Food borne viruses Flashcards
All food borne virus have one characteristic that make it available for spreading, compared to COVID, what is it
all food borne are not enveloped
Poliovirus structure
•Poliovirus has an RNA genome and a protein capsid (non-enveloped)
What type of virus is poliovirus, does it cause a lot of diseases?
- Poliovirus is an enterovirus (infection occurs via the fecal oral route)
- Viremia: •In the 5% of cases where viremia occurs, minor symptoms such as fever, headache, and sore throat occurIn about 1% of cases paralytic poliomyelitis occurs
What is the result of poliomyelitis?
- virus enters the central nervous system (CNS) and replicates in the motor neurons of the spinal cord, brain stem, and motor cortex
- This results in destruction of motor neurons and temporary or permanent paralysis.
Is poliovirus eradicated?
•In most of the world, poliovirus is mainly a historical issue, however, some developing countries are still affected–Endemic transmission is continuing in Afghanistan, Nigeria and Pakistan
With what products poliovirus is associated?
•Associated with milk, and milk products–More commonly spread via the fecal oral route person-to-person
What methods can be done to protect from he virus
- Pasteurization of milk at above 70∘C for 30 seconds deactivates virus
- The inactivated poliovirus vaccine (IPV) or the oral poliovirus vaccine (OPV) is very effective at preventing illness
Are there different types of poliovirus, how they are distinguished?
- There are three serotypes of poliovirus PV1, PV2, and PV3 and each have a slightly different capsid protein
- Capsid proteins define cellular receptor specificity and virus antigenicity
What is Circulating-Vaccine Derived Polio Virus
•Circulating vaccine-derived polio virus (cVDPV) could emerge if the weakened live virus contained in oral polio vaccine (OPV), shed by vaccinated children, is allowed to circulate in under-immunized populations for long enough to genetically mutate to a form that causes paralysis.
What is HAV
Hepatis A Virus
Structure of HAV
•HAV is a non-enveloped single-stranded RNA virus
How HAV is transferred?
•HAV is spread through a fecal oral route, but mostly affects the liver, causing viral hepatitis.
Symptoms and complications if any for HAV
- Most cases have few or no symptoms (especially in young children).
- When symptoms do occur thy can last 8 – weeks and include nausea, vomiting, diarrhea, jaundice, fever, and abdominal pain.
- Acute liver failure may occur, mostly in the elderly.
Is there an immunity against HAV
•A single infection leads to lifelong immunity
How HAV can be prevented
- The HAV vaccine is very effective for prevention – and it appears to also give lifelong immunity
- Hand washing and properly cooking food in areas where the disease is endemic are also important
Were there outbreaks in developed world of HAV
-One in US from strawberries from Egypt
-Frozen fruits with HAV in Costco in Canada
What procedures can HAV survive, with what food it is associated
- HAV survives mild pasteurization and exposure to high temperatures, it is resistant to desiccation and can remain infectious for several months on frozen foods
- In Canada, foodborne outbreaks of HAV are most associated with fresh and frozen produce, frozen berries, and pomegranate arils. Outbreaks have also been associated with shellfish, and oysters
How can you HAV is spread from intestine to liver?
- Infection generally occurs in the intestine, but then HAV enters the bloodstream
- The blood carries the virus to the liver where it can multiply in hepatocytes
Clinical Illness and Viral Shedding: scheme, how detection is made, virus in faces
The indicator for liver failure picks, when viremia picks
- HAV is excreted in feces towards the end of the incubation period.
- Diagnosis is made by the detection of IgM antibodies in the blood – IgM is only present following acute HAV infection
- The presence of IgG means that the acute phase has passed, and the person is immune to further infection
What is the most common gastroenteritis cause in the world and in Canada
Norovirus
The structure of norovirus (NoV)
Noroviruses are positive-sense RNA, non-enveloped
How NoV is manifested, cure
There are no vaccines or effective treatments
Infections cause non-bloody diarrhea, vomiting, and stomach pain
Typical recovery occurs in 1-3 days
How NoV is spread, what is the peak season
- Norovirus illness can happen year-round, but outbreaks are more common in fall and winter months
- Vomiting appears to allow the virus to spread via “airborne transmission”
- Noroviruses are found in the stool or vomit of infected people
- People infected with norovirus can be contagious from the moment they start feeling ill to at least three days after they have recovered
Where the most NoV happens
Long term facility
Food sources of NoV in Canada
- Shellfish and salad ingredients are most implicated in norovirus outbreaks
- Any type of foods can also be contaminated by infected food handlers
- Many outbreaks have been traced to food that was handled by a single infected person
Rotavirus structure
•Rotavirus is also a non-enveloped virus – but is double-stranded DNA
Is rotavirus widespread? in what population
- Rotaviruses are the 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
Is there vaccine for rotavirus
_ there was, then declined, now since 2006 there is one again
Rotavirus: symptoms, reason of death
- Rotavirus causes a mild to severe disease characterized by nausea, vomiting, watery diarrhea and low-grade fever
- Once a child is infected by the virus, there is an incubation period of about two days before symptoms appear
- The period of illness is acute
- Symptoms often start with vomiting followed by four to eight days of profuse diarrhea
- Dehydration is more common in rotavirus infection than in most of those caused by bacterial pathogens, and is the most common cause of death related to rotavirus infection
