018 Parasite Infections of GI tract

Question 1

What are cysts/ova?

Answer 1

Resistance structures that can exist in the outside world. This releases the next stage during environmental triggers.

Question 2

What is Giardiasis?

Answer 2

Protozoa causing girada

Question 3

Symptoms of giardiasis

Answer 3

Ranges from immunosuppressed to immunocompetent; bulky diarrhoea; sulphurous smell diarrhea; fat globules present

Question 4

Why is the smell of giardiasis so distinct?

Answer 4

Giardia is an anaerobic organism, so its respiratory chain uses sulphur-containing compounds.

Question 5

How does giardiasis work?

Answer 5

Deconjugates bile salts to gain fatty acids, presence of fat in intestine alter osmotic balance causing water drawn into the gut; binds strongly to the surface of the mucosa blocking absorption.

Question 6

What is the incidence of giardasis?

Answer 6

Protective immunity; 20% prevalence in endemic areas

Question 7

What is ameobiasis ?

Answer 7

Protozoa causing entamoeba infection

Question 8

What is the pathogenesis of ameobiasis?

Answer 8

Actively invades mucosa and can disseminate to other organisms through passage of hepatic portal vein

Question 9

What are the symptoms of ameobiasis?

Answer 9

Range of symptoms; asymptomatic, colic frequent bowel movements; dysentery due to disruption of gut wall, meningitis due to disseminated disease

Question 10

How is giardiasis transmitted?

Answer 10

Although there is developed immunity, cysts still form to cause contamination through the diarrhoea.

Question 11

Which protozoa is a flagellate protozoa?

Answer 11

Giardiasis

Question 12

Which protozoa is from the apicomplexan parasite family?

Answer 12

Cryptosporidium paryum

Question 13

What is a apicomplexan parasite?

Answer 13

It means the front end of the parasite has series of organelles that can invade host cells.

Question 14

Which animal hosts the reservoir of cryptosporidium parvum?

Answer 14

Cattle

Question 15

Describe the life cycle of the cryptosporidium parvum

Answer 15

oocyst invades the intestinal mucosa, there is division of the protozoa but no cysts are formed so it is not transmitted

Question 16

Which type of helminth is able to transmit through direct invasion?

Answer 16

Hookworm

Question 17

What is the life cycle of Ascaris lumbricoides?

Answer 17

Females shed 200,000 eggs per day. They remain infective for long periods of time. Eggs then hatch in the gut and the larval stages occur around the body and undergoes pulmonary migration.

Question 18

What are the symptoms of Ascaris lumbricoides?

Answer 18

Asthma - like presentation, malnutrition, B12 deficiency

Question 19

What is cutaneous larval migration?

Answer 19

When worm has left but has left a trail of immune response against the worm

Question 20

What is the life cycle of hookworm?

Answer 20

They have a larval stage that is in the warm, moist environment. It invades the skin, enter through lymph nodes and then go through tracheo-oesophageal migration.

Question 21

Symptoms of the Amylostoma duodenale and Necator amencacus

Answer 21

Clinical manifestations include itchy papules in the skin, migration through lungs and iron & protein loss.

Question 22

Describe the life cycle and symptoms of of trichuris trichuria

Answer 22

Found in warm, humid climates. This is usually only symptomatic in children (due to protective immunity). Clinical manifestations include bloody diarrhoea (with no fever), rectal prolapse (due to agitation), anaemia, wasting and eosioniphilia.

Question 23

Which type of helminth results in reinnoculation?

Answer 23

Strongyloides stercoralis

Question 24

Describe the significance of Enterobius vermicularis

Answer 24

This is a pinworm found in the caecum and perianal region. It can cause severe scratching. Diagnosed by scotch tape test.