Anthrax

• Anthrax is a noncontagious zoonotic disease caused by the spore-forming Bacillus anthracis.
• Bacillus anthracis is a large gram positive, aerobic, spore-bearing bacillus.
• Spores of Bacillus anthracis are highly resistant and can survive for years in soil, water, or contaminated animal products.
• Bacillus anthracis is the only obligate pathogen within the genus Bacillus.
• Anthrax outbreaks in ruminants can lead to high mortality.
• Infectious form of anthrax is spores.
• Route of transmission of anthrax is through ingestion, inhalation, introduction through skin abrasions or wounds, mechanical by biting flies.
• Nagkakaroon ng biting flies sa area kapag umuulan o merong patay na baka where the flies to feed on.
• Usual cause of infection in production animals is through ingestion of feed contaminated with bone or other meal from infected animal.
• Depending on the route of infection, host factors, and potentially strain-specific factors, anthrax can have different clinical manifestations.
• Bacillus anthracis has two large extracellular plasmids: pX01 and PX02 that are essential for its full virulence.
• Struggle to breathe or have convulsions
• Treatment of these infections is challenging as the first sign of infection is often death.
• Biosecurity involves control of scavengers in infection control.
• One indication of the cause of death is if the blood does not clot.
• Edema factor is responsible for these infections.
• Antimicrobials should not be administered within 1 week of vaccination as it can make the vaccine ineffective.
• Isolation of sick animals is a crucial part of infection control.
• pX01 encodes three anthrax exotoxin components: protective antigen PA, lethal factor (LF), Edema factor (EF).
• Tremble or have a high temperature
• Use of insect repellents is necessary due to biting flies in infection control.
• High doses of penicillin is the treatment for these infections.
• Bloody discharge coming from the nose or mouth is another indication of the cause of death.
• Some infections are characterized by localized, subcutaneous edema, and swelling usually in the neck, thorax, and shoulders.
• Quarantine is necessary for 2 weeks before movement off the farm and 6 weeks if going to slaughter.
• Cleaning and disinfection are essential in infection control.
• Prevention of these infections involves annual vaccination using a live attenuated spore vaccine, done at least 2 - 4 weeks before the season when outbreaks may be expected.
• The three exotoxin components of anthrax produce edema toxin and lethal toxin.
• pX02 encodes proteins that synthesize the unique poly-D-y-glutamic acid capsule, confers resistance to phagocytosis.
• Three forms of anthrax are cutaneous, gastrointestinal, and inhalational.
• After wound inoculation, ingestion, or inhalation, anthrax spores infect macrophages, germinate, and proliferate.
• pX02 is responsible for the resistance to phagocytosis.
• Cutaneous and GI infection can lead to toxemia, which can progress to bacteremia, causing damage to blood vessels and organs.
• PA is produced by Bacillus anthracis, which causes local necrosis and extensive edema, which are frequent characteristics of the disease.
• The death of Bacillus anthracis leads to the release of massive amounts of spores into the environment.
• Bacillus anthracis multiplies and produces lethal toxin (LT) and edema toxin (ET), which disrupt cellular processes, causing tissue damage, fluid accumulation, and cell death.
• PA binds to host cell receptors, allowing EF and LF to enter cells.
• Bacillus anthracis can infect macrophages, germinate once in favorable conditions, and proliferate as the bacteria multiply in the lymph nodes, leading to toxemia, bacteremia, and increased toxin production.
• In cutaneous and GI infection, proliferation can occur at the site of infection and in the lymph nodes draining the site of infection.
• Sporulation and transmission of Bacillus anthracis occurs within the host.