How do protozoans move?
Cillia
Pseudopods
Flagella
Leishmania mexicana
Leishmania tropica
Leishmania major
Transmitted by Phlebotomus sandflies.
Most benign form
Found in south america, middle east, and africa
Anywhere sand flies are
Sand flies inject protozoan into bite wound
Forms cutaneous lesion with protozoans on edges
Leishmania braziliensis
Mucocutaneous leishmania
More serious than cutaneous
Life cycle a little different
Many mammals harbor organism
Organism forms lesion in skin
Lesion disappears
Organism travels throughout body in macrophages (containing amastygotes)
Settles in urinary tract and oral region
Entire soft pallet of oral cavity can erode away completely
Needs medical intervention
Leishmania donovani
More restricted distribution
Different life cycle
Macrophages travel throughout body
Can invade phagocytic cells throughout the body
Infects spleen liver and bone marrow
80% fatal untreated
Domesticated animals are reservoir hosts
Trypanosoma cruzi (American Trypanosomiasis)
Chagas disease
Reduviid (“kissing bug”) defecates trypomastigotes → enter bite → amastigotes in tissues → back to vector.
African Trypanosomiasis
african sleeping sickness
Only in africa
Transmitted by tsetse fly
Tsetse fly bites and injects protozoan
Enter lymphatic system to develop
Enter blood supply and reproduces
Depletes glucose supply
Organism goes to CNS
Swelling of lymph nodes on the back of the neck
Trypanosoma brucei gambiense (west Africa)
African sleeping sickness
Few animals that can harbor this animal (pigs)
Trypanosoma brucei rhodesiense (east africa)
Most animals serve as reservoir hosts
What is an apical complex?
A suite of organelles used for penetration of host cells
Entamoeba histolytica
Amoebiasis
Trophozoite and cyst stage
T phase has red blood cells
Cyst stage has a chromatoidal bar
Humans only reservoir host
Obtained from ingesting cyst contaminated water (feces)
4 nuclei replicate in cyst and out bursts 8 T phase
Invades tissues immediately
Eat tissue in large intestine
Can last months in sewage but 2-3 weeks on the ground
Giardia lamblia
More than one nucleus
Trophozoite and cyst stage
Cyst infectious to another animals
Prefer anaerobic environment
Life cycle
One parasite spreads to another host through ingestion of cyst in freshwater
Divides by binary fission
Live on surface of villi
Encyst on small intestine and leave through feces
Malabsorption syndrome
Results in diarrhea
Parasite excludes the absorption of fats
Toxoplasma gondii
Entirely parasitic
Sister order to malaria
Apical complex (suite of organelles involved in penetration of host cells
Worlds most successful parasite
Found globally
Infects every single mammal and bird species on the planet
Inflicts radical behavior changes in intermediate host
Toxo produces eggs (oocysts) in cat poop
Changes behavior of mice to get eaten by cat
Humans infected by eating undercooked beef (bradyzoites) and from eating cat poop
Flu like symptoms and swelling of lymph glands
Very dangerous to pregnant people (who have NOT had toxo until pregnancy) and immunocompromised people
Toxo impairs recall and global functioning
May make people have slower reaction times and more likely to consume alcohol
Toxo makes us take more risks
Toxo leads to death in sea otters from pathology and changing behavior
Also leads them to be eaten by sharks
The plasmodiums lifecycle
Gamogony (sexual)- production of gametes
Sporogony (asexual)- production of sporozoites
Lifecycle in mosquito (infectious to people)
Schizogony (asexual) - production of merozoites (causes symptoms in human host)
Use apical complex to pierce and enter red blood cell
Mosquito bites human, transmits sporozoites
Sporozoites find way to liver
Once in liver undergo schizogony (exo-erythrocytic - not in red blood cells) (exo-erythrocytic initial stage of infection in liver)
Mature liver schizons burst to create merozoites
These find red blood cells to infect
Can go through one of 2 pathways from here:
1 erythrocytic cycle: merozoites invade red blood cells and can undergo schizogony in red blood cells over and over again
Infect red blood cell, turn into trophozoites, replicate into merozoites, then bursting blood cell releasing merozoites to infect new red blood cells
2: can infect red blood cell then undergo gamogony
This stage infectious to mosquito when taking a blood meal
If mosquito gets both male and female version, they come out in their gut and merge to form a zygote
Zygote transforms into ookinete
Ookinete is mobile and goes through wall of gut into body cavity to form oocyst
Sporozoites develop then burst from oocyst, then go to salivary glands to be injected into next host
Plasmodium vivax
can lay dormant in a host by forming a hypnozoite in liver
Plasmodium falciparum
Most severe malaria
Plasmodium malariae
72 hour fever cycle
