Viral GI II Flashcards
What is the family of poliovirus? What is the genome type?
Picornavirus
+ssRNA
Is polio stable at high or low pHs? What is the consequence of this?
Low, survives stomach
What is the mode of transmission for polio?
Fecal-oral route
What are the three serotypes for polio?
P1-3
What is the incubation period for polio?
6 to 20 days
What percent of polio are asymptomatic?
95%
How is the polio virus shed?
In stool for weeks
What three countries is polio still endemic to?
Afghanistan
Nigeria
Pakistan
What are the clinical manifestations of “abortive” polio? Does this lead to paralysis?
Sore throat
Fever
GI symptoms
does not lead to paralysis
What are the clinical manifestations of nonparalytic aseptic meningitis from polio? How long does it last?
Non-specific prodromal symptoms
Stiffness in back, neck or legs (usually unilateral)
Last 2-10 days
What percent of polio cases result in flaccid paralysis?
<1%
What percent of people infected with polio will have nonparalytic aseptic meningitis?
1-2%
How do you diagnose polio?
Isolate from stool/CSF and sequence
What was the first vaccine for polio?
Inactivated vaccine by Saulk
What is the current polio vaccine?
Sabin, attenuated virus
Does the vaccine strain in the Sabin vaccine replicate? How many strains does it provide protection?
Yes
Three strains
What is VAPP? How often does it occur with the Sabin vaccine?
Vaccine-associated paralytic poliomyelitis
1 in every 2x10^6
What is the standard polio vaccine today?
Inactivated vaccine
How is the inactivated vaccine for polio made? Is there a risk for VAPP?
Grown in tissue cultures, and inactivated through formaldehyde
No risk for VAPP
What are the symptoms of viral gastroenteritis?
N/v/d
Inflammation of the stomach and intestines
What are the four virus families that cause viral gastroenteritis? Which ones are enveloped?
Rotavirus
Norovirus
Adenovirus
Astroviruses
None are enveloped
What is the mode of transmission for viral gastroenteritis?
Fecal oral
What is the incubation period for viral gastroenteritis vs bacterial? Why does the viral strain usually take longer to develop?
hour to 7 days for bacteria
1-3 days for virus (d/t need to replicated)
Which cause of gastroenteritis causes vomiting more prominently, bacterial or viral?
Viral, usually
What type of diarrhea do viral causes of gastroenteritis?
Watery–never bloody
How do you diagnose viral gastroenteritis?
One of exclusion–if stool culture is negative for bacterial causes
What is the major concern with viral gastroenteritis?
Dehydration
What is the treatment for dehydration caused by gastroenteritis?
IV or oral rehydration
What are the signs of severe dehydration?
Rapid pulse Tears absent Skin tenting Sunken eyes Lack of urination
What is skin tenting?
Pinching skin to see if dehydrated
What is the setting for viral vs bacterial gastroenteritis?
Bacterial = poor sanitation places
Viral = similar in both developed and developing countries
What percent of children have had an infection with rotovirus by age 5?
95%
When is the most severe disease of rotavirus occur?
3-24 months of age
What percent of gastroenteritis is caused by rotavirus?
5-10%
What is the family of rotavirus? Genome?
Reovirus
dsRNA
What happens when the rotavirus enters a host cell?
Changes shape from sphere to star-like thingy with pores
What is the incubation period of rotavirus? How long do symptoms last?
1-3 days followed by 4-7 days of symptoms
Is fever seen with rotavirus infection?
Yes, 1/3 of pts have >102 F
Is rotavirus an opportunistic pathogen with HIV infections?
No
When is the rotavirus season?
Varies for different regions of the US, but spring time here
What is the most prevalent type of rotavirus?
G1
What is the pathogenesis of rotavirus?
Infecting epithelial layer, and causing damage and malabsorption (vili blunting)
How many viral particles of rotavirus are needed for infection? How many are shed in the stool
10^9 release in stool
What is the toxin that rotavirus produces? What does it do?
NSP4, causes Ca release
What is viliblunting?
Destruction of microvili caused by rotavirus
How do you diagnose rotavirus?
EIA (enzyme immunoassay) from stool
EM or RT-PCR iff needed
What is the treatment for viral gastroenteritis?
Rehydration
What is the prevention technique for rotavirus?
Handwashing/Sanitize fomites
Vaccine
Which type of immunoglobin do babies receive from their mothers through breast milk that protects them from rotavirus?
IgA
What are the two vaccines against rotavirus? Which strains are these protective against? What type of vaccine is it?
Rotateq or rotarix
G1-4, G9
Live attenuated human for rotratrix
Reassortment from bovine for rotateq
When do children get vaccinated against rotavirus?
before 12 weeks of age
What is intussusception? Is there a concern for this with rotavirus?
a medical condition in which a part of the intestine invaginates (folds into) into another section of intestine.
This is no longer a concern with current vaccines
How is the rotavirus vaccine administered?
Oral inhalation
Which population does norovirus usually infect?
All ages
What is the incubation period for norovirus?
24-48 hours
What are the symptoms of norovirus infection?
n/v/d
Low grade fever
What is the pathology of norovirus?
Similar to rotavirus, micovilli blunting
What family does norovirus belong to? Genome type?
Caliciviridae family
+ssRNA
Who is particularly susceptible to norovirus infection [hint: not age or immune status]? Why is this the case?
Specific blood types more than other people
May be d/t infecting immune cells
What is the mode of transmission for norovirus? Can it be spread from person-person?
Fecal oral route (vomit aerosolization, food handling)
Can be transmitted from person-person
How does norovirus usually spread? Where does this usually occur?
Foodborne
Long-term care facilities
What is the genome type of the adenovirus? Is there an envelope? Which serotypes cause GI disease?
dsDNA
Naked capsid
40 and 41 serotypes
What is the incubation period for adenovirus? How long do symptoms last?
8-10 days
7-8 days of symptoms
What are the symptoms of infection with GI adenovirus?
n/v/ watery diarrhea
Is there seasonal variation of adenovirus?
nope
Which part of the population are usually infected with adenovirus?
Children
How do you diagnose adenovirus?
Antibody detection in stool sample
What is the family of the sapovirus?
Caliciviridae family
What is the genome type of astroviruses?
+ssRNA
How long does immunity last for norovirus?
Short
What are the usual places where the weakness caused by polio is observed? How long does it have to continue before it is deemed permanent?
Usually, unilateral lower limbs
12 months
How does polio cause paralysis?
Infection and replication within neurons
