Causative OrganismScientific classification:- • Bacteria Kingom • Firmicutes Phylum • Bacilli Class • Bacillacea Family • Bacillus Genus • B. anthracis Species
Causative Organism * Bacillus Species The genus bacillus includes large aerobic. Gram-positive rods occurring in chains. Most members of this genus are saprophytic organisms prevalent in soil, water, and air and on vegetation. Spores may remain viable in soil for years
Causative OrganismB cereus can grow in foods and produce an enterotoxin or an emetic toxin and cause food poisoning.may occasionally produce disease in immunocompromised humans . B anthracis, which causes anthrax, is the principal pathogen of the genus.
Causative Organism * MorphologyThe typical cells, measuring 1 x 3 - 4 micron.have square ends and are arranged in long chains.spores are located in the center of the nonmotile bacilli.
Causative Organism IdentificationOn Culture:-Colonies of B anthraces are round and have a "cut glass" appearance.Haemolysis is uncommon with B anthraces.
Causative Organism IdentificationGrowth in gelatine stabs resembles an inverted fir tree.
Causative OrganismGrowth Characteristics:- The saprophytic bacilli utilize simple sources of nitrogen and carbon for energy and growth. The spores are resistant to environmental changes, withstand dry heat and certain chemical disinfectants for moderate periods, and persist for years in dry earth
Disease Exit Type :- Anthrax is primarily a Zoonotic disease ( eg. goats, sheep, cattle, horses, etc;) other animals (eg, rats) are relatively resistant to the infection
Disease Exit Infection To Human Humans become infected incidentally by contact with infected animals or their products.
Disease ExitMode Of Transmision cutaneous anthrax by the entry of spores through injured skin. gastrointestinal anthrax (rarely) by the mucous membranes. inhalation anthrax :- by inhalation of spores into the lung .
Pathogenesis growth of the vegetative organisms via lymphaticsTo Man or Animal to the bloodstream From dead body to Env.
PathogenesisB anthracis that does not produce a capsule is not virulent and does not induce anthrax in test animals. The poly-D-glutamic acid capsule is antiphagocytic. The capsule gene is on a plasmid.
Virulence Factors Anthrax Toxin:-Toxin Structure:- Anthrax toxin is made up of three proteins:- protective antigen (PA). edema factor (EF). lethal factor (LF).
Virulence Factors Anthrax Toxin:- EF is an adenylyl cyclase; with PA it forms a toxin known as edema toxin. LF plus PA form lethal toxin, which is a major virulence factor and cause of death in infected animals. Toxins responsible for tissue damage and edema
Clinical Findings In humans, approximately 95% of cases are cutaneous anthrax and 5% are inhalation. 100% 90% 80% 70% 60% Column1 50% Series 2 40% 30% Series 1 20% 10% 0% cutanous Pulmonary GIT
Clinical Findings Gastrointestinal anthrax is very rare; it has been reported from Africa, Asia, and the United States following occasions where people have eaten meat from infected animals. The bioterrorism events in the fall of 2001 resulted in 22 cases of anthrax: 11 inhalation and 11 cutaneous. Five of the patients with inhalation anthrax died. All the other patients survived.
Cutaneous Anthrax Clinical Picture :- The lesions typically are 1–3 cm in diameter and have a characteristic central black eschar. Marked edema occurs. Lymphangitis and lymphadenopathy and systemic signs and symptoms of fever, malaise, and headache may occur.
Cutaneous Anthrax Cutaneous Anthrax Vesicle Development Day 2 Day 4 Eschar Formation Day 6 Day 10 Day 7
Cutaneous Anthrax Sequelae :-1) Healing After 7–10 days the eschar is fully developed. Eventually it dries, loosens, and separates. healing is by granulation and leaves a scar. It may take many weeks for the lesion to heal and the edema to subside.
Cutaneous Anthrax Sequelae :-2) Death In as many as 20% of patients, cutaneous anthrax can lead to sepsis, the consequences of systemic infection (including meningitis ) and death
Inhalation Anthrax Preview:- Incubation period: 1-7 days (range up to 43 days). Infection occure by inhalation of B.Anthrasis spores. Case-fatality: 1) without antibiotic treatment – 85%- 97% 2) with antibiotic treatment – 75% (45% in2001)
Inhalation AnthraxClinical Picture:- The early clinical manifestations are associated with marked hemorrhagic necrosis and edema of the mediastinum.
Inhalation Anthrax Clinical Picture:- Rapid deterioration with fever, dyspnea, cyanosis and shock. Hemorrhagic pleural effusions follow involvement of the pleura; cough is secondary to the effects on the trachea.
Inhalation Anthrax Chest X-rays isChest X-Ray :- advised as an initial method of inhalation anthrax detection, but it is sometimes not useful for patients without symptoms. Find a widened mediastinum and pleural effusion
Inhalation AnthraxChest X-Ray :- Substernal pain may be prominent, and there is pronounced mediastinal widening visible on x-ray chest films
Gastrointestinal anthraxPreview:-Animals acquire anthrax through ingestion of spores and spread of the organisms from the intestinal tractThis is Rare in Humans, Gastrointestinal anthrax is Extremely Uncommon.
Gastrointestinal anthraxClinical Picture :-Abdominal pain, vomiting, and bloody diarrhea are clinical signs.Sepsis occurs, and there may be hematogenous spread to the gastrointestinal tract, causing bowel ulceration, or to the meninges, causing hemorrhagic meningitis.
Laboratory Diagnostic Tests Specimens:- Specimens to be examined are fluid or pus from a local lesion, blood, and sputum.Gram Stain :- Gram stain shows large gram-positive rods.
Laboratory Diagnostic TestsDirect Examination : Stained smears from the local lesion or of blood from dead animals often show chains of large gram-positive rods. Carbohydrate fermentation is not useful. . Anthrax can be identified in dried smears by immunofluorescence staining techniques. immunofluorescence staining of sporation
Laboratory Diagnostic TestsCulture : Nutrient broth non motile on blood agar plates, the organisms produce nonhemolytic gray to white colonies On Mixed Flora a rough texture and a ground- glass appearance. Comma-shaped outgrowths (Medusa head) may project from the colony.
Laboratory Diagnostic TestsLab Characters Virulent anthrax cultures kill mice upon intraperitoneal injection. Demonstration of capsule requires growth on bicarbonate-containing medium in 5–7% CO2. Lysis by a specific anthrax -bacteriophage may be helpful in identifying the organism.
Anthrax Vaccines Development By Years 1881 Pasteur develops first live attenuated veterinary vaccine for livestock 1939 Improved live veterinary vaccine 1954 First cell-free human vaccine 1970 Improved cell-free vaccine licensed
Anthrax VaccinesPreparation: Immunization to prevent anthrax is based on the classic experiments of Louis Pasteur. In 1881 he proved that cultures grown in broth at 42–52 C for several months lost much of their virulence be injected live into sheep and cattle without causing Louis Pasteur disease; subsequently, such animals proved to be immune.
Anthrax VaccinesPreparation: Four countries produce vaccines for anthrax. Russia and China use attenuated spore- based vaccine administered by scarification. The US and Great Britain use a bacteria- free filtrate of cultures adsorbed to aluminum hydroxide
Anthrax VaccinesPre-exposure VaccinationThe current US FDA approved vaccine contains cell-free filtrates of a toxigenic nonencapsulated nonvirulent strain of B anthracis.The vaccine is available only to the US Department of Defense and to persons at risk for repeated exposure to B anthracis.
Anthrax VaccinesVaccination ScheduleInitial doses at 0, 2, and 4 weeks.Additional doses at 6, 12, and 18 months.Annual booster doses thereafter.Alternative schedules being investigated.
Anthrax VaccinesPost-exposure Vaccination No efficacy data for postexposure vaccination of humans. Postexposure vaccination alone not effective in animals Combination of vaccine and antibiotics appears effective in animal model
Anthrax VaccinesPrecautions and ContraindicationsSevere allergic reaction to a vaccine component or following a prior dose.Previous anthrax disease.Moderate or severe acute illness. • By: El Omda
Treatment Many antibiotics are effective against anthrax in humans, but treatment must be started early. Ciprofloxacin is recommended for treatment; penicillin G, along with gentamicin or streptomycin, has previously been used to treat anthrax. • By: El Omda
Chemoprophylaxis prophylaxis with ciprofloxacin or doxycycline should be continued for 4 weeks while three doses of vaccine are being given, or for 8 weeks if no vaccine is administered. In the setting of potential exposure to B anthracis as an agent of biologic warfare. • By: El Omda
Epidemiology Soil is contaminated with anthrax spores from the carcasses of dead animals. These spores remain viable for decades. Perhaps spores can germinate in soil at pH 6.5 at proper temperature.
EpidemiologyGrazing animals infected through injured mucous membranes serve to perpetuate the chain of infection.
Prevention & ControlControl measures include :-(1) disposal of animal carcasses by burning or by deep burial in lime pits,(2) decontamination of animal products.(3) protective clothing and gloves for handling potentially infected materials.(4) active immunization of domestic animals with live attenuated vaccines. Persons with high occupational risk should be immunized. • By: El Omda