Anthrax as a Disease, Anthrax

¶ … Anthrax As a disease, anthrax primarily affects farm animals, such as cattle, goats, pigs, sheep and horses, and is caused by the bacterium known as Bacillus anthracis which is almost always fatal in these types of animals. Humans most often acquire this disorder when a break in the skin comes into contact with an infected animal, but it can also be acquired by inhaling the spores of the bacterium.

As to its basic characteristics, anthrax usually begins with a reddish-brown lesion that ulcerates and then forms a dark scab (Glanze, 2002, p. 74). In humans, the signs and symptoms that follow includes internal hemorrhaging, muscle pain, headache, fever, nausea, and vomiting. This is known as the cutaneous form; the other form, sometimes called woolsorter's disease, is often fatal unless treated early. Treatment for both of these forms is penicillin G.

Or tetracycline; there is also a vaccine for veterinarians and for those whom anthrax is an occupational hazard, such as farm workers (Glanze, 2002, p. 73). Kenneth Todar, one of the leading bacteriologists in the United States, provides a very detailed and accurate description of the various types of anthrax bacterium and how they differ related to composition, place of origin, epidemiology and transmission.

With Bacillus anthracis, the first bacterium of its kind to be studied in the laboratory in 1877 by Robert Koch who "demonstrated its ability to form endospores" and was one of the first to produce experimental anthrax by injecting the bacterium directly into the blood of animals, is very similar to Bacillus cereus, usually found within soil habitats in many countries, and to Bacillus thuringiensis, "the pathogen for the larvae of lepidoptera or butterflies.

These three types of anthrax bacterium also possess identical size related to cellular structure and morphology and form "oval spores located centrally in a non-swollen sporangium" (2008, Internet). However, Bacillus thuringiensis is somewhat different from the other two types in relation to its pathogenicity, "pertaining to the ability of a pathogenic agent to produce a disease" (Glanze, 2002, p. 887) and through the production of an intercellular parasporal crystal, "tightly-packed insect protoxin molecules which are produced by strains during the creation of resting spores" ("Focus on Anthrax," 2001, Internet) linked to spore formation.

Some of these types of crystals are currently used by farmers as a form of insecticide to control the formation and spread of certain pests. With Bacillus cereus, this type of bacterium can usually be found living in the soil habitats of many regions of the world and is relatively easy to isolate from foodstuffs like grain and spices.

This type generally causes two kinds of food-borne intoxications as opposed to infections -- first, it may cause nausea, vomiting and severe abdominal cramps and has an incubation period of not more than six hours. This type closely resembles the familiar Staphylococus aureus which produces food poisoning. Secondly, this type often produces diarrhea with an incubation period of not more than sixteen hours and is similar to food poisoning caused by Clostridium perfringens.

In most cases, both of these types of bacterium lasts in human beings less than twenty-four hours (Todar, 2008, Internet).

As to laboratory diagnosis, the causative agent of the anthrax disease, the bacterium Bacillus anthracis, "secretes a toxin made up of three proteins -- a protective antigen (PA), an oedema factor (OF) and a lethal factor (LF)." The first protein "binds to cell-surface receptors on the host's cell membranes" and after being cleaved by a protease, it "binds to the two toxic enzymes, OF and LA then mediates their transportation into the cytosol where they exert their pathogenic effects" ("Focus on Anthrax," 2001, Internet).

In addition, the anthrax bacterium is usually diagnosed in a clinical setting through obtaining a culture and then an isolation of the causative agent, "or by measuring specific antibodies in the blood of individuals with suspected cases" ("Anthrax," CDC, 2008, Internet). Under most conditions, the bacterium is cultured from "the blood, skin lesions, fluid from the lungs or respiratory secretions, spinal fluid, or other affected tissues" before any type of treatment procedure is done.

Also, the detection of DNA or bacterial antigens and antibodies "are important tools for diagnosis because positive culture is unlikely" after antibiotic treatment has been commenced ("Anthrax," CDC, 2008, Internet). As to prevention and treatment, when the anthrax bacterium shows up in farm animals and other valuable livestock, some type of control measure is immediately put into place.

For example, if the bacterium has already killed a number of animals, all carcasses are removed and disposed, usually through incineration or burning which helps to sterilize the soil upon which the animals lived and grazed while alive. Also, all remaining animals are quarantined and vaccinated so as to ensure that the bacillus does not spread to other geographical areas. However, in some countries, such measures are impractical and rather difficult to enforce, due to a number of social/cultural conditions.

With vaccinations, these are only used in humans which represent high-risk groups, such as with farmers or other agricultural workers who might have been exposed to the bacillus. With treatment, some form of antibiotic is almost always administered either before or immediately following exposure or the onset of the disease ("Anthrax," WHO, 2009, Internet).

Although the disease of anthrax has been around for hundreds of years and has caused much devastation in countries that lack sufficient governmental programs geared toward intervention and prevention, since the attack on the World Trade Center in New York City in September of 2001, new interest has been placed on this potentially fatal bacterial infection, especially related to using anthrax as a weapon in a terrorist attack in the form of a "dirty bomb." Only last month, researchers in the field of bacteriology released some new information regarding a drug, proposed by the Human Genome Sciences, Inc., which has been shown to be effective in humans exposed to the anthrax bacterium.

Obviously, this new interest is due to what occurred in 2001 soon after 9/11 when "letters carrying powdered anthrax killed five people," thus raising new fears that anthrax "could be used again in a biological attack" in the United States (Richwine, 2009, Internet). This new drug, referred to as Abthrax or raxibacumab, is now being stockpiled by the U.S. government which recently ordered 65,000 doses as an emergency precaution in case another incident involving anthrax as a terrorist weapon should ever occur.

However, the Food and Drug Administration has not yet approved of the drug's use in humans, partially because the FDA feels that this drug may interfere with the already proven effectiveness of certain antibiotics which are currently used to treat the anthrax bacterium in humans. Similarly, researchers at the Albert Einstein College of Medicine in Israel have recently identified "two small protein fragments that could be developed into an anthrax vaccine" which may have less side effects than the vaccine currently available.

According to college spokesman Nareen Abboud, "Our research was motivated by the fact that the current anthrax vaccine has significant limitations and there is great need for a better one," a possible reference to fears that in the near future, anthrax may become more widespread as a result of human population growth and an increase in the number of domesticated farm animals in Third World nations, especially Africa ("Einstein Scientists," 2009, Internet).