Viruses Flashcards
What is a virus?
acellular infectious agent
obligate intracellular parasites
What two ways can viral capsomers self-assemble?
Helical - spiral or helix
Icosahedral - equilateral
What are the components of a viral genome?
single or double stranded
RNA or DNA
What are the 6 stages of viral replication?
Adsorption - attach to host
Penetration - viral endocytosis
Uncoating - fusion of vesicle; RNA and capsid released
Biosynthesis - protein production, viral replication
Assembly - spikes inserted into membrnae; nucleocapsid formed
Release - enveloped viruses bud off; naked viruses lyse
Four effects of Viral Infections?
Cytopathic - inclusion bodies and giant cell
Malignant Transformation - host cells –> cancer cells
Persistent Infection - chronic or latent
Lytic Infection - acute onset of S&S
Poliomyelitis Virus (MR, MT, Patho)
MR = humans, esp kids
MT = PTP, fecal-oral, contact w/ throat/nasal secretions, contaminated vehicles/fomites
Patho = oral ingestion, alimentary tract, blood, CNS
Poliomyelitis Virus (RF, S&S, Comps)
RF = living w/ infected, lack or no vaccine, poor sanitation/hygiene, immunocompromised
S&S = sore throat, V, fever, headache, fatigue, musc pain/weakness, stiffness
Comps = paralysis of resp muscles
Poliomyelitis Vaccine
inactivated polio vaccine or killed virus (IPV)
Influenza (MR, MT, Patho)
MR = aquatic birds
MT = droplet, droplet nuclei, contact
Patho = aerosol inoculation, resp tract replication, desquamation of resp epithelium, influenza
Influenza (RF, S&S, Comps)
RF = age (young, old), immunocompromised, chronic illness, preg, obesity, facility living
S&S = fever, chills, cough, runny nose, musc ache, headache, fatigue, V/D
Comps = pneumonia, febrile seizure, hospitalization, death
Influenza Vaccine
trivalent or quadrivalent
Measles Virus (MR, MT, Patho)
MR = humans
MT = PTP, airborne, direct contact w/ droplets, nasal/throat secretions, contaminated fomites
Patho = inoculation of resp tract, resp tract replication, viremia, rash
Measles Virus (RF, S&S, Comps)
RF = poor-no vaccine, international travel, vit A deficiency, immunocompromised
S&S = fever, cough, runny nose, conjunctivities, Koplik’s spots (white lesions), maculopapular rash
Comps = encephalitis, brain damage, CNS involvement, hospitalizations, death
MMR Vaccine
attentuated/weakened live virus
Mumps Virus (MR, MT, Patho)
MR = humans
MT = droplet, direct contact w/ infected saliva
Patho = inoculation of resp tract, local replication, viremia, systemic infection
Mumps Virus (S&S, Comps)
S&S = fever, headache, muscle aches, fatigue, parotitis (swollen salivary glands); orchitis (swollen testes), oophoritis (swollen ovaries)
Comps = meningitis, encaphalitis, pancreatitis
Rubella Virus (MR, MT)
MR = humans
MT = PTP via droplet spread, direct contact w/ nasopharyngeal secretions
Rubella Virus (S&S, Comps)
S&S = similar to Measles except low grade fever, absence of Koplik’s spots, less intense rash
Comps = arthralgia, arthritis; congential rubella syndrome (microencephaly, fetal death, cataracts, deafness, developmental delay)
Hep B Virus (MR, MT)
MR = humans, esp chronic carriers
MT = PTP via contact w/ blood and body fluids (IV drug use, needlestick, contaminated blood, sex, congenital transmission)
Hep B Virus (S&S, Comps)
S&S = fever, N/V, fatigue, abd/joint pain, dark urine, jaundice
Comps = cirrhosis, hepatocellular carcinoma
Hep B Vaccine
subunit vaccine (recombinant DNA product) containing surface antigen
HPV (MR, MT)
MR = humans
MT = PTP via direct contact (sex), skin-to-skin, sharing contaminated fomites
HPV (RF, S&S, Comps)
RF = high # of partners, early age, immunocompromised, coinfection
S&S = asymp
Comps = cancers of reprod organs and throat
HPV Vaccine
subunit vaccine (recombinant DNA tech)
Chickenpox Virus (MR, MT)
MR = humans
MT = PTP via resp droplets, direct contact w/ vesicular fluid of blisters
Chickenpox Virus (Patho)
droplets - resp tract - lymphatics - viremia - mucous membrane and skin
Chickenpox Virus (S&S, Comps)
S&S = rash, fever, fatigue, headache, anorexia
Comps = bacterial skin infections, pneumonia, encephalitis, sepsis
Chickenpox Vaccine
live attenuated viruses
Rotavirus Diarrhea (MR, MT)
MR = humans
MT = PTP, contact w/ fomites, contaminated feces, resp droplets
Rotavirus Diarrhea (RF, S&S, Comps)
RF = age < 35mos, immunocompromised, child care settings, seasonal (winter/spring)
S&S = acute gastroenteritis, fever, stomach pain, V/D, anorexia
Comps = hospitalization, dehydration
Rotavirus Diarrhea Vaccine
oral vaccine or attenuated live vaccine
