virus Flashcards
unique characteristics of virus
have no energy, float around until contact host, have protein coat called capsid and lipid layer that surrounds it- with genetic material inside. Genetic material DNA or RNA
viral structure from inside out
nucleic acid (RNA or DNA), capsid (protein coat), envelope (not all viruses have)
how to viruses reproduce
they can’t reproduce on their own, must invade a cell and use their sources to make more virus
cytomegalovirus (CMV) definition
very common, infects almost everyone, most are asymptomatic (latent) while healthy
CMV risk factors
AIDS (AIDS defining illness- CMV retinitis), bone marrow recipients, chemo pts, actively infected moms can pass to baby (hearing loss, developmental disabilities), transplant patients
CMV s/sx
latent- asymptomatic or mild flu-like
active: pneumonia, splenomegaly, LAD, extreme fatigue; HIV retinitis, GI sx, encephalitis
CMV dx
CMV PCR test
CMV tx
no cure. immunocompromised may be treated with ganciclovir. High risk pt may be put on anti-viral prophylaxis (valganciclovir)
antiretroviral therapy for AIDS
where do WBC originate and where do they go
originate in bone marrow, migrate to lymphatic system- lymph nodes, spleen, thymus
types of lymphatic cells
T cells and B cells
lymphatic system function
transport & storage- filters out dead cells and invading organisms. Each lymphatic cell has R that recognize invading organism- (Rs match only with specific antigen)
T- cell name and facts
named for thymus- mature there. 2 types- helper cells and killer cells
phagocytic cell fxn
eat bacteria, presents part of it on surface to T-helper cell to join with and activate it
activated T-helper cell function
activate B cells which divide to make plasma cells (antibodies) and memory cells. Also activate KILLER t-cells
epstein-barr virus pathophys
transmitted through oropharyngeal secretions. Infects B-cells in oropharyngeal epithelium, which spread infection through entire reticular endothelial system (liver, spleen, peripheral lymph nodes). Healthy T-cell resposne- control EBV infection and lifelong suppression of EBV
how EBV infection occurs
acute- ineffective T-cell response= mono. Sequela- B-lymphocyte malignancies: hodgkin, non-hodgkin, oral hairy leukoplakia, leiomyoma, burkitt lymphoma
complications of EBV
peritonsillar abscess, mastoiditi, meningitis, guillain-barre, pneumonia, ILD, hepatitis, pancreatitis, myocarditis, splenic rupture, malignancies
EBV s/sx
fatigue, fever, exudates, inflamed throat, swollen lymph nodes in neck, nausea, enlarged spleen/liver, rash (2nd to amoxicillin), sx 2-4wk but can last for months
EBV dx
heterophiles antibody test (mono spot). If -, consider viral capsid antigen (IgM suggest accuse infx, IgG marker for past EBV infxn)
EBV tx
supportive: IV fluids, acetaminophen + NSAIDs, steroids controversial, refrain from physical activity x4wk
What is the most common cause of gastroenteritis in the US?
noroviris
top 3 common settings of norovirus
hospitals/ nursing home, restaurant or banquet, school or daycare (outbreaks on cruises)
norovirus s/sx
cramping, N/V/D, low grade fever, chills, muscle aches, fatigue last 1-3days
norovirus dx
PCR assay (usually just clinical)
norovirus tx
prevention & supportive care
Rotavirus epidemiology
was leading cause of diarrhea in infants/kids prior to vaccine. common in winter
rotavirus s/sx
vomiting, watery diarrhea, anorexia, dehydration last 3-8days
rotavirus dx
PCR assay
rotavirus tx
prevention, supportive care
rabies carriers- rabiesvirus
unvaccinated dogs, racooms, skunks, fox, coyote, groundhog, bat
rabies s/sx
animal: strange behavior
human: tingling or itching at site of bite, anorexia, HA, fever, aerophobia/ hydrophobia (irrational fear of water), convulsions, agitation, usually fatal
rabies dx
consult ID for assay
rabies tx
wound care, prophylaxis (3 doses), rabies immunoglobulin (w/o prophylaxis- 3 doses vaccine + Ig… w/ prophyax- 2 doses vaccine + Ig). amoxicillin/ clavunate. Tetanus booster
west nile virus epidemiology
mosquito born illness- can infect horses, birds, dogs, other mammals
west nile s/sx
symptoms of mild infection last 3-6days- fever, malaise, myalgia, HA, back pain, rash, eye pain, nausea/ anorexia, vomiting. Serious- 1% with meningitis, encephalitis and paralysis
west nile dx
blood test- Ab to virus, LP for meningitis, MRI for encephalitis
west nile tx
most recover without tx. Severe- IV therapy and pain meds. prevention
chikungunya definition
self limiting mosquito born illness caused by mosquito infected with the virus
Chikungunya s/sx
symptoms begin 3-7 days after bitten by infected mosquito. Triad= high fever, rash, all over body/ joint pain (African word for walk bent over)
chikungunya dx
clinical- often check for dengue and malaria infxn also. Blood test
chikungunya tx
supportive care, prevention
zika definition
mosquito born illness, reported in returning travelers
zika s/sx
incubation period unknown (days or weeks), fever, rash, joint pain, red eyes. If pregs- microcephaly and other poor pregnancy outcomes
zika dx
clinical, blood test
zika tx
supportive care, prevention, pregs avoid traveling to endemic areas
