Test 2 (week 2) Flashcards
What is the best known pathogenic yeast?
Candida albicans. Candida is in the gastrointestinal and vaginal microbiomes (normal flors)
causes lung infections that often spread to the skin and central nervous system.
Cryptococcus neoformans
eukaryotic single-cell organisms (protozoa) or complex multi-cellular organosms (Helminths)
parasites
either single cell organisms (typically yeast) or complex multi-cellular forms (mold)
fungi
typically form thread-like hyphae and usually form conidia (spores)
molds
tapeworms made up of an attachment end (scolex) with many, many segments (proglottids)
cestodes
roundworms
nematodes
leaf-shaped flukes that infect the gastrointestinal tract.
trematodes
How are filoviruses transferred?
Filoviruses are transmitted through direct contact with blood or bodily fluids (saliva, sweat, feces, urine, vomit, breast milk, and semen).
Filoviruses initially infect _____.
macrophages and dendritic cells
How do filoviruses typically enter human populations?
Filoviruses typically enter human populations by handling bushmeat (wild animals hunted for food) and contact with infected bats
where do you typically see yellow fever today?
Today, yellow fever is found primarily in subtropical areas of Africa and South America
What carries yellow fever to humans?
mosquitos
How does the Hantavirus get to humans?
Hantaviruses cause persistent infections of rodents and may cause disease in humans following transmission through aerosolized excreta
What are the two most common species of plasmodium that infect humans?
P. falciparum
P. vivax
describe the Exoerythrocytic stage (1st stage) in plasmodium life cycle
** no symptoms of disease are seen in this stage**
Sporozoites introduced at bite site in mosquito saliva–>
Infects hepatocytes and undergoes asexual replication
(Product of replication are merozoites)
Describe the erythrocytic stage (second stage) in plasmodium life cycle.
Merozoites infect red blood cells (RBCs).
Asexual replication occurs in RBCs.
-Ring-stage (Early Trophozoites)
-Late Trophozoites
-Schizonts
Some merozoites develop into male and female gametocytes within RBCs
this stage is where you see clinical manifestations
What causes the cyclic fever spikes in plasmodium infections?
spikes occur when RBCs are lysed by parasites
The quartan fever cycle is characteristic of ____.
malaria
The tertian fever cycle is characteristic of _____.
P. falciparum
P. vivax
how are plasmodium parasites transmitted to humans?
Transmitted through the bite of a female Anopheles mosquito
What is the treatment plan for plasmodium vivax?
P. vivax – give chloroquine and then primaquine
What is the treatment plan for plasmodium falciparum (poses greatest risk of mortality)?
pretty much anything but chloroquine
describe positive polarity RNA viruses.
- viral RNA genome directly serves as mRNA
- synthesizes viral encoded transcriptase
Describe negative polarity RNA viruses.
- Viral RNA genome CANNOT serve as mRNA
- Viral RNA transcriptase must be included within virion
- The transcriptase copies genomic RNA into complementary positive-sense mRNA that is used to synthesize viral proteins
Where does viral RNA replication occur?
cytoplasm
Where does viral DNA replication occur?
nuclues
Which RNA virus is not replicated in the cytoplasm?
influenza–> happens in nucleus
Which DNA virus is not replicated in the nucleus?
poxvirus–> happens in cytoplasm
What is the MOA of Acyclovir (and other herpes drugs for that matter)?
are analogs of nucleosides that prevent DNA chain elongation
What are the prototype herpes drugs?
Acyclovir
Which is metabolized in the liver: NRTIs or NNRTIs?
NNRTIs; because of this, you can see drug interactions
What are the different classes of drugs used to treat HIV?
NRTIs, NNRTIs, protease inhibitors, and entry inhibitors
What is the mechanism of action of NRTIs?
NRTIs are analogs of nucleosides but lack a 3’ hydroxyl group
–>Attachment of the next nucleotide is impossible
What is the mechanism of action of NNRTIs?
bind to site on viral transcriptase and prevent further RNA to DNA synthesis
What is the mechanism of action of protease inhibitors?
inhibit the HIV proteases needed to assemble the coat structures correctly
What is the mechanism of action of entry inhibitors?
Attachment of many HIV strains requires two receptors on human cells
Drugs bind to this receptor or the proteins that can block attachment and entry of HIV into the cell
What are the prototype NRTIs?
Abacavir, Didanosine, Lamivudine
What are the prototype NNRTIs?
Efavirenz, Nevarapine
What are the prototype protease inhibitors?
Retonavir, Atazanavir
What are the prototype entry inhibitors?
Miravoc, Enfuvirtide
What is the prototype CMV drug?
Ganciclovir
What are the general adverse effects of NRTIs?
Lactic acidosis producing:
Hepatomegaly, steatosis (higher fat storage in cells)
What are the general adverse effects of NNRITs?
multiple drug interactions since it is degraded in the liver
What are the general adverse effects of Protease inhibitors?
-Use in HAART has led to carbohydrate and lipid metabolism disorders
-Cross-inhibits endogenous lipid-regulating proteins
-Leads to altered body fat disposition
“buffalo hump” and gynecomastia
-Hyperglycemia and insulin resistance
What is the MOA of Amantadine and Rimantadine?
Block the M2 proton ion channel of the virus
-Inhibits uncoating of the virus in cells
Thus preventing replication
What are the adverse effects of Amantadine and Rimantadine?
GI, dizziness, slurred speech
What are the primary influenza drugs?
Oseltamivir, Zanamivir
What are the primary Hepatitis drugs?
Interferon-alpha, Ribavirin
What is the MOA for Oseltamivir and Zanamivir
- Inhibit neuraminidase A and B
- Reduce viral spreading
What is the MOA for interferon-alpha?
- Host cytokine that exerts complex antiviral, immunomodulatory and antiproliferative actions
- Enhances phagocytic activity of macrophages
- Augmentation of the proliferation and survival of cytotoxic T cells.
What are the adverse effects of interferon-alpha?
GI irritation flu-like syndrome fatigue severe depression alopecia thyroid dysfunction mental confusion
What is the MOA for Ribavirin?
Prodrug – when active, represents RNA nucleotide; Inhibits GTP formation, mRNA capping, and block RNA-dependent polymerases
IT MUST BE USED WITH ANOTHER ANTIVIRAL DRUG, DOES NOT LIKE BEING ALONE
What are the adverse effects of ribavirin?
hemolytic anemia
