Viral Gastroenteritis Flashcards
What is viral gastroenteritis and who is at high risk?
- Inflammation of the stomach and intestines caused by viral infections, characterised by diarrhoea and vomiting.
- High risk groups are; Children under age 5, old age people especially in nursing homes and the immunocompromised
What are some important viruses which can cause gastroenteritis and who are these most likely to affect?
- Norovirus (calciviridae) affects people of all ages,
- Sapovirus (calciviridae) Affects people of all ages,
- Rotavirus - Mainly affects children under 2, elderly and immunocompromised,
- Adenovirus 40 and 41 - Mainly affects children under 2, elderly and immunocompromised,
- Astrovirus - Mainly affects children under 2, elderly and immunocompromised.
Describe features of norovirus and its transmission
- Non enveloped, single stranded RNA virus. Most common strain in the UK is GII-4 strain.
- Transmitted via person-person (foecal-oral, aerosolised by toilet flush or fomites), can also be food/water borne. It is very infectious, has a 24-48 hour incubation period and can shed virus for up to 3 weeks.
What are the clinical features of Norovirus
Presents with;
- Vomiting,
- Non-bloody diarrhoea,
- Nausea,
- Abdominal cramps,
- Headache and muscle aches,
- Dehydration in the young and elderly
What are the complications and treatment for Norovirus
Complications - Childhood hospitalisation due to dehydrations, elderly patients can develop post infectious complications and in organ transplant patients can get chronic diarrhoea.
Treatment - Oral/IV fluids, antispasmodics, analgesia and antipyretics. Immunity only lasts 6-14 wks so can get it yearly
What are some infection control measures for Norovirus
- Isolation/cohorting
- Exclude symptomatic staff untill 48hrs symptom free,
- Do not move patients or admit new patients,
- Cleaning of area for 48 hours after last case symptomatic with actachlor or hot soapy water.
- Hand hygiene is essential as contaminated hands are the most common vector for spread of virus
Describe features of rotavirus and its modes of transmission
- It is double stranded, non enveloped RNA.
Virus of the reoviridae family, it has 11 strands of RNA so potential for antigenic variation.
Most common in children as immunity is acquired with exposure - Low infectious dose is required for infection. it is mainly spread person to person via faeco-oral route or fomites. Stool can be infectiours for 10+ days
Describe the clinical features of rotavirus
- Watery diarrhoea,
- Abdominal pain,
- Vomiting
- Loss of electrolytes leading to dehydration,
- Incubation period is 1-3 days and the duration of symptoms can be up to 7days.
What are the complications which can arise from rotaviral infections?
- Severe, chronic diarrhoea,
- Dehydration,
- Electrolyte imbalance,
- Metabolic acidosis,
- Immunodeficient children may have more severe/persistent disease
Explain the immunity acquired against rotavirus
- Occurs due to antibodies against VP7 and VP4.
- The 1st infection is usually severe and doesn’t lead to permanent immunity but subsequent infections are less severe.
- Rotavirus vaccine introduced into childhood immunisation schedule which is 85% effective for first 2 yrs of life
Describe features of Astrovirus
- Astroviridae which is single stranded, non enveloped RNA virus.
- Causes less severe gastroenteritis than other pathogens.
- Sporadic infections, usually in children.
Describe features of adenovirus
- Adenoviridae which is double stranded.
- Adenovirus 40 and 41 cause gastroenteritis.
- Symptoms: Fever and watery diarrhoea,
- Treatment: Supportive
How is viral gastroenteritis diagnosed?
PCR testing of vomit/stool at virology labs
