Macy

• Anthrax


  Woolsorters' Disease, Cumberland Disease, Maladi Charbon, Malignant Pustule, Malignant Carbuncle, Milzbrand, Splenic Fever, Siberian Fever

  
• Bacillus anthracis


  Spore forming, Gram-positive aerobic rod, Family: Bacillaceae

  
• B. anthracis


  • Has two plasmid-mediated virulence factors: pOX1- exotoxin complex is associated with symptoms, pOX2- interferes with phagocytosis

  
• Biofilm formation


  Pivotal strategy in B. anthracis virulence by augmenting its survival in hostile environments, enabling its resistance to antimicrobial agents, facilitating its persistent environmental presence, and, ultimately, contributing to the persistent and chronic nature of anthrax infections

  
• Anthrax is a worldwide disease, responsible for 80% of herbivore deaths

  
• In the Philippines, only 82 suspected anthrax cases were recorded from January 1, 2017 to December 31, 2023

  
• Transmission

  Bacilli enter the body via ingestion, inhalation, or penetration through disrupted skin
• Infectious dose of B. anthracis in humans by any route is not precisely known, but an aerosol challenge is estimated to be 8,000–50,000 spores, and the infectious dose may be as low as 1-3 spores

  
• Occupational Risk


  • Workers handling animal products (wool, meat, hair, skin, bone, or bone products)
  • Animal health officers, veterinarian
  • Livestock workers, particularly in anthrax endemic area
  • Households or breeders who have discovered their livestock died and consumed meat contaminated with anthrax spores
  • Military personnel
  • Laboratory workers handling anthrax samples
  • Emergency response workers handling bioterrorism

  
• Incubation period in animals

  1. 14 days, typically 3-7 days in herbivores inoculated orally, 1 to 2 weeks in pigs
• Clinical forms in animals

  • Peracute, acute
  • Subacute or chronic
• Anthrax in ruminants

  • Peracute systemic disease is common, sudden death is often the only sign, staggering, trembling and dyspnea is sometimes noted shortly before death, followed by rapid collapse and, in some cases, terminal convulsions

  
• Anthrax in ruminants (acute form)


  • Ill for a short period (typically up to 2 days) before they die, fever and excitement may be noted initially, but this is often followed by depression, stupor and anorexia, other clinical signs may include: disorientation, muscle tremors, dyspnea, hematuria, diarrhea, congested mucous membranes, and small scattered hemorrhages on the skin and mucous membranes

  
• Anthrax in pregnant cows


  • May abort, and decreased milk production, milk may also appear bloody or discolored with a yellow tinge

  
• Anthrax in ruminants


  • Subcutaneous edematous swellings, often in the ventral neck, thorax and shoulders, but sometimes at other sites including the genitalia, pulmonary anthrax with a productive cough and an acute course has been reported rarely

  
• Anthrax in dying animals


  • Usually found bloated, without rigor mortis or incomplete rigor mortis, and absence of clotting of the blood is the most prominent characteristic

  
• Anthrax in horses


  • Acute course is common, frequently reported clinical signs: fever, anorexia, depression, other signs of sepsis, severe colic and, in some cases, bloody diarrhea, death usually occurs within 48–96 h, some horses have swellings on the neck, sternum, lower abdomen and genitalia

  
• Anthrax in pigs


  • Septicemia and sudden death occur occasionally, more often have mild subacute to chronic cases characterized by localized swelling, fever and enlarged lymph nodes, the throat can swell rapidly, intestinal involvement can result in anorexia, vomiting, diarrhea (which may be bloody) or constipation, some pigs with anthrax recover

  
• Anthrax in dogs, cats and wild carnivores

  • Usually resembles the disease in pigs, with gastrointestinal and/or pharyngeal signs

  
• Anthrax in birds

  • Reported to be an acute septicemic disease, with death occurring soon after the clinical signs appear

  
• Cutaneous anthrax in humans

  • Ranges 1-20 days, but most clinical cases tend to develop within 7-10 days, initially appears as a papule, which may become surrounded by small fluid-filled vesicles that release clear or sanguineous discharge, papular stage → the vesicular stage with blisters →erupt into hemorrhagic lesions → eschar stage, which appears 2–6 days after the hemorrhagic vesicles dry out →depressed black scab (malignant pustule) and may be surrounded by significant redness and edema (swelling)

  
• Gastrointestinal (including oropharyngeal) anthrax in humans

  • Malaise, a low fever and mild gastrointestinal signs such as nausea, vomiting, diarrhea and anorexia, followed by the acute onset of severe abdominal pain, hematemesis and bloody diarrhea, initial symptoms in the oropharyngeal form can include fever, a sore throat, dysphagia, hoarseness, and swelling of the neck from edema and cervical lymphadenopathy, intestinal anthrax has a case fatality rate of 25%–75%

  
• Inhalation (pulmonary) anthrax in humans

  • Extremely uncommon, frequently manifests as mild, nonspecific symptoms such as fever, lethargy, a moderate cough, or chest pain (upper respiratory tract symptoms are extremely uncommon)

  
• Diagnosis

  Blood culture, tissue aspirates and pharyngeal swabs, Gram-stain, polychrome methylene blue (M'Fadyean stain), PCR assays, anthrax immunochromatographic test (AICT), skin hypersensitivity test using anthraxin, serology
• Treatment, Prevention and Control

  • Penicillins, Streptomycin, Tetracyclines, Modified live vaccines, Quarantine, Proper carcass disposal, Improvements in industry standards to reduced occupational exposure, Postexposure antibiotic prophylaxis, continued for at least 60 days, and vaccination are recommended for people who were exposed to aerosolized anthrax spores