Norovirus and Hauntavirus

Question 1

What is the CDC for how many people get sick each year from foodborne illnesses in the United States?

Answer 1

48 million people

Question 2

What percentage of foodbourne illnesses are due to noroviruses?

Answer 2

58%

Question 3

Norovirus was a leading cause of ___ ___, but salmonella caused more hospitalizations and more deaths.

Answer 3

foodbourne outbreaks

Question 4

What is norovirus?

Answer 4

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.

Question 5

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.

Answer 5

90

Question 6

It is important to keep in mind that norovirus continuously circulates in humans and humans can be ___ infections.

Answer 6

asymptomatic

Question 7

Where and when was Norovirus originally identified?

Answer 7

Norwalk, Ohio; 1968

Question 8

Norovirus is a Category B agent on the list of possible Bioterrorism agents?

Answer 8

It lasts long, and it’s highly contagious.

Question 9

What are the symptoms of norovirus?

Answer 9

Vomiting, diarrhea, cramps

Question 10

Norovirus is responsible for __% of all viral gastroenteritis cases.

Answer 10

96

Question 11

Describe the structure of norovirus.

Answer 11

Single stranded RNA virus with no envelope

Question 12

How many genogroups does norovirus have?

Answer 12

5

Question 13

What three norovirus genogroups are found primarily in humans?

Answer 13

1, 2, 4

Question 14

How does norovirus trigger vomiting and diarrhea?

Answer 14

By causing inflammation; vomiting and diarrhea happen for release

Question 15

How does norovirus spread throughout the body?

Answer 15

Virus binds to carbohydrates on mucosal epithelial cells, infects cells, replicates quickly, and lyses cells

Question 16

Describe the seasonality of norovirus.

Answer 16

Has winter seasonality similar to influenza but outbreaks can occur at any time of the year

Question 17

What is gastroenteritis?

Answer 17

Inflammation of stomach and intestines

Question 18

Why is it important that there norovirus has 1-15 genotypes?

Answer 18

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.

Question 19

Severe cases of norovirus can require hospitalization because of…

Answer 19

dehydration.

Question 20

What is the treatment for dehydration by norovirus?

Answer 20

IV fluids

Question 21

Symptomatic individuals usually shed high amounts of virus in the first - days, but can remain infected after symptoms pass and shed virus for ___.

Answer 21

2, 5, weeks

Question 22

In an outbreak of norovirus, as many as __% of infected people have asymptomatic infections.

Answer 22

35

Question 23

What is one possible genetic aspect to susceptibility?

Answer 23

One study suggests that people who express less carbohydrates for binding the virus are less likely to get symptoms.

Question 24

What two foods triggered big norovirus outbreaks?

Answer 24

Raspberries and oysters

Question 25

Is transmission of norovirus strictly fecal-oral?

Answer 25

No! Aerosol droplets can help spread the virus too.

Question 26

What are the three reasons why norovirus can repeatedly cause outbreaks?

Answer 26

1. Highly contagious
2. Extremely stable in environment
3. Many different genotypes, hard to build up protective immunity to all different types

Question 27

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)

Answer 27

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.

Question 28

In healthy adults, symptoms of norovirus only last - days and the virus is cleared in less than a ___.

Answer 28

2, 3, week

Question 29

When can norovirus become chronic?

Answer 29

In elderly or children with genetic immunodeficiency or adults or children with another form of immunosuppression (like transplant recipients)

Question 30

What does it mean for norovirus to be chronic?

Answer 30

It lasts for 6-12 months

Question 31

What are the three main ways to prevent norovirus?

Answer 31

1. Wash your hands (hand sanitizers are also helpful, but not as effective)
2. Washing surfaces with strong detergent or diluted bleach
3. Isolation of cases

Question 32

What are the four reasons why studying norovirus is difficult?

Answer 32

1. Humans are the only host and no animal model has been created
2. Virus cannot be grown in lab – makes it difficult to understand and diagnose
3. 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
4. Diagnosis of infection is only done by detection of viral RNA in stool samples from the individual

Question 33

Why is norovirus called “cruise ship virus”?

Answer 33

Many norovirus outbreaks occur in enclosed spaces (long-term facilities, cruise ships, military ships, prisons, schools)

Question 34

Where else is norovirus prevalent (not cruise ships)?

Answer 34

Nursing homes

Question 35

What is hauntavirus?

Answer 35

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.

Question 36

Where and when was there an outbreak of hauntavirus? (2)

Answer 36

1. Four Corners region of the US in May 1993

2. Valley fever

Question 37

How did CDC identify hantavirus as a “new” infectious agent?

Answer 37

Test antibodies from infected individuals for reactivity to known agents

Question 38

Is there a cure or vaccine for hantavirus?

Answer 38

No

Question 39

Why is it hard to understand how hantavirus kills?

Answer 39

Lack of a good animal model to study the disease progression

Question 40

Detail the typical human disease course for hantavirus pulmonary syndrome.

Answer 40

Asymptomatic period of 9-35 days → onset of fever/chills → rapid deterioration of lung function → vascular leakage, pulmonary edema (fluid in lungs)

Question 41

What is the animal reservoir for hauntavirus?

Answer 41

Deer mice

Question 42

What is a possible environmental factor for the 1993 Four Corners hantavirus outbreak?

Answer 42

Increased rainfall in the spring increased food availability which resulted in a sudden explosion in the rodent population