L18 - Protozoan Biology Flashcards
What are some challenges encountered by protozoal parasites
- infecting host cells may involve migration and parasite motility
- undergo transmission
- gaining nutrients x adapt to diff environments
- avoid being killed
- maintaining balance between proliferation and forming long term infection and transmission
What are some examples of apicomplexan parasites and what are their characteristics
Malaria, toxoplasmosis, cryptosporidiosis
- related parasites
X diff modes of transmission and diefinitive hosts - diff infection characteristics (acute vs chronic infection)
- diff degree and types of pathology
Malaria
- causative agent
- definitive hosts (male vs female)
- where?
- plasmodium spp
- anopheles mosquitoes are the definitive hosts
- Africa
What is the lifecycle of plasmodium falciparum
• Involves two hosts: human and mosquito.
• Mosquito injects protozoan parasite (Plasmodium) into the human during a blood meal.
• Parasite infects red blood cells (RBCs), causing ongoing infection.
• When another mosquito feeds on the infected human, it ingests parasite forms.
• Inside the mosquito, male and female forms join, developing into infectious forms.
• The mosquito can now transmit malaria to another human.
Is malaria acute or chronic? What are its symptoms?
And nasty flew like illness that can rapidly develop into a life-threatening condition. It is an acute disease with symptoms such as severe anaemia, coma, hypoglycaemia, acidosis or failure, respiratory distress, pregnancy, complications and still birth severity usually decreases after multiple infections.
When does the malaria disease occur during the parasite’s asexual blood stage cycle
During asexual cycle, the parasite, numbers, amplify rapidly, and the infected, ere sites, cited here and sequestral within tissues, including the brain
match the plasmodium stage to the statement
sporozoite
gametocyte
ookinete
Sporozyte is injected into the human host, when the mosquito feeds,gametocyte refers to sexual stages that form in the human. Ookinete is formed from macrogametocyte and microgametocyte
What is toxoplasmosis
A disease that and healthy hosts causes mild flu like. Symptoms. Chronic infection is asymptomatic infection during pregnancy can lead to fetal encephalitis and immuno compromised people can cause severe disease and neuropathology including headache, confusion. Poor coordination, seizures. Lung problems caused by opportunistic. Infection blurred vision caused by severe inflammation of the retina.
Toxoplasma
- intermediate hosts?
- definitive hosts?
- what happens during chronic infection
- how does transmission to cats occur
- how does transmission occur
Intermediate hosts can be virtually any mammalian species, definitive host or cats sexual cycle takes place in the cat got epithelium during chronic infection, parasite forms, assist and tissues, including muscle and brain transmission to cats occur via prediction. Transmission occurs via congestion of contaminated, faeces, or meat containing parasite cysts
What are some examples of kinetoplastid parasites and what are its characteristics
Sleeping sickness,chagas diseases, leishmaniasis
Related parasites, vectorborne diseases
- definitive hosts are insects
- diff niches in host
-diff mechanisms of establishing chronic infections
Key characteristics of African trypanosomiasis (sleeping sickness)
Transmitted by the tsetse fly(definitive host)
Causative, agent of sleeping sickness in humans, and Nagana In domestic livestock
Two forms of human African Tripos, so my asses (Bruce I gambiense and Bruce I rhodesiense)
Describe the lifecycle stages of African trypanosomiasis
Tsetse fly is the definitive host there is the fly stage and the human stage it moves into the god then to salivary gland. There’s two types of mini stages, the replicating stage, and the adapting to infection stage.
Where does human African trypanosomiasis proliferate? Where does it move to
Proliferate. Extra cellularly in the host bloodstream..
During the early stage infection, there is inflammation anaemia and organ dysfunction. It moves to the nervous system at a later stage of infection where it causes neurological damage and dysfunction leading to coma, systemic organ failure and death.
Once in their host, how do paradise survive long enough to be transmitted? Where does they live?
They must not kill the host too quickly, and they must evade the host immune response
They do this by hiding in host cells , live free in the, or they live in protected sites, e.g. gut or brain
Plasmodium challenges to transmission during cellular life what are the advantages and disadvantages?
Advantages
- gain nutrients from their host cell
-Shielded from the host immune system
-Hostels are readily available and are accessible to the mosquito vector, which makes transmission very efficient
Disadvantages
- Parasite must convert terminally different differentiated erythrocytes into cells with nutrient uptake systems
- Remodelling of the red cell membrane by the parasite results in increased red cell rigidity
How does apicomplexan parasites use gliding motility to invade host cells
- use by motile stages of the life cycle to migrate to their host cell , and actively propel themselves into the wholesale
-substrate dependent. Some motility does not involve or silly or Shapeshifting. It goes like a caulk screw in 3-D movement of action and filament, punches, parasite forward and edition backwards.
Cell cellular parasites can escape immune detection by hiding in host cells. During invasion, they must:
Evade, hostile, killing mechanisms and prevent host cell apoptosis
Why is RBC a good niche for plasmodium
- abundant and accessible(taken up by mosquito vectors)
-contain many nutrients
-no MHC antigens for antigen presentation
Describe the antigenic variation and sequestration in plasmodium falciparum
PfEMP1 (plasmodium, falciparum erythrocyte membrane protein one) I composed of building blocks of DBK and CIDR binding domains with variable sequence. High recombination
What us PfEMP1
Protein that is present on RBC of infected RBC
Describe the trade-off strategy between survival and reproduction of malaria parasites
Either invest in survival, asexually or transmission through commuter sites, so we maximise transmission opportunities whilst maintaining infection
What causes anaemia in malarial host infection
Parasite, invades red blood cells, and they burst as parasites, submerge and new cells are infected
What are the challenges advantages and disadvantages encountered during extra cellular life of human afrucan tryoanosomes?
Advantages
- Glucose and nutrient rich environment
-Readily accessible to insect vector
Disadvantaged
- Fully exposed to the host immune system
-Proliferative stages cannot survive in the tsetse Fly gut
What is VSG coat
It is a variant surface glycoprotein that covers the parasite to shield it by hiding in variant protein. it has an intervenous and a sea terminus. The terminus has high variable sequence, which has the antigenic diversity, whereas the sea terminus is a conserved region that involves surface packing and anchoring
