export_gi viruses ii (1) Flashcards
Poliovirus family and features
Picornavirus
+ssRNA
Acid tolerant
Three poliovirus serotypes
P1, P2, P3
Poliovirus transmission
Fecal-oral route
Poliovirus incubation period
6-20 days
Clinical features of poliovirus
95% asymptomatic
Abortive poliomyelitis
Nonparalytic aseptic meningitis
Flaccid paralysis
Abortive poliomyelitis
Sore throat
Fever
Vomiting and abdominal pain
Constipation
Nonparalytic aseptic meningitis
Stiffness in back, neck, legs
Lasts 2-10 days
Poliovirus diagnosis
Virus in stool
Isolates must be sequenced (wild type or vaccine strain)
Original polio vaccine
Inactivated vaccine (Salk strain)
Later polio vaccine
Trivalent, live attenuated oral polio vaccine (Sabin strain)
Since it can cause VAPP, we switched back to the inactivated in 2000
VAPP
“Vaccine-Associated Paralytic Poliomyelitis”
1 in 2 million vaccines will revert to a neurotropic strain that causes CNS symptoms
Poliovirus prevention
Inactivated vaccine
Viruses that can cause gastroenteritis
Rotaviruses
Noroviruses
Adenoviruses
Astroviruses
Features of all viruses that cause gastroenteritis
Non-enveloped
Fecal-oral transmission
Differences between viral and bacterial gastroenteritis
Viral - similar incidence throughout world, 1-3 days, vomiting is prominent, non-bloody diarrhea is common, diagnosis of exclusion
Bacterial - more common in poor hygiene regions, hours-7 days, vomiting less prominent but found with preformed toxins, prominent diarrhea frequently with blood, diagnosis with culture
The biggest concern with viral gastroenteritis
Dehydration due to watery diarrhea
Rapid, weak pulse, sunken eyes, no tears, skin tenting, lack of urination
Virus that causes the highest incidence of gastroenteritis in children
Rotavirus
Rotavirus incubation period
1-3 days
Rotavirus symptoms
Vomiting and diarrhea for 4-7 days, occasional cough, coryza
Some patients have a fever
Rotavirus pathogenesis
<10 particles needed to initiate disease
Malabsorptive diarrhea
Produces a toxin (NSP4) that causes Ca2+ release
Diagnostic sign of rotavirus
Villi blunting
Diagnosis of rotavirus
EIA from stool sample
EM, or RT-PCR (less common)
Treatment of rotavirus
Rehydration therapy
Prevention of rotavirus
Sanitize toys, wash hands, IgA in colostrums, vaccines
Rotavirus vaccine
Two live attenuated, oral vaccines
Protective against G1-G4, G9
Norovirus family and features
Caliciviridae family
Non-enveloped
+ssRNA
Norovirus pathogenesis
Binds to specific histo blood-group Ags
Norovirus incubation
24-48 hours
Norovirus symptoms
Nausea, vomiting, diarrhea for 24-60 hours
Low grade fever in about half of patients
Norovirus transmission
Fecal-oral
Adeovirus family and features
dsDNA
Naked capsid
Serotypes 40 and 41 cause gastroenteritis
Adenovirus incubation
8-10 days
Adenovirus symptoms
Watery, non-bloody diarrhea for 7-8 days, may be accompanied by fever and vomiting
Adenovirus diagnosis
Ab based assay
Sapovirus family
Also Caliciviridae (like Norovirus)
Astrovirus features
Star-shaped
+ssRNA
