Viruses minus Basic Flashcards
herpes simplex virus 1
features / diseases
herpes labialis - waist up
eicosahedrical core
cold sores, corneal ulcers, encephalitis, neonatal herpes
herpes simplex virus 1
pathogenesis
lytic in epithelial cells vesicular rash (lips and nose) lysogenic in trigeminal ganglia herpatic neuritis herpes whitlow
herpes simplex virus 1
epidemiology
80% americans, 40% recurrent
60% asymptomatic
herpes simplex virus 1
prevention
avoid contact with lesions
herpes simplex virus 2
features / diseases
herpes genitalis - waist down
eicosahedrical core
neonatal herpes
herpes simplex virus 2
pathogenesis
lytic in epithelial vesicular rash (genitals) lysogenic in sacral ganglia herpatic neuritis herpes whitlow
herpes simplex virus 2
prevention
avoid contact with lesions
varicella - zoster
features / diseases
chicken pox
shingles
viremia
systemic infection
varicella - zoster
pathogenesis
same as herpes
repetitive shingles in elderly, can lead to neuritis
varicella - zoster
prevention / treatment
avoid contact with lesions
no drugs necessary if immunocompetentantivirals
epstein barr virus
features / diseases
infectious mononucleosis
lymphomas and cancer
epstein barr virus
pathogenesis
60-70% asymptomatic
sometimes symptoms for up to 1 year
increased number of lymphocytes is a sign
tonsils/spleen become enlarged, can cause strep
infects WBCs
cytomegalovirus
features / diseases
most common cause of congenital abnormalities
fever, lethargy in healthy
pneumonia, hepatitis, retinitis in immunocomp
cytomegalovirus
pathogenesis
lytic in epithelial cells
lysogenic in neurons and WBCs
histology- owl eye inclusion
cytomegalovirus
prevention
pregnant women without CMV stay away from kids
exposure before pregnancy does not transfer to baby
isolation of shedding individuals
herpes virus 8
diseases
Kaposi’s sarcoma
herpes virus 8
pathogenesis
lysogeny in neurons and WBCs
sometimes asymptomatic
herpes virus 8
transmission
increased risk if immunocomp (HIV)
5-20% incidence
herpes virus 8
prevention
avoid direct contact
papillomavirus (HPV)
features / diseases
100 types of virus (30 genital, 70 skin)
papillomas: benign skin tumor, genital warts
cervical/ penis cancers
papillomavirus (HPV)
pathogenesis
slow replication
hard to grow in lab
inhibits checkpoint proteins in cell cycle
HPV 16/18 inactivate tumor suppressor genes (p53, Rb), increase risk of mutations
increase in number and size of lesions increases risk of cancer
80% of cases are single small lesions
influenza
features / diseases
genome in 8 segments
hemagglutinin (16) and neuraminidase (9) in envelope
respiratory infection only
(A- most common, humans, can cause pandemic
B- limited epidemics in humans
C- mostly in animals)
seasonal flu
pandemic flu (every 20 years, killed 4% world pop in 1918)
influenza
pathogenesis
replicates in nucleus
lytic in lungs
antigenic shift: avian flu + regular flu -> new deadly virus
host immune response worse than infection
mumps
features / diseases
paramyxovirus
mumps- parotid gland swelling
mumps
pathogenesis
upper respiratory tract first
viremia
to parotid, testes/ ovaries, pancreas
measles
features / disesases
single stranded RNA (negative)
paramyxovirus
measles
pathogenesis
lytic in immune cells
viremia to skin
starts in upper respiratory tract
rash caused by cytotoxic T clls
measles
epidemiology
30 million cases/year worldwide
causes epidemics
rubella
features / diseases
single stranded RNA (positive)
togavirus
rubella and congenital rubella syndrome
rubella
pathogenesis
lytic in nasopharynx and lymph nodes
spreads via blood to organs and skin
human immunodeficiency virus
features / diseases
lentivirus (retrovirus) single stranded RNA has GP120 and GP41 glycoproteins to regulate inflammation = GP120 attacks CD4 cells = CP31 attacks CCR5, CXCR4 diploid virus HIV-1, HIV-2
human immunodeficiency virus
pathogenesis
infects WBCs, destroys helper T cells lysogeny- hides in host chromosome steps: 1. virus fuses, enters cell 2. reverse transcriptase converts RNA to DNA 3. DNA becomes double stranded 4. DNA carried into nucleus by integrase (lysogeny) 5. copies make viral RNA and mRNA 6. protease breaks DNA to make proteins 7. viral assembly and budding healthy: 120-1500 CD4 cells/ul AIDS: 200-500 CD4 cells/ul acute retroviral syndrome: 3 months asymptomatic: 7-10 years, decrease 50 CD4 cells/ year AIDS: several years until death
human immunodeficiency virus
transmission
unprotected sex (receptive and anal are riskier)
other STDs increases risk
sharing needles
human immunodeficiency virus
prevention / treatment
condoms
reverse transcriptase or protease inhibitors in cocktail of drugs
rotavirus
diseases
most common cause of gastroenteritis in children
rotavirus
pathogenesis
lytic in intestinal tissue
causes lesions in intestines
diarrhea
norovirus
diseases
“stomach flu”
most common viral gastroenteritis in adults
norovirus
pathogenesis
lytic in intestinal tissue
causes lesions in intestines
diarrhea
norovirus
transmission
fecal oral (water) cruise ships
rhinovirus
features / disesases
100+ types in upper respiratory tract mild resistance to detergents/ bases susceptible to acid common cold
rhinovirus
pathogenesis
lytic in lungs
rhinovirus
transmission
hands
can survive in environment for a few days
via fomites
americans have 3 infections / year
rhinovirus
prevention / treatment
wash hands
no vaccine because too many types
hepatitis (all types)
symptoms
inflammation of liver jaundice hemoglobin -> bilirubin, biliverdin recycling liver inflam -> deposit intermediates in liver -> jaundice fever lack of appetite nausea dark urine pale feces infection resolves in 2-4 weeks
hepatitis A
features
enterovirus
denatured capsid proteins by boiling
survives weeks in environment and stomach
hepatitis A
pathogenesis
infects enterocytes, also mouth and throat
spreads through blood to liver
lytic in liver
cleared by infected cells, can cause further damage
no chronic infection
hepatitis A
transmission
direct or indirect contact
50% US pop exposed, 90% developing countries
low mortality
hepatitis A
prevention / treatment
formaldehyde killed vaccine
travelers, children, anal-oral sex
hepatitis B
features
double stranded DNA
in liver cells
hepatitis B
pathogenesis
RNA -> DNA with reverse transcriptase DNA -> viral proteins sometimes lysogeny with integration DNA -> viral DNA polymerase -> DNA lytic in liver cells
hepatitis B
transmission
direct transmission only
asians more susceptible
90% infected neonate -> chronic carriers
cirrhosis: liver tissue replaced by scar tissue; or liver failure or cancer
hepatitis B
prevention / treatment
virus subunits vaccine
health professionals, STDs, IV users, transfusions
treatment only for chronic carriers
alpha interferon
inhibitors of reverse transcriptase and viral DNA polymerase
hepatitis C
features
single stranded RNA
hypervariable genome
in liver cells
hepatitis C
pathologenesis
RNA -> DNA reverse transcriptase
hard to control replication because virus keeps changing
immune system attacks
alcoholism increases disease
75% infected become chronic carriers
10% of cases cause cancer, cirrhosis, liver failure
hepatitis C
transmission
4 million americans infected
direct contact only
hepatitis C
prevention / treatment
avoid blood contact (drug users)
alpha interferon
reverse transcriptase inhibitors
new drugs with 50%+ cure rate
hepatitis D
features
defective virus
only infects HBV individuals
no capsid protein genome
hepatitis D
pathogenesis
uses capsid of HBVincreases liver damage speed
hepatitis E
features
major cause of enteric transmitted hepatitis in asia, africa, india, mexico, but rare in US (diff from HAV)
can infect pigs
hepatitis E
pathogenesis
20% infected pregnant women -> fatal hepatitis (75% mortality)
hepatitis E
transmission
direct and indirect contact
