralis
Direct parasitic cycle AND indirect free-living cycle

Transmission: Infective Larvae
Worldwide distribution
Penetrate the skin

Question 13

What are the sx of Strongyloides?

Answer 13

Larvae can cause pneumonitis (larvae migrate through the lungs

In AIDS Patients:
Hyper infection syndrome (massive autoinfection with filariform larvae)

Question 14

What is pinworm?

parasite and transmission

Answer 14

Parasite: Enterobius vermicularis

Transmission: Fecal-oral
Uptake of infective eggs

Question 15

What is the most common parasitic helminth in the US?

Answer 15

Pinworm
Children (daycare centers)
Elderly (nursing homes)

Question 16

What are the sx and the diagnosis of pinworm?

Answer 16

Initial symptoms: Perianal itching (particularly in the morning)

Diagnosis
Pinworm eggs recovered from stool sample
Pinworm eggs recovered by scotch tape method

Question 17

What is ascaris?

parasite and transmission?

Answer 17

Parasite: Ascaris lumbricoides

Transmission: Oral route
Uptake of infective eggs
Worldwide distribution

Question 18

What are the sx and diagnosis of ascaris?

Answer 18

**Larvae **can cause pneumonitis with eosinophilia (larvae migrate through the lungs)

Adult Worms
Obstruction of small intestine, bile ducts, and trachea, Appendicitis

Diagnosis: ascaris eggs recovered in stool sample, has a rough lining (surface) -know this

Question 19

How do ascaris eggs look like?

Answer 19

They have a rough surface

Question 20

What is pork tapeworm?

parasite and transmision?

Answer 20

Parasite: Taenia solium

Transmission
1. Oral Route: Consumption of infected undercooked pork
-Leads to tapeworm in GI
2. Fecal-Oral Route: Uptake of infective eggs
-Leads to cysticercosis

Question 21

What is the sx and diagnosis of pork tapeworm?

Answer 21

Infection with eggs:
* Developing larvae can cause cysticercosis
* Neurocysticercosis: MOST COMMON helminth infection of the CNS

Diagnosis:
* Proglottids in stool

The adult tapeworm is made up of many small segments, called proglottids,each about the size of a grain of rice. As the tapeworm matures inside the intestine, these segments (proglottids) break off and pass into the stool.

Question 22

What is the sx and diagnosis of pork tapeworm?

Answer 22

Infection with eggs:
* Developing larvae can cause cysticercosis
* Neurocysticercosis: MOST COMMON helminth infection of the CNS

Diagnosis:
* Proglottids in stool

The adult tapeworm is made up of many small segments, called proglottids,each about the size of a grain of rice. As the tapeworm matures inside the intestine, these segments (proglottids) break off and pass into the stool.

Question 23

What is dog tapeworm (hydatid disease)?

parasite and transmission

Answer 23

Parasite: Echinococcus granulosus

Transmission:
1. Fecal-Oral Route: Uptake of infective eggs
-Causes Hydatid Disease
-Cysticercosis in the lung and liver

Question 24

What is Schistosomiasis (Bilharzia)?

parasite and transmission

Answer 24

Parasites: Schistosoma species
Transmission:
-Aquatic snails as intermediate host
-Infective cercariae larvae penetrate the skin

Question 25

What are the three Schistosoma Species?

Answer 25

Schistosoma mansoni
Schistosoma haematobium
Schistosoma japonicum

Question 26

What is Schistosoma mansoni species ?

type of infection, the location and the type of spine

Answer 26

Hepatic/intestinal infection
Africa, Middle East, Latin America
LATERAL spine

Question 27

What is Schistosoma haematobium species?

type of infection, the location and the type of spine

Answer 27

Urinary infection
Africa and Middle East
TERMINAL spine

Question 28

What is the Schistosoma japonicum species?

type of infection, the location and the type of spine

Answer 28

Hepatic/intestinal infection
Southeast Asia
NO spine

Question 29

What are the sx of Schistosomiasis (Bilharzia)

Answer 29

Larvae can cause** mild dermatitis** at site of penetration

Adult Worms release eggs causing:
* Ulceration
* Splenomegaly/Hepatomegaly
* Developmental Retardation
* Inflammatory granuloma and tissue
* Hypertrophy of the bladder
* Periportal Fibrosis