GI Parasites 1/2

Question 1

What is a parasite?

Answer 1

A parasite is an organism that is biologically and metabolically dependent on another organism.

Question 2

What is an ectoparasite?

Answer 2

The life cycle of the parasite is dependent on the cutaneous surface of another organism

Question 3

What is a paratenic host?

Answer 3

The parasite lives in the organism; is still infectious; BUT THERE IS NO MATURATION OR DEVELOPMENT

Question 4

What are the 3 types of lice? How do they differ? Where are the eggs located?

Answer 4

Lice - is an obligate blood sucking parasite.

1. Pediculus Humanis: Body Hair - eggs usually found in clothing.
2. Pediculus Capitis: Head lice - most common type of lice- nits are found in the hair. Hair follicle = round
3. Pthrium Pubis: Crabs: Pubic lice - nits are found in the hair. Hair follicle = oval.

There is no crossing over from one niche to another.

Question 5

What are mites? Their life cycle? Symptoms? Treatment?

Answer 5

1. Mites are a parasite that like to infect crevices - including elbows, inter webs; FLEXOR SURFACES.
2. Mites tunnel into the epidermis.
3. Their life cycle is on a single host.
4. Symptoms: itch, dermatitis
5. Treatment: Ivermectin

Question 6

What are ticks? Symptoms?

Answer 6

1. Ticks are a parasite. Usually wait and jump onto a target as they pass by. They like to wait perched at the top of a grass blade and such.
2. They cause rapid paralysis.
3. The male is not toxic, it is the female people should be worried about.

Question 7

What are protozoa? What is their general life cycle?

Answer 7

1. Protozoa are single celled eukaryotic cells; not true parasites.
2. They are either in their feeding state: TROPHOZOITES or their ‘hibernating/storage’ form = CYSTS. Cysts usually contain 1-2 trophozoites.

Question 8

What is Ent/Amoeba Histolytica? Pathogenesis/Transmission? Symptoms? Prolonged effect? Diagnosis Methods? Treatments?

Answer 8

1. AH is a parasite infection. It is the most common protozoan infection.
2. It invades the colon and is transmitted via the fecal route.
3. Symptoms/Prolonged Effect: Diarrhea, lesions in the brain and liver.
4. Diagnosis: Fecal Cysts
   Treatment: Metronizadole, Paramycin, abscess drainage.

Question 9

What is Giardia Intestinalis? Structural characteristics? Transmission? Symptoms? Treatment?

Answer 9

1. Giardia is a protozoan infection.
2. It’s trophozoite form has 8 flagella, and it has suction disks that allow adherence to the colon.
3. Transmitted: Fecal Route (cysts), Zoonotic - possums>H2O>humans drink the cysts.
4. Symptoms: small volume/acute/chronic diarrhea, malabsorption, bloating, flatulence, dysentery
5. Treatment: -dazole

Question 10

What is toxicoplasmosis gondii? What is the definitive host? Is there a population of ppl that are most at risk for damage? Symptoms? Treatment?

Answer 10

1. OBLIGATE INTRACELLULAR PARASITE.
2. Infects all animals, and some birds. Acquired through uncooked meats.
3. Cats are the definitive host.
4. INFECTION ARE PERSISTENT FOR LIFE.
5. Pregnant women if infected with TPG - 1st trimester - miscarriage or 2nd/3rd trimester: mental retardation/blindness
6. Usually asymptomatic - can lodge into tissue.
7. No treatment.