Bioterrorism and medical countermeasures

Name: Bioterrorism and medical countermeasures
Uploaded: 2017-08-24T09:45:29+00:00
Duration: PTM31S47
Channel: Stacey Featherstone
Description: Bioterrorism and medical countermeasures

Bioterrorism and medical countermeasures
Dr. Marwan Jabr Alwazzeh Assoc. Prof. of Medicine Consultant Internist/Infectious Diseases University of Dammam

What is Biological Warfare?
The use, for hostile purposes, of living organisms, whatever their nature, or infective material derived from them, which are intended to cause disease or death in man, animal, or plants

Bioweapens recent history
Bioweapons have a long history. Recent uses include: U.S, Canada, Great Britain, Japan, and the Soviet Union with anthrax during World War II Post World War II, NATO and the Warsaw Pact nations had bioweapons programs Other countries Bioterrorism

The threat of biological warfare
Biologic agents are likely to be used as weapons because: Relatively easy to procure Potentially inexpensive to produce Unless the terrorists announced the release of agent, detection of the attack would be challenging (odorless, colorless and tasteless) Can be used to attack people, economies and food supplies Cause fear, panic and social disruption

Biological warfare arsenal of the Cold Ware Superpowers (U.S)
Anticrop weapons Incapacitating agents Lethal agents Wheat-stem rust Rye-stem rust Rice-blast spore Venezuelan equine encephalitis Staphylococcal Enterotoxin B Brucella suis Coxiella burnetii Bacillus anthracis Botulinum toxin Francisella tularensis

Biological warfare arsenal of the Cold Ware Superpowers (Soviet Union)
Smallpox Yersinia pestis Bacillus anthracis Botulinum toxin Venezuelan equine encephalitis virus Francisella tularensis Coxiella burnetii Marburg virus Influenza virus Burkholderia mallei Rickettsia typhi

The Ideal Bioweapon Contagious Virulent Robust Difficult to detect
Drug-resistant User-controllable

Characteristics of biological attacks
Incubation periods A delay is likely between the release of the agent and the knowledge that the occurrence is a sinister act A short window of opportunity exists between the first wave and the second wave Several inherent differences that make biological weapons different than conventional or chemical. Covert attack most likely – Perpetrators will be long gone. May be weeks before the attack is detected. No “scene” where victims will be treated or decontaminated. Because of covert attack and incubation – victims may very widely spread out geographically anthrax attack showed that agent may be widely dispersed as well. One of the few disasters/terrorist events where primary healthcare providers are first responders We may be discovering new cases/outbreaks for days, weeks, even months Hoaxes have potential to cause significant impact on healthcare system, law enforcement. (and panic) The potential for casualties is massive (staggering) – especially with agents that spread person to person Ann EM 34: 221

Characteristics of Biological attacks
Victims widely dispersed and likely to present for days to weeks Potential for many casualties “First responders” may be health care providers

Hypothetical dissemination of some infectious agents
Total casualties Deaths Downwind carriage Agent 125000 95000 >>20 km Anthrax 100000 55000 10 km Plague 30000 >20 km Tularemia 35000 9500 1 km Tick-borne encephalitis 85000 19000 5 km Epidemic typhus 500 Brucellosis 150 Q-fever 400 Venezuelan equine encephalitis Casualty figures assume 50 kg of dried agent, disseminated along a 2-km line upwind of a population center of

Critical agents for public health preparedness
Category C Category B Category A Emerging threat agents (e.g., nipah virus, hantaviruses, pandemic influenza viruses) Coxiella burnetii Brucellae Burkholderia mallei Burkholderia pseudomallei alphaviruses Rickettsia prowazekii Certain toxins (e.g., ricin, SEB) Chlamydia psittaci Food safety threat agents (e.g., salmonellae, E. coli O 157:H7) Water safety threat agents (e.g., vibrio cholera) Variola virus Bacillus anthracis Yersinia pestis Botulinum toxin Francisella tularensis Filoviruses and arenaviruses

CDC CATEGORY A AGENTS Ease of dissemination
Agents that would have maximum impact on population: Ease of dissemination Person-to-person transmission High mortality Need for public health preparedness The CDC has developed lists of agents that have the potential for use as biologic weapons. The agents are divided into category A,B,C. The different categories are based mostly on public heath impact of the different bioagents and to some degree likelihood of use. Category A agents have the highest potential for impact. These agents have a high potential for mortality. Several may be spread person to person. Easy to disseminate. Highest priority for public health preparedness! All of these agents have already been weaponized, some of them have actually been used. Category A Variola major (Smallpox), Bacillus anthracis (Anthrax),Yersinia pestis (Plague), Clostridium botulinum (botulinum toxins), (Botulism), Francisella tularensis (Tularemia), Filoviruses and Arenaviruses (e.g., Ebola virus, Lassa virus)--Viral hemorrhagic fevers.

ANTHRAX Infectious agent: Bacillus anthracis – rod-shaped, Gram- positive, spore forming bacteria Primarily endemic and epidemic zoonotic disease

ANTHRAX Bacillus anthracis has characteristics that make it attractive as biological weapon: Easy to obtain Grows readily in easily prepared media Can be easily induced to form spores Spore size and durability

ANTHRAX

CLINICAL FORMS OF ANTHRAX
Cutaneous form: 7 days after exposure to infected hides or meat, a painless or mildly pruritic papule forms The lesion rapidly enlarges and ulcerates, often accompanied by significant surrounding edema and regional lymphadenopathy The case fatality rate of cutaneous anthrax is 20% without antibiotic treatment, and <1% with antibiotics.

Gastrointestinal form Rare natural occurrence Results from consumption of insufficiently cooked meat of infected animals Typically develop massive gastrointestinal bleeding and sepsis Fatal outcome in 50% of cases Oropharyngeal anthrax

Inhalational form Present within 1-6 days of exposure (but perhaps up to several month later) Person-to-Person spread extremely rare Nonspecific febrile prodrome Pneumonia is rare, but there is usually mediastinitis and plural fusion Fatal outcome in 45-85% of cases Anthrax Meningitis manifests in 50% of Inhalational Anthrax patients

CXR classically shows mediastinal widening with clear lung fields Non-contrast chest CT was useful in leading to a presumptive diagnosis in some patients

Diagnosis Blood culture (on blood agar) is the gold standard and is very specific (100% before antibiotic initiation) Culture from the cutaneous lesion (from vesicle) Stool culture Immunohistochemical stains PCR

Treatment Cutaneous form Systemic and route unknown:
Initial empirical should be include ciprofloxacin or doxycycline plus one or tow additional effective antibiotics Human anthrax immune globulin (in clinical trials)

Postexposure prophylaxis
Oral ciprofloxacin, levofloxacin or doxycycline for at least 60 days Anthrax Vaccine Adsorbed (AVA) (under investigation) Contact precautions

SMALLPOX Two forms: Variola Major and Variola Minor
Variola virus - Orthopox virus Two forms: Variola Major and Variola Minor Global eradication was in 1980, but remaining viral stocks exist Smallpox caused by the virus Variola major. Two forms: Variola major = 20-40% mortality in unvaccinated. Variola minor = 1% mortality in unvaccinated No non-human reservoirs. Has survived through history by continual human to human transmission. Probably responsible for 100 million deaths during the 20th century alone. WHO declared smallpox eradicated in 1980 – vaccination in U.S. ceased shortly thereafter. Researchers estimate that vaccinated individuals retain immunity for approximately 10 years. Currently there are two WHO-approved repositories of variola virus: CDC in Atlanta and the Russian State Research Center of Virology and Biotechnology in Koltsovo (former Soviet Union). According to the former deputy director of the biological weapons program in the Soviet Union (Ken Alibeck), massive amounts of smallpox were produced since 1980. Notice that for most of these agents the incubation period runs around 1-2 weeks. May present with nonspecific febrile prodrome.

SMALLPOX Droplet-borne infection
Person-to-person spread very rapid and would likely infect 35-50% of unvaccinated case contacts Incubation period: 7-17 days Nonspecific influenza-like symptoms of prodromal phase The rash appears in centrifugal pattern Mortality: less than 1% in the minor form and 20 to 50 % in the major form

SMALLPOX RASH These photos show different stages of the smallpox rash DIFFERENCE BETWEEN VARICELLA AND VARIOLA Maculopapular => vesicular => pustular => scabs => scars Starts in mouth/face then hands/forearms then legs then trunk. Synchronous = all same stage. Becomes distinctive when pustular – umbilicated.

SMALLPOX RASH

Diagnosis The Diagnosis primarily clinical
Viral culture (vesicle fluid) PCR Electron microscopy

Treatment There is no specific treatment Supportive care
Antiviral drugs (Cidofovir) Vaccina immune globulin

Strict contact and respiratory isolation until all scabs have separated Smallpox vaccine (within 4 days of exposure) Near complete protection lasting at least 5-10 yrs Vaccinia immune globulin is also effective the antiviral drug cidofovir

Plague Infectious agent: Yersinia pestis – a non-motile, Gram-neg., coccobacillus

Plague Plague is primarily a zoonotic disease
In nature, fleas living on rodents spread infection to humans As a bioterrorist weapon – inhalation of aerosol leads to pneumonia and sepsis

Plague Three forms: Bubonic plague (rare person-to-person spread)
Pneumonic plague (person-to-person spread) Septicemic (rare person-to-person spread)

Bubonic Plague Incubation period: 2-6 days Bite of infected flea
Characteristic “bubos” grossly enlarged, extremely tender lymph nodes Suppurative lymphadenopathy and fever

Bubonic Plague If untreated, can lead to pneumonic or septicemic forms of plague

Pneumonic Plague Short incubation: 2 to 3 days Aerosolized bacilli
Short, febrile prodrome Rapid progression to severe pneumonia Fatality: 100% if untreated within 24 hours of symptom onset Pneumonic plague is caused by inhalation of aerosolized Yersinia pestis bacilli. Presents within about a week. Short febrile prodrome with rapid progression to severe pneumonia. Death occurs by respiratory failure and circulatory collapse. Can also spread to CNS and cause plague meningitis in about 6%. Mortality of untreated bubonic plague is about 60%, less than 5% with prompt treatment. In untreated pneumonic plague mortality is nearly 100% - survival unlikely if treatment delayed beyond 18 hours of infection. Person to person spread is possible by droplet transmission

Often fatal even when treated “Black Death”
Septcemic Plague Rare, usually seen secondary to pneumonic or bubonic forms of plague Progression: Purpura Disseminated intravascular coagulation (DIC) Acral necrosis Often fatal even when treated “Black Death”

Diagnosis Wayson, Wright’s, Giemsa stains
Blood, sputum and CSF culture Serologic tests provide a diagnosis retrospectively

Treatment Rapid antibiotic therapy Streptomaycin or Gentamycin
Alternative ciprofloxacin or doxycycline Beta-lactams,rifampin, and macrolides are ineffective

Strict respiratory isolation until 48 hrs of effective antibiotic therapy Ciprofloxacin or doxycycline for 7 days after exposure

Tularemia A zoonotic, bacterial infection caused by Francisella tularensis, a tiny, pleomorphic, poorly staining Gram-negative coccobacillus

Tularemia Commonly found in ticks living on rabbits and transmitted by handling the animal or by tick bite

Tularemia Inhalation of aerosol leads to pneumonia and sepsis
Incubation period: 3 to 5 days (range 1 to 14) Person-to-person transmission is unusual Sudden onset with influenza-like symptoms such as fever, chills, malaise, profuse sweating, headache and nausea Pulse-temperature dissociation

Tularemia CLINICAL FORMS
Ulceroglandular (Most common form in naturally occurring cases) Glandular Occuloglandular Oropharyngeal These are the forms of Tularemia recognized by the CDC Ulceroglandular Most common form in naturally occurring cases Cutaneous ulcer with regional lymphadenopathy—progresses to pneumonia in approximately 30% of cases Glandular Regional lymphadenopathy with no ulcer Oropharyngeal Stomatitis or pharyngitis or tonsillitis and cervical lymphadenopathy Intestinal Intestinal pain, vomiting, and diarrhea Pneumonic Primary pleuropulmonary disease Typhoidal Fibrile illness without early localizing signs and symptoms Pathophysiology: Humans become infected after introduction of the bacillus by inhalation, intradermal injection, or oral ingestion. The clinical form of disease reflects the mode of transmission. Some authors classify the disease as typhoidal (predominance of systemic symptoms), pneumonic (pulmonary findings), or ulceroglandular (regional symptoms). ( Tularemia: Kerry O Cleveland, MD, et al.) Multiple forms of tularemia depending on route of transmission. In naturally occurring disease the most common form is ulceroglandular which occurs after inoculation of skin (bite of deer fly). This form causes a skin ulcer and regional lymphadenopathy. UG tularemia progresses to pneumonia in approx 30% cases. Primary clinical forms vary in severity and presentation according to virulence of the infecting organism, dose, and site of inoculum. The onset of tularemia is usually abrupt, with fever (38oC–40oC), headache, chills and rigors, generalized body aches (often prominent in the low back), coryza, and sore throat. A pulse-temperature dissociation has been noted in as many as 42% of patients. A dry or slightly productive cough and substernal pain or tightness frequently occur with or without objective signs of pneumonia, such as purulent sputum, dyspnea, tachypnea, pleuritic pain, or hemoptysis. Nausea, vomiting, and diarrhea may occur. Sweats, fever, chills, progressive weakness, malaise, anorexia, and weight loss characterize the continuing illness. In general, tularemia would be expected to have a slower progression of illness and a lower case-fatality rate than either inhalational plague or anthrax. Milder forms of inhalational tularemia would be indistinguishable from Q fever; another potential bioterrorism agent; establishing a diagnosis of either would be problematic without reference laboratory testing. (CDC website)

Tularemia CLINICAL FORMS Pneumonic (Primary pleuro-pulmonary disease)
Typhoidal Abrupt onset of febrile illness in 3-5 days Rapid progression to life-threatening pneumonitis in 80% of typhoidal cases Case fatality rate for typhoidal tularemia is 35% in untreated patients

Tularemia

Diagnosis Sputum Gram’s stain is invariably negative
Culture of Blood, sputum or plural fluid is slow and insensitive Serologic tests more sensitive PCR available

Treatment Rapid antibiotic therapy (Mortality rate > 60% in untreated cases) Streptomaycin or Gentamycin Alternative ciprofloxacin or doxycycline Cefteriaxone is ineffective

Strict contact precautions Ciprofloxacin or doxycycline for 14 days after exposure A live attenuated vaccine available, but not recommended for postexposure prophylaxis

Botulism Clostridium botulinum – a spore forming, anaerobic Gram-positive bacillus No person-to- person transmission Incubation period: 12 to 72 hours

Botulism There are 7 neurotoxins (A-G)
LD50 =0.001 µg/kg (the most potent chemical warfare agent) Affect the motor nerve terminus with irreversibly blocks the release of acetylcholine Muscle paralysis lasts until axonal branches regenerate

Botulism Food-born botulism (ingested toxin)
Gastrointestinal and Infant botulism (Clostridium botulinum) Wound botulism(Clostridium botulinum) Iatrogenic botulism (Botox) Pulmonary botulism(inhaled aerosolized toxin) Infant = caused by infants who ingest C. botulinum spores. Infants have no gut flora and spores can germinate liberating large amounts of botulinum toxin. Classic association is with infants getting contaminated honey. Babies present with poor feeding, poor muscle tone. In texts this is reported as most common form. Wound = seen usually in injection drug users who inject themselves with contaminated drug. Spores are able to germinate in an abscess cavity and liberate toxin. Patients most commonly present with bulbar symptoms – like diplopia or difficulty swallowing. Frequently the contaminated wound can’t be found. At UC Davis this is the most common form we see. In fact, in California, stores of botulinum antitoxin are kept at LAX, SFO, and at UC Davis (we have our own store because of the number of cases we see). Iatrogenic = newest form. Caused by iatrogenic injection of Botox. May cause unwanted paralysis of individual muscles (the case I saw was neck muscle paralysis – patient couldn’t hold head up). I don’t think systemic poisoning from iatrogenic injection has been reported (?). Food-born = from contaminated canned foods. Spores in can germinate and release toxin into food. This is why food must be properly heated in a pressure cooker when home canning. GI = Occurs in patients with surgically altered gut physiology. Allows botulinum spores to germinate in gut and liberate toxin. Pulmonary = Due to inhalation of aerosolized botulinum toxin. This is what we are concerned about with weaponized botulinum toxin. Only a few cases have occurred – some lab workers were accidentally exposed.

Botulism Classic triad: Lack of fever Clear sensorium
Symmetric descending flaccid paralysis Symptoms include ptosis, diplopia, dysarthria, dysphagia, dry mouth, and Muscle weakness

Diagnosis Cases presenting with the classic syndrome can be diagnosed clinically Mouse bioassay (confirmatory test)

Treatment Supportive care particularly ventilatory support
Botulinum antitoxins (IV)

Asymptomatic persons: Botulinum antitoxin is not recommended for prophylaxis (10% hypersensitivity reactions) Symptomatic persons: Botulinum antitoxin and carefully monitoring

Viral Hemorrhagic Fevers (VHFs)
Virus Family Disease (Virus) Natural Distribution Usual Source of Human Infection Respiratory transmission Incubation (Days) Arenaviridae Arenavirus Lassa fever Africa Rodent yes 5-16 Argentine HF (Junin) South America 7-14 Bolivian HF (Machupo) 9-15 Brazilian HF (Sabia) Venezuelan HF (Guanarito) Bunyaviridae Phlebovirus Rift Valley fever Mosquito 2-5 Nairovirus Crimean-Congo HF Europe, Asia, Africa Tick 3-12 Hantavirus Hemorrhagic fever with renal syndrome, hantavirus pulmonary syndrome Asia, Europe, worldwide 9-35 Filoviridae Filovirus Marburg and Ebola Unknown 3-16 Flaviviridae Flavivirus Yellow fever Tropical Africa, South America 3-6 Dengue HF Asia, Americas, Africa Unknown for dengue HF, 3-5 for dengue

All share the potential for severe disruption of vascular permeability (vascular endothelial damage) and bleeding diathesis (DIC) Think at VHF in every case with unexplained leukopenia, thrombocytopenia and hepatitis

Sudden onset of fever, muscle aches, headache, followed by vomiting, diarrhea, rash and bleeding

Progresses rapidly to hypotension, shock, mucosal and GI bleeding, edema and end-organ failure

Confirmed diagnosis can be made for most VHFs serologically Some viruses can be cultured Supportive therapy is crucial for all patients Antiviral therapy (Ribavirin IV) has been used experimentally for Crimean-Congo HF, Lassa, Rift Valley fever and HF caused by hantaviruses

All patients should be placed in respiratory and contact isolation Oral Ribavirin can be used after high-risk exposure to Crimean-Congo HF, Lassa, Rift Valley fever and HF caused by hantavirus

Horses or Zebras? Outbreak of rare disease
Seasonal disease at wrong time Unusual age distribution Unusual clinical symptoms Unusual epidemiologic features Outbreak in region normally not seen

Horses or Zebras? Rapidly increasing disease incidence in a healthy population Multiple diseases in one patient Dead animals (especially multiple species) History of visible cloud Claims by aggressors Fulminant disease presentations Travel history

The Ideal Bioweapon Contagious Virulent Robust Difficult to detect
Drug-resistant User-controllable

“Please, don’t forget these zebras”

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