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The Biologic Incident

The Biologic Incident. Management of Biological Casualties. Hospital Management of Biological Casualties. Biological Warfare Agents Terminal Objective. Be able to describe the various types of biological warfare agents and recognize the signs and symptoms of exposure.

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The Biologic Incident

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  1. The Biologic Incident Management of Biological Casualties

  2. Hospital Management of Biological Casualties

  3. Biological Warfare AgentsTerminal Objective • Be able to describe the various types of biological warfare agents and recognize the signs and symptoms of exposure. • Be able to describe how to properly manage and treat infectious victims • Know which agents are a risk for secondary transmission and how to protect against this spread using personal protective equipment (PPE) and isolation measures.

  4. Biological Warfare (BW) Agents - History • Oldest of the NBC triad of agents • Used for > 2,000 years • Sieges of middle ages • Smallpox blankets given to Native Americans • Germany in World War I • Japan in World War II

  5. Aerosol / Infectivity Relationship Infection Severity Particle Size (Micron, Mass Median Diameter) The ideal aerosol contains a homogeneous population of 2 or 3 micron particulates that contain one or more viable organisms Less Severe More Severe 18-20 15-18 7-12 4-6 (bronchioles) 1-5 (alveoli) Maximum human respiratory infection is a particle that falls within the 1 to 5 micron size

  6. BW - Epidemiologic Clues • Large epidemic with high illness and death rate • HIV(+) individuals may have first susceptibility • Respiratory symptoms predominate • Infection non-endemic for region • Multiple, simultaneous outbreaks • Multi-drug-resistant pathogens • Sick or dead animals • Delivery vehicle or intelligence information

  7. BW - Epidemiological Information • Travel history • Infectious contacts • Employment history • Activities over the preceding 3 to 5 days

  8. Biological Agents - Types and Characteristics Bacteria Viruses Toxins

  9. Bacteria as Biological Agents • Bacteria • Single celled microorganism • Invade tissue; cause inflammatory reaction or produce toxins • May form spores • Anthrax • Plague • Tularemia • Q Fever

  10. Anthrax - Microbiology • Bacillus anthracis - gram +, spore-forming bacillus • Endemic infection in animals • Humans develop infection naturally from handling contaminated fluids or hides (“Woolsorters Disease”)

  11. Anthrax - Pathogenesis • Inoculation, ingestion, or inhalation of spores which may travel to the regional lymph nodes • Vegetative bacteria produce edema factor and lethal factor (toxins) • Inhalation route has highest mortality and is most likely route to be used by terrorists • Inhaled anthrax causes a mediastinitis rather than a pneumonia • Untreated skin infection - 21% mortality if septicemia develops (treated 1%)

  12. Cutaneous Anthrax

  13. Gastrointestinal Anthrax

  14. Inhalational Anthrax • 2 to 6-day incubation period followed by fever, myalgias, cough, and fatigue • Initial improvement followed by abrupt onset of respiratory distress, shock, and death in 24 to 36 hours • Physical findings are nonspecific, pneumonia is rare • Chest x-ray - may show widened mediastinum with or without a bloody pleural effusion • 50 % of cases have associated hemorrhagic meningitis

  15. Prevention of Secondary Anthrax Transmission • No documented cases of person-to-person transmission of inhalational anthrax has ever occurred • Cutaneous transmissions are possible • Universal precautions required

  16. Anthrax - Soviet Incident An accident at a Soviet military compound in Sverdlovsk (microbiology facility) in 1979 resulted in an estimated 66 deaths downwind. Biological Warfare research, production and storage facility Path of airborne Anthrax MOSCOW Sverdlovsk

  17. Inhalational Anthrax - Sverdlovsk

  18. Inhalational Anthrax Post Mortem - Sverdlovsk

  19. BW Anthrax - Diagnosis • Clinical picture of sudden onset of respiratory distress with mediastinal widening on x-ray • A small number of patients may present with GI or cutaneous anthrax • Gram stain of blood and blood cultures - but these may be late findings in the course of the illness • ELISA and immunohistology testing may confirm diagnosis but samples must go to reference laboratory

  20. Anthrax - Treatment Acute Treatment • Usually futile in severe mediastinitis patients who inhaled or ingested spores • Ciprofloxacin - 400 mg IV q 8 to 12 hr • Doxycycline - 100 mg IV q 12 hr X 4 wks • Vaccination begins at the start of drug therapy • Post-exposure • Oral prophylaxis • Ciprofloxacin (500 mg po q 12 h) X 4 wks until 3 doses of vaccine • Doxycycline (100 mg po q 12 h) X 4 wks until 3 doses of vaccine • FDA licensed vaccine

  21. Anthrax - Pediatric Treatment Prophylaxis • Penicillin • Doxycycline IV Therapy • Penicillin • Doxycycline

  22. Anthrax Disease Complex Summary 1 - 6 days ABRUPT ONSET GI Inhalational Tracheobronchial Lymphadenitis Cutaneous Mediastinitis, cyanosis, stridor, pulmonary edema Hemorrhagic Meningitis Papule Õ vesicle edema + eschar 50% 24 - 36 hours Toxic shock and Death 20% Resolve

  23. Plague - Microbiology • Yersinia pestis - gram(-), non-motile, non-spore forming bacillus • Fleas living on infected rodents spread infection to humans • Recovery offers temporary immunity

  24. Plague - Pathogenesis • Produces disease by being consumed by macrophages and transported to regional lymph nodes, causing regional adenitis • Bacteremia - spread to other organs (lungs, spleen, liver, and brain)

  25. Plague Transmission Fleas (active or dormant) Aerosol PNEUMONIC Surface contact Rodent BUBONIC and SEPTICEMIC SECONDARY PNEUMONIC and OROPHARYNGEAL

  26. Pneumonic PlaguePrevention of Secondary Infection • Secondary transmission is possible and likely • Standard, contact, and aerosol precautions for at least 48 hrs until sputum cultures are negative or pneumonic plague is excluded

  27. Plague Endemic Counties Counties with Plague-Positive Samples 1970 - 1994

  28. Inhalational (Pneumonic) Plague Signs and Symptoms • 2 to 3 day incubation period followed by high fever, myalgias, chills, HA, and cough with bloody sputum • In contrast to anthrax, pneumonia and sepsis develop acutely and may be fulminant with patients developing dyspnea, stridor, cyanosis, and circulatory collapse • Patchy infiltrates or consolidation seen on chest x-ray

  29. Bubonic PlagueSigns and Symptoms • Erythema, fever, rigors • Bubo formation in regional lymph nodes • Bubo aspiration and gram stain is diagnostic • Differentiate from • Tularemia • Cat-scratch fever • Staph-strep lymphadenitis

  30. Acral Gangrene Acral gangrene may be a late complication of pneumonic or septicemic plague, and may occur in the finger, toes, earlobes, nose, and penis.

  31. Plague - Acral Gangrene

  32. Plague - Diagnosis • Gram stain and culture of lymph node aspirates, sputum, or CSF samples • Bipolar staining “Safety Pin” may be present • Immunoassays are also available

  33. Plague - Treatment • Care is otherwise supportive • Vaccine effective only for bubonic plague • Prophylaxis - tetracycline or doxycycline • Antibiotics must be started within 24 hours of symptoms to impact survival • Streptomycin (30 mg/kg/day IM divided BID for 10 days) • Doxycycline (100 mg IV BID for 10 days) • Chloramphenicol for plague meningitis Respiratory isolation mandatory for at least the first 48 hours of treatment

  34. Plague - Pediatric Treatment Prophylaxis • Doxycycline • Trimethoprim/Sulfamethoxazole IV Therapy • Streptomycin (over 1 year of age) • Gentamicin • Chloramphenicol

  35. Plague Disease Complex Erythema Fever/rigors ­ APTT ecchymosis DIC Tender bubo 1 - 10 cm Inhalational Pharyngitis 2 -3 days Sudden onset 9% 2 - 10 days 24 hrs Stridor, cyanosis, productive cough, bilateral infiltrates Fulminant Pneumonia Systemic Toxicity Fever, URI syndrome Liver enzymes ­­ 6% late meningitis Leukemoid reaction Respiratory failure & circulatory collapse Gram - ve rods in sputum

  36. Viruses as Biological Agents • Smallpox • Viral Hemorrhagic Fevers (VHF) • Venezuelan Equine Encephalitis (VEE)

  37. Viruses - General Characteristics • RNA or DNA within a protein coat • Require a host to function and survive • Many viruses attack a specific type of cell causing disease or cancer

  38. Viruses - General Characteristics • May cause disease through direct cytopathic effect, immune complex deposition and other effects • May result in end-organ system failure, vascular damage • Few antiviral medications available • Vaccination is the most effective means of preventing infection

  39. Smallpox - Microbiology • Variola (Var-ï-óla) virus, an Orthopox virus, both minor and major forms of smallpox exist • Structure is a large DNA virus • Declared eradicated in 1980 and the U.S. stopped its civilian vaccination in 1981, U.S. military stopped in 1985

  40. Smallpox - Pathogenesis

  41. Smallpox - Case Study • In 1963, en route by air from Australia to Sweden, a seaman stops in Djakarta, Singapore, Rangoon, Calcutta, Karachi, Teheran, Damascus, and Zurich • Fifteen days later he develops a fever and rash • Diagnosed with smallpox; 19 cases identified • More than 300,000 vaccinated worldwide

  42. Smallpox - Diagnosis & Treatment DIAGNOSIS • Clinical presentation • Demonstrate virus from vesicular sampling via electron microscopy • Confirmation by tissue culture • TREATMENT • Supportive • Vaccine still available from CDC • Immune globulin may also be available from CDC

  43. Smallpox - Prevention of Secondary Infection • Contagious • All contacts are quarantined for at least 17 days • Infectious until all scabs are healed over

  44. Monkeypox Virus

  45. Smallpox / Monkeypox - Clinical Course Summary Exanthema on face, arms, hands Macules ®papules ® pustular vesicles Inhalational 8 - 10 days Replication in regional node of airways 12 day incubation 2 - 3 days Scabs separate + pt non-infective Flat Smallpox Viremia Acute malaise, fever, rigors, headache variants Hemorrhagic Smallpox rapid death before typical lesions + mental status changes

  46. Viral Hemorrhagic Fevers (VHF) - Microbiology • RNA viruses causing high fevers and generalized vascular damage • Human infections by insect bites or by contact with blood and body fluids

  47. VHF Pathogenesis • Fever, myalgias, prostration • Cases evolve into shock and generalized mucous membrane hemorrhage • Conjunctival injection, petechial hemorrhage, and hypotension • Abnormal renal and LFT - poor prognosis • Mortality varies; 50 - 80% Ebola Zaire • Disease severity and survival depends on various host factors; target organ is the vascular bed.

  48. VHF Treatment • Hemodynamic resuscitation and monitoring • Invasive Swan Gantz catheter as feasible • Careful fluid management • use of colloid • Vasopressors and cardiotonic drugs • Cautious sedation and analgesia • No anti-platelet drugs or IM injections • Coagulation studies and replacement of clotting factors / platelet transfusions

  49. Prevention of Secondary VHF Transmission • No vaccine is available at this time • Single room w/ adjoining anteroom as only entrance • handwashing facility with decontamination solution • Negative air pressure if possible • Strict barrier precautions • gloves, gown, mask. shoe covers, protective eyeware/faceshield • consider HEPA respirator for prominent hemorrhage, vomiting, diarrhea, cough

  50. Prevention of Secondary VHF Transmission • Chemical toilet • All body fluids disinfected • Disposable equipment/sharps into rigid containers and autoclaved/incinerated • Double-bag refuse-outside bag disinfected • Electronic/mechanical equipment can be paraformaldehyde disinfected

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