Parasitology

Question 1

what is Medical Parasitology?

Answer 1

the study of invertebrate animals capable of causing disease in humans and animals.

Question 2

what is a Parasite:

Answer 2

an organism that lives at the expense of another organism (host)

Question 3

what is the difference between Ectoparasite and Endoparasite

Answer 3

Ectoparasite: on the surface of hosts
Ticks, lice
Endoparasite: within the body of the host
Worms, protozoa

Question 4

How does a parasite cause damage?

Answer 4

Nutritional deprivation
Direct trauma/obstruction
Inflammation

A successful parasite does not want to kill its host

Question 5

what are the Modes of Transmission of parasites

Answer 5

1- Via an intermediate, ingestion of larvae in the tissue of another host
2-fecal-oral route, ingesting feces that has eggs or larvae
3-active skin penetration:
4-injection by blood-sucking insects

Question 6

Giardia lamblia mechanism

Answer 6

a Protozoa that has 2 stages
-first the Cysts (resistant stage) Typically shed in stools, found in Streams, lakes, wild and domestic animals, Contaminated water, fruits and vegetables, the cysts is the Infective stage, its Resistant to chlorination
and it Spread by fecal-oral route (ingestion) needs 10-25 cysts
- the second stage is the Trophozoites caused by gastric acid (active stage) where the parasite Lives in the intestine and attaches to intestinal villi

Question 7

Giardia lamblia incubation period and symptoms.

Answer 7

Incubation: 1-4 weeks (multiplies by longitudinal binary fission), average 10 days
Symptoms:
Acute, onset of foul smelling, watery diarrhea, cramps, flatulence and steatorrhea.
10-14 days
Diagnosis: microscopy of stool sample, 1/day for 3 days

Question 8

Naegleria fowleri

mechanism

Answer 8

a Protozoa
found in Soil at the bottom of lakes
Seasonal: summer, warmer temperatures
Transmission: contact with nasal mucosa in people who get immersed in water
Invades nasal mucosa (swims up the nostrils), travels to the brain (and causes neurological infection
look at slid 44 for life cycle

Question 9

Naegleria fowleri symptoms

Answer 9

Causes Primary Amebic Meningoencephalitis (PAM)

• Intense frontal headache, sore throat, fever, altered sense of taste and smell, nuchal rigidity (stiff neck)
• Death: 4-5 days
• Diagnosis: CSF sample, ameba and red blood cells

Question 10

what are Helminths,

Answer 10

parasitic worm

Question 11

what are the types of Helminths with ex

Answer 11

1-Flatworms

• Tapeworms: cestodes
• Flukes: trematodes

2-Roundworms: -nematodes

Question 12

What is the most common helminth infection in the United States?

Answer 12

pinworms (Enterobius vermicularis)

Question 13

Enterobius vermicularis mechanism

Answer 13

Pinworms
we get it through the Ingestion of eggs then it Migrates to large intestine then it Mature into adults (2-6 weeks)
Females lay thousands of eggs in the perianal folds

Question 14

Enterobius vermicularis symptoms, and diagnosis

Answer 14

Symptoms: pruritus, loss of sleep, fatigue

• Scotch tape test
• Treat entire family

Question 15

Dracunculus medinensis mechanism

Answer 15

Nematode (roundworm)
transmission through Ingestion of intermediate host
-Copepod (animals also can be reservoirs): Cyclops
-then Worm larvae released in the stomach
-then it Penetrate through GI walls
-then it Migrate to extremities (arms and legs)

Question 16

Dracunculus medinensis diagnosis

Answer 16

Forms a vesicle on the skin (1yr after exposure)

Ulcerates, female worm is exposed

Question 17

Dracunculus medinensis region

Answer 17

common in Asia & Africa