Bioterrorism: Getting the Big Picture

1. Bioterrorism: Getting the Big Picture Texas Society of Infection Control Practitioners

2. This program has been created and made possible through a grant from the Texas Department of Health.

3. Goal • At the end of this workshop Infection Control Practitioners will be able to describe various components necessary to develop and implement a successful bioterrorism preparedness program

4. Objectives • Name the 6 Category A Biological Agents, treatment and prophylaxis • Discuss appropriate laboratory support systems for dealing with bioterrorism events • Describe key concepts of Mental Health in Disasters/Bioterrorism

5. Objectives • List appropriate infection control precautions for Category A biological agents • Identify security, transportation and communication needs in your facility • Identify roles of external agencies in a disaster event

6. Definition of Bioterrorism • The unlawful use, or threatened use, of microorganisms or toxins derived from living organisms to produce death or disease in humans, animals, or plants. The act is intended to create fear and/or intimidate governments or societies in the pursuit of political,religious, or ideological goals. Saint Louis Unversity School of Public Health

7. Bioterrorism Agents • Potentially hundreds • Features of most likely agents • Availability • Ease of production • Lethality • Stability • Infectivity Saint Louis Unversity School of Public Health

8. Bioterrorism: A Legitimate Threat • Most agents relatively easy to produce • Availability of information on the Internet • Access to dual use equipment • Relatively inexpensive • 1970 study–cost of 50% casualty rate per km2 • conventional - $2,000 • nuclear - $800 • anthrax - $1 Saint Louis Unversity School of Public Health

9. Bioterrorism: A Legitimate Threat • Dissemination may cover large area • Difficult to detect release • Symptoms occur days or weeks later • Some have secondary spread Saint Louis Unversity School of Public Health

10. Bioterrorism: A Legitimate Threat • Use can cause panic • Users able to protect selves • Users can escape before effect Saint Louis Unversity School of Public Health

11. Bioterrorism: A Legitimate Threat • Former Soviet scientists successfully weaponized many agents • Active research was undertaken to engineer more virulent strains Saint Louis Unversity School of Public Health

12. Bioterrorism: A Legitimate Threat • With the collapse of the Soviet Union, microbe stock & technology has possibly landed in hands of terrorists • State sponsorship of terrorism • At least 17 nations are known to have offensive biological weapons programs Saint Louis Unversity School of Public Health

13. Delivery Mechanisms • Aerosol likely route for most agents • Easiest to disperse • Highest number of people exposed • Most contagious route of infection • Food / Waterborne less likely • Only effective for some agents Saint Louis Unversity School of Public Health

14. Epidemiology • Clues suggesting a bioweapon release • Large numbers present at once (epidemic) • Previously healthy persons affected • High morbidity and mortality • Unusual syndrome or pathogen for region • Recent terrorist claims or activity • Unexplained epizootic of dead, sick animals Saint Louis Unversity School of Public Health

15. Role of Primary Care Physician • Have a high level of suspicion • Keep BT agents in differential diagnosis • Recognize typical BT disease syndromes • Be aware of unusual epidemiologic trends • Know treatment/prophylaxis of BT agents • Know how to report suspected BT cases Saint Louis Unversity School of Public Health

16. Bioterrorism-DiseasesRisk Category A

17. Category A Biological Agents • Can be easily disseminated or transmitted from person to person • Result in high mortality rates and have the potential for major public health impact • Might cause public panic and social disruption • Require special action for public health preparedness Centers for Disease Control

18. Category A Biological Agents • Anthrax • Botulism • Plague • Smallpox • Tularemia • Viral Hemorrhagic Fever Centers for Disease Control

19. Category B Biological Agents • Are moderately easy to disseminate • Result in moderate morbidity rates and low mortality rates • Require specific enhancements of CDC's diagnostic capacity and enhanced disease surveillance Centers for Disease Control

20. Category B Biological Agents • Brucellosis • Epsilon toxin of Clostridium perfringens • Food safety threats • Salmonella • E. coli O157:h7 • Shigella Centers for Disease Control

21. Category B Biological Agents • Glanders • Melioidosis • Psittacosis • Q Fever • Ricin toxin • Staphylococcal enterotoxin B Centers for Disease Control

22. Category B Biological Agents • Typhus fever • Viral encephalitis • Water safety threats • Vibrio cholerae • Cryptosporidium Centers for Disease Control

23. Category C Biological Agents • Third highest priority agents include emerging pathogens that could be engineered for mass dissemination in the future because of: • availability • ease of production and dissemination and • potential for high morbidity and mortality rates and major health impact Centers for Disease Control

24. Category C Biological Agents • Emerging infectious diseases • Nipah virus • Hantavirus Centers for Disease Control

25. Common Clinical Manifestations of Bioterrorism Agents • Skin lesions w/fever • Acute respiratory distress w/fever • Influenza-like illness • Neurologic syndromes

26. Skin Lesions w/Fever • Smallpox • Cutaneous Anthrax

27. Acute Respiratory Distress w/Fever • Inhalation Anthrax • Pneumonic Plague

28. Flu-like Illnesses • Tularemia • Inhalational Anthrax • Viral Hemorrhagic Fever • Smallpox • (Pretty much everything except the kitchen sink!)

29. Neurologic Illnesses • Ricin • VX • Sarin gas • Mustard gas • Botulism

30. Smallpox

31. Smallpox: History • Caused by variola virus • Most deaths of any infectious disease • ~500 million deaths in 20th Century • ~2 million deaths in 1967 • Known in ancient times • Described by Ramses • Natural disease eradicated • Last U.S. case – 1949 (imported) • Last international case – 1978 • Declared eradicated in 1979 Photo: National Archives Saint Louis Unversity School of Public Health

32. Smallpox: Bioweapon Potential • Features making smallpox a likely agent • Can be produced in large quantities • Stable for storage and transportation • Known to produce stable aerosol • High mortality • Highly infectious • Person-to-person spread • Most of the world has little or no immunity Saint Louis Unversity School of Public Health

33. Smallpox: Bioweapon Potential • Current concerns • Former Soviet Union scientists have confirmed that smallpox was successfully weaponized for use in bombs and missiles • Active research was undertaken to engineer more virulent strains • Possibility of former Soviet Union virus stock in unauthorized hands Saint Louis Unversity School of Public Health

34. Smallpox: Bioweapon Potential • Nonimmune population • <20% of U.S. with substantial immunity • Availability of virus • Officially only 2 stocks (CDC and Russia) • Potential for more potent attack • Combined with other agent (e.g. VHF) • Engineered resistance to vaccine Saint Louis Unversity School of Public Health

35. Smallpox: Bioweapon Potential • Delivery mechanisms • Aerosol • Easiest to disperse • Highest number of people exposed • Most contagious route of infection • Most likely to be used in bioterrorist attack • Fomites • Theoretically possible but inefficient Saint Louis Unversity School of Public Health

36. Smallpox: Epidemiology • All ages and genders affected • Incubation period • From infection to onset of prodrome • Range 7-17 days • Typical 12-14 days Saint Louis Unversity School of Public Health

37. Smallpox: Epidemiology • Transmission • Airborne route known effective mode • Initially via aerosol in BT attack • Then person-to-person • Hospital outbreaks from coughing patients • Highly infectious • <10 virions sufficient to cause infection • Aerosol exposure <15 minutes sufficient Saint Louis Unversity School of Public Health

38. Smallpox: Epidemiology • Person-to-person transmission • Secondary Attack Rate (SAR) • 25-40% in unvaccinated contacts • Relatively slow spread in populations (compared to measles, etc.) • Higher during cool, dry conditions • Historically 3-4 contacts infected • May be 10-20 in unvaccinated population • Very high potential for nosocomial spread • Usually requires face-to-face contact Saint Louis Unversity School of Public Health

39. Smallpox: Epidemiology • Transmission via fomites • Contaminated hospital linens/laundry • May have been successfully used as weapon in French-Indian War Saint Louis Unversity School of Public Health

40. Smallpox: Epidemiology • Infectiousness – Rash is marker • Onset approx one day before rash • Peaks during first week of rash • ? Carrier state possible • Some data show virus detectable in saliva of contacts who never become infected • Unclear if they can transmit infection, but theoretically possible Saint Louis Unversity School of Public Health

41. Smallpox: Epidemiology • Infectious Materials • Saliva • Vesicular fluid • Scabs • Urine • Conjunctival fluid • Possibly blood Saint Louis Unversity School of Public Health

42. Smallpox: Epidemiology • Role of index case severity • Does not predict transmissibility • Does not predict severity of 2° cases • Role of prior vaccination • Immunity wanes with time • Maintain partial immunity for many years • Partial immunity reduces disease severity • Reduces transmissibility (less virus shed) Saint Louis Unversity School of Public Health

43. Smallpox: Epidemiology • Mortality • 25-30% overall in unvaccinated population • Infants, elderly greatest risk (>40%) • Higher in immunocompromised • May be dependent on ICU facilities • Dependent on virus strain • Dependent on disease variant Saint Louis Unversity School of Public Health

44. Smallpox: Epidemiology • Factors that allowed smallpox eradication • Slow spread • Effective, relatively safe vaccine • No animal/insect vectors • No sig. carrier state (infected die or recover) • Infectious only with symptoms • Prior infection gives lifelong immunity • International cooperation Saint Louis Unversity School of Public Health

45. Smallpox: Microbiology • Variola virus – the agent of smallpox • Orthopoxviridae family • 2 strains of variola • Variola major • Variola minor • Vaccinia • Used for current vaccine • Namesake of “vaccine” • Cowpox – used by Jenner in first vaccine • Monkeypox – rare but serious disease from monkeys in Africa Saint Louis Unversity School of Public Health

46. Smallpox: Microbiology • Variola major • Classic smallpox • Predominant form in Asian epidemics • Highest mortality (~30%) Saint Louis Unversity School of Public Health

47. Smallpox: Microbiology • Variola minor • Same incubation period, mode of transmission, clinical presentation • Causes milder disease • Less severe prodrome and rash • Mortality ~1% • Discovered in 20th century • Started in S. Africa • Was most predominant form in N. America Saint Louis Unversity School of Public Health

48. Smallpox: Microbiology • Environmental survival • Longest (>24hr) in low temp/low humidity • Inactive within few hours in high temp/humidity • Dispersed aerosol • completely inactivated within 2 days of release Saint Louis Unversity School of Public Health

49. Smallpox: Pathogenesis • Virus lands on respiratory/oral mucosa • Macrophages carry to regional nodes • Primary viremia on Day 3 • Invades reticuloendothelial organs • Secondary viremia on Day 8 Saint Louis Unversity School of Public Health

50. Smallpox: Pathogenesis • White Blood Cells infected • WBCs migrate capillaries, invade dermis • Infects dermal cells • Influx of WBCs, mediators cause vesicle • Systemic inflammatory response • Triggered by viremia • Sepsis, multiorgan failure, often DIC Saint Louis Unversity School of Public Health