Norovirus and Hauntavirus Flashcards
To pass this class.
What is the CDC for how many people get sick each year from foodborne illnesses in the United States?
48 million people
What percentage of foodbourne illnesses are due to noroviruses?
58%
Norovirus was a leading cause of ___ ___, but salmonella caused more hospitalizations and more deaths.
foodbourne outbreaks
What is norovirus?
Norovirus is a very contagious virus that causes vomiting and diarrhea. Anyone can get infected and sick with norovirus. You can get norovirus from: Having direct contact with an infected person. Consuming contaminated food or water.
Over __% of children in the world have norovirus by the time they are two years of age, and spread of virus may be on the increase.
90
It is important to keep in mind that norovirus continuously circulates in humans and humans can be ___ infections.
asymptomatic
Where and when was Norovirus originally identified?
Norwalk, Ohio; 1968
Norovirus is a Category B agent on the list of possible Bioterrorism agents?
It lasts long, and it’s highly contagious.
What are the symptoms of norovirus?
Vomiting, diarrhea, cramps
Norovirus is responsible for __% of all viral gastroenteritis cases.
96
Describe the structure of norovirus.
Single stranded RNA virus with no envelope
How many genogroups does norovirus have?
5
What three norovirus genogroups are found primarily in humans?
1, 2, 4
How does norovirus trigger vomiting and diarrhea?
By causing inflammation; vomiting and diarrhea happen for release
How does norovirus spread throughout the body?
Virus binds to carbohydrates on mucosal epithelial cells, infects cells, replicates quickly, and lyses cells
Describe the seasonality of norovirus.
Has winter seasonality similar to influenza but outbreaks can occur at any time of the year
What is gastroenteritis?
Inflammation of stomach and intestines
Why is it important that there norovirus has 1-15 genotypes?
This means that there can be many strains and there is no long-term protective immunity to any given strain: you can get infected with many different strains again and against with the same strain.
Severe cases of norovirus can require hospitalization because of…
dehydration.
What is the treatment for dehydration by norovirus?
IV fluids
Symptomatic individuals usually shed high amounts of virus in the first - days, but can remain infected after symptoms pass and shed virus for ___.
2, 5, weeks
In an outbreak of norovirus, as many as __% of infected people have asymptomatic infections.
35
What is one possible genetic aspect to susceptibility?
One study suggests that people who express less carbohydrates for binding the virus are less likely to get symptoms.
What two foods triggered big norovirus outbreaks?
Raspberries and oysters
Is transmission of norovirus strictly fecal-oral?
No! Aerosol droplets can help spread the virus too.
What are the three reasons why norovirus can repeatedly cause outbreaks?
- Highly contagious
- Extremely stable in environment
- Many different genotypes, hard to build up protective immunity to all different types
Most people that get infected with norovirus make protective ___ antibodies that prevent reinfection with that strain of virus, but it has its limits. What are they and what does this mean? (2)
IgA
Immunity only lasts for six months AND this protective immunity is only strain specific. Thus, there is always a new norovirus strain that can cause an outbreak and there is very little hope for a vaccine to protect against the many different strains of norovirus.
In healthy adults, symptoms of norovirus only last - days and the virus is cleared in less than a ___.
2, 3, week
When can norovirus become chronic?
In elderly or children with genetic immunodeficiency or adults or children with another form of immunosuppression (like transplant recipients)
What does it mean for norovirus to be chronic?
It lasts for 6-12 months
What are the three main ways to prevent norovirus?
- Wash your hands (hand sanitizers are also helpful, but not as effective)
- Washing surfaces with strong detergent or diluted bleach
- Isolation of cases
What are the four reasons why studying norovirus is difficult?
- Humans are the only host and no animal model has been created
- Virus cannot be grown in lab – makes it difficult to understand and diagnose
- Diagnosis can be done through the detection of norovirus specific antibodies but this does not tell you if a person has an active infection with shedding virus
- Diagnosis of infection is only done by detection of viral RNA in stool samples from the individual
Why is norovirus called “cruise ship virus”?
Many norovirus outbreaks occur in enclosed spaces (long-term facilities, cruise ships, military ships, prisons, schools)
Where else is norovirus prevalent (not cruise ships)?
Nursing homes
What is hauntavirus?
Single-stranded, enveloped RNA viruses found in the dropping of deer mice and other wild rodents. Characterized by flu-like symptoms that can progress rapidly to potentially life-threatening breathing problems.
Where and when was there an outbreak of hauntavirus? (2)
- Four Corners region of the US in May 1993
2. Valley fever
How did CDC identify hantavirus as a “new” infectious agent?
Test antibodies from infected individuals for reactivity to known agents
Is there a cure or vaccine for hantavirus?
No
Why is it hard to understand how hantavirus kills?
Lack of a good animal model to study the disease progression
Detail the typical human disease course for hantavirus pulmonary syndrome.
Asymptomatic period of 9-35 days → onset of fever/chills → rapid deterioration of lung function → vascular leakage, pulmonary edema (fluid in lungs)
What is the animal reservoir for hauntavirus?
Deer mice
What is a possible environmental factor for the 1993 Four Corners hantavirus outbreak?
Increased rainfall in the spring increased food availability which resulted in a sudden explosion in the rodent population
