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41 Cards in this Set

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What is the difference in enveloped and naked viruses?
enveloped - viruses that have a membrane around their capsid; these viruses are more sensitive to drying, heat, and disinfectants

naked - those viruses that have no membrane around their capsid
What is the cause of 5th disease/slapped cheek disease?
parvovirus B19 - erythema infectiosum

bright red cheeks bilaterally in a child and then progresses to also cause a reticular rash of the arms

capable of causing aplastic anemia in anyone with bone marrow path
Which HPV types are most common in warts (papillomas)? Carcinomas?
papillomas - 1-4 (plantar and skin), 6 and 11 (genital)

carcinomas - 16, 18, 30s-50s
What virus increases children's risk for intussusception?
adenovirus infections

usually infects URT - causing fever, exudative pharyngitis with sore throat, coryza, and conjunctivitis - can progress to bronchitis or pneumo

in children, promotes excessive peyer's patch enlargement - risk for intussusception
In the smallpox rash, what stage are the lesions in at any one time?
all lesions are at the same stage of evolution at any one time

first infects URT, then lymph nodes, then blood, enters organs, re=enters blood, then spreads to skin

fever, malaise, then rash on face that later spreads to trunk, then extremities

rash - macule to papule to vesicle to pustule
What is the infecting dose for Hep B?
low infectious dose - easily transmitted

vertical transmission during birth and breastfeeding - blood, sex

those infected will be (+) HBsAg
Where does herpes in the mouth usually rest? Genital herpes?
mouth - trigeminal ganglion

genital - lumbar and sacral dorsal root ganglion
How is HSV1/2 diagnosis made?
screen with Tzanck smear - will see multinucleated giant cells

followed by fluorescent antibody staining or ELISA

painful vesicles; fluid filled with virus and decubitus - very infectious
What does herpes encephalitis cause?
causes necrosis of one temporal lobe

fever, headache, vomiting, altered mental status

usually occurs during a current outbreak elsewhere - oral usually

high death rate - treat with acyclovir begun immediately - before testing
What are the 2 stages of VZV?
1) chicken pox - infects UR mucosa - spreads by blood to skin causing vesicular rash (dew drop) on trunk first then spreads - crusts and becomes pruritic

2) shingles - re-activation of latent VZV. Vesicles erupt along the sensory nerve course of a dermatome
What are the 3 causes of exudative pharyngitis?
strep pyogenes - strep pharyngitis - PAIN, fever

adenovirus - adenovirus infection - conjunctivitis, red eyes

EBV - mono - FATIGUE
How is CMV transmitted?
via body fluids - milk, placenta, birth canal, saliva #1, sexually , blood, organ transplant

does NOT produce heterophile Abs

latency site - leukocytes, kidney, cervix

Dx - CMV Ab, Owl eye intranuclear inclusions (multinucleated giant cells with very prominent intranuclear inclusions
When will you see CMV retinitis
common in AIDS pts with a CD4 <50.

pizza pie retina - causes blindness

Tx - ganciclovir
What is caused by HHV-8 infections?
Kaposi's sarcoma

most common cancer in AIDS pts - inactivates RB gene - uncontrlled cell growth

malignancy of vascular endothelium with extravsation of blood - dark purple, float to nodular lesions on skin, in oral cavity, GI tract, on sole and in l ungs

B cells become neoplastic too - primary effusion lymphoma
WHat RNA virus is responsible for the common cold?
Rhinovirus (picornaviridae)

transmitted by respiratory droplets and dired droplets
What are the 4 types of polio?
inapparent asymptomatic infection

abortive poliomyelitis - most common - mild, fever, headache, sore throat, n/v, recovery

non-paralytic poliomyelitis - fever, headache, stiff neck

paralytic poliomyelitis - flaccid paralysis - preceded by painful muscle spasm
What does rotavirus cause?
pediatric gastroenteritis (#1 cause in children)

replicates in small intestine mucosal cells, leading to diarrhea
What can influenze A, B lead to?
atypical pneumo (quickly fatal)

secondary bacterial pneumo (fatal)

Reye's syndrome in children (if given aspirin)

Flu A is endemic with the potential of causing a pandemic (due to surface glycoproteins H and N)

Flu B is epidemic
What are the H and N antigens?
H - hemagglutin - bind to a cell surface receptor to initiate infection. The immune system perceives this as an antigen, thereby producing antibody to it and preventing future diesase

N - neuraminidase - cleave the cells neuraminic acid to allow for release of newly produced virus from the cell. The immune system perceives this as an antigen, thereby producing antibody to it that aids in reducing the severity of the disease
What is the progression of measles?
enters upper resp tract - enters blood - enters RES - enters skin vasculature endothelium - rash (stars on face and goes downward)

koplik spots (red lesions with white center) in mouth - then rash and high fever
What xray sign is seen with croup?
steeple sign - due to swelling of soft tissue around trachea

causes harsh barking cough an stridor
What is the #1 lower respiratory infection of infants?
RSV (respiratory syncytial virus)

also a major cause of OM in children and pneumo in elderly

causes URI in adults
What is SARS?
sever acute respiratory syndrome

caused by the coronavirus

severe atypical pneumo with high fever, nonproductive cough, dyspnea, headache, and hypoxia

xray shows ground glass infiltrates without cavitation
What are the 4 families that include arboviruses?
RNA viruses that are arthropod borne

Togaviridae
Flaviviridae
Bunyaviridae
Reoviridae
What are the two different infections from alphavirus (togaviridae)?
Eastern Equine Encephalitis
V - mosquito
R - birds
H - humans, horses
encephalitis, high fever, 50% fatal - mostly SE US

Western Equine Encephalitis
V - mosquito
R - birds
H - humans, horses
encephalitis, high fever, may be fatal - Western US
What is the difference between Dengue Fever and Dengue Hemorrhagic Fever?
DF:
V - mosquito
R - humans and monkeys
world-wide in warm, humid environments - high fever, rash, bone/joint pain, then symptom free for several days, then high fever with new rash

DHF
same vector, reservoir and range as for DF.
Occurs with re-exposure to DF after having a past history of DF
high fever, shock due to hemorrhage, SEVERE - often fatal
What causes California Enceophalitis?
Bunyavirus

V - mosquito
R - rodents
H - humans

occurs mostly in north central US - usually mild with headache, but may be evere with headache, confusion, fever; rarely causes death
What colorado tick fever?
Coltivirus

V - wood tick
R - small rodents
H - humans

occurs in rocky mountains - high fever, HA, retro-orbital pain, severe myalgia, then remission x several days - fever for several weeks

Reoviridae family
What is Hantavirus Pulmonary Syndrome?
bunyavirus (robovirus - rodent borne)

V/R - deer mice
H - humans
transmitted via respiratory route
occurs thru-out US, but mostly in western US

flu-like symptoms, then acute resp failure - 60% mortality rate, even with hospital support
What is the MOA of rabies virus?
virus in saliva of infected mammal - virus injected into skin - multiples at bite site - travels retrograde up sensory neurons to CNS - multiplies in CNS and cause encephalitis - kills neurons and oligodendrocytes - also travels down nerves to salivary glands and other organs - excreted with saliva production

(+) negri bodies
What causes norovirus gastroenteritis?
norovirus (calicivirus) - fecal oral route
usually occurs at schools, camps, cruise ships

nausea, vomiting, diarrhea x12-24 hours
What is kuru?
trembling disease

spongiform encephalopathy

rigid limbs, pathologic bursts of laughter
terminal state marked by placidity and muteness
death within 3-12 months secondary to decubitus ulcers or pneumo
acquire via cannibalism of human brain
What is seen in Crutzfeld-Jakob Disease?
memory deficits, ataxia, rigidity - 40-60 y/o

terminal state marked by akinesia and muteness - death within 3-12 months of symptom onset - usually by pneumo

acquired via tisue transplants (contaminated with CNS tissue) or human growth hormone (from pituitary) or intracerebral electrodes.
How do retroviruses infect humans?
enveloped RNA viruses whose RNA undergoes "reverse transcription" after infection of the target cell.

the RNA is transcribed to make DNA via an enzyme known as reverse transcriptase.
What are the major HIV genes and gene products?
gp 160 - when cleaved becomes gp 41 and 120

gp 41 binds CCR5 or CXCR4
gp 120 binds CD4 receptors

gag - gene that codes for the capsid protein of HIV - p24

pol - gene that codes for multiple enzyme for HIV, including reverse trancriptase

env - gene that codes for glycoroteins that exist on the envelope of HIV - gp 41 and 120

tat - gene for transactivation of transcription (increases transcription rate)

nef - gene that works to decrease class 1 MHC synthesis on infected cells; induces healthy CD8 cell death
How is HIV acquired?
sexually, IV drug use, breast feeding or birth canal, transplacentally, blood transfer

takes many more viral particles to establish an HIV infection compared to Hep B

acts as a super Ag, working to actually be physically presented to DC4 T cels by antigen presenting cells.
What is the treatment for HIV?
HAART - highly active antiretroviral therapy

2 nucleoside reverse transcriptase inhibitors (NRTI) + EITHER (1 protease inhibitory OR 1 non-nucleoside reverse transcriptase inhibitors (NNRTIs) or 1 integrase inhibitory
Describe the acute stage of HIV
begins 2-4 weeks after infection and resolves in 2 weeks

fever, lymphadenopathy, sore throat, lethargy - rash on trunk and extremities (not soles and palms)

anti-HIV Ab are generally formed within 3-4 weeks after infection

eventually a set-point viral load is established
Describe the middle, latent stage of HIV
lasts for years; asymptomatic

clinically latent - virus is not latent (CD4 continues dropping)

in later months of latent stage, some symptoms start to arise: increasing frequency of fatigue, weight loss, persistent fevers, lymphadenopathy, as well as infections - HSV, Candida
What is the prophylaxis and treatment for Pneumocystis carinii pneumonia (P jirovecie P)
P - start with CD < 200 - trimethoprim-sulfamethaoxazole
OR dapsone
OR dapsone + pyrimethamine + leucovorin
2nd line - pentamidine OR atovaquone

T - sulfamethoxazole-trimethoprim OR dapsone + trimethoprim
alt: primaquine + clindamycin OR atovaquone alone
What is the treatment of CMV retinitis?
ganciclovir (DOC) + Valganciclovir until CD4 > 100