Foodborne Viral Infections

Question 1

Give me the characteristics of Poliovirus

Answer 1

• RNA genome
• Protein capsid (non-enveloped)
• Is an enterovirus (infection occurs via the fecal oral route)
• 95% of the time only transient viremia occurs and infection is asymptomatic

Question 2

In 5% of cases where viremia occurs (poliovirus) symptoms include:

Answer 2

• fever
• headache
• sore throat
• in 1% of cases paralytic poliomyelitis occurs

Question 3

what is paralytic poliomyelitis :

Answer 3

• a paralytic disease of when the virus enters the CNS and replicates in the motor neurons of the spinal cord, brain stem, and motor cortex
• it results in the destruction of motor neurons and temporary or permanent paralysis

Question 4

Poliovirus can be associated with the consumption of which product?

Answer 4

milk and milk-products

pasteruization of milk at above 70C for 30s deactivates the virus

Question 5

What are the 2 types of vaccines used to prevent poliovirus?

Answer 5

• Inactivated poliovirus vaccine (IPV)

- Oral poliovirus vaccine (OPV)

Question 6

What are the 3 serotypes of poliovirus and how do they differ:

Answer 6

-PV1 (most common in nature)
-PV2 (likely eradicated)
-PV3 (likely eradicated)
they each have a slightly different capsid protein

Question 7

Give me the characteristics of Hepatis A Virus (HAV)

Answer 7

• single stranded RNA
• non-enveloped
• spread through fecal oral route, but mostly affects the liver, causing viral hepatitis
• most cases have few or no symptoms (especially in young children)

Question 8

What happens when symptoms occur in HAV

Answer 8

• symptoms can last 8 weeks
• include nausea, vomiting, diarrhea, jaundice, fever, and abdominal pain
• acute liver failure may occur mostly in elderly

Question 9

How can HAV spread ?

Answer 9

• spread by eating food or drinking water that is contaminated with infected feces
• shellfish which have not been sufficiently cooked are a relatively common source
• it can also spread from an infected person if there is sustained close contact
• kids that are asymptomatic can still infect others
• **-a single infection leads to lifelong immunity ***

Question 10

What can you do for HAV prevention?

Answer 10

• HAV vaccine (very effective and appears to give lifelong immunity)
• the majority of children in the developing world have been infected and are thus immune by adulthood
• hand washing and properly cooking food in areas where the disease is endemic are also important

Question 11

For HAV, recovery usually occurs without ongoing liver disease , though the treatment for acute liver failure is a ________

Answer 11

transplant

Question 12

HAV outbreaks in North America occured do to which type of product?

Answer 12

frozen strawberries (fronzen fruits)

Question 13

HAV survives ____________ and exposure to ______________ it is resistant to desiccation and can remain infectious for several months on frozen foods

Answer 13

mild pasteurization

high temperatures

Question 14

HAV infection generally occurs in the ________________, by then HAV enters the_________

Answer 14

intestine
bloodstream
(the blood carries the virus to the liver where it can multiply in hepatocytes)

Question 15

HAV is excreted in large numbers in the stool about ________ prior to the appearance of symptoms

Answer 15

11 days

Question 16

Diagnosis of HAV is made by the detection of ______ in the blood

Answer 16

IgM antibodies in the blood - IgM is only present following acute HAV infection

Question 17

The presence of ______ means that the acute phase has passed (HAV), and the person is immune to further infection

Answer 17

IgG

Question 18

Talk to me about Norovirus :

Answer 18

• It is the most common cause of gastroenteritis world wide and in Canada
• There are no vaccines or effective treatments
• Infections cause non-bloody diarrhea, vomiting and stomach pain
• Typically recovers in 1-3 days
• positive-sense RNA, non-enveloped

Question 19

Where is the illness easily spread (Noroviruses):

Answer 19

• in group settings where people are in close contact
• schools
• hospitals
• childcare facilities
• nursing homes
• cruise ship

Question 20

(Norovirus) : vomiting appears to allow the virus to spread via ____________

Answer 20

airborne transmission

Question 21

________ and _______ ingredients are most implicated in norovirus outbreak

Answer 21

shellfish and salad

any type of foods can also be contaminated by infected food handlers

Question 22

Give me the characteristics of Rotavirus:

Answer 22

• non-enveloped virus
• double stranded DNA
• most common cause of diarrheal disease among infants and young children
• nearly every child in the world is infected with rotavirus once by the age of 5

Question 23

why was the 1998 Rotavirus vaccine removed from the market in 1999

Answer 23

because it increased the risk of a type of bowel obstruction in one in every 12,000 cases

Question 24

Talk to me about the symptoms of rotavirus :

Answer 24

• nausea
• vomiting
• watery diarrhea
• low-grade fever
• incubation period of 2 days before symptoms appear in the child
• the period of illness is acute
• symptoms start with vomiting followed by 4 to 8 days of profuse diarrhea
• dehydration is more common in rotavirus infection than in most of those bacterial pathogens and is the most common cause of death related to rotavirus infection