GI Parasites (Protozoa & helminthes)

Question 1

What is the source of a GI disease that is caused by protozoa and helminthes?

Answer 1

Contaminated food and water

Question 2

What are the different types of parasites?

Answer 2

1) Unicellular (protozoa)

2) Multicellular (Helminths “parasitic worms”)

Question 3

What are the different types of protozoa and what is their speciose?

Answer 3

1) Amoeba (entamoeba histolytics)

2) Flagellates (Giardia lambila)

3) Coccidia (cryptospordium parvum, cyclospora cayetanensis)

Question 4

What is meant by amebiasis?

Answer 4

• Common disease, that is encountered in the hospitals
• It is an infection of the large intestine and sometimes the liver (amebic hepatitis)

Question 5

What is the parasite that causes amebiasis?

Answer 5

Entamoeba histolytica (which has two forms, an active “trophozoit” and inactive “cyst”)

Question 6

How is the entamoeba histolytica transmitted?

Answer 6

It is transmitted by ingesting the cyst, from one person or through the food/water

• If the active one (trophozoites) was ingested, it would not survive due to the exposure to the gastric contents

Question 7

What are the complications of Entamoeba histolytica infection?

Answer 7

1) Caused by the invasion of Entamoeba histolytica to the wall of the intestine leading to amoebic dysentry that causes intestinal ulcers (flask-shaped), bleeding, increased mucus production and diarrhea

2) Entamoeba histolytica might pass into the bloodstream travelling to the liver, brain or the lungs

• They also form pockets of infection (abscesses)

Question 8

What is the clinical presentation of Entamoeba histolytica?

Answer 8

• Acute amoebiasis:

1) Diarrhea

2) Dysentery (with frequent small bloody stool)

• Chronic amoebiasis

1) GI Symptoms

2) Fatigue

3) Weight loss

4) Bloody stools

5) Occasional fever

• The most common symptom is bloody diarrhea

Question 9

What happens if Entamoeba histolytica goes to the blood?

Answer 9

Mainly they infect the liver as the liver is responsible to remove the trophozoites from the blood, forming abscess (causing amoebic hepatitis), and the aspiration of the liver will yield a brownish-yellow pus

• Other metastatic lesions include:

1) Cerebral amoebiasis

2) Amoebic pericarditis

3) Cutaneous amoebiasis

4) Splenic abscess

-FYI REMEMBER THE PIC IT MIGHT COME IN THE OSPE

Question 10

What is the lab diagnosis of amoeba infections?

Answer 10

1) Stool microscopy

• Finding trophozoites in the diarrheal stools or cyst

2) Stool culture

3) Radiological findings (for extraintestinal amoebiasis)

Question 11

What is giardiasis (lambliasis)?

Answer 11

• Infection of the small intestine caused by (giardia lambila)
• Giardia lamblia is the most common cause of water-borne disease
• More common in children than adults (as they drink pool water, getting a foul smelling fatty diarrhea “giardiasis”)
• Exists in the trophozoite and cystic forms
• Watery but not bloody diarrhea

Question 12

What is the parasite that causes the most water borne diseases?

Answer 12

Giardia lambila

Question 13

What are the symptoms of a giardia lambila infection?

Answer 13

• Shows up 1-2 week after exposure

1) Watery diarrhea

2) Foul smelling diarrhea

3) Gas

4) bLOATING AND ABDOMINAL CRAMPS

5) Weight loss

6) Dehydration

Question 14

How to diagnose a giardialambila infection?

Answer 14

1) Stool microscopy, one stool sample over the period of three days should be take as giardia might appear in stool on a given day but not the following

2) Sometimes taking a tissue sample from the small intestine

Question 15

What is the cryptosporidium infection?

Answer 15

• Cryptosporidiosis (AKA crypto) is a highly contagious infection of the small intestine, due to the exposure to the cryptosporidium parasite, which lives in human intestines and can cause diarrhea is passed in the stool of an infected person
• Spread through the fecal-oral route often through contaminated water
• Common in immunocompromised and young children
• Mild and does not last for more than 4-5 days

Question 16

What are the most common species that causes cryptosporidium infection?

Answer 16

1) Cryptosporidium parvum

2) Cryptosporidium hominis

Question 17

What are the clinical symptoms of cryptosporidium infection?

Answer 17

2) Frequent and watery diarrhea (most common)

2) Stomach cramps

3) Nausea, vomitting, fever, weight loss

Question 18

What is the laboratory diagnosis of cryptosporidium infection?

Answer 18

1) Stool microscopy examination (stained by acid-fast staining)

• he cyst will be changed to oocyst which can be found in the stool
• This oocyst is visualized using a special stain “Acid fast stain” (IMP for OSPE)

Question 19

What is cyclosporiasis?

Answer 19

• Caused by Cyclospora cayetanensis (A parasite composed of one cell)
• It is human exclusive
• It infects the S.I

Question 20

What are the symptoms of cyclosporiasis?

Answer 20

1) Severe watery diarrhea (main)

2) Loss of apetite

3) Weight loss

4) Stomach cramps

5) Bloating, nausea, fatigue

Question 21

What is the laboratory diagnosis for cyclosporiasis?

Answer 21

• Microscopic examination of the stool by detecting oocytes
• Modified Ziehl-Neelsen or Kinyoun acid-fast staining, can help in identifying the cyclospora

Question 22

What are the different GI helminths?

Answer 22

1) Intestinal Nematodes

2) Intestinal cestodes

3) Intestinal trematodes

Question 23

What are the characteristic of helminths?

Answer 23

1) Multicellular

2) They form eggs instead of cysts

3) Their life cycle includes:

• Egg stage (cycle begins with the production of eggs by adult helminths residing in the host organism, which passes out by excretion)
• Larval stage (once outside the host’s body, the eggs may undergo development into larval stages)
• Infective “worm” stage (After undergoing development, the infective stage of the helminth is reached. This stage may involve the formation of a cyst, encysted larvae, or another form of resistant stage that can survive harsh environmental conditions and facilitate transmission to the definitive host)

Question 24

What are the common parasitic nematodes (specie) of the humans?

Answer 24

1) Ascaris lumbricoides (Roundeworm)

2) Ancylostoma duodenale (HOOKWORMS)

3) Enterobius vermicularis (Pinworm)

4) Trichuris trichiura (Whipworm)

5) Trichinella spiralis (threadworm)

Question 25

What does ascaris lumbricoides cause?

Answer 25

Ascariasis - It is a roundworm that is one of the most common cause of intestinal worm infection, associated with poor personal hygiene and sanitation

Question 26

What is ascariasis?

Answer 26

It is an infection of the small intestine

Question 27

What is the life cycle of ascaris lumbricoides?

Answer 27

1) Infective stage: Embryonated eggs - Ingestion of eggs, where the hists digestive juices acts on the eggshell to release the larva into the S.I - The larvae then penetrates the intestinal mucosa and enters the lymphatics and mesenteric vessels, where is can be carried into the liver, right heart, and finally to the lungs

Question 28

How to diagnose ascaris lumbricoides?

Answer 28

1) Direct fecal film 2) Finding the adult worm in the feces, vomit and tissue

Question 29

What are the major species of hookworms that can infect humans?

Answer 29

1) Necator americanus 2) Ancylostoma duodenale - They live in the small intestine, and most prevalent in tropical and subtropical zones - A heavy infection with one might provoke anemia "AKA yellow laziness"

Question 30

What is the lifecycle of a hookworm?

Answer 30

- Larvae takes a free-living mode - The (filari form larva) is the infective stage - The transmission occurs as (skin peetration, or orally swallowed, or maternal-child)

Question 31

Where does hookworms reside?

Answer 31

In the upper part of the small intestine

Question 32

What is the difference between a hook worm and protozoa?

Answer 32

Hookworm larvae itself can travel and infect “not the inactive eggs” (while in the protozoa; it’s the cyst “inactive form” that had the ability to infect other body parts)

Question 33

What are the symptoms of a hookworm infection?

Answer 33

1) Skin rash which is typically raised and itchy 2) Iron deficiency anemia

Question 34

What is the lab diagnosis of a hookworm?

Answer 34

1) Eggs in feces 2) Hookworm larvae in sputum

Question 35

What is the diseases caused by pinworms (Enterobius vermicularis)?

Answer 35

Enterobiasis - Embryonated eggs are the infected form - Human-human transmission

Question 36

What is enterobiasis?

Answer 36

It is a world-wide infection occuring most frequently in school or pre-school-children and in crowded conditions

Question 37

What are the most common symptoms of enterobiasis?

Answer 37

1) Itching in the anal area (especially at night)

Question 38

How to diagnose Enterobius vermicularis (pinworm)?

Answer 38

1) Perianal itching 2) Microoscopic examination 3) Grahm's scotch tape swab (using a piece of sticky tape to pick up any eggs or worms that may be around the anal area in the morning before washing or a bowel movement, then observed under the microscope)

Question 39

What is the disease caused by whipworm (trichuris trichiura)?

Answer 39

Trichuriasis - Transmitted by the mouth

Question 40

Where does a trichuriasis infection occur?

Answer 40

Large intestine

Question 41

What are the symptoms of trichuriasis?

Answer 41

- Most frequently asymptomatic 1) Heavy infections 2) Abdominal pain 3) Diarrhea 4) Rectal prolapse 5) Possibly growth retardation

Question 42

How to diagnose a whipworm infection?

Answer 42

Discovering the eggs in feces via either saturated brine flotation method or direct fecal smear

Question 43

What is trichinella spiralis?

Answer 43

The pork worm (under cooked pork products) - It causes diarrhea, abdominal pain, fatigue, nausea and vomitting

Question 44

What is the parasitic cause of taeniasis disease?

Answer 44

1) Taenia solium (pork tapeworm) - It is usually asymptomatic unless the larvae finds its way to the CNS where it can cause neurocysticercosis (which can cause seizures) 2) Taenia saginata (beef-tapeworm) - Infects human when they eat cysticerci (larval form of the parasite) in raw or uncooked beef, but this parasite does not cause cysticercosis

Question 45

What is the tapeworm that cause neurocysticerocosis?

Answer 45

Taenia solium (pork-tapeworm)

Question 46

What are the sign and symptoms of taeniasis?

Answer 46

- People infected with T.sanginata experience more symptoms as it sis bigger than T.solium 1) Abdominal pain 2) Loss of apetitie 3) Weight loss 4) Upset stomach 5) Active passing of the proglottids (tapeworm segments) in feces "the most imp sign"

Question 47

How to diagnose taeniasis?

Answer 47

1) Examination of stool sample - Stool specimen are examined on three different days, and in the lab for taenia eggs using a microscope 2) Antigen in blood and CSF - Diagnosis of neurocysticercosis usually requires MRI or CT brain scans

Question 48

What is hydatid disease?

Answer 48

- Dog tapewrom - Caused by an infection of echinococcus granulosus in the larval stage - This larval formation of the tapeworm can lodge in various body sites where they form a fluid-filled sac known as a hydatid cyst - Hydatid cyst are round and cystic, they have a cuticle germinal layer wall, its contents are cystic fluid, brood capsules, protoscolexm forming cyst in the liver (most common), lungs and brain

Question 49

What are the symptoms of hydatid disease?

Answer 49

- It depends on the size, location and number of cysts 1) Dysfunction of the liver, lung or nervous system due to pressure from the cyst 2) Allergy due to the rupture of the cyst which might cause a severe allergic reaction - If the cyst rupture regeneration might occur - It requires surgery most of the time

Question 50

How to diagnose hydatid disease?

Answer 50

1) Parasitological examination 2) Cysts in organs or calcified cysts that are visualized using X-rays, CT or ultrasound 3) Serological examination