Classifications of Sarcodina (ameba)

Question 1

Classification of medically important protozoa

How it is classified

Answer 1

A. style of movement
B. Mode of reproduction
C. Stages in the life cycle

Question 2

What are the four classifications of the Protozoa

Answer 2

1. Sarcodina (ameba)
2. Mastigophora (Flagellata)
3. Ciliophora (Ciliata)
4. Sporozoa

Question 3

Sarcodina (ameba) Characteristics

Answer 3

Major locomotion - pseudopodia (false feet)
Most are free living ( some have flagella)
Reproduction- binary fission (asexual)
Usually form cyst as inactive form
Forms trophozite as active form

Question 4

Mastigophora ( Flagellata) Characteristics

Answer 4

Motility - flagella 
Reproduction- sexual and asexual
Forms cyst and trophozoite 
Most species are free living 
Some are parasite and human pathogens 

(Trypanosoma and Leishmania - blood pathogen)
Giardia- intestinal [parasite with four flagella
Trichomonas - reproductive tract parasite with six flagella

Question 5

Ciliophora (ciliata) Characteristics

Answer 5

Movement- Celia
Use Celia for attachment and feeding
Reproduction- transverse fission ( asexual)
Most free living
One pathogen ( Balantidium coli (lives in animal intestines)

Question 6

Sporozoa characteristics

Answer 6

Movement - not prominent ( flagella or pseudopodia)
Reproduction- asexual and sexual stages
Most form cysts
Entire groups are parasites

Plasmodium - cause of Malaria

Question 7

Sarcodina Ameba General Characteristics

Answer 7

1. Mobile and parasite to human intestine
2. Reproduce by simple asexual division
3. Most common in lower GI tract
4. Some form non- feeding , non mobile cyst stage which is infective to human
5. Transmission- ingestion of cyst in fecal contaminated food/water

Question 8

Life cycle of Ameba

Answer 8

Cyst —- trophozoites (1 nucleus) —– one trophozoite —- cyst

Once cysts are ingested they form into trophozoite
As trophozoites move along with bowel movement the environment becomes drier and the trophozoites start to under go encystation

Question 9

Entamoeba histolytica

Answer 9

Amebic dysentery in human and other primates

large mobile trophozoite) ( small non mobile cyst containing 4 nuclei

Question 10

E. Histolytica pathogenesis

Answer 10

Trophozoites attach to mucous of cecum and large intestine with pseudopod
Maturation/ reproduction- binary fission
90% patients are asymptomatic ( do not invade superficial layer)

Question 11

Clinical amebiasis

Answer 11

Intestine: target cecum, appendix, colon and rectum
Secretes enzymes that dissolves tissues and leaves small ulceration
Symptoms:
Bloody dysentery

Question 12

Amebic hepatitis

Answer 12

necrotized liver cells and fluid develop at the site of invasion of trophozoites
Symptoms:
Enlarged liver, fever, chills, leukocytosis

Question 13

Pulmonary amebiasis

Answer 13

By direct penetration of the diaphragm get to the lung

Question 14

Protection of E. Histolytica

Answer 14

Antibody IgA secreted in lumen of intestinal tract

Question 15

Negelaria fowler

Answer 15

Free living ameba
Normally found among water fowl in standing still water
In animals causes intestinal damage
Accidental parasites of human that causes meningoencephalitis
Naegleria is small, flask shaped that moves by single pseudopod

Question 16

Primary Acute meningoencephalitis life cycle

Answer 16

Infection begins in nasal passage— Amebic form- nasal mucosa—- multiplication —– migrates to olfactory nerves (dead smell)—– crosses the cribiform plate—- enters brain and meanings—- rapid destruction of brain and spinal tissue— hemorrhage and coma—– dead in a week