Fig. 6.9

Table 6.1

Most common foodborne viruses in the US are: Hepatitis A, Norovirus, Rotavirus Viral gastroenteritis -> schools, child care facilities, and nursing homes, and can also occur in other group settings, such as banquet halls, cruise ships, dormitories, and campgrounds Water, salads, shellfish, iced drinks, and other ready-to-eat foods are common sources of viral foodborne illnesses. The points of potential contamination determine the appropriate intervention strategy for preventing a viral foodborne disease

http://www.youtube.com/watch?v=xrZNzjYjIuA

Fig. 6.4

Fig. 6.6

Fig. 6.11

Fig. 6.12

Fig. 6.13

Fig. 6.14

Fig. 6.15

Fig. 6.16

Table 6.2a

Viruses smallest infections agents intracellular parasites-can reproduce only in host cells can not carry on independent metabolism viruses are not cellular – not autopoietic consist only of a nucleic acid either DNA or RNA, surrounded by a protein coat.

Viruses continued the protein coat of the virus determines what type of cells the virus can parasitize & acts to protect the nucleic acid inside a virus that attacks the bacterial cells is known as a phage or bacteriophage a phage consists of a head made from a protein membrane with 20 facets (sides) surrounding either DNA or RNA, the tail combines a collar attached to a tail sheath

Ebola Virus

6 months-5 or more years, up to 10 years. HIV/AIDS Incubation period (the period between becoming infected and the actual development of the symptoms) 6 months-5 or more years, up to 10 years. Sometimes a mild illness--flu like symptoms appears 7-14 days after infection Sometimes no symptoms appear for years. It is accepted that once infected with HIV, AIDS will develop at some time in the future in all cases. Opportunistic infections associated with AIDS can be treated.

Hepatitis Viral hepatitis is the most common liver disease found worldwide Hepatitis A - RNA virus, usually spread by fecal-oral route; transmitted person-to-person by ingestion of contaminated food or water or through direct contact with an infectious person, tens of millions of individuals worldwide are estimated to become infected with Hep A each year Hep A infection rates are higher in areas with low hygiene standards Symptoms: fatigue, fever, jaundice, nausea, appetite loss

Hepatitis B (HBV) DNA virus Long incubation period—up to 6 months Risk factors for HBV infection include working in a healthcare setting, transfusions, tattooing, extended overseas travel, and residence in an institution acute illness causes liver inflammation, vomiting, jaundice and death (rare) The infection is preventable by vaccination

Hepatitis C HCV is spread primarily by blood-to-blood contact associated with intravenous drug use, poorly sterilized medical equipment and transfusions An estimated 130–170 million people worldwide are infected with hepatitis C No vaccine, but treatment with a combination of interferon and ribavirin (nucleoside inhibitor – stops RNA synthesis) is about 70% effective

Hepatitis D Super-infects some patients who are already infected with HBV HBV is required as a helper to initiate infection caused by a small circular enveloped RNA virus blood borne

Hepatitis E single-stranded RNA virus HEV has a fecal-oral transmission route Hepatitis E most common in developing countries and hot climates Widespread in Southeast Asia, northern and central Africa, India, and Central America Spread mainly through fecal contamination of water supplies or food; person-to-person transmission is uncommon.