Rota, Calici, Viral Diarrhea Flashcards
What are the classic symptoms of viral gastroenteritis?
Acute onset watery diarrhea (without blood or mucus) Nausea Intestinal cramping Myalgia Low-grade fever
Viral diarrheas typically have __________ incubation periods and ___________ durations of symptoms.
short; short
Viral diarrhea is typically transmitted _____________.
by fecal-oral transmission
In the U.S., children typically have ________ cases of viral diarrhea per year, while worldwide children have _________ cases per year.
1-2; 6-7
How many deaths per year do viral diarrhea typically cause?
2.5 million
Which cells are typically affected in viral diarrhea?
Mature enterocytes
What intestinal pathology is often caused by viral diarrhea?
Blunting of villi
____________ can disrupt transepithelial fluid balance.
Viral enterotoxins
In most individual cases, _____________ does not help in the diagnosis and treatment of viral diarrhea.
knowing which virus it is (however, it is important in outbreaks)
PCR can identify viral nucleic acid in stool, but ______________.
healthy people can test positive
Many times, viruses are grown in human cells. However, with viral diarrhea, _____________.
most do not grow well in human cells or cell lines
The mainstay of treatment for viral diarrhea is ______________.
oral rehydration therapy
A recent study showed that one of the biggest predictors of development of nosocomial infections is _________________.
what the person before you had in the same hospital room
The most common cause of contagious viral diarrhea belongs to which virus family?
Caliciviruses
What kind of virus is norovirus?
ssRNA, circular, non-enveloped, with viral-encoded proteases
Norovirus surpassed _____________ as the most common viral diarrhea (due to the use of vaccines for the latter).
rotavirus
Norovirus binds to ______________.
FUT2 (an enterocyte antigen); if people are FUT2 negative, then they cannot be infected with norovirus
True or false: humans typically don’t develop immunity to norovirus.
False. We develop a short-lived (~six-month) immunity.
What type of virus is rotavirus?
22 dsRNA segments
Rotavirus is non-___________, but it has ______________.
enveloped; protein shells
There are many types of rotavirus. Which is the most infectious for humans?
A (A-G can all infect humans)
Rotavirus typically infects which cells?
Intestinal epithelial cells (again leading to villus flattening –like norovirus)
What is NSP4?
Non-secreted protein (a molecule made by rotavirus that can induce immunity)
The symptoms of rotavirus are typically ___________.
longer than those of norovirus
Which viral diarrhea is seasonal?
Rotavirus (rota means wheel –think of the turning of the seasons)
The initial vaccine against rotavirus was withdrawn due to _______________.
a 1:10,000 incidence of intussusception
There are now __________ vaccines to rotavirus.
oral (given at 2, 4, and 6 months)
The hospitalization rate of rotavirus has decreased by ______________ since the introduction of the rotavirus vaccine.
85%
Adenoviruses can cause gastroenteritis, but they more commonly cause ___________________.
URIs, conjunctivitis, pneumonia, and hemorrhagic cystitis
Which virus needs to be activated by trypsin?
Astrovirus
What makes viral diarrhea so infectious?
It can be shed for a long time (up to eight weeks) after someone recovers.
Which strain of norovirus is currently most common?
GII.4 Sydney
What shape is norovirus?
Round (like a golf ball with cup-shaped indentations)
What covering does rotavirus have?
It is a naked virus (remember the David on the Calici Beach?) with three protein layers – like gobstoppers –that confer acid stability. Specifically, VP7 and VP4 confer acid protection.
Describe the structure of rotavirus.
Part of the reovirus family, rotavirus is a naked dsRNA virus with eleven segments.
Where are rotaviruses assembled?
In the RER
What causes rotavirus to be harmful?
Enterotoxin NSP4, which induces chloride permeability
True or false: rotavirus almost always causes symptoms.
False. About 50% of infections are asymptomatic.
When is rotavirus season?
Winter (like the snowy mountains in the Sketchy video)
The star-shaped virus needs what to become fully active?
Trypsin activation (this is Astrovirus)
True or false: there is no vaccine for norovirus.
True, but there is one currently in development. It is thought that it might be like the seasonal flu vaccine in that you’d have to get it every year or so.
True or false: rotavirus incidence peaks in the 0-24 month age bracket.
False. Infants up to six months typically have maternal antibodies and are thus immune. Thus, incidence peaks between 6-24 months.
What test can diagnose rotavirus definitively?
ELISA (the diaper stick)
Which adenovirus serotypes can cause gastric symptoms?
40 and 41
