Protozoa Flashcards
What are the four classes of protozoan parasites?
Amoebas. Ciliates. Flagellates. Apicomplexans.
What is some evolutionary evidence of endosymbiosis?
Mitochondria and chloroplasts contain their own ribosomes, sensitive to antibiotics sequencing data demonstrates gene transfer
What are protozoa?
- Phylogenetically diverse
- Single celled
- Motile
- Lack chlorophyll
- Grouped on phenotype
- Eukaryotic parasites mostly
What are the main features of Amoebas?
- Move by amoeboid movement
- Usually no structural cell wall
- Shell wall compromised of CaCO3
What is amoeboid movement?
Use pseudopodia formed by cytoplasmic extensions of the cell
What diseases do Amoebas cause in humans?
- Entamoeba histoytica - causes amoebic dysentry
- Infects 50million
- Correlates to poor sanitation
- Person often produces no symptoms
- More susceptible when stressed
- Severe = trophozoites enter intestine tissue, intestine gets inflamed
What are the features of Ciliates?
- Paramecium
- Cilia to aid propulsion and attracts food (deep grove for food)
- Contain endosymbionts (bacteria)
Where are Ciliates found?
Marine and freshwater
What diseases do Ciliates cause in humans?
Not human infectious
What are the main features of Flagellates?
- Move using single flagellum or multiple flagella
What diseases do Flagellates cause?
- Parasitic infection in humans
- Dysentry
- Typanosoma, Brucei (african sleeping sickness)
- Leishmania
- Giardia
- Trichomanas
What are the 2 sources of genetic material of Kinetoplastid parasites?
Nucleus and Mitochondria
What are the ‘TriTyps’?
Trypanosoma Brucei. Trypanosoma Cruzi. Leishmania.
What are the key features of Trypanosoma Brucei?
- Extracellular
- Live in the bloodstream
- Alters rhythm
- Infects CNS, brain and tissue
- Wasting phenotypes
- Causes African sleeping sickness
What are the issues caused by African sleeping sickness?
- Lethal
- Threatens livestock
- 36 countries
- No vaccines
- Causes a coma
- Rapid multiplication
- Neurological changes
What are the key features of Trypanosoma Cruzi?
- Intracellular and extracellular forms
- Swollen eye
- Deficate next to the bite so when you scratch the bite you infect yourself
- Kills through engorgement of the heart
- No vaccines
- 30% develop heart disease
- America
- Wild
What are the key features of Leishmania?
- Primary reservoir are dogs (1/10 in Brazilian dogs have it)
- Worldwide 98 countries
- Vector = sandfly
- Resistance is rising
- People with HIV and leishmania have their immune systems destroyed
How do T. brucei avoid the immune system?
They can change their surface proteins so hard to recognize as foreign and destroy
What treatments are there for T. brucei?
- Arsenic based, chemotherapy
- Arsenic derivatives, very toxic and do not pass the blood/brain barrier
- Eflornithin, blocks enzyme required for parasite proliferation
- Managed to make into pills
What are the features of Apicomplexans?
- Intracellular
- Relatively non-motile except gamete stage
- All obligate parasites = serious disease
- Apical organelles enable parasites to invade host cells
What diseases do Apicomplexans cause?
Toxoplasma gondii and malaria
What are the key features of Toxoplosma gondii?
- Global disease
- multiple vertebrate hosts
- reproduces in intestine
What are the key features of malaria?
- Deadly
- Within erythrocytes
- Spread by female Anopheles mosquito
- Chracterised by cycles of fever and chills
- Bursting of RBC, each RBC releases 20 new merozites plus toxic compounds
Why is P. falciparum so pathogenic?
- Knobs and cytoadherence
- Infect RBC develop surface knob contains parasite proteins
- Causes RBC to stick to blood vessels and block capillaries
- Results in liver and brain damage, ‘cerebral malaria’
