Viruses

Viruses
Several viruses also cause foodborne illness. Viruses differ from bacteria in that they are smaller, require a living animal or human host to grow and reproduce, do not multiply in foods and are not complete cells.

Ingestion of only a few viral particles is enough to produce an infection.

Humans are host to a number of viruses that to reproduce in the intestines and then are excreted in the feces.

Thus, transmission of viruses comes from contact with sewerage or water contaminated by fecal matter or direct contact with human fecal material.

Raw or uncooked molluscan shellfish (oyster, clams, mussels and scallops) are the food most often associated with foodborne viral diseases.

Human pathogenic viruses are often discharge into marine waters through treated and untreated sewage.

As shellfish filter contaminants from these polluted waters, they store them within their edible tissues.

Shellfish grown and harvested from polluted waters have been implicated in outbreaks of viral diseases.

The other main source of transmission is from infected food workers who have poor personal hygiene.

Therefore, proper hand washing and using a clean water supply are vital to controlling the spread of foodborne viruses.

Hepatitis A is a virus commonly associated with foodborne infections. The incubation period for hepatitis A, before a person develops an symptoms, is anywhere from 10 to 50 days.

It is during this period before symptoms appear that a carrier is most infectious and most likely to spread the disease.

Hepatitis A and many other viral and bacterial pathogens, is most often transmitted via a fecal oral route.

The fact that a person is infectious even before they know they have the disease makes it difficult to control.
Viruses