Viruses Flashcards
Rotavirus
dsRNA virus-unique
most common cause of diarrheal disease among infants and children under 5
Nearly every child has been infected at least once by rotavirus by age 5
Pathogenesis
most common in childern under 5
infects epithelial cells in small intestine
Viral replication,cell lysis, Disease
Causes disease “Gastroenteritis”
Infects animals- not diseased until consumed by humans-pathogen of livestock
Transmitted by the fecal-oral route: Eating,Hands, Touching surfaces/objects that are contaminated
Viral shedding: during sickness,3 days after recovery
Clinical manifestations
2 days after exposure: can last 3 to 8 days
Symptoms: Severe watery diarrhea-black or contain pus, Crying with few or no tears, Dry mouth +Throat,Unusual sleepiness/ fussiness
Treatment + Preventation
Antibiotics are not effective, drink plenty of fluids, vaccination,oral rehydration, and rest
Handwashing important, vaccination
Hepatitis B (HBV)
Taxonomy: Family- Hepadnaviridae
Structure: Enveloped virus,Icosahedral nucleocapsid, core
Genome
Partially ds but not covalently closed (ccc)
complete -Dna strand +shorter +Dna strand
Single-stranded gap +Relaxed circular
Transmission
Most common viruses: 2 billion people infected, 1 million die
Infects only humans and non-human primates
highly contagious: Exposure to infected blood+bodily fluids
Infection
infects hepatocytes-liver cells
the only site of replication
travels through blood: separated from the bloodstream,infectious virions bind to receptors on hepatocyte surface
Proteins
surface proteins: small ,medium, large (Enevolope)
Core protein: a structural component of nucleocapsid
Polymerase protein: DNA repair, reverse transcription
X protein: required for viral replication,virulence factor
Replication
Nucleocapsid in cytoplasm to nucleus cccDNA
Rnas transcribed by cellular RNA pol
pregenomic RNA packaged into nucleocapsids
Reverse-transcribed by viral polymerase
Persistance
Short and long term outcomes
immune response tries to clear infected cells
repeated cycles of injury and regeneration
Disease
Hbv-related chronic liver disease-intergrated into own genome-liver cancer
symptoms don’t appear early:weight loss,loss of appetite,liver failure,etc.
Treatment +Preventation
Vaccine +antiviral
Don’t share needles,get vaccinated, avoid sharing personal hygiene items
Epstein Barr virus
Taxonomy: Herpesviridae
Structure: Enveloped, Icosaherdal nucleocapsid
Genome
dsDNA linear
Encodes everything it needs: nucleotides
Tegument
Transmission +infection
Salivia:kissing virus
Sharing glass or food utensils
Infects epithelial cells and spreads to tonsils
Salivary glands (epithelial) to lymphocytes (b-cells) tonsils
Infectious mononucleosis
Latency in b cells, clonal expansion, T cells target infected b cells,Equilibrium reached-symptoms cease, can cause cancer
Symptoms
incubation period of about 4 to 6 weeks,resolve overtime,swollen neck, abrupt onset of sore throat,etc.
Treatment and prevention
No treatment or vaccine
Once have, have for life
Avoid kissing someone who is sick, don’t share personal items,wash hands
Corona virus
SARS-coV2
Taxonomy: coronaviridae
Structure:Enveloped,helical nucleocapsid
Genome
ssRNA linear
Structural proteins
nonstructural proteins-copy genome
Transmission + Infection
infected person breathes out droplets that contain virus
-breathing in these, can land on the eyes,nose, or mouth, or contamination from infected surfaces
Infects lung epithelial cells
Causes covid19
Viral replication: flu-like symptoms-immune response, cell death
sometimes no symptoms, sometime permanent loss
can be mild,moderate, or severe
Treatment +prevention
Vaccine +antiviral treatments
Avoid people
