Norovirus in food diseases

1. ÇUKUROVA UNIVERSITY
Prepared by
Abbas Rahama
PhD student

2. Food poisoning by viruses

3.  Norovirus
 Norovirus, sometimes referred to as the winter vomiting bug, is the
most common cause of gastroenteritis. Infection is characterized by
non-bloody diarrhea, vomiting, and stomach pain. Fever or
headaches may also occur.
 Norovirus results in about 685 million cases of disease and 200,000
deaths globally a year.(1)

4.  The Norovirus is a stomach and intestinal virus that’s very
contagious. It passes easily through direct or indirect
contact with an infected person. It can spread quickly in
close quarters such as hospitals, schools, and day care
centers.

5.  Most people have some experience with norovirus. It’s a common
illness of the stomach and intestinal tract. Norovirus can also be a
source of food poisoning, because you can get it from eating
contaminated food. The results are the same no matter how you get it.
(2)

6.  Norovirus symptoms
 Symptoms of infection usually start somewhere between 12 and 48
hours after you’ve been exposed to the virus. They can range from
quite mild to severe. Some signs and symptoms of norovirus are:
o Nausea And Vomiting
o Abdominal Cramping Or Pain
o Watery stools or diarrhea

7. o Low-grade Fever
o Chills
• The term “chills” refers to a feeling of being cold without an apparent cause. You get this
feeling when your muscles repeatedly expand and contract and the vessels in your skin
constrict. Chills can occur with a fever and cause shivering or shaking.
o Headache
o Generalized Body Aches

8.  Symptoms usually last between 24 to 72 hours after ingestion of
contaminated food.
 Severe diarrhea can lead to dehydration, which should be considered
a medical emergency.
 Signs and symptoms of dehydration include:
o Dry Mouth And Throat
o Decreased Output Of Urine Or Dark Urine
o No Wet Diaper For 6 To 8 Hours In Infants
o No Urine In 12 Hours For Children

9. o Sleepiness And Fatigue
o Headache
o Confusion
o Rapid Heart Rate
o If your child cries without producing tears, that’s a common sign of significant
dehydration.(3)

10. Electron Micrograph of Norovirus particles in
feces

11.  Viruses Dehydration can be life-threatening, especially for the
following groups:
o People with A weakened immune system
o People with preexisting health conditions
o The very old and the very young
o Organ or stem cell transplant recipients

12.  It’s estimated that in some cases, about 30 percenttrusted source
of the time, the virus causes no symptoms at all. This is especially
common in children.(4)

14.  Transmission
 Noroviruses are transmitted directly from person to person
(62–84% of all reported outbreaks) and indirectly via
contaminated water and food.
 They are extremely contagious, and fewer than twenty
virus particles can cause an infection (some research
suggests as few as five).

15.  Transmission can be aerosolized when those stricken with
the illness vomit, and can be aerosolized by a toilet flush
when vomit or diarrhea is present; infection can follow
eating food or breathing air near an episode of vomiting,
even if cleaned up.
 The viruses continue to be shed after symptoms have
subsided and shedding can still be detected many weeks
after infection.

16.  Shellfish and salad ingredients are the foods most often implicated in
norovirus outbreaks.
 Ingestion of shellfish that have not been sufficiently heated under 75
°C poses a high risk for norovirus infection.
 Transmission can also occur indirectly, such as when food, water, or
surfaces become contaminated. Just touching an infected doorknob or
cellphone could start the chain reaction. When someone vomits, the
virus can become airborne, so if it gets in your mouth, it can end up in
your intestinal tract.(5)

18.  Pathophysiology
 When a person becomes infected with norovirus, the virus replicates
within the small intestine.
 The principal symptom is acute gastroenteritis, characterized by
nausea, forceful vomiting, watery diarrhea, and abdominal pain, that
develops between 12 and 48 hours after exposure, and lasts for 24–72
hours.

19.  The number of deaths from norovirus in the United States is estimated
to be around 570–800 each year, with most of these occurring in the
very young, the elderly, and persons with weakened immune systems.

20.  A few things can increase your risk of getting the
infection, such as:
 Spending time in a hospital, nursing home, school, or day care center. The
virus spreads particularly fast in close quarters. For this reason, your risk
may also be higher on a cruise ship, hotel, or in a resort setting.
 Contact with an infected person, especially if you’re caring for a sick person
and are exposed to their vomit or stool.

21. o Sharing food, drinks, plates, cups, or utensils with an infected person.
o Eating food or drinks prepared in unsanitary conditions.
 With some illnesses, having a single infection gives you immunity for
life. Vaccines can provide immunity to others. But that’s not the case
with norovirus. There’s no vaccine, and having it once won’t save you
from getting it again. In fact, you can get it many times.
 Trusted Source throughout your life.(1)

22.  Diagnosis
 Clinically
 Norovirus is often diagnosed based on symptoms and a physical
exam. A stool sample may be analyzed in a lab to confirm the
diagnosis.

23.  Laboratory dagnosis
 Serologic dagnosis
 Tests such as ELISA that use antibodies against a mixture of
norovirus strains are available commercially, but lack specificity and
sensitivity

24.  Molecular Diagnosis
 Specific diagnosis of norovirus is routinely made by polymerase
chain reaction (PCR) assays or quantitative PCR assays, which
give results within a few hours. These assays are very sensitive
and can detect as few as 10 virus particles.

25.  Prevention
 After infection, immunity to the same strain of the virus the genotype
protects against reinfection for between 6 months to 2 years.
 This immunity does not fully protect against infection with the other
diverse genotypes of the virus.
 Hand washing with soap and water is an effective method for reducing
the transmission of norovirus pathogens.
 Alcohol rubs (≥62% isopropyl alcohol) may be used as an adjunct, but
are less effective than hand-washing, as norovirus lacks a lipid viral
envelope.(6)

26.  Vaccine
o In LigoCyte announced in 2007 that it was working on a vaccine and had
started phase 1 trials. The company has since been taken over by Takeda
Pharmaceutical Company.
o As of 2019, a bivalent (NoV GI.1/GII.4) intramuscular vaccine had
completed phase 1 trials.
o The vaccine relies on using a virus-like particle that is made of the
norovirus capsid proteins in order to mimic the external structure of the
virus. Since there is no RNA in this particle, it is incapable of reproducing
and cannot cause an infection.(7)

28.  Treatment
 There is no specific medicine to treat people with norovirus illness.
Norovirus infection cannot be treated with antibiotics because it is a
virus. Treatments aim to avoid complications by measures such as the
management of dehydration caused by fluid loss in vomiting and
diarrhea.(8)

29. Reference
1) https://en.wikipedia.org/wiki/Norovirus#
2) https://www.healthline.com/health/norovirus#
3) Mayo Clinic Staff. (2017). Norovirus infection: Symptoms and
causes.mayoclinic.org/diseases-conditions/norovirus/symptoms-causes/dxc-
20306338.
4) Dehydration. (2016).connecticutchildrens.org/health-
library/en/parents/dehydration/"Norovirus (vomiting bug)". nhs.uk. 2017-10-19.
Retrieved 8 June 2018.
5) Heijne JC, Teunis P, Morroy G, Wijkmans C, Oostveen S, Duizer E, Kretzschmar M,
Wallinga J (2009). "Enhanced Hygiene Measures and Norovirus Transmission during
an Outbreak". Emerg. Infect. Dis. 15 (1): 24–30. doi:10.3201/eid1501.080299. PMC
2660689.

30. 6) "Preventing Norovirus Infection". CDC. 5 May 2017. Retrieved 29 December
2017.
7) Leon, Juan (2008). "Chapter 9". In Vajdy, Michael (ed.). Immunity Against
Mucosal Pathogens. Springer. p. 232. ISBN 978-1-4020-8412-6.
8) Norovirus: Treatment. (2016).cdc.gov/norovirus/about/treatment.html.