From notes Flashcards
HIV is a ____ which is its genus name
lentivirus
Where is HIV2 mostly found?
in africa
how does HIV2 differ from HIV1?
tends to develop more slowly and to be milder; less infectious early
HIV is NOT a ___ genome so instead it just has:
NOT a segmented genome; just has 2 copies of the same RNA
gp120 of HIV binds to what?
a CD4 T lymphocyte
In HIV, where does translation into viral proteins occur?
cytoplasm
What is the most opportunistic infection in HIV patients?
pneumocystis
What is another name for kaposi’s sarcoma which is often a clinical consequence of HIV/AIDS?
malignant neoplasms
What is the first step in diagnosing HIV?
conducting a rapid test
What does a rapid HIV test look for?
looks for Ab that binds to HIV (b/c there are HIV antigens on the filter of the test)
If a rapid HIV test is positive, what must be done?
a western blot confirmatory test
If a rapid HIV test is negative, what must be done?
nothing; pt doesn’t have HIV
What are the two types of specimens you can use for a western blot test?
- venipuncture for whole blood
2. oral fluid specimen
What must be done after an initial western blot test for HIV?
if the patient is negative or there are indeterminate western blot results, must do follow-up testing after 4 weeks
new HIV guidelines from the CDC requires routine HIV screening for who?
all people between 15-64
HIV screening is now based on ___ and NOT based on ___
age; risk
During L&D, a woman with undocumented HIV status should have what done?
rapid testing
If the rapid HIV test conducted on a woman during L&D is positive, what should be done?
initiate ARV prophylaxis on basis of rapid test result
Rapid HIV testing of the newborn is recommended if:
mothers HIV status is unknown at delivery
If a rapid HIV test on a newborn is positive, what should be done?
initiate ARV prophylaxis within 12 hours of birth
What are the 4 targets/treatment strategies for HIV?
- reverse transcriptase
- protease inhibitors
- fusion inhibitors
- integrase inhibitors
What are 2 co-receptors on lymphocytes that can also help HIV bind?
Chemokine Receptors: CCR5 & CXCR4
What happens with HIV’s positive-sense RNA strand?
It is not translated to make the nucleocapsid proteins!!! Instead, Reverse Transcriptase makes a DNA copy of the RNA strand. This DNA copy then enters the nucleus & is integrated into the genome of the host cell via integrase. As long as this host cell lives, it will be infected with viral DNA.
How does replication of HIV affect the rest of the body?
Replication of HIV causes a gradual decrease in CD4+ cells.
Why is a decrease in CD4+ cells bad?
This allows more opportunistic infections to arise; Body can’t fight off microbes that you encounter every day and usually have no problem killing.
What’s the difference between HIV and AIDS?
HIV – is when the virus in the body (Pt makes Ab’s specific to HIV).
AIDS – is when opportunistic infections start occurring; doesn’t necessarily have to be caused by HIV.
How long does it take before AIDS begins to present in HIV patients?
Usually takes at least 7 years before opportunistic infections begin to occur. • Patient usually dies from an opportunistic infection.
How are HIV-1 and HIV-2 similar?
Both have the same mode of transmission and both are associated with similar opportunistic infections and AIDS.
How do HIV-1 and HIV-2 differ?
HIV-2 tends to develop more slowly and is an overall milder disease. It’s also less infectious early. HIV-2 is mostly found in Africa; not much HIV-2 in US.
how is HIV diagnosed?
anti-HIV antibodies (seroconversion) by ELIA or rapid test
Is HIV a tough virus?
No; easily killed by drying, high level detergents, household bleach, alcohol, formaldehyde, and heat (56˚C for 30 minutes)
Dried blood won’t even transmit it
what do HIV fusion inhibitors do?
Blocks entry into the host cell by not allowing gp120 to bind to the CD4+ receptors.
What are the 2 life stages of protozoan parasites?
- trophozoite (soft, fragile, growing in the body)
2. cyst (hard, non replicating, able to survive outside of the body) tends to be the part thats transmitted
What do species of the Plasmodium family cause?
malaria
Plasmodium are parasites of the:
red blood cells
How are Plasmodium species transmitted?
transmitted via Anopheles species
How many types of Anopheles species are there? How many transmit malaria?
430 species of Anopheles; 30-40 transmit malaria.
Plasmodium require what 2 hosts to survive throughout a population?
- mosquito (for sexual reproduction; must have an Anopheles mosquito in order to transmit malaria)
- human (or other animal) for asexual reproduction
Transmission of malaria is usually found in what type of climate?
Tropical and subtropical areas
What makes P. falciparum cause such a severe infection?
P. falciparum infects all RBCs (no preference whether the RBC is young, mid-, or old). Therefore, parasitemia is usually higher.
Where malaria is endemic, what do doctors do for patients with a fever?
The patient is usually given a presumptive diagnosis of malaria without lab confirmation. (So, treatment can start early!)
Why do patients infected with Plasmodium vivax or Plasmodium ovale often experience relapses (several additional attacks) months or years without symptoms?
Relapses are due to dormant liver stage parasites, or hypnozoites, that may reactivate.
***Treatment to reduce the chances of such relapses should follow the treatment of the first attack.
What is the gold standard for diagnosing malaria?
microscopy of blood
What is the drug of choice to treat parasites in the blood?
chloroquine
What is the drug of choice to treat dormant liver forms of parasites & to prevent relapses?
primaquine
Which 2 Plasmodium species don’t have dormant liver stages?
P. falciparium and P. malariae
What causes sickle cell anemia?
sickle cell anemia is a single amino acid mutation in the hemoglobin gene; if a child receives 2 mutated hemoglobin genes, they’ll end up with sickle cell anemia
The number of heterozygous (good copy & bad copy) sickle cell anemia cases are highest where:
where P.falciparum is found
Where is sickle cell anemia highly prevalent/common?
Africa
Toxoplasma gondii is a protozoan that infects and grows inside of:
animals (MOSTLY CATS)
How is toxoplasma gondii transmitted?
fecal-oral ingestion of the oocytes (female gametocyte) that are in the cats feces
Why is Toxoplasma gondii especially dangerous to pregnant woman?
Pregnant woman can ingests the oocytes and have tissue cysts that form in the fetus’s eye, which may lead to blindness.
***Tissue cysts are generally not a problem if they grow anywhere else.
What is Giardia lamblia and what disease does it cause?
Giardia lamblia is a single-cell flagellate protozoan that causes giardiasis or “Hiker’s Diarrhea.”
What symptoms present with giardiasis?
Mild diarrhea & severe malabsorption (difficulty digesting or absorbing nutrients from food)
What asymptomatic (~50%) animal is giardia often found in?
beavers
How do you treat giardia?
metronidazole
How can you diagnose giardia?
both the cysts and trophozoites can be found in stool sample
Trichomoniasis vaginalis differs from giardia mainly in that:
it DOES NOT have a cyst form
What are they symptoms of Trichomoniasis for men? Women?
Men – usually asymptomatic
Women – frothy, yellow-green discharge with a strong odor
How is Trichomoniasis treated?
Metronidizole
Where is the parvovirus found?
in respiratory secretions: saliva, sputum and nasal secretions
Where does the parvovirus grow?
grows in red blood cell precursors
What is another name for parvovirus B19?
fifth disease; erythema infectiosum; slapped face rash
How is the parvovirus diagnosed?
- characteristic rash
- serology
- look for IgM in pregnant women (newly exposed)
- may shift to IgG later (when blood is drawn relative to when virus is in the body
What kind of cells does HPV target?`
HPV infects the epithelial cells of the skin and mucous membranes
Where does HPV replicate?
HPV must replicate near the skin’s surface with all the dead keratin cells. (Development of the epithelium is essential for the development of the viral particles.)
How fast is HPV replication?
viral replication of HPV is slow
What does HPV cause?
warts
HPV virus types are roughly ____ which means genital types have ___
roughly tissue specific
genital types have affinity for genital skin and mucosa
How is HPV on the surface of the skin spread?
spread by skin to skin contact
There are about ___ serotypes of HPV that cause genital infections
40
what are the two serotypes of HPV that are associated with cervical CA?
16 and 18
How is a persistent HPV infection characterized?
by persistently detectable type-specific HPV DNA
What is the most important risk factor for precancerous cervical cellular changes and cervical cancer?
persistent oncogenic HPV infection
HPV is thought to be responsible for about ___% of anal cancers
90%
HPV is thought to be responsible for about ___% of vaginal cancers
65%
HPV is thought to be responsible for about ___% of vulvar cancers
50%
HPV is thought to be responsible for about ___% of penile cancers
35%
Recent studies show that about ___% of oropharyngeal cancers are linked to HPV
60%
Babies born to a mother with genital warts occassionally develop warts in the ____
respiratory tract
How do you treat genital warts?
warts can be removed by patient applied topicals, provider applied topicals, surgery, or freezing (laser); this doesn’t necessarily cure the infection; recurrences are frequent, especially in the first few months
What are the usual symptoms of HPV?
usually has no signs or symptoms
The most common manifestation of HPV infection in men is ____
genital warts
High risk HPV types seldom cause ___
genital warts
Detection of high risk HPV infection in a woman doesn’t mean she’s been cheating b/c:
HPV infection can be present for many years before it is detected; no method can determine when HPV infection was acquired
GARDASIL contains:
capsid protein antigens that were made in yeast.
How does the GARDASIL vaccine work?
it contains capsid protein antigen. The capsid proteins then self-assemble to “look” like the virus but can’t replicate
What are the 4 serotypes contained in the GARDASIL vaccine?
6, 11, 16, 18
HSV1 causes:
fever blisters
HSV2 causes:
genital herpes
Varicella Zoster virus causes:
chickenpox and shingles
Epstein-Barr Virus (EBV) causes:
infectious mononucleosis and some cancers
Cytomegalovirus causes :
mono-like illness
What causes roseola?
HHV 6 & 7
What does the herpes virus bring with it that is important for drug targets?
brings the gene for its own polymerase
What makes the herpes virus so fragile?
its an enveloped virus that can’t survive if it dries out
What type of cells does HSV1&2 infect?
epithelial cells
In patients with HSV1 or 2, epithelial cells are destroyed by:
the replication of the virus
How are the lesions seen in those with HSV1 or 2 described?
vesicular lesions
In those with HSV1 or 2, host defenses resolve ___ but DO NOT resolve ___
resolve the local lesion; does NOT resolve latency
Herpes infection: during primary infection, the virus enters the _____ and migrates along axons to ____ in the CNS
- enters peripheral sensory nerves
- sensory nerve ganglia
When the herpes virus becomes a latent infection in the nerve cells, the viral DNA is considered a ___ and is NOT integrated
episome
