Unit 3 Eukaryal Microbe Pathogenesis Flashcards
Why are treatments against eukaryotic pathogens limited?
So what is preferred?
Our cells are eukaryotic
Avoid infection in the first place
Regardless of pathogen type, the microbe must gain access to a susceptible host, evade or overcome host defenses, get nutrients, and exit the body
!
Malaria is caused by a…
It is called (the microbe)
Protozoan (eukaryotic)
P. Falciparum
This microbe needs to infect two or more species to complete its life cycle
P. Falciparum
Female mosquitoes for malaria serve as the ____ host, where sexual replication occurs in the salivary glands and is released as it starts to take blood meal
Definitive Host
Humans in malaria serve as _____ hosts, asexual replication and differentiation occur here
Intermediate Hosts
Can mosquitoes get infected by a malaria infected human?
Yes, part of its life cycle
This protozoan is simpler, the life cycle is in a single species. Cysts in contaminated water are ingested. Cramps and violent diarrhea are symptoms.
G. Lamblia (Giardia)
Cysts from giardia develop within human into
These replicate in the small intestine and produce new cysts in the ____
New cysts are eliminated in the host’s
Trophozoites
Large Intestine
Feces
Animals tend to be more tolerant of the g. lamblia pathogen. It’s more persistent in humans.
Rarer in more developed areas of the world (no water sanitation)
!
What is the other name for giardia?
Beever Fever
their fecal material is in the water supply because they damn it, has cysts
Some eukaryal microbes only cause disease if the immune responses are
What are some examples?
impaired (immunocompromised)
HIV/AIDS, or immunosuppression from drug therapies or another disease state
Is AIDS only caused by HIV?
No, it is an immunodeficiency syndrome that can be caused by radiation, chemicals, chemotherapy, or autoimmune disorders coupled with meds
This disease is caused a yeast fungus, yeast is usually part of our normal flora. It is an opportunistic infection associated with AIDS that leaves a white coating around the lips
What is the name of the microbe?
Thrush
Candida Albicans
If a baby is infected with cadida albicans (thrush), it should go away eventually with treatment. In adults, it probably means they are
Immunocompromised
This is a type of fungi that causes pneumonia, but rarely in healthy individuals. It can even be a part of their normal flora. Only occurs in immunocompromised individuals (HIV infected)
Pneumocystis jirovecii
This is a protozoan that can lead to taxoplasmosis, causes encephalitis in immunosuppressed individuals which is much more severe. Associated with a cat’s fecal material. Dangerous if you’re pregnant, can cross placenta and infect the baby.
Taxoplasma gondii
This is a protozoan associated with gastroenteritis, again a bigger problem if you’re immunosuppressed, leads to chronic violent diarrhea
Cryptosporidium muris
This is a method eukaryal pathogens use of periodically changing/switching surface proteins on the immune system which confuses and delays immune responses. Difficult to make a vaccine
What protozoans exhibit this evasion strategy?
Antigenic Variation
Trypanosomes
These two trypanosomes are associated with chronic and acute sleeping sickness
Spread by the ___ fly
Trypanosoma brucei gambiense (Chronic)
Trypanosoma brucei rhodesiense
Tsetse Fly
This trypanosoma is spread by the kissing bug, that causes chagas disease which damages the heart and vital organs, can lead to death.
Tyrpanosoma cruzi
This trypanosoma is caused by a sandfly and causes dermal leishmaniasis, affects the skin
Leishmania major
Malaria, caused by ____, ultimately causes the death of red blood cells aka ____ in humans as infecting them is part of its life cycle. Inflammation (fever,aches, pains) can become a large problem as well as anemia, clogged capillaries, among other things which cause tissue damage
P. Falciparum
Erythrocytes
Malaria is a global problem, 300-500 million people are infected per year and 1 million die from malaria each year
In the US, when was malaria a big problem?
How did they get rid of it?
!!
The Civil War
Chemicals and dumping oil in mosquito reservoirs (things we can’t do now)
In the replication of plasmodium falciparum, within humans, ______ are released (burst out) from infected erythrocytes and ingested by feeding mosquitoes
Gametocytes
Within mosquitoes, gametocytes differentiate in gametes, fuse and form a diploid ookinete which forms an oocyst and undergoes meiosis, producing haploid
Sporozoites (this is the important part to remember)
These can be transmitted to humans when an infected mosquito bites
Sporozoites
What do sporozoites initially infect?
They replicate to release _______, which ultimately infect erythrocytes and are later released as _____
Liver Cells
Merozoites
gametocytes
So in sum, what are released into human bloodstream via the mosquito salivary glands?
Sporozoites
The effects (symptoms) of P. Falciparum on humans is mostly a result of destruction of ____
Erythrocytes (red blood Cells)
The destruction of red blood cells caused by P. falciparum leads to
Anemia
How does the p. falciparum parasite (merozoites) attach to the red blood cells?
Merozoite surface proteins (MSPs)
Suggests a method for treatment
Mutant or deficient forms of MSPs limit the invasive potential of P. falciparum strains
!
Once inside an erythrocyte, merozoites obtain hemoglobin from the host cell through their
Digestion of hemoglobin releases
Cytostomes (protozoan version of a mouth)
Heme (iron part)
The merozoitic parasite converts heme into nontoxic
Hemozoin
What’s the best route to prevent infection with P. falciparum
Getting rid of the mosquitoes
For example, insecticide treated mosquito blocking sleeping nets to prevent the transmission of P. Falciparum
This antimalarial drug blocks the formation of hemozoin, leaving a toxic com,pound in the parasites
Is resistance becoming a problem?
Better understanding of ___ may yield better treatments
Better diagnostic tools may provide earlier treatment with better outcomes
Chloroquine
Yes.
MSPs
What is the other treatment for malaria that isn’t chlorquine
Vaccines.
These are macroscopic parasites that are not miscroscopic, but their eggs or larvae are. They share many attributes of their microscopic eukaryal pathogenic counterparts
Helminths (worms)
Do helmints need to enter, attach, and obtain nutrients?
They tend to cause disease as the obtain _____
Yes
Food (from the individual)
This is the most common worm, can cause intestinal blockage. Places with little access to medical care it is especially harmful
Roundworm
This helminth leads to organ damage in the digestive tract
Schistosomes
This worm causes elephantiasis by blocking the lymph vessels, where tissue fluids accumulate
Lymphatic Filariae
This is the infection caused by the roundworm that infects over 1.5 billion people
What route is it spread through?
Ascariasis
Fecal Oral Route
Where do the pathogens of ascariasis (roundworm) typically mature, which affects the host’s (human’s) ability to absorb nutrients
The small intestine
Ascariasis typically manifests as…..
slower growth and decreased weight gain in children! Big problem in countries where there is limited food, especially bad in children because of their increased base metabolic rate
Can also lead to life threatening situation by blocking the intestine
What would lead to less infection of the roundworm?
Sanitation/sewage treatment
People that get infected with roundworms, etc have less autoimmune disorders of the gut like Crohn’s disease.
!
Can treat autoimmune disease by adding eggs of worms that don’t ultimately cause infection
This is an infection in over 200 million people worldwide caused by the larvae of the flatworm. Long term infections can damage organs via inflammation, resulting in malnutrition and devopmental problems. Transmission can occur via contaminated water
Schistosomiasis
Is the life cycle of schistosoma sp more or less complex than ascaris?
Why?
More complex
Freshwater snails are an intermediate host
Can eukaryal pathogens affect evolution?
Yes
What is the example of humans and evolution in response to eukaryal pathogens?
What type of evolution is it?
P. Falciparum (malaria)
Co-evolution
THis disease results from hemoglobin mutation. Under certain conditions, red blood cells take on an abnormal shape leading to their destruction
Sickle Cell Disease
Why is the sickle cell trait widely carried in genomes of individuals of African and Mediterranean descent?
Malaria can’t infect people with sickle cell of heterozygous individuals because they are protected from it
If you have both normal genes for Hb, are you more or less susceptible to malaria?
If you have both genes for sickled Hb, what occurs?
If you have heterozygous genes, what occurs?
More.
Sickle Cell disease (less flexible red blood cells that clog the capillaries)
You are immune to sickle cell but carry the gene for sickle cell disease
