CLINICAL FEATURES
EPIDEMIOLOGY
LAB DIAGNOSIS
PROPHYLAXIS
TREATMENT
k.vanya
Clinical features
Clinical features of B.anthracis:
Anthrax is a zoonotic disease.
Anthrax
“coal” ,comes from black
colour of eschar
 Route of infection: ingestion / inhalation of
spores /it may enter directly through skin.
 Infective material: discharges from mouth ,
nose &rectum of infected animals.
 The large no. of bacilli present in those
discharges sporulate in soil and remain as
source of infection.
 Direct spread from animal to animal is rare.


it causes fatal septicemia, but some times it
is localized/resemble cutaneous diseases in
humans.
 acquired from animals directly / indirectly.
 Based on clinical features, Anthrax
is divided into 3 types

cutaneous pulmonary intestinal
 All
these lead to fatal septicemia/meningitis
Cutaneous anthrax


Also called “hide porter’s disease”, as it is
common in dock workers,
Route of infection: infection enter through
abraded skin.
◦ Also by shaving brushes made of animal hair

Usual sites: face,neck,hands,arms&back
Lesion starts as papule 1-3 days after infection

becomes vesicular (fluid clear/blood stained)

Malignant pustule:
 The whole area congested, edematous &
several satellite lesions filled with yellow
fluid/serum arranged around central
necrotic lesion which is covered by black
eschar.

resolves spontaneously.
Complications: 10-20% develop fatal
septicemia/meningitis

Malignant pustule

Congested

Edematous

Satellite lesions
Pulmonary anthrax
Also called “wool sorter’s disease”.
 Because it is common in wool factories.
 Route of infection: due to inhalation of
dust from infected wool.
 More severe than others.
 Complications:

hemorrhagic pneumonia (common)
hemorrhagic meningitis(rare)
Intestinal anthrax
Rare
 Mainly in primitive communities i.e. who
eat dead bodies of animals died of
anthrax.


Complication:
violent enteritis with bloody diarrhea
with high fatality rate


Based on occupation
industrial
non-industrial
Industrial: such as meat packing/wool
factories.
Non-industrial:
associated with animals(butchers &farmers)


Rarely stomoxys calcitrans –biting insect
transmit infection mechanically.
Epidemiology:
Rare in western countries
 Large epidemics
russia&zimbabwe
(1978-80)
 Recently visakha agency has outbreaks of
cutaneous anthrax
 Andhra –tamilnadu region


Cutaneous,meningoencephalitic infections
Laboratory diagnosis
1)microscopy
2)culture
Type of test
based on
availability
of specimens
3)Animal
inoculation
4)Serological
demonstration of
anthrax Ag in tissue
Specimens:
 swab, fluid/pus from pustule-cutaneous
anthrax
 Sputum-pulmonary anthrax.
 Blood-septicemia anthrax.

Microscopy:
 Gram positive bacilli arranged in large
chains.


Capsule --Clear halo around bacillus in
Indian ink preparation

Direct flourescent antibody test: capsule
specific staining for poly saccharide Ag

Mc fadyean’s reaction :Amorphous purple
material – characteristic of B.anthracis.

Employed for presumptive diagnosis in
animals
Mc fadyean’s reaction
Culture : inoculated on nutrient agar
incubate at 37 c for overnight.
-medusa head colonies
 Gelatin stab culture : inverted fir tree

Animal inoculation : white mouse / guinea
pigs
injected with exudate /culture
 Animal dies in 48 hrs


Serology ( Ascoli Thermo Precipitin Test ):
Tissues are ground up in saline and
boiled for 5 mins and filtered.
Then this extract layered over anti
anthrax serum in a narrow tube.
+ve case :ring of precipitate appears at
junction of two liquids with in 5minutes.

mainly used for rapid diagnosis when
sample received is putrid and viable bacilli
less likely found
CDC(centers for disease control)guide
lines:
 Any large gram positive baciili with
general morphology, cultural features of
anthrax-non motile, on hemolytic on
blood agar,catalase positive given
presumptive report as anthrax.
 Initial confirmation-lysis by gamma
phage,DFA test.
 Further confirmation:PCR test

Other methods :
Polymerase chain reaction : used for
conformation of anthrax bacilli.
 ELISA assay for antigen detection
 X-ray and CT scan
 Lysis by gamma phage

PROPHYLAXIS:
General methods :
 improvement of factory hygiene
 proper sterilization of animal products ,
carcasses of animals suspected to have
anthrax are buried deep in lime.
Active immunization
Spore is common infective form
 Sterne vaccine contains spores of non
capsulated avirulent mutant strain
 Animal is protected for a year with single
injection of spore vaccine
 Extensively used in animals
 Not safe for human use

Contd….
Alum precipitated toxoid prepared from
protective antigens used in persons
occupationally exposed to anthrax
infection.
 Safe and effective in humans
 Given in 3 doses IM at intervals of 6
weeks

Treatment:




Before 2001, 1st line of treatment was
penicillin G
◦ Stopped for fear of genetically engineered
resistant strains
60 day course of antibiotics
Ciprofloxacin
◦ fluoroquinolone
◦ 500 mg tablet every 12h or 400 mg IV every
12h
◦ Inhibits DNA synthesis
Doxycycline
◦ 6-deoxy-tetracycline
◦ 100 mg tablet every 12h or 100 mg IV every
12h
◦ Inhibits protein synthesis

For inhalational, need another antimicrobial
agent
◦ clindamycin
◦ rifampin
◦ chloramphenicol

Anthrax infection gives permanent
immunity&2nd attacks are rare.
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