Human Anthrax: Update of the Diagnosis and Treatment

Abstract

Anthrax is one of the most important zoonotic diseases which primarily infects herbivores and occasionally humans. The etiological agent is Bacillus anthracis which is a Gram-positive, aerobic, spore-forming, nonmotile, rod-shaped bacillus. The spores are resistant to environmental conditions and remain viable for a long time in contaminated soil, which is the main reservoir for wild and domestic mammals. Infections still occur in low-income countries where they cause suffering and economic hardship. Humans are infected by contact with ill or dead animals, contaminated animal products, directly exposed to the spores in the environment or spores released as a consequence of a bioterrorist event. Three classical clinical forms of the disease, cutaneous, gastrointestinal and inhalation, are seen, all of which can potentially lead to sepsis or meningitis. A new clinical form in drug users has been described recently and named “injectional anthrax” with high mortality (>33%). The symptoms of anthrax in the early stage mimics many diseases and as a consequence it is important to confirm the diagnosis using a bacterial culture or a molecular test. With regards to treatment, human isolates are generally susceptible to most antibiotics with penicillin G and amoxicillin as the first choice, and ciprofloxacin and doxycycline serving as alternatives. A combination of one or more antibiotics is suggested in systemic anthrax. Controlling anthrax in humans depends primarily on effective control of the disease in animals. Spore vaccines are used in veterinary service, and an acellular vaccine is available for humans but its use is limited.

Suspected cutaneous anthrax in a yak herder in a highland community in Bhutan, 2023: A case report

“…Cutaneous anthrax is the most common type of human anthrax that occurs with localized lesions commonly seen on exposed areas like the face, neck, hands, and legs 11 . The incubation period is between 2 and 7 days (range 1–19 days) 1,11,12 . The skin lesion begins with initial pruritus over the bacteria‐inoculated site, followed by the formation of a small papule (2–3 days), and a ring of vesicles around it (3–4 days).…”

Early Hormone Administration and Antibiotic Treatment is Key to Managing Cutaneous Anthrax

“…According to the recommendations of the World Health Organization (WHO), penicillin G is the preferred drug for treating anthrax [13]. However, studies have shown that although Bacillus anthracis is highly susceptible to penicillin in laboratories, patients with high levels of the bacteria, such as those with inhalational anthrax, may develop penicillin resistance due to the production of beta-lactamase [14][15][16][17]. Therefore, some researchers suggested that quinolone antibiotics, such as cipro oxacin or doxycycline, might be more appropriate initial treatments for patients before drug sensitivity results are available [15][16][17].…”

“…However, studies have shown that although Bacillus anthracis is highly susceptible to penicillin in laboratories, patients with high levels of the bacteria, such as those with inhalational anthrax, may develop penicillin resistance due to the production of beta-lactamase [14][15][16][17]. Therefore, some researchers suggested that quinolone antibiotics, such as cipro oxacin or doxycycline, might be more appropriate initial treatments for patients before drug sensitivity results are available [15][16][17]. Additionally, cephalosporins, aminoglycoside antibiotics, and carbapenems are also effective against B. anthracis [15][16][17].…”

“…Therefore, some researchers suggested that quinolone antibiotics, such as cipro oxacin or doxycycline, might be more appropriate initial treatments for patients before drug sensitivity results are available [15][16][17]. Additionally, cephalosporins, aminoglycoside antibiotics, and carbapenems are also effective against B. anthracis [15][16][17]. For patients with cutaneous anthrax who have severe edema, incision and drainage should be avoided, and tracheotomy should be performed with caution [16,17].…”

The sporadic resurgence of anthrax in sub-Saharan Africa: intricacies and challenges to controlling a potentially fatal zoonotic disease

“…The microbe, in its vegetative state, infects herbivorous animals through contact with contaminated matter. Humans subsequently become infected through contact with ill or dead animals and/or ingestion of contaminated animal products [3] .…”