Transmission of amebas; Sporozoa; Hemosporidians

Question 1

Entamoeba histolytica

Answer 1

Trophozoites in large intestine begin encystment in firming stools
Trophozoite form found in stool of dysentery patients; cyst in semisolid stools; metacyst in formed stools
Metacysts infective to new host

Question 2

Naegleria fowleri

Answer 2

transmitted through water entering nasal passages (especially hot pools, or stagnant water in the summer)

Question 3

Toxoplasma gondii

Answer 3

Transplacental - ̴3500 congenitally infected babies/year – U.S. – early embryonic death, stillbirth, retardation, blindness, etc.

Question 4

Cryptosporidium sp

Answer 4

Fecal-oral contamination
Municipal water supplies
Swimming pools – chlorination doesn’t kill

Question 5

Sarcocystis sp.

Answer 5

FH infected by eating tissue cyst in herbivores (very prevalent) – herbivores infected by ingesting sporocysts from carnivore feces.

Question 6

Plasmodium sp.

Answer 6

Stages in RBCs/hepatocytes of vertebrate  transmitted to mosquito during blood meal  development in mosquito  to vertebrate during feeding

Question 7

Babesia bigemina

Answer 7

tick, Boophilus annulatus – very host specific 1-host tick; transovarian transmission of B. bigemina occurs