Anthrax or Bacillus anthracis is a naturally occurring gram-positive encapsulated bacterial rod that lives in the soil in its spore state and is found practically throughout the world. The bacterium produces spores upon exposure to air and is ineffective only in its spore form. Contact with anthrax infected animal products such as raw meat (from goat or cattle) or inhalation of the spores can result to infection.
Anthrax at present is recognized as the most likely weaponized biological agent that can easily be engineered and mass produced. Approximately 8,000 – 50,000 spores must be inhaled by the human body in order for the bacteria to produce visible clinical symptoms and produce damage to the body. Aerosol anthrax, which is a common delivery of choice by terrorist groups as an offensive attack to a human populace is usually odorless and invisible that can travel at a great distance before it can start to infect people. In other words, terrorists who use anthrax as a biologic weapon can release it at a site several miles away from its supposed target community.
History of weaponized anthrax
Anthrax has been known to be a highly debilitating agent which was used as a weapon as early as the 1500 BCE by the ancient Egyptians. In 1979, anthrax was deliberately released in Sverdlovsk, Russia wherein it resulted in a widespread morbidity and mass casualties. Japan in 1995 was also a target of Anthrax attack which was released with Sarin gas which resulted in several injuries but no reported casualties since the method of its delivery was poorly designed by the malefactors. In 2001, anthrax spores were placed in letters and was mailed through the United States which resulted in 7 fatalities due to inhalation and cutaneous exposure to the biological agent.
Clinical manifestations of anthrax
Anthrax is caused by replicating bacteria that release toxins that result in hemorrhage, edema and tissue necrosis. There are three primary methods of infection caused by anthrax. One is through skin contact, inhalation and gastrointestinal ingestion. Skin contact us the most common which can be manifested by edema with pruritus and maculae/papule formation which eventually leads to ulceration, 1-to-3-mm vesicles. Ingestion of anthrax results in fever, nausea and vomiting, abdominal pain, bloody diarrhea and occasional parasitic ascites. If left untreated, the bacterium can affect the terminal ileum and cecum of the large bowel resulting in sepsis. Inhalation anthrax is the most severe clinical manifestation since it involved respiration and oxygenation. Initial signs and symptoms normally include cough, headache, fever, vomiting, chills, weakness, mild chest discomfort, and difficulty in breathing. Inhalation of anthrax can progress to include meningitis with sub-arachnoid hemorrhage and death within 24-36 hours.
Treatment and standard precautions of anthrax
At present, penicillin is the most effective antibacterial agent
against anthrax. Standard precautions are the only precaution necessary to protect the emergency respondent or clinical staff providing care to a patient infected with anthrax. The infected patient is normally not contagious and the disease cannot spread from person to person. Equipment should be properly cleaned, disinfected or disposed properly based on the standard protocol of a health care facility. Although at present there is a vaccine developed to protect against anthrax, it is not widely used because of the intricate multiple-time interval between vaccines which makes it not feasible and convenient for the majority of people.