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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