Infectious

Anthrax

Malignant Pustule, Malignant Edema, Woolsorters’ Disease, Ragpickers’ Disease, Maladi Charbon, Splenic Fever Community
Lecture 37
Eman Adnan Al-kaseer

Overview

Organism History Epidemiology Transmission Disease in Animals Disease in Humans Prevention and Control
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THE ORGANISM

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The Organism

Bacillus anthracis Large, gram-positive, non-motile rod Two forms Vegetative, spore Over 1,200 strains Nearly worldwide distribution
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The Spore

Sporulation requires: Poor nutrient conditions Presence of oxygen Spores Very resistant Survive for decades Taken up by host and germinate Lethal dose 2,500 to 55,000 spores
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HISTORY

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Sverdlovsk, Russia, 1979

94 people sick – 64 died Soviets blamed contaminated meat Denied link to biological weapons1992President Yeltsin admits outbreak related to military facilityWestern scientists find victim clusters downwind from facilityCaused by faulty exhaust filter Al-Madena Copy

South Africa, 1978-1980

Anthrax used by Rhodesian and South African apartheid forces Thousands of cattle died 10,738 human cases 182 known deaths Black Tribal lands only
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Tokyo, 1993

Aum ShinrikyoJapanese religious cult“Supreme truth”Attempt at biological terrorismReleased anthrax from office building Vaccine strain usedNo human injuries Al-Madena Copy

U.S., 2001

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U.S., 2001

22 cases 11 cutaneous 11 inhalational; 5 deaths Cutaneous case 7 month-old boy Visited ABC newsroom Open sore on arm Anthrax positive
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U.S., 2001

CDC survey of health officials 7,000 reports regarding anthrax 1,050 led to lab testing 1996-2000 Less than 180 anthrax inquiries Antimicrobial prophylaxis Ciprofloxacin 5,343 prescriptions
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TRANSMISSION

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Human Transmission

Cutaneous Contact with infected tissues, wool, hide, soil Biting flies Inhalational Tanning hides, processing wool or bone Gastrointestinal Undercooked meat
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Human Transmission

Tanneries Textile mills Wool sorters Bone processors Slaughterhouses Laboratory workers
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Animal Transmission

Bacteria present in hemorrhagic exudate from mouth, nose, anus Oxygen exposure Spores form Soil contamination Sporulation does not occur in a closed carcass Spores viable for decades
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Animal Transmission

Ingestion Most common Herbivores Contaminated soil Heavy rainfall, drought Carnivores Contaminated meat Inhalation Mechanical (insects)
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EPIDEMIOLOGY

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Anthrax Distribution

20,000 to 100,000 cases estimated globally/year http://www.vetmed.lsu.edu/whocc/mp_world.htm
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Anthrax in the U.S.

Cutaneous anthrax Early 1900s: 200 cases annually Late 1900s: 6 cases annually Inhalational anthrax 20th century: 18 cases, 16 fatalities
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Anthrax in the U.S.

Alkaline soil“Anthrax weather”Wet springFollowed by hot, dry periodGrass or vegetation damaged by flood-drought sequenceCattle primarily affected Al-Madena Copy

DISEASE IN HUMANS

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Cutaneous Anthrax

95% of all cases globallyIncubation: 2 to 3 daysSpores enter skin through open wound or abrasionPapule  vesicle  ulcer  escharCase fatality rate 5 to 20%Untreated – septicemia and death Al-Madena Copy

Day 2

Day 4
Day 6
Day 6
Day 10
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Case Study: Cutaneous Anthrax

North Dakota, 2000 67 year old man Helped in disposal of 5 cowsthat died of anthrax Developed cutaneous anthrax Recovered with treatment
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Gastrointestinal Anthrax

Incubation: 2 to 5 days Severe gastroenteritis common Consumption of undercooked or contaminated meat Case fatality rate: 25 to 75% GI anthrax not documented in U.S. Suspected in Minnesota outbreak
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Case Study: Gastrointestinal Anthrax

Minnesota, 2000 Downer cow approved for slaughter by local veterinarian 5 family members ate meat 2 developed GI signs 4 more cattle died B. anthracis isolated from farm but not from humans
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Inhalational Anthrax

Incubation: 1 to 7 days Initial phase Nonspecific (mild fever, malaise) Second phase Severe respiratory distress Dyspnea, stridor, cyanosis, mediastinal widening, death in 24 to 36 hours Case fatality: 75 to 90% (untreated)
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Diagnosis in Humans

Identification of B. anthracis Blood, skin, secretions Culture PCR Serology ELISA Nasal swabs Screening tool
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Treatment

Penicillin Most natural strains susceptible Additional antibiotic options Ciprofloxacin Treatment of choice in 2001 No strains known to be resistant Doxycycline Course of treatment: 60 days
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Prevention and Control
Humans protected by preventing disease in animals Veterinary supervision Trade restrictions Improved industry standards Safety practices in laboratories Post-exposure antibiotic prophylaxis
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Vaccination
Cell-free filtrate At risk groups Veterinarians Lab workers Livestock handlers Military personnel Immunization series Five IM injections over 18-week period Annual booster
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