VI- Viral GI Flashcards
poliovirus transmission
fecal-oral route
-incubates 6-20 days
-will shed in stool for weeks after infection
serotypes of poliovirus
P1, P2, P3
-only wild type (P1) not eradicated
poliovirus infection route
- oral pharynx and GI tract
- hematologic spread to lymphatic and CNS
- viral spread along nerve fibers
- destruction of motor neruons = paralysis
poliovirus presentation
- usually symptomatic
- minor non-CNS illness/abortive poliomyelitis - sore throat, fever, vomit, abdom pain, constipation
- nonparalytic aseptic meningitis- nonspecific prodromal symps, stiff back/neck/legs, duration 2-10 days
- flaccid paralysis
diagnosing polio
- virus isolated from stool
- isolates sequenced to determine if wild type or vaccine strain
sabin vaccine
live attenuated, trivalent, oral
-reps in GI tract then sheds in stool for 5 weeks
-can revert back to neurotropic strain for CNS symps = vaccine assocaited paralytic poliomyelitis VAPP or cVDPV
inactivated polio vaccine
-antigens to all 3 serotypes
-IM injection
-no risk for VAPP
-4 dose schedule
viral gastroenteritis presentation
- nausea
- diarrhea
- vomitng
4.
viruses that cause gastroenteritis
- rotavirus
- norovirus
- adenovirus 40 and 41
- astrovirus
key viral vs bacterial GE
- days long incubation since virus needs to enter cell and replicate, bacteria only need few hours
- nonbloody/watery diarrhea, bacteria freq bloody
signs of severe dehydration
-rapid weak pulse
-sunken eyes without tears
-skin tenting
-lack of urination
treat with IV rehydration (instead of oral for mild)
rotavirus presentation
- watery, nonbloody diarrhea
- vomiting
- cough and coryza
- some high fever
last 4-7 days after 1-3 day incubation
esp if immunodeficient but not HIV
rotavirus pathology
-villi blunting of small intestine = malabsorption
-toxin NSP4 for Ca release
rotavirus treatment
- diagnose with stool sample
- rehydration therapy
- prevent fecal oral transmission by sanitizing, IgA in colostrum, vaccine
rotavirus vaccine
- RV1 = rotatrix, live attenuated strain of human rotavirus
- RV5 = rotateq, protective GI -G4, G9, reassortment between human/bovine
vaccine doses
rotavirus
RV1 = 2 doses, 2 mo and 4 mo
RV5 = 3 doses, 2/4/6 mo
norovirus presentation
- nausea
- vomit
- watery nonbloody diarrhea for 24-60 hours
- low grade fever in half
- all age groups
after 24-48 hr incubation
norovirus pathology
- non enveloped +ssRNA
- preference for specific blood antigens/types
- fecal oral transmission aka close contact, fomites, waterborne, contaminate food
norovirus prevention
- no vaccine or antivirals
- surface disinfection
- stringent personal hygiene practices
adenovirus pathology
- dsDNA with naked capsule and fiber protein at vertices
- serotypes 40 and 41 cause GE
adenovirus presentation
- in kids
- watery non bloody diarrhea for 7-8 days
- maybe vomiting and fever
after incubation 8-10 days
adenovirus treatment
- diagnose with antibody test
- prevent with environment disinfection and personal hygiene
astrovirus
+ssRNA
-all age groups susceptible exposed to contaminated food and drink
mumps symptoms
- swollen tender parotid glands or submandibular
- prodrome of malaise and anorexia
mumps complications
- meningitis
- orchitis (testicular inflamm) in postpubertal males but not affect fertility
- deafness
- myocarditis rare but fatal
mumps spread
- entry into respir tract
- spread to local lymph nodes
- primary viremia
- spread to salivary glands, testes, ovaries, pancreas, CNS
- viremia
- generalized spread around body
- viremia
aka cycles in/out of blood stream
mumps diagnosis
- acute onset of uni/bilateral tender, self limiting swelling of parotid or other salivary gland 2+ days without other apparent cause
usually resolve in 10 days
mumps transmission
direct contact with respir droplets, saliva, contaminated fomites
mumps vaccine
part of MMR and MMRV subcutaneous injection
-mumps, measles, rubella, varicella
-1st dose at 12-15 mo, 2nd at 4-6 yrs OR if adult then 1 dose for all or 2 doses high risk
only 88% effective with 2 doses
