Anthrax
Whitney Mikesell BIO 112

Anthrax is an acute infectious disease, which is potentially fatal, caused by the spore-forming bacterium Bacillus anthracis. Anthrax is most commonly found to infect wild and domestic animals such as cattle, goats, sheep, camels, and other herbivores. But, it has been found to infect humans who are exposed to the infected animals or tissue from the infected animals. Although humans can be infected with anthrax and it is classified as a highly contagious disease it hasn’t been found to have spread from one human to another. The first mention of Anthrax as an illness actually appears in the Bible in Exodus chapter 9. It says that it was the fifth plague inflicted on Egypt. But, the best ancient account of anthrax is by the Roman poet Virgil (70-19 BC). He wrote four Georgics, instructive verse works on agriculture. The third Georgic is devoted to raising animals, and contains a passage on veterinary medicine that concludes with a detailed account of an epizootic that occurred in the district of Noricum, in the eastern Alps. Virgil describes the disease in sheep, cattle, horses, dogs, and other domestic and wild animals. Although the narrative contains errors and traces of poetic license, it includes many facts. Virgil understood the severity of the infecting source, as well as the potential for transmission of the disease to humans. Anthrax continued to be a fatal disease affecting both humans and animals through the Middle Ages. In the 18th century an epidemic destroyed nearly half of the sheep in Europe. In the 19th century anthrax was the focal point of one of the central developments in the history of medicine. In 1850 Pierre Rayer and Casimir-Joseph Davaine discovered small thread-like bodies in the blood of sheep affected by anthrax. Even though there is no evidence that they initially regarded these as being significant, they seemed to continue to find this same organism in all the animals affected with the disease. During the 1870’s scientists, including Robert Koch and Louis Pasteur, continued to study anthrax. In 1876, Koch was able to trace the complete life cycle of the anthrax bacillus for the first time. He stated that anthrax could only be transmitted from one host to another by transfer of bacilli. Pasteur went on to study the disease and in 1881 came up with the anthrax vaccine for animals, which was the first vaccine containing attenuated live organisms. Beginning in the 1900’s, human cases of inhalation anthrax occurred in the United States among textile and tanning industry workers who processed goat hair, goat skins, or wool. The incident of the disease decreased significantly during the 20th century because of vaccinations and better working conditions. Finally in the 1950’s a human anthrax vaccine was developed by the Army

Chemical Corps, which was replaced by a vaccine licensed in 1970. Anthrax continued to be present worldwide, outside the United States, with an annual occurrence of 20,000-100,000 in the first half of the 20th century, and approximately 2000 cases yearly during the second half. In 1980, Philip Brachman, of the Centers for Disease Control, published a review of inhalation anthrax. The number of affected people had declined so much that throughout the entire 20th century, to that point, there had been only 18 cases of human inhalation disease reported in the United States and only 16 of those cases were fatal. Human anthrax has three major clinical forms: cutaneous (through skin), inhalation (through the respiratory tract), and gastrointestinal (by ingestion). Around 95% of all anthrax cases are cutaneous. This occurs when the bacterium enters a cut or abrasion on the skin usually from handling contaminated wool, or hair. Symptoms of this sort of infection begin with raised itchy bumps that resemble an insect bite, but within 1-2 days develop into a vesicle and then a painless ulcer. With this form of anthrax about 20% of untreated cases will result in death. Deaths are rare with appropriate anti-microbial therapy. Inhalation is the most common type of anthrax in the United States. The symptoms resemble that of a common cold. If left untreated for several days, the symptoms may progress into severe breathing problems and shock. At this point, inhalation anthrax is usually fatal. Fatality rates range from 90% to 100% for this form of anthrax because it is usually much more serious and usually fatal. Gastrointestinal anthrax is usually the result of eating contaminated meat. This type of anthrax is characterized by an acute inflammation of the intestinal tract. The initial signs of loss of appetite, vomiting, and fever are usually followed by abdominal pain, vomiting of blood, and severe diarrhea. Twenty-five to sixty percent of the time, intestinal anthrax results in death. Fatality rates range from 25% to 75% for gastrointestinal anthrax. As for all forms of anthrax, if treatment is prompt, the patient affected has a much higher chance of surviving than someone who isn’t as prompt about getting to the doctor to get help. All symptoms, whether it’s cutaneous, inhalation, or gastrointestinal anthrax, usually occur within seven days of coming into contact with the disease. When symptoms arise the best thing to do is go directly to the doctor. For treatment to be effective anthrax has to be caught early. Otherwise, it could result in death. Doctors can prescribe antibiotics that are effective after they have diagnosed the affected person. Penicillin is the antibiotic of choice that doctors use to help treat anthrax. Anthrax is diagnosed by isolating B. anthracis from the blood, skin lesions, or respiratory secretions or by measuring specific antibodies in the blood of persons with suspected cases. There is a vaccine for anthrax that is reported to be 93% effective in protecting against anthrax. The vaccine is called a cell-free filtrate vaccine. This means that it contains no dead or live bacteria in the preparation. The final product contains no more than 2.4 mg of aluminum hydroxide as adjuvant, which is just an agent added to the drug to increase or aid its effect. The Advisory Committee on Immunization Practices recommend that these people should be vaccinated for anthrax: people who work with it directly in the laboratory, people who work with imported animal hides or furs, people who handle potentially infected animal products in high-incidence areas, and military personnel deployed to areas with high risk for exposure to the organism. Where is anthrax now? It is still a major issue but not a common occurrence in the United States today. It is still a current issue for the United States because anthrax is considered to be a potential agent for the use in biological warfare. Worldwide though, there are still outbreaks of anthrax in developing countries or countries without veterinary public health programs. Certain regions of the world (South and Central America, Southern and Eastern Europe, Asia, Africa, the Caribbean, and the Middle East) report more anthrax in animals than others. Although Bacillus anthracis is present in most of the world, anthrax is most common in agricultural regions where it occurs in animals. In the United States there hasn’t been a major issue with anthrax since September 11th. This is again why anthrax is still an issue for the United States because of terrorists’ threats. Fortunately with better defense systems, better living conditions, and cleaner working environments for people who are more at risk, along with vaccinations, the United States is attempting to control and prevent another outbreak as deadly as some before. There were several reported cases directly following September 11th throughout October and November of that same year. Most of the cases reported were from postal workers and other people who would have handled infected mail along with some people who actually received infected mail. These people were usually affected by inhaling the anthrax and would get symptoms like that of the common cold. The survival rate during this outbreak was higher than the less than 15% that had previously been reported from the 20th century outbreaks. This decline in deaths is thought to be due to the initiation of combination antibiotic therapy during the early phase of the illness. Also, it is thought that this decline is due to the earlier diagnosis and better supportive care of the disease as a whole. Despite all these improvements and precautions, I think that George Sternbach MD of Emergency Medicine Service at Stanford University says it best; “it is clear that anthrax remains a deadly infection. Though long in decline, it has re-emerged as an instrument of biological warfare and terror, and it seems doubtful that this ancient scourge is prepared to pass quietly into history.”