Outbreaks of gastrointestinal anthrax, rare and dangerous, usually afflict villages in developing countries, where animal vaccination and meat inspection programs are not in place or simply fail. They can occur when undercooked infected meat from local livestock or from wild animals makes it to the table. Depending on the outbreak, 25 to 100 percent of gastrointestinal anthrax victims are likely to die. Medical research (autopsy and tissue analysis) on the process of infection in authentic gastrointestinal anthrax is almost nonexistent.
Inhalation anthrax results from inhaling microscopic anthrax spores (one to five microns in diameter) deep into the lungs. Untreated inhalation anthrax is almost always fatal, but even in textile factory settings, where it has been best documented, it has proved exceptionally rare. For example, in one report of 117 cases of "woolsorter's disease" (as anthrax has been called since early industrial times), strung out over more than two decades, from 1933 to 1955, there was only one (fatal) case of inhalation anthrax; the rest were cutaneous. Other scattered fatal cases of inhalation anthrax were reported in the United States during this same time period: a football player who may have contracted the disease from playing-field soil, a San Francisco woman who beat bongo drums made of infected skin, a construction worker who handled contaminated felt, and several gardeners whose infection was traced to contaminated bone meal fertilizer. In the best-researched incident, in Manchester, New Hampshire, in 1957, inhalation anthrax killed four woolen-mill workers. In the same year, a man and woman living near a Philadelphia tannery also died of inhalation anthrax.
The terms gastrointestinal and inhalation, as noted, refer to the portal of entry, how the pathogen entered the body, not necessarily to specific clinical manifestations. According to the few published reports of cases, fatal gastrointestinal anthrax and inhalation anthrax are characterized by similar initial symptoms. At first the patient may experience the aches, chills, mild fever, and nausea characteristic of influenza. In many cases, there is a brief respite from the symptoms, a "false recovery." Then, as the infection progresses, there may be high fever, severe pain in either the abdomen or chest or both, congested breathing, dizziness, bloody vomiting, and diarrhea.
Regardless of the portal of entry, if the anthrax infection is internal, not merely cutaneous, it is termed systemic, and its treatment is highly problematic. Antibiotics are the first line of defense and can kill the anthrax bacteria or halt its growth. But because the bacteria produce a toxin that rapidly floods the blood and lymph system, sending the patient into shock, no remedy may be possible once serious symptoms begin. An unchecked anthrax infection sweeps rapidly through the body, causing massive toxic shock and internal ulceration and bleeding. During this process, a secondary pneumonia infection can develop, possibly in both patients who have eaten infected meat and patients who have inhaled anthrax spores.