This document provides information on viral gastroenteritis. It discusses several viruses that can cause acute gastroenteritis in humans, with rotavirus and norovirus being the most common. Rotavirus is the leading cause of severe diarrhea in infants and children worldwide. It outlines the symptoms of viral gastroenteritis as vomiting, watery diarrhea, nausea, fever, abdominal pain, and headache. Dehydration is a potential complication if left untreated. The document also discusses transmission, pathogenesis, diagnosis and treatment of rotavirus and norovirus infections.

1. VIRAL GASTROENTERITIS

2. INTRODUCTION
• Viral gastroenteritis is a common infection of the
stomach and intestines that results in vomiting and
diarrhoea.
• Viral gastroenteritis causes millions of cases of
diarrhea each year.
• Anyone can get viral gastroenteritis and most people
recover without any complications, unless they
become dehydrated.

3. • Viral gastroenteritis most common among
children
• All ages are affected
• Several viruses cause acute gastroenteritis in
human , most common is rotavirus
• Viral gastroenteritis is also known as stomach
flu( inflammation of stomach and Intestines)

4. SYMPTOMS OF VIRAL
GASTROENTERITIS
• The main symptoms of viral gastroenteritis are
– vomiting
– watery diarrhoea.
• Other symptoms may include
– nausea
– fever
– abdominal pain
– headache
– muscle aches.
• Dehydration can follow.
• Symptoms can take between one and three days to develop and
usually last between one and two days, sometimes longer

5. virus genome Gastroenteritis features
ROTAVIRUS Segmented
dsRNA
Group A: most common cause of severe
diarrheal illness in children world wide
Group B: causes outbreaks of diaeehea in
adults in China
CALCIVIRUSES
NOROVIRUSES ssRNA Causes outbreaks of vomoting and
diarrheal illness in all ages
SAPOVIRUS
ASTROVIRUS
ssRNA
ssRNA
Causes sporadic cases and occational
outbreaks of diarrheal illness in infants ,
young children, and in elderly
ADENOVIRUS (type40-41) dsDNA Second most common viral agents of en
demic diarrheal illness of infants and
young children worldwide
In some cases HSV and
cytomegalovirus also ca
uses viral diarrhea
CAUSES OF VIRAL GASTERITIS

6. ROTAVIRUS
• First identified as cause of diarrhea in 1973
• Most common cause of severe gastroenteritis
in infants and children
• Rotavirus is very stable and may remain viable
in the environment for weeks or months if not
disinfected.

7. MORPHOLOGY
• Size :60-80nm
• Icosahedral symmetry
• Rotavirus is a double-stranded RNA virus of the
family Reoviridae.
• Surrounded by a triple layered capsid
• 6 structural viral proteins (VP1 to VP7 except VP5)
and 6 non structural protein
• VP6 is group specific
• VP7 (forms the outer capsid layer)&VP4 (forms
spikes that emanate through the outer capsid layer)
are strong inducers of neutralizing antibodies and
are type specific

8. • Classification of rota virus
TRADITIONAL GROUP
Further classified into
7 major groups(A-G)
Based on antigenic
composition of group
specific VP6. most
human diarrhea is
caused by group A
and to a much lesser
extent, by groups B
and C
BINARY SYSTEM OF TYPING
( A glycoprotein or G type antigen) and VP4 (a
protease sensitive or P type antigen) are used for the
typing of rotavirus.
Both serotyping and genotyping metgods are
available

9. PATHOGENESIS
• The virus enters the body through the mouth.
• Viral replication occurs in the villous epithelium of
the small intestine.
• The NSP 4 acts as enterotoxin and induces
secretion by altering epithelial cell function and
permeability
• Damaged cells may slough into the intestinal
lumen and release viruses in feces
• Viral excretion usually lasts 2-12 days
• Prolonged in patients with poor nutrition or HIV
infection

10. • Recent evidence indicates that up to two-thirds
of children with severe rotavirus gastroenteritis
show the presence of rotavirus antigen in serum
(antigenemia).
• Infection may result in decreased intestinal
absorption of sodium, glucose, and water, and
decreased levels of intestinal lactase, alkaline
phosphatase, and sucrase activity, and may lead
to isotonic diarrhea.

11. Clinical Features
• The incubation period for rotavirus diarrhea is short, usually less
than 48 hours.
• The clinical manifestations of infection vary and depend on
whether it is the first infection or reinfection.
• The first infection after 3 months of age is generally the most
severe.
• Infection may be asymptomatic, may cause self-limited watery
diarrhea, or may result in severe dehydrating diarrhea with fever
and vomiting.
• Up to one-third of infected children may have a temperature
greater than 102°F (39°C).
• The gastrointestinal symptoms generally resolve in 3 to 7 days.
• The clinical features and stool characteristics of rotavirus
diarrhea are nonspecific, and similar illness may be caused by
other pathogens.
• As a result, confirmation of a diarrheal illness as rotavirus
requires laboratory testing.

12. complication
• Rotavirus infection in infants and young children
can lead to severe diarrhea, dehydration,
electrolyte imbalance, and metabolic acidosis.
• Children who are immunocompromised because
of congenital immunodeficiency or because of
bone marrow or solid organ transplantation may
experience severe or prolonged rotavirus
gastroenteritis and may have evidence of
abnormalities in multiple organ systems,
particularly the kidney and liver.

13. Rotavirus Epidemiology
• Rotavirus occurs throughout the world
• Reservoir Human –GI tract and stool
• Transmission Fecal-oral, fomites , close person-to-
person contact and
• Temporal pattern Fall and winter (temperate areas)
• Communicability 2 days before to 10 days after
onset of symptoms

14. Laboratory Diagnosis
• The most widely available method for
confirmation of rotavirus infection is detection of
rotavirus antigen in stool by
– enzyme-linked immunoassay (EIA).
• Several commercial test kits are available that
detect an antigen common to human rotaviruses.
These kits are simple to use, inexpensive, and
very sensitive.

15. • Other techniques
– electron microscopy,
– reverse transcription polymerase chain reaction,
– nucleic acid hybridization,
– sequence analysis, and culture) are used primarily in
research settings.
• Rotavirus antigen has also been identified in
the serum of patients 3–7 days after disease
onset, but at present, routine diagnostic testing
is based primarily on testing of fecal specimens.

16. Rotavirus Vaccines
• RV5 (RotaTeq) contains five reassortant
rotaviruses developed from human and bovine
parent rotavirus strains
• vaccine viruses suspended in a buffer solution
• contains no preservatives or thimerosal
• RV1 (Rotarix) contains one strain of live
attenuated human rotavirus (type G1PA[8])
• provided as a lyophilized powder that is
reconstituted before administration
• contains no preservatives or thimerosal

17. Rotavirus Vaccine Efficacy
• Any rotavirus gastroenteritis: 74%-87%
• Severe gastroenteritis: 85%-98%
• Both vaccines significantly reduced physician
visits for diarrhea, and reduced rotavirus-
related hospitalization

18. Rotavirus Vaccine Recommendations
• Similar estimates of efficacy and safety
between RV1 and RV5
• No preference for one vaccine over the other

19. Rotavirus Vaccine Recommendations
• Routine vaccination of all infants without a contraindication
• 2 (RV1) or 3 (RV5) oral doses beginning at 2 months of age
*may be started as early as 6 weeks of age
• For both rotavirus vaccines
• maximum age for first dose is 14 weeks 6 days*
• minimum interval between doses is 4 weeks
• maximum age for any dose is 8 months 0 days
• ACIP did not define a maximum interval between doses
• No rotavirus vaccine should be administered to infants older
than 8 months 0 days**
• It is not necessary to restart the series or add doses because
of a prolonged interval between doses

20. Rotavirus Vaccine Recommendations (contin…….)
• ACIP recommends that providers do not repeat the dose if the
infant spits out or regurgitates the vaccine
• Any remaining doses should be administered on schedule
Doses of rotavirus vaccine should be separated by
at least 4 weeks.
• Complete the series with the same product whenever possible
• If product used for a prior dose or doses is not available or not
known, continue or complete the series with the product that
is available
• If any dose in the series was RV5 (RotaTeq) or the vaccine
brand used for any prior dose is not known, a total of 3 doses
of rotavirus vaccine should be administered
• Infants documented to have had rotavirus gastroenteritis
before receiving the full course of rotavirus vaccinations
should still begin or complete the 2- or 3-dose schedule

21. Rotavirus Vaccine Contraindications
• Severe allergic reaction to a vaccine
component (including latex) or following a
prior dose of vaccine
• latex rubber is contained in the RV1 oral applicator
• History of intussusception
• Severe combined immunodeficiency (SCID)

22. Rotavirus Vaccine Precautions*
• Altered immunocompetence, (except severe
combined immunodeficiency, which is a
contraindication) Limited data do not indicate a
different safety profile in HIV-infected versus HIV-
uninfected infants
• HIV diagnosis not established in infants due for
rotavirus vaccine
• Vaccine strains of rotavirus are attenuated
• These considerations support rotavirus vaccination of
HIV-exposed or infected infants
• Acute, moderate or severe gastroenteritis or other
acute illness

23. Rotavirus Vaccine Adverse Reactions
• RV5
– Diarrhea 18.1%
– Vomiting 11.6%
– Also greater rates of otitis media, nasopharyngitis and
bronchospasm
• RV1
– Irritability 11.4%
– Cough or runny nose 3.6%
– Flatulence 2.2%

24. Vaccine Storage and Handling
• Rotavirus vaccine should be maintained at
refrigerator temperature: 35°F–46°F (2°C–
8°C).

25. NOROVIRUS
• Formally called Norwalk-like Virus
• Noroviruses are members of a group of viruses called
caliciviruses
• Highly diverse group of ssRNA viruses
• Rapidly evolving
• Infection with norovirus affects the stomach and
intestines, causing an illness called gastroenteritis.

26. • According to the CDC, NoVs are highly
contagious, with as few as 10 -100 virus particles
being sufficient to cause infection.
• Transmission
– NoVs are transmitted primarily through food or water
contaminated with fecal material.
– NoVs can also spread via droplets of vomit.
– Transmission can also occur indirectly when the virus is
transferred to the mouth via the hands after contact with
environmental surfaces that have been contaminated with either
feces or vomit.

27. Symptoms of Norovirus
• Nausea
• Vomiting
• diarrhea accompanied by abdominal cramps.
• Some people complain of
– headache
– Fever
– Chills
– muscle aches.
– ***Symptoms are usually brief and last only one or two days.
However, during that brief period, people can feel very ill and
vomit or have diarrhea, often violently and without warning,
many times a day.
• Symptoms usually begin 24-48 hours after exposure to
the virus, but can appear as early as 12 hours after
exposure.

28. LAB DIAGNOSIS
• Norovirus can often be found in stool
specimens of infected persons by using special
tests.
• Diagnosis is often based on the combination
of symptoms and the short duration of illness.

29. TREATMENT
• There is no specific treatment.
• no vaccines are currently available.
• Severely dehydrated persons may need to
receive intravenous (IV) fluids in a healthcare
setting.

30. PREVENTION
• Wash hands with soap and warm water after toilet visits and
before preparing or eating food.
• Wash raw fruits and vegetables and steam oysters before
eating them.
• Thoroughly clean and disinfect contaminated surfaces
immediately after an episode of illness by using a bleach-
based household cleaner.
• Immediately remove and wash clothing or linens that may be
contaminated with the virus after an episode of illness (use
hot water and soap).
• Flush or discard any vomitus and/or stool in the toilet and
keep the surrounding area clean.
• Food handlers with symptoms of Norovirus should not
prepare or touch food during their illness and for three days
after they recover

31. GENERAL ASPECTS OF VIRAL
GASTERITIS
• Viral gastroenteritis is transmitted from
person to person. Viruses are present in the
stool and vomit of people who are infected.
• When an infected person vomits, the virus can
become airborne.