Foodborne Dz: Viral Flashcards Preview

RUSVM Epi Summer 17 > Foodborne Dz: Viral > Flashcards

Flashcards in Foodborne Dz: Viral Deck (45)
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1

T/F: Viruses are the most common cause of foodborne illness

TRUE

2

T/F: Testing for viral etiologies of diarrheal dz is routinely done

FALSE

3

Hepatitis __ virus accounts for about 90% of viral hepatitis infections worldwide

A

4

T/F: Majority of Hepatitis A infections are asymptomatic

TRUE

****infection in infancy or childhood is asymptomatic

5

Where does hepatitis A replicate? How is it shed?

replicates in the liver and causes hepatitis

then the virus is shed into bile and is excreted in the feces

6

Many cases of hepatitis A are acquired when _______

Traveling

7

Who is the most important reservoir of Hepatitis A?

Humans

via feces

The virus is shed 1-3 weeks before illness and up to several weeks after recovery ***long shedding period

8

T/F: In areas with high endemicity of Hepatitis A there are numerous clinical cases reported

FALSE

*in these areas the majority of the population are infected as children - therefore there is minimal clinical dz

*occurs in least developed countries with poor socioeconomic status

9

In more developed countries where there is a low endemicity of Hepatitis A, is there a high or low clinical disease?

There are more outbreaks of clinical disease

In these countries, the average age of infection goes up. More adults are susceptible

*remember in children/young people - they tend to be asymptomatic

10

What are the modes of transmission of Hepatitis A and which is most important?

Direct: Fecal-oral = most important (close personal contact, poor personal hygiene, infected food handlers)

Vehicle: food, water contaminated with feces (improper sewage tx)

*associated foods = shellfish from contaminated waters, raw produce, Contaminated drinking water, Uncooked foods and cooked foods that are not reheated after contact with an infected handler

11

What is the incubation period of hepatitis A?

average is 28 days
Can range from 15-50 days

12

What is the duration of illness associated with Hepatitis A?

varies from 2 weeks to 3 months

13

What clinical signs will be associated with a Hepatitis A infection?

fatigue, dark urine, jaundice, flu-like symptoms
Nausea/vomiting, anorexia, fever, malaise, or abdominal pain

14

What is described as a positive case definition of hepatitis A according to the CDC?

1. discrete onset of clinical signs: nausea, anorexia, fever, malaise, or abd pain
2. Jaundice or elevated serum aminotransferase

AND

Either positive serologicatl test for IgM to Hep A
OR
An epidemiological link to a lab confirmed case (within the household/sexual partner)

15

How can Hep A be prevented?

1. Target the host: Vaccination (this will reduce the reservoir)

2. Target the vehicle: proper sewage/water tx, proper preparation, cooking, and handling of food - wash veggies and fruit, ***good sanitation

3. Block transmission: personal hygiene and hand washing

16

What is the group of related single stranded RNA, non-enveloped viruses, that cause acute gastroenteritis in humans, and are also known as "winter vomiting disease"?

Noroviruses

(family- calicivirues)

6 recognized groups

17

What is the most common cause of foorborne illness around the world?

noroviruses

18

Noroviruses account for ____% of all KNOWN foorborne illnesses in the US

58%

(only 20% of all domestically acquired foodborne illness)

19

Who is the reservoir of Noroviruses?

How is it shed?

PEOPLE

Feces** and vomit
Shedding begins 18 hours post infection - usually lasts for about 28 days (ranges from 13-56d)

**95 billion viral particles per gram of feces

20

T/F: Once infected with a norovirus, you will gain immunity and likely not be infected again

FALSE

*there are multiple strains with little cross protection

21

What are the modes of transmission of noroviruses?

1. Direct: fecal oral route (close personal contact, poor personal hygiene)

2. Vehicle:
a- food/water contamination with feces (Infected food handlers = MOST IMPORTANT) Also improper sewage tx
--> associated foods: shellfish harvest from contaminated waters, raw produce, uncooked or cooked foods that are not reheated after contact with infected handler

b- FOMITES: surfaces contaminated with fecal material (virus can survive at least one week on counters/surfaces)

22

What is the incubation period and duration of illness of noroviruses?

Incubation= 12 to 48 hours

Duration of illness = 24 - 72 hours

23

What clinical signs are associated with noroviruses?

Nausea, acute onset of vomiting, watery non-bloody dhr with abdominal cramping

24

What are the Kaplan Criteria used to determine if an outbreak was caused by a norovirus? (there are four requirements)

1. Mean (median) illness duration = 12-60 hours
2. Mean (median) incubation period = 24-48 hours
3. More than 50% of people affected --> vomiting
4. No bacterial agent found

(other diagnosis done by Real time PCR of stool/vomit/environmental samples)

25

Who is norovirus treatment most important for?

Children

Supportive care: fluids/electrolytes

26

How can norovirus be prevented?

1. Target vehicle: proper preparation, cooking, handling of food (MOST IMPORTANT), good sanitation

2. Block transmission: personal hygiene, and hand washing

27

T/F: Outbreaks of norovirus are often smaller scale

FALSE

Often larger due to: multiple potential modes of transmission, prolonged asymptomatic shedding, virus stability in environment, lack of cross protective immunity

28

The increase in gastroenteritis on cruise ships is primarily attributed to ______

Noroviruses

29

What shellfish has norovirus been known to be transmitted through?

Raw oysters

30

T/F: Strains of rotavirus in animals and people are distinct

TRUE