024 Viral Infections of GI tract Flashcards
What % are viruses responsible of infective diarrhoea?
75%
Does adenoviruses 1-39 cause gastroenteritis?
No
Does Enteroviruses cause gastroenteritis?
No
What types of viruses are able to cause systemic disease?
Unenveloped viruses
Which immunity is associated with systemic illnesses?
IgG and IgA
Which immunity is associated with localised infections?
IgA
Do systemic or localised viral infections have longer incubation period?
Systemic illneses
What is the most common childhood infections associated with gastroenteritis?
Rotaviruses and noroviruses; sometimes adenoviruses
What are the signs of inflammatory diarrhoea in feces?
Pus in feces
What genome do rotaviruses contain?
RNA genome with 11 segments that can undergo reassortment.
Why are there bacteriophages in species?
Viruses in bacteria
What is the most common infection of gastroenteritis in all ages?
Noroviruses
Incubation period of rotavirus?
24-72 hr incubation period
What are the symptoms of rotaviruses?
Vomiting and diarrhoea, abrupt onset of abdominal cramps, lasts 4-6 duration. Most severe symptoms in young children but can be asymptomatic in adults.
What is the pathogenesis of rotavirus?
Following ingestion, virus multiplies in columnar cells of the villi of the small intestine. Damage to villi leads to loss of water and electrolytes, diarrhoea & dehydration.
How many segments are in the rota virus genome?
11 segments
How do you treat secretory diarrhoea?
By replacing fluids and metabolites lost
How do we diagnose the causative virus of gastroenteritis?
In a patient stool sample, there will be lots of viruses present. To determine which is causative species, we must take two samples 10 days apart to analyze which virus has antibodies surrounding them.
What is the most efficient method to detect rotaviruses?
Detecting antigen in faeces by latex agglutination. PCR can be used to detect nucleic acid but this takes time and since rotavirus is an RNA virus, you need to use reverse transcriptase to form DNA. EM can also be used.
Which two types of adenoviruses cause gastroenteritis? What is special about them?
Type 40 and 41; they do not grow in culture
How long does the rotavirus cause illness for?
6-7 days until cells are replaced
Where do rotaviruses have higher mortality?
Asia and Africa
Which types of vaccination is used against the rotavirus?
Live attenuated vaccine
Live animal-human virus reassortment
What do we use to detect norovirus?
Reverse transcription PCR
Why dont we use use latex agglutination to detect norovirus?
There is little of th evirus present in the feces sample.
What is the infectious dose of norovirus?
10 viruses through aerosol transmission (vomiting) and faecal-oral route.
Symptoms of the norovirus?
Projectile vomiting and diarrhoea
Discuss the immunity of the norovirus
Mucosal immunity tends not to persist and we lose it after a few months. It is also very strain specific.
What is the structure of enteroviruses?
Unenveloped RNA viruses that are stable at acidic pH.
Explain immunity of noroviruses
Newborn babies have maternal immunity however this fades away over time.
Example of diseases caused by enteroviruses?
Febrile illness, CNS disease, haemorrhagic conjunctivitits, hand food and mouth disease
What is the pathogenesis of enteroviruses?
Systemic infection entering through faecal oral route, multiplying in gut lymphoid tissue and entering the blood through lymphatics. Some may also leave the body via faeces to continue infecting others.
Which ages does the norovirus affect?
All ages
Which is the only gastro-enteritis virus that can be food or water bourne?
Norovirus
