Download anthrax

ANTHRAX
ANTHRAX
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- Etiologic agent: Bacillus anthracis Cohn 1875.
- Large (8 x 1.2 mm) Gram positive, nonmotile,
weakly hæmolytic; central spores, straight ends,
encapsulated in vivo, produces long chains.
- Pathogenic to herbivores, man, lab animals.
- Habitat: Parasitic; persists in “cursed” fields.
- Sporulation only in aerobic conditions.
- Capsule antigen: poly D-glutamic acid g-peptide
- Immunogenic protein toxin, edematizing, lethal.
Bacillus anthracis: culture
(blue)
(red)
B. anthracis on Blood Agar
Bacillus anthracis in a lesion
Inflammatory cells
Bacilli
Lymph node: necrosis, large bacilli
STAGES OF INFECTION
• Encounter: organism and body surfaces
• Adhesion: generalized and receptor-specific
• Initial multiplication  in situ colonization
• Invasion  breaching of anatomic barriers
• Lymphatic stage  invasion of bloodstream
• Generalized infection, metastases  local
colonizations, “tropisms” of certain organisms.
Natural history of Anthrax
• Encounter: defines disease type and outcome:
• Herbivores: Spores germinate, are eaten, and oral
lesions or abrasions mediate  blood invasion
• Man: Spores in wool, hair, hide  skin or lung
Vegetative forms in meat  bowel lesions
• Adhesion: spores or vegetative forms stick to
tissues and multiply until they breach anatomic
barriers:
• Invasion: first local, then lymphatic,
and
later
• Generalized infection  leading to death.
Malignant pustule
• Anthrax proper, Charbon
• In endemic areas, through contact with infected
animals
• In industry, contact with hides, bones, wool, hair
• Occasionally, brushes, bone, ivory, clothes,etc.
• History in days: incubation of 3 to 4 days; then,
– 1) Initial pimple or papule, single or multiple
– 2) Vesicle ring around papule - initially, clear fluid
– 3) Papule ulcerates, dries, becomes dark eschar
– 3) Edema develops, becomes angry red
– 3-on) No local pain, but local ganglia grow tender
– 4) Eschar blackens, grows on vesicles, thickens
Ulcer
and
vesicle
ring
Black
eschar.
Redness
remains
Site of Malignant pustule
• Head: usually no complication
• Face: severe, superinfection; gangrene near eye
• Neck, breast or chest wall: massive edema, over thorax
and sometimes involving scrotum
• Shoulders, arms: may be multiple, small lesions
• Forearms, fingers: atypical on palms
• General symptoms, fever, chills, depend on site.
• Weakness, hypotension are danger signs.
Notice the edema and typical lesions
Very localized
thumb lesion.
Tough
subcutaneous
tissues limit
the lesion
Notice small finger ulcer,
but large edema and erythema
The forehead
lesion is minimal.
This could be due
to the localization
or to a previous
state of immunity
Taken from the AFIP Atlas
Pulmonary Anthrax
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Aspiration anthrax - Requires high inoculum
- Man resists over 2,000 inhaled spores/day .
Onset abrupt - The patient is acutely ill in hours:
fever, dyspnea, cyanosis, rales, tachycardia, feeble
pulse, hypotension. Vomiting, sweating, anxiety.
Death in 2 or 3 days if untreated.
Lesions in mediastinal lymph nodes, carried there by
alveolar macrophages, causing edema, toxemia,
bacteremia.
Woolsorter’s Disease (AFIP)
THE SVERDLOVSK
ANTHRAX OUTBREAK
• An outbreak of anthrax occurred during April, 1979, among people
who lived or worked in a narrow zone downwind of a Soviet military
microbiology facility in Sverdlovsk (now Ekaterinburg) Russia. In
addition, livestock died of anthrax within a larger downwind zone.
The facility was suspected by western intelligence of being a
biological warfare research facility. Intelligence analysts attributed the
outbreak to the accidental airborne release of anthrax spores. The
Soviets maintained that the outbreak was de to ingestión of
contaminated meat purchased on the black market. Finally, in 1992,
President Yeltsin of Russia admitted that the facility had been part of
an offensive biological weapons program, and that the disease in
animals and people resulted from an accidental release of anthrax
spores.
Gastric and Intestinal Anthrax
• Acute gastro-enteritis, abdominal pain,
prostration.
• Often fatal.
• Intestinal lesions edematous, with black
eschar • obstruction, enlarged, hemorrhagic
mesenteric lymph nodes.
Cecal Lesion
from eating undercooked Carabao... (AFIP)
Anthrax Meningitis
• Usually a complication of anthrax
septicemia.
• Subarachnoid haemorrhage is a common
feature
• Very often fatal
Anthrax meningitis: Subarachnoid
Haemorrhage (AFIP)
Anthrax - Disease in animals
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Fulminating, acute, subacute or chronic.
Apoplectic death: “fall” - animals found dead.
Acute: excitable, then depressed, cardiac and
respiratory distress, trembling, staggering,
convulsions.
• Edematous lesions, blood exudes, incoagulable.
• Death in 1-2 days, or 4-5.
• Chronic infection in more resistant animals: pigs.
The inoculated mouse is jumpy, its hair is
raised, its tail stiff , and has an unsure gait
There’s fluid in the peritoneal
cavity: ascitis
Organs are edematous, spleen is
black and congested
Prevention
• Control in animals. Annual vaccination protects.
• Disposal of animal carcasses: disinfect with oil,
burn, bury deep, covered with quicklime.
• Spores will NOT form inside the carcass, and
putrefaction kills the Bacillus. Flies feeding on
incoagulable blood may be a problem.
Global Health Network
Epidemiology Supercourse: Zoonoses
An anthrax site near the road. Notice the
epidemiology team, recently obtained skin
A more remote anthrax site (2 slides)
A typical cowgirl.
Notice building
materials, number of different animals
Global Health Network
Epidemiology Supercourse: Zoonoses
Prevention
• Control in animals. Annual vaccination protects.
• Disposal of animal carcasses: disinfect with oil,
burn, bury deep, covered with quicklime.
• Spores will NOT form inside the carcass, and
putrefaction kills the Bacillus. Flies feeding on
incoagulable blood may be a problem.
Veterinary Dr. vaccinating in an anthrax site
An anthrax death. Notice flies
feeding on blood and secretions
A community asset:
empiric “vet” couple.
Notice vaccine ampule on chair
Burning a carcass in a hole... Not deep enough
Prevention
• Industrial protection. Gloves, masks,
disinfection of materials prior to handling.
Mostly impractical!
• Information, charts, education for
awareness.
• Reporting of sudden illness in risk areas,
lesions.
Diagnosis
• High suspicion level - Inquire on dead or
sick cattle• Examine papules/lesions: scrape, prepare
Gram stain, culture.
• If needed, blood culture or CNS culture.
Treatment
• Penicillin continues to be the treatment of
choice.
• iv treatment was adopted to provide enough.
• Do not incise lesions.
• Eschar is not dangerous after treatment.
• The patient must remain hospitalized until
fully cured.
BIOTERRORISM
How real is it?
Well, there WERE some bacteria
prepared for biological warfare...
Anthrax was a “first choice”!
EMERGING INFECTIOUS
DISEASES
Vol 4 No 5 July-August 1999
• Special Issue
• The Threat of Biological Attack: Why Concern Now?
• David W. Siegrist
Potomac Institute for Policy Studies, Arlington, Virginia, USA
• For a biological attack to occur, three elements
must be in place: a vulnerable target, a person or
group with the capability to attack, and the intent
(by the perpetrator) to carry out such an attack.
Category A Biological Weapons
(Recommendations of the CDC Strategic Planning Workgroup, MMWR,
April 21, 2000 / 49(RR04);1-14)
• High-priority agents include organisms that pose a
risk to national security because they :
 can be easily disseminated or transmitted
person-to-person;
 cause high mortality, with potential for
major public health impact;
 might cause public panic and social
disruption;
and
 require special action for public health
preparedness
Category A agents include
• Variola major (smallpox);
• Bacteria: Bacillus anthracis (anthrax); Yersinia
pestis (plague); Clostridium botulinum toxin
(botulism); Francisella tularensis (tularaemia);
• Filoviruses: Ebola hemorrhagic fever, Marburg
hemorrhagic fever;
and
• Arenaviruses: Lassa (Lassa fever), Junín
(Argentine hemorrhagic fever) and related viruses.
EMERGING INFECTIOUS DISEASES ARTICLE (CONTINUING)
The United States is unprepared to deal
with a biological attack. (other nations also)
Over the past several years, preparedness
strides have been made, especially in the
largest cities. However, much of the
needed equipment is not available.
Pathogen sensors are not in place to
detect that a biological attack has taken
place. New medicines are needed.
In combating terrorist attacks, treatment is
a more practical approach than prevention;
yet many biological agents are extremely
difficult to treat with existing medicines
once the symptoms appear.
In addition, many of the most important
prophylactic drugs have limited shelf lives
and cannot be stockpiled. Moreover, their
effectiveness could be compromised by a
sophisticated attacker.
SOOOOO................
It’s clear a vaccine
for human use (BOTH
FOR MILITARY AND
CIVILIAN PERSONNEL)
needed.....
is
• The Schedule (for the U.S.A. Armed Forces)
 May 18, 1998: Secretary of Defense
William Cohen approved the vaccination
plan
based
on
the
successful
completion of all testing and operational
criteria
 Between now and about 2005, the
entire force, including all new service
member will begin receiving the six-shot
series of the anthrax vaccination in a
phased immunization program
The first three shots are given in twoweek intervals. The following three shots
are administered at 6, 12, and 18 months.
The program also includes an annual
booster