Bacillus Anthrax:Clinical manifestation, Diagnosis and treatment
Introduction:
- Anthrax is a zoonoses
- Occurs primarily in herbivores.
- “Man is relatively resistant to infection with B. anthrax”
- Aerosolized anthrax — 10,000 spores required to produce lethal disease.
- Few as one to three spores may be adequate to cause disease in some setting
- According to The Workmen’s Compensation Act, 1923, Anthrax is considered an occupational disease
Routes
- Humans become infected when B. anthracis spores are introduced into the body by the following routes:
- Contact with infected animals or contaminated animal products
- Insect bites
- Ingestion
- Inhalation
- In humans anthrax occurs in following forms
1. Cutaneous anthrax
- Cutaneous anthrax is most common.
- It follows the entry of infection through the skin.
- The whole area is congested and edematous
- The lesion starts as macule
- Progress through papular and vesicular or pustular stages
- Formation of an ulcer with a blackened necrotic eschar.
- The lesion is painless.
- It is called malignant pustule.
- Hide porter’s disease.Satellite nodule around inguinal region
- Caused by contact with contaminated hair, wool, hides or products
- Cutaneous anthrax generally resolves spontaneously
- But 10-20% of untreated patients may develop septicemia.
2. Pulmonary anthrax
- Woolsorters’ diseaseIt causes hemorrhagic pneumonia.
- Occupational hazard for people who sorted wool
- Most dangerous form of inhalational anthrax
3. Intestinal anthrax
- It is rare.
Laboratory Diagnosis
Mc-Fadyean’s Reaction
- Blood films containing anthrax bacilli are stained with polychrome methylene blue stain for few seconds
- Examined under microscope
- Amorphous purplish material is noticed around bacilli.
- This represents the capsular material and is characteristic of anthrax bacilli.
Culture Characteristics of Bacillus anthracis
- On agar plate: Frosted glass appearance
- On gelatin stab culture: Inverted fir tree appearance
- Immunofluorescent microscopy
- confirm identification.
- Ascoli’s thermoprecipitin /Elek’s gel precipitation test
- Sample is putrid,
- demonstrate anthrax antigen in tissue extract. .
- Antibody by immunoassays
- Confirm diagnosis.
Treatment
- Penicillin is drug of choice.
- In penicillin allergy →
- ciprofloxacin, erythromycin, tetracyline or chloramphenicol.
Exam Important
Introduction:
- Anthrax is a zoonoses
- “Man is relatively resistant to infection with B. anthracis”
- Few as one to three spores may be adequate to cause disease in some setting
- According to The Workmen’s Compensation Act, 1923, Antrax is considered an occupational disease
Forms
1. Cutaneous anthrax
- Cutaneous anthrax is most common.
- The whole area is congested and edematous
- The lesion starts as macule
- Progress through papular and vesicular or pustular stages
- Formation of an ulcer with a blackened necrotic eschar.
- The lesion is painless.
- Its called malignant pustule.
- Hide porter’s disease.
- Cutaneous anthrax generally resolves spontaneously
- But 10-20% of untreated patients may develop septicemia.
2. Pulmonary anthrax
- Woolsorters’ diseaseIt causes hemorrhagic pneumonia.
- Occupational hazard for people who sorted wool
- Most dangerous form of inhalational anthrax
3. Intestinal anthrax(rare)
Laboratory Diagnosis
Mc-Fadyean’s Reaction
- Blood films containing anthrax bacilli are stained with polychrome methylene blue stain for few seconds
- Examined under microscope
- Amorphous purplish material is noticed around bacilli.
- This represents the capsular material and is characteristic of anthrax bacilli.
Culture Characteristics of Bacillus anthracis
-
- On agar plate: Frosted glass appearance
- On gelatin stab culture: Inverted fir tree appearance
- Ascoli’s thermoprecipitin /Elek’s gel precipitation test
- Penicillin G is the DOC
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