Rabies and Public Health

1. Rabies and Public Health History Epidemiology Pathogenesis Response

2. History • A recognized disease as early as 2300 BC • Aristotle wrote about rabies in 322 BC • Saliva of rabid dogs was recognized as “venomous” in the 1st century AD

3. History • First documented case in US • Virginia, 1753 • Colonial times-1950s • Dogs highest vector risk • 1960s-today • Wildlife greatest reservoir

4. Historyzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz • Raccoon rabies: • Noticed in FL in mid 50s • Spread to VA in 1970s • Seen everywhere but sw VA • Skunk rabies • Present in low levels in sw VA since 1960s

7. Epidemiology

8. Epidemiology

9. Cases of Animal Rabies, Virginia, 1999-2003

10. Rabies distribution

11. Disease Transmission • Almost always a bite • Virus cannot enter intact skin • Virus can cross mucus membranes • Less efficient • Breaks in skin are a risk only if wet saliva gets in wound

12. Pathogenesis • Virus enters the body • Virus enters NM junctions • Travels via peripheral nerves to spinal cord • Then to brain stem and forebrain

13. Disease in Animals • Two major clinical types in dogs and cats • Furious • Restless, irritable, disoriented, seizures • More common in cats • Paralytic • Extremity paralysis, altered bark, salivating • More common in dogs

14. The Disease in Man • Initial clinical symptoms include anxiety, headache, mild fever, irritation at bite site • Progresses to muscle spasms, difficulty swallowing, hydrophobia • Clinical course is typically short

15. Rabies Timeline incubation exposure virus shed. signs death dogs 10 d-6 m 0-5d 0-8d hu 5d-6y 2-14d Other ? ? ?

16. Laboratories • Fairfax County HD • Norfolk HD • DCLS Southwest Micro lab. • DCLS Central lab.

17. Testing • An animal involved in significant human exposure. • An animal involved in significant domestic animal exposure. • A bat when significant human exposure can not reasonably be determined.

18. Significant exposure • Bite • Saliva contact with mucus membrane or skin break

19. Testing • Direct Fluorescent Antibody(DFA) • May be used on fresh or decomposed tissue. • Produces sensitive and rapid results. • Considered the most reliable of all available technologies. • Daily quality control steps assure accuracy.

20. Principles of DFA Fluorochrome-labeled Antibody to Rabies Virus Rabies Virus infected Cell Labeled Antibody-Rabies Virus

21. DFA Results < Positive Brain Negative Brain >

22. Public Health Response

23. Public Health Response • Human exposed to dog, cat or ferret • Observe animal for 10 days • Test if illness or death w/in observation period • Should be discussed with health director • IS NOT DEPENDENT ON VACCINATION STATUS

24. Public Health Response • Human exposed to livestock • Typically 10-14 days observation • Possibly testing + Post exposure tx. (PEP)

25. Public Health Response

26. Public Health Response • Vaccinated dog, cat or ferret exposed • Proof of current immunization • Immediate booster • 45 days confinement • Testing if signs of rabies develop

27. Public Health Response • Unvaccinated dog, cat, ferret exposed • Euthanize or 6 months isolation • Vaccinate one month prior to release • Test if signs of rabies develop

28. Public Health Response • Expired vaccination • Euthanize or 6 month isolation • Vaccinate immediately and one month prior to release • Depending on the circumstances, some of these animals can be considered as currently vaccinated

29. Public Health Response • Livestock exposed • Vaccinated • Boost and 3 months observation • Unvaccinated • Immediate slaughter or • 6 months observation

30. Public Health Response • Wildlife exposures • No observation time • High risk species • Low risk species • Test when possible or situation warrants

31. Public Health Response • Control/Education • Vaccinate dogs and cats • Wildlife vaccination initiatives • Animal control • Avoid direct contact with wildlife • Pre-exp. vaccination for high risk professions

32. Public Health Response • Control/Education • Prompt attention to bites • Good communication with all parties involved in follow up • Prompt PEP when necessary

33. Recent cases in Virginia • 1998-unknown exposure, silver haired bat variant, prison in work program • 2003-raccoon variant, no history of exposure, diagnosed 3 months after death

34. Rabies Fun Facts • Early treatments for rabies in people included: • Total immersion in salt water • Lighting gunpowder in wounds • Blood letting

35. Rabies Fun Facts • Famous bite victims: • Emily Bronte • Cardinal Crescence, 1532 • Rabies was eradicated from the Scandinavian countries as early as 1832 • Some MDs used to advise that if a dog drank after biting, the dog could not be rabid

36. Interesting situations • Concerning non-bite exposures • Bat • Raccoon • Goat • Concerning low risk exposures • Monkey

37. Post Exposure Potpourri • Peruvian PEP • Old PEP • PEP reactions

38. Good Resources • www.vdh.virginia.gov • VDH Programs • Epidemiology Program • Zoonotic and Environmental Epi.

39. Good Resources • www.cdc.gov/healthypets • www.cdc.gov/ncidod/dvrd/rabies • www.nasphv.org

40. Questions?