biowarfare agents

7/28/2019 Biowarfare Agents

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Warfare AgentsBiological

By: Christian John N. Gabrito and Eugene B. Naval

University of Santo Tomas

Faculty of Pharmacy

Clinical Pharmacy


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Baci l lus

Anthrac is

(Anthrax)

Gram positive spore

forming rod

Toxin production when

protective antigen

combines: Edema factor

Lethal factor


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Incidence of Anthrax (US)

Incidence of naturally-acquired anthrax isextremely rare ( 1-2 cases of cutaneousdisease per year).

GI anthrax is rare, but may occur asexplosive outbreaks associated w/ ingestionof infected animals

Worldwide

incidence is unknown but B.anthracis is present in most of the world

Source: Centers for Disease Control and Prevention


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Mechanism of Toxicity

Inhalational, cutaneous exposure, oringestion

Germination occurs upon ingestion by

the macrophages and transportationto the lymph nodes

Lethal factor: local necrosis and

toxemia Edema factor: fluid accumulation in

the lungs


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Day 2

Site of Detection:

Vesicle Fluid

Blood

Mode of Detection:

Gram stain

ELISA

PCR Chest X-ray


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Day 4

Site of Detection:

Vesicle Fluid

Blood

Mode of Detection:

Gram stain

ELISA

PCR Chest X-ray


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Day 4Site of Detection:

Vesicle Fluid

Blood

Mode of Detection:

Gram stain

ELISA

PCR

Chest X-ray


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Day 7 & 15

Site of Detection:

Vesicle Fluid

Blood

Mode of Detection:

Gram stain

ELISA

PCR Chest X-ray


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Yersinia

Pestis

(Plague)

Gram negative rod-shaped bacterium

Facultative anaerobe

Three main forms: Pnuemonic Septicimic Bubonic plague


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Incidence of Plague in the

US First introduced in the US in 1900.

Between 1900 and 2010, 999 confirmed orprobable human plague cases occurred.

Over 80% of the US plague cases have beenthe bubonic form.

In recent decades, 7 human plague caseseach year (range: 1-17 cases per year)

Worldwide, between 1000 2000 cases/year(WHO)

Source: Center for Disease Control and Prevention


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Mechanism of Toxicicty

Inhalational or bite from an infected

flea

Dissemination through lymphatics,

where bacteria multiple -> lymph node

necrosis

Bacteremia, septicemia, endotoxemia

-> shock, coagulopathy, coma


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Site of Detection: Blood

Cerebrospinal fluid

Lymph node aspirate

Sputum

Mode of Detection:

Fluorescent Antibody

testing

PCR Chest X-ray


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Francisel la

tularensis

(Tularemia)Gram negative

coccobacillus

Fastidious

Facultative intracellular

bacteria

Requires cysteine for

growth


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Incidence of Tularemia

Listed as a rare disease by the Office of

Rare Disease (ORD) of the National Institutes

of Health (NIH). This means that Tularemia affects less than

200,000 people in the US population.

Source: RIGHT DIAGNOSIS from healthgrades Database,

http://www.rightdiagnosis.com/t/tularemia/prevalence.htm


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Mechanism of Toxicicty

Exposure to bodily fluids of infectedanimals or bites of ticks or mosquitoes

Initial focal, suppurated necrosis -> bacterialmultiplication w/in macrophages ->dissemination to lymph nodes, lungs, spleen,liver and kidneys.

Aerosolized bacteria may also be inhaled

Lungs lesions progress to pneumonicconsolidation and granuloma formation ->chronic interstitial fibrosis


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Site of Detection: Blood

Sputum

Mode of Detection:

Biopsy

Direct fluorescent

antibody

Serology

Chest X-ray


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Variola major(Small pox)

DNA virus

Humans are the onlyreservoir

Route of entry Air droplets/aerosols

from highly infectiousviral shedding of skinlesions


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Incidence of Smallpox

The disease was eradicated after asuccessful worldwide vaccination program.

The last case of smallpox in the US was in

1949. The last naturally occurring case was in

Somalia in 1977.

Source: Center for Disease Control and Prevention


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Mechanism of Toxicity

Virus particles reach the LRT cross themucosa -> travel to lymph nodes, wherethey replicate and cause viremia ->further spread in spleen, bone marrowand lymph nodes.

Secondary viremia occurs -> spreads todermis and oral mucosa

Death results from toxemiaassociated with circulating immunecomplexes and soluble variola antigens


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Site of Detection:

Blood

Scabs

Mode of Detection: Light microscopy

Electron microscopy

Cell culture

PCR


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Management

A. Emergency and Supportive measures.

Supportive care treat hypotension

Isolate patients B. Specific Drugs and Antidotes

Antibiotics

Vaccines C. Decontamination

D. Enhanced elimination


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A. Emergency and

Supportive Treat a) hypotension with IV fluids and

vasopressors and b) respiratory failure withassisted ventilation

Isolate patients w/ suspected plague, smallpox or who may be highly contagious. Patientisolation is not needed for suspected anthraxor tularemia.

Drugs causing hypotension: sympatholyticagents, membrane-depressant drugs, fluidloss or third spacing, peripheral venous orarteriolar dilation


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Hypotension

Assessment physiologic derangements(vomiting, diarrhea, bleeding), apparentvolume depletion (vasodilation, arteriolar

dilation, depression of cardiac contractility,dysrhythmias), hypothermia

Complications can cause acute renal tubulenecrosis, brain damage, cardiac ischemia and

also Metabolic acidosis Differential Diagnosis rule out Hypothermia,

Hyperthermia, Fluid loss by gastroenteritis,Blood loss, MI, Sepsis, and Spinal Cord injury


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Hypotension

Treatment

Maintain open airway and assist ventilation

Hypotension assoc. w/ hypothermia will not be

relieved with fluid therapy but by rewarmingthe patient.

IV fluid with NS 10-20ml/kg

Administer dopamine 5-15mcg/kg/min

NaHCO3 for TCA and other channel , Glucagonfor beta receptor antagonist overdose,Propranolol for theophylline, caffeine andmetaproterenol


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B. Specific drugs and

antidotes

1. Antibiotics anthrax, plague andtularemia are susceptible tofluoroquinolones, tetracyclines, and

aminoglycosides Ciprofloxacin 400mg IV q 12 hours

(children: 20-30 mg/kg/day up to 1 bid

Doxycycline 100 mg PO/IV q 12 hours(children 45kg: 2.2mg/kg), Note:discoloration of teeth in children (


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antidotes

Gentamicin 5 mg/kg IM or IV once daily, orstreptomycin.

Antibiotics should be continued for 60 days

in patients with anthrax.

Post-exposure antibiotic prophylaxis(after exposure to anthrax, plague or

tularemia)

2. Vaccine anthrax and smallpox vaccines


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Decontamination

Remove all potentially contaminated

clothing and wash with patient thoroughly

with soap and water Dilute bleach (0.5%) and ammonia are

effect for cleaning surfaces

All clothing should be cleaned with hotwater and bleach.


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Warfare AgentsChemical(Nerve Agents)


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Nerve agents

Include GA (tabun), GB (sarin), GD (soman)and the other G-series nerve agents.

Named as such because German scientistsfirst synthesized them, beginning with GA in1936.

Volatile liquids making them a serious risk for2 types of exposure dermal contact andinhalation

Potent organophosphorus agents that causeinhibition of acetylcholinesterase andsubsequent excessive muscarinic and nicotinicstimulation.


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Tabun

Solubility = 72 g/L

pKa =

(RS)-Ethyl N,N-Dimethylphosphoramidocyanidate


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Toxicokinetics

Absorption Ocular exposure, oral ingestion, inhalation and

dermal contact

Peak effects are seen within 20-30 mins

Distribution High concentrations in the hypothalamus

Metabolism

Nonspecific enzymes in serum and liver(aliesterases)

Excretion disappear rapidly from the blood, with rapid formation

of


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Sarin

Solubility =

pKa =

(RS)-Propan-2-yl methylphosphonofluoridate


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Toxicokinetics

Adsorption Ocular exposure, oral ingestion, inhalation and

dermal contact


Distribution Brain, liver, kidney, and plasma

Metabolism Nonspecific enzymes in serum and liver

(aliesterases)

Excretion

Urinary (metabolic product: IMPA)


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Soman

Solubility = 21g/L

pKa =

3,3-Dimethylbutan-2-yl methylphosphonofluoridate


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Toxicokinetics

Adsorption Ocular exposure, oral ingestion, inhalation and dermal

contact


Distribution evenly distributed in the brain with higher levels in the

hypothalamus

Metabolism Nonspecific enzymes in serum and liver (aliesterases)

Excretion stored in body depots and releases toxicity over time

disappear rapidly from the blood, with rapid formation of

hydrolysis products (metabolic product: Pinacolyl phosphonicacid)


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Signs and Symptoms

In general nerve agents producesymptoms of muscarinic and nicotinic

overstimulation:

Excessive salivation and sweating Copious pulmonary secretions

Muscle fasciculations

Respiratory arrest


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Site of Detection

Blood

Mode of Detection:

M8 and M9 paper M256 and M256A1 kits

CBC

BUN

Creatinine

ABG

Chest X-ray


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Warfare AgentsChemical(Vesicants)


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Vesicants (blister agents)

Lewisite combines with thiol moieties in

many enzymes and also contains trivalent

arsenic. Lewisite affects cellular enzyme systems and

damages the mucous membranes, liver,

gallbladder, kidneys, and skin.


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Lewisite

Solubility = 0.5g/L

pKa =

2-chloroethenylarsonousdichloride


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Toxicokinetics

Absorption skin, eyes, and respiratory tract, as well

as by ingestion and via wounds

Distribution

all organs and tissues of the body

Excretion

Urinary


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Signs and Symptoms

Skin blistering Chronic conjunctivitis

Keratitis

Chemical pneumonitis

Chronic bronchitis


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Site of Detection

There are no specific blood or urinelevels that will assist in diagnosis or

management

Mode of Detection: M8 and M9 paper

M256 and M256A1 kits


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Management

A. Emergency and supportive measures

B. Specific drugs and antidotes - Atropine,Pralidoxime, Diazepam, Vesicants, Choking

agents,

C. Decontamination

Physical Removal

Chemical deactivation of chemical agents Oxidation

Hydrolysis


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A. Emergency and supportive

measures

Maintain an open airway and assist

ventilation if necessary. Administer

supplemental oxygen.

Treat hypotension, seizures and coma, if

they occur.


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antidotes Nerve agents:

Atropine 0.5 2mg IV/IM initially and repeatdose as needed; for persistent wheezing;Note: will reverse muscarinic but not nicotinic

Pralidoxime (2-PAM) specific antidote fororganophosphates, given immediately formuscle weakness and fasciculations as 1-2ginitial bolus dose (20-40mg/kg in children) IVover 5- 10mins.

Diazepam anticonvulsant therapy for theonset of seizures; initial dose is 10 mg IM/IV inadult patients or 0.1 0.3 mg/kg in children.


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antidotes

Vesicants

British anti-lewisite (BAL) chelating agent

used in the treatment of arsenic, mercuryand lead poisoning, originally was

developed for the treatment of lewisite

exposure.

Topical BAL recommended for eye and skin

exposure to lewisite.


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C. Decontamination

Physical removal removal of clothing,

flushing of exposed skin and eyes;

Chemical deactivation of chemical agents

Oxidation dilute sodium or calcium

hypochlorite (0.5%) can oxidize susceptible

chemicals.

Hydrolysis alkaline hydrolysis ofphosphorus-containing nerve agents; dilute

hypochlorite is slightly alkaline.


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Sarin Poisoning on Tokyo Subway


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INTRODUCTION

On March 20, 1995, terrorists releasedsarin, an organophosphate (OP) nerve gas

at several points in the Tokyo subway

system, killing 11 and injuring more than5,500 people.

Sarin OP anticholinesterase compound

and may include other nerve agents suchas tabun, soman and VX gas.


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Details of the Incident

Nerve gas was released in commutertrains on 3 different Tokyo subway lines.

Sarin was concealed in lunch boxes and

soft-drink containers placed on subwaytrain floors and was later punctured w/

umbrellas before leaving the trains.


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Classifying the Injured

3 categories: a) mild severity principallymobile and had mainly eye problems

related to miosis, rhinorrhea and mild

headache, b) moderate severityimmobile or complained of mod. degree

dyspnea, vomiting, severe headache or

w/ neurologic complications, c) critical-

cardiac or respiratory arrest


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Critical Category

Five were in critical conditions Three patients had cardiopulmonary arrest

(CPA) and 2 were unconscious and had

respiratory arrest Of these 5, three were successfully

resuscitated and able to leave the hospital

while 1 didnt respond to CPR and died withconspicuous miosis and the other died of

irreversible brain damage


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Critical Category

The 3rd patient collapsed and laterresponded to CPR. A generalized

convulsive seizure 1 hr later ceased after

5 mg of Diazpem IV. After initial 1g andsubsequent 0.5g/hr of Pralidoxime iodide

IV, victim regained consciousness.


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Moderate Category

Patients showed sign and symptomsother than eye problems or mildheadache after first 6-hour observation.

Miosis was the most common signpresent while other ophthalmicsymptoms were ocular pain, blurredvision, and visual darkness.

Dyspnea, nausea, vomiting, muscleweakness, coughing, agitation, andfasciculations were common


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Moderate Category

Hospitalized patients were treated with2mg of IV Atropine sulfate and 2g of PAM

after causative agent was confirmed. IV

diazepam for fasciclulations. Miosis was unresponsive to IV atropine

SO4 so mydriatic agents, such as 0.5%

tropicamide and 0.5% phenylephrine,were applied topically


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Mild Category

Mainly with eye problems IV atropine SO4, in doses up to 2mg had

no effect

After administration, patients complainedof palpitations.


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Laboratory Data

A histogram of Serum ChE levels measured

by 5-5; dithiobis (2-nitrobenzoic acid)

method from blood samples taken after

sarin exposure in the 451 hospitalized

patients and outpatients.


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Histogram of Serum ChE levels


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Laboratory Data

Half the patients showed decreased ChElevels and 74% showed decreased ChE

levels.

Those treated with larger doses of PAM(3g or more) than with lower doses (less

than 3g), showed a tendency for serum

ChE levels to improve faster in the groupreceiving larger doses.


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Discussion

Most common signs and symptomsmiosis and miosis-related symptoms such

as visual darkness.

Almost all showed ocular disorders,including marked miosis, ocular pain,

headache especially with near vision, and

blurring vision.


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Discussion

Major respiratory symptoms rhinorrhea,cough and dyspnea.

Severely ill victims respiratory failure

due to CNS involvement, a nicotinic effecton the respiratory muscles and/or

muscarinic effect on the smooth muscle

and secretory glands of the airway,resulting in bronchoconstriction and

excess bronchial secretion.


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Discussion

Attempted to relieve symptoms byadministering IV atropine SO4 but not

effective in counteracting miosis.

Instead, topical application was effectivebut caused side effects such as mydriasis.

Pxs tolerated repeated application of

commercial eye drops with combinedTropicamide and Phenylephrine HCl.


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Discussion

Atropine SO4 to mild ill victims wasadverse.

IV PAM was initiated once causative agent

was distinguished. Principal mode of action of PAM: displace

nerve agent that binds ChE.


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QUESTIONS


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Identification

1. What is the causative agent ofanthrax?

2. What is the causative agent of

tularemia?3. What is the causative agent of small

pox?

4. What is the causative agent ofplague?

5. Give three nerve gas agents? (3 pts.)


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Modified True or False

8. A. Yersinia pestis is Gram positive bacteriaB. It is an aerobic bacterium

9. A. Bacillus anthracis is a gram negativebacteria

B. It is a rod shaped bacteria

10. A. Francisella tularensis is a gram negativebacteria

B. It requires cysteine for growth

11. A. Variola major appears pink on gramstaining

B. Animals can be a reservoir for theirsurvival


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Modified True or False12. A. Tetracycline are effective treatment for small pox

B. Antibiotics are used for 7 days in patients with anthrax

13. A. Skin blistering is a characteristic sign of tabunpoisoning

B. Lewisite produces muscarinic overstimulation

14. A. Lewisite is detected in blood

B. CBC can be used to assist in diagnosing lewisitepoisoning

15. A. Diazepam is used for the inset of seizuresB. Atropine will reverse both muscarinic and nicotinicreceptors

16. A. BAL is used to treat lewisite exposure

B. Pralidoxime is used as an antidote foror ano hos hate oisonin


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Odd man out

17. A. SarinB. Soman

C. Tabun

D. Lewisite

18. A. Anthrax

B. Small pox

C. Tularemia

D. Plague


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Odd man out

19. A. PneumonicB. Septicimic

C. Bacteremic

D. Bubonic

20. A. Ceftriaxone

B. Ciprofloxacin

C. Doxycycline

D. Gentamicin


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Sources

CDC | Bioterrorism. (n.d.). CDC EmergencyPreparedness & Response Site. Retrieved February 21,2013, from http://www.bt.cdc.gov/bioterrorism/

Chemistry of GB (Sarin). (n.d.). Noblis: For the best ofreasons. Retrieved February 21, 2013, fromhttp://www.noblis.org/MissionAreas/nsi/ChemistryofLeth

alChemicalWarfareAgents/Pages/Sarin.aspx Gupta, R. C. (2009). Handbook of toxicology of

chemical warfare agents. London: Academic Press.

Gupta, R. C. (2012). Veterinary toxicology basic andclinical principles(2nd ed.). Oxford: Academic.

Marrs, T. C., Maynard, R. L., & Sidell, F. R.(2007). Chemical warfare agents: toxicology andtreatment(2nd ed.). Chichester, West Sussex, England:Wiley.

Olson, K. (2012). Poisoning & drug overdose (6th ed.).New York: McGraw Hill Medical

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