1. Viral Diseases of the Digestive and Lymphoid Organs
Plate 84
Viral Diseases of the Digestive and Lymphoid Organs

4. Viral Gastroenteritis
Viral gastroenteritis: inflammation of stomach and intestines
Often called “stomach flu”, although it is not caused by the influenza virus
Symptoms: primarily diarrhea and vomiting, but also headaches, fever, and stomach-ache

5. Yellow fever Sometimes known as “yellow jack” or “black vomit”
Called “yellow fever” because of the jaundice that it causes
RNA icosahedral (Flaviviridae family) virus

6. Symptoms
3-6 days of incubation, then 3-4 days of fever and muscle pain
Most patients improve and symptoms disappear
15% of patients enter a 2nd toxic phase:
Bleeding from mouth, nose, eyes, and/or stomach
Kidney failure
Jaundice
50% mortality in 14 days
No cure, just treatment for symptoms

7. Symptoms Jaundice – “yellowing” of skin and eyes
Bile passes from the gallbladder and/or liver into the bloodstream

8. Transmission The virus is transmitted via mosquito bites
Virus passes from the mosquito’s saliva to the human bloodstream
Can also pass from monkeys to mosquitoes to humans
Aedes aegypti mosquito

9. Transmission
Estimated 200,000 cases and 30,000 deaths per year worldwide
Vaccine is very effective
Cases have increased over the past 20 years due to urbanization, deforestation, and climate change

10. Philadelphia
Summer 1793, French refugees (some who had Yellow Fever) fled the Haitian Revolution and came to Philadelphia
By November 1793, about 5,000 Philadelphians had died (more than 10% of population)
Summer 1794, Yellow Fever returned, but not as severely, and also in 1796 and 1797
Another severe epidemic came in 1798, killing 1,292 Philadelphians
At the peak of the 1798 epidemic, all but 7,000 residents had left the city

11. Dengue Fever Also known as “break-bone” fever
RNA icosahedral (Flaviviridae family) virus

12. DF - Symptoms
Dengue fever has symptoms which can be very similar initially to flu
Most people suffer from headaches and fever, some get muscle and bone pains
An infected person can feel tired for up to three months, but will not usually need treatment
May lead to Dengue Hemorrhagic Fever (DHF), which is potentially lethal

13. DF - Symptoms (continued)
Itchy rash. Everywhere I had ever been injured hurt again. Achy like the flu but worse. Exhausted. Literally took months to regain full energy and stamina.

14. DF - History
Dengue fever originated in primates and “jumped” to humans years ago
Because of disruption from WWII and international trading of cargo, the Aedes mosquito has spread to tropical regions around the world
Not until 1981 that the disease became problematic in Latin America and the Caribbean

15. DF - Location
40% of the world’s population live in areas where they are at risk for dengue transmission
WHO estimates that there are million infections a year and 22,000 deaths

16. DF - Treatment
There is no cure for dengue fever nor is there specific medication for it
Patients should rest, take pain-relievers, and drink plenty of fluids

17. DF - Transmission
Dengue viruses are mainly transmitted by the bite of infected Aedes aegypti mosquitoes

18. Mononucleosis The “kissing disease”
Epstein-Barr virus (human herpesvirus 4)

19. Mono - Symptoms

20. Mono - Symptoms

22. Mono Symptoms - Swollen Tonsils

23. Mono - Transmission
Virus spread through salivary drops

24. Hepatitis A
RNA enterovirus (hepatitis A virus – HAV)

25. HAV - Symptoms Can cause: Swelling of the liver Jaundice Fatigue
Loss of appetite
Diarrhea

26. HAV - Transmission
Spread primarily by food or water contaminated by stool from an infected person
Eating food prepared by someone with HAV who did not wash their hands after using the bathroom

27. Hepatitis B
Hepadnavirus (hepatitis B virus – HBV)

28. HBV - Symptoms Short-term HBV resembles symptoms of the flu
Possible symptoms include fever, dark urine, vomiting, and jaundice
Long-term HBV (chronic HBV) lasts a lifetime and can lead to scarring of the liver, liver failure, and liver cancer
Interferon can be used to slow the virus from damaging the liver

29. HBV - Transmission
HBV is spread through contact with blood, semen, or other body fluids of an infected person

30. Hepatitis C Symptoms Long term Info.
jaundice, fatigue, dark urine, nausea
Long term
infections (55-85%), leading indication for transplant,
Info.
No vaccine, interferon, do not share personal items, rarely STD

31. Hepatitis D Symptoms Long Term Info.
jaundice, fatigue, tea-colored urine joint pain
Long Term
more sever acute disease & risk of failure
Info.
acquires along with HBV

32. Hepatitis E Symptoms Long Term Info.
Jaundice, dark urine, loss appetite, fatigue
Long Term
no long term often seen in pregnancy
Info.
highest among yo, contaminated water