Healthcare Hygiene magazine September 2020 September 2020 | Page 8
under the microscope
By Rodney E. Rohde, PhD, MS, SM(ASCP)CM SVCM, MBCM, FACSc
Norovirus: It’s Not Just
on Cruise Ships
When one reads or hears about the noroviruses (NoV), they
likely think about a rough voyage on a cruise ship. Norovirus
illness may be called “food poisoning,” “stomach flu,” or “stomach
bug.” They are the leading cause of foodborne illness and can
be found in healthcare setting outbreaks as well as in community
outbreaks. NoV may be referred to as the winter vomiting bug but
it is not related to influenza (flu). These viral agents can survive for
long periods outside a human host depending on the surface and
temperature conditions. Since they are non-enveloped viruses, NoV
survive for weeks on hard and soft surfaces. Studies show survival
for months and possibly even years in contaminated still water.
Typically, they will be viable on surfaces used for food preparation
for up to a week after contamination.
NoV are a genetically diverse group of single-stranded
positive-sense RNA, non-enveloped viruses belonging to the
family Caliciviridae. According to the International Committee
on Taxonomy of Viruses, the genus Norovirus has one species:
Norwalk virus. Serotypes, strains and isolates include Norwalk virus,
Hawaii virus, Snow Mountain virus, Mexico virus, Desert Shield
virus, Southampton virus, Lordsdale virus, and Wilkinson virus.
Noroviruses are genetically classified into at least seven different
genogroups (GI, GII, GIII, GIV, GV, GVI, and GVII), which can be
further divided into different genetic clusters or genotypes. GI
and GII are responsible for most human acute gastroenteritis and
other genogroups are found in bovine and mice.
Unfortunately, one of the hallmark characteristics of NoV is the
incredible effectiveness in transmission and infection. Those who
are experiencing an illness with this viral agent can shed billions of
norovirus particles. It only takes a few virus particles to make other
people sick. Vomiting, in particular, transmits infection effectively
and appears to allow airborne transmission. Studies have shown
that one person can infect up to 14 other people and there are
numerous outbreaks involving hundreds (or more) of people
especially in close quarters (cruise ships, daycares, schools, etc.).
This organism is notorious for its survival on surfaces in all
environments. Here, I will introduce NoV and information aimed
at a general understanding of the characteristics of this pathogen
in the environment. Primarily, I will utilize information obtained
from the Centers for Disease Control and Prevention along with
professional experience.
How does this virus spread? This virus spreads easily
and efficiently primarily via the fecal – oral route, including the
following:
●eat or drink NoV contaminated food or drink,
●touch surfaces or objects contaminated with norovirus then
put your fingers in your mouth, or
●have direct contact with someone who is infected with
norovirus, such as by caring for them or sharing food or eating
utensils with them,
●septic tank leaking at the source (into a well),
●when an infected person vomits or poops in the water,
●improperly treated water sources, such as not enough
chlorine,
What are the common symptoms? NoV causes inflammation
of the stomach or intestines (acute gastroenteritis). Symptoms
usually develop 12 to 48 hours after exposure and resolve within
1 to 3 days. If you have norovirus illness, you can feel extremely
ill, and vomit or have diarrhea many times a day. This can lead
to dehydration, especially in young children, older adults, and
people with other illnesses. Symptoms can include:
●diarrhea
●vomiting
●nausea
●stomach pain
●or less commonly, fever
●headache
●body aches
Can NoV be treated?
Since a virus causes this infection, there is not any specific
treatment required if there are no complications such as
dehydration. Severe dehydration may require hospitalization for
treatment with fluids given through your vein (intravenous or IV
fluids). One should watch for signs of dehydration in children
who have norovirus illness. Children who are dehydrated may cry
with few or no tears and be unusually sleepy or fussy.
What should one do for prevention of this infection?
This virus, and other microbes, may be transmitted to
patients because of their persistence on environmental surfaces
in the healthcare environment. As I have often mentioned, all
#SurfacesMatter all the time to everyone in the war on pathogen
transmission. NoV can live for long periods on environmental
surfaces and shared equipment when they are not properly
cleaned and disinfected. Likewise, the same applies in the
community environment.
Practice proper hand hygiene by washing your hands
thoroughly with soap and water
●especially after using the toilet or changing diapers,
●always before eating, preparing, or handling food (cook
seafood thoroughly), and
●before giving yourself or someone else medicine.
Laboratory diagnosis
This virus (infection) is diagnosed by detecting viral RNA
(genetic material) or viral antigen. Diagnostic tests are available
at all public health laboratories and many clinical laboratories,
and most use reverse transcription- real-time polymerase chain
reaction (RT-qPCR) or immunoassays to detect norovirus.
Rodney E. Rohde, PhD, MS, SM(ASCP)CM SVCM, MBCM,
FACSc, serves as chair and professor of the Clinical Laboratory
Science Program at Texas State; associate director for the
Translational Health Research Initiative; as well as associate dean
for research in the College of Health Professions. Follow him on
Twitter @RodneyRohde / @TXST_CLS, or on his website: http://
rodneyerohde.wp.txstate.edu/
8 september 2020 • www.healthcarehygienemagazine.com