Anthrax not so big a threat

by Mike Kroll

The term ''anthrax'' conjures up more than a heavy-metal band these days. Shortly after President Bush declared War on Terrorism came the first reports of Americans becoming sick and dying with anthrax. Letters containing it were sent to Congressional offices and several news organizations. Clearly, terrorists were going beyond the use of jetliners as missiles and entering the realm of bioterrorism. Since September 11th, few people in this country have been unaffected by the fear and uncertainty of what may happen next.

Trace amounts of anthrax were found in post offices and every unidentified white powder became ominous to many. A disease few Americans had even heard of quickly took center stage. Amidst the growing atmosphere of fear and near hysteria, there has been little factual information about the true nature of this infection.

According to the Illinois Department of Public Health (IDPH), ''Anthrax is an acute infectious disease caused by the spore-forming bacterium Bacillus anthracis. Anthrax is most common in agricultural regions where it occurs in animals. When anthrax affects humans it is usually due to an occupational or recreational exposure to infected animals or their products. Anthrax in livestock has occurred in the United States.''

Douglas Hoefling, Director of the Illinois Department of Agriculture Animal Disease Laboratory in Galesburg, and a veterinarian by training, goes a step further. ''Anthrax is naturally present in soil in parts of the United States with a history of raising livestock. It's a bacteria most often affecting grazing animals such as cattle and sheep but very, very rare in dogs or cats. Most typically it is found in dry and dusty agricultural areas where anthrax-infected livestock historically had been. When an animal dies from the effects of anthrax the bacteria can be maintained in spore form for decades in the soil.''

Hoefling has spent the last 34 years with the Illinois Department of Agriculture, most of it working specifically with animal diseases, and has never personally come across a case of anthrax. ''The last Illinois case of anthrax in animals was in 1978 when an infected sheep was brought to the Danville area from Texas. It was discovered after the sheep suddenly died and was brought to the University of Illinois lab.''

The IDPH claims that the last reported case of humans infected with anthrax in Illinois was in 1960. Hoefling does say that naturally occurring anthrax is hardly rare in the U.S. A number of states -- including Texas, Minnesota, and the Dakotas -- have historically suffered from repeated outbreaks of anthrax among livestock and, occasionally, wildlife. Anthrax has been a significant problem in Texas and, just this year, Minnesota suffered a significant outbreak.

Anthrax can take any of three forms: cutaneous; respiratory or intestinal. Cutaneous occurs when anthrax spores are exposed to cuts or wounds in the skin and seldom results in death. Most deadly instances of anthrax involve either inhaling spores into the lungs or eating food contaminated with spores. In either case, the anthrax spores germinate into bacteria once inside the body and cause severe flu-like symptoms, fever, abdominal distress, shock and ultimately, potentially death. The respiratory and intestinal versions of anthrax ''progress at a rapid rate with shock developing in 3-5 days, followed shortly by death.''

''Anthrax spores are very hearty and resilient,'' explained Hoefling. ''They can live for decades or more in the soil until disturbed and ingested or inhaled by an animal. During the 1993 floods, we were quietly very concerned about the possibility of anthrax spores being disturbed and carried with the floodwaters downstream from Minnesota.''

Hoefling and other disease experts agree that anthrax is not spread via contact either in animals or humans. In the case of cattle and sheep, the first sign of an anthrax problem usually is the sudden death or two or three animals and the veterinarian diagnoses anthrax.

''The generally accepted treatment of livestock presumed to be infected with anthrax is to inject common antibiotics; typically penicillin is found to be successful,'' explained Hoefling. ''A wide variety of commonly available and inexpensive antibiotics have been shown to be effective in treating anthrax in livestock. There also exist vaccines for animals that have been demonstrated to be effective. Here in Illinois use of such a vaccine requires a Department of Agriculture permit and both the animals receiving the immunization and the farm involved will be placed under quarantine.''

Veterinary pathologist Neil Dyer is Director of the Diagnostic Laboratory at North Dakota State University in Fargo. That state has been unfortunate enough to suffer endemically from outbreaks of anthrax among livestock. He says: ''Most of our experiences are cases where a rancher sees the sudden unexpected death of cattle or horses. While there have been instances of anthrax in North Dakota wildlife, it is rare and we don't have many sheep ranches here. Anthrax in North Dakota is essentially a problem for cattle; we see some 50 infected cattle for every infected horse.''

''The most common means of infection seems to be alimentary or ingested. Infected animals and even humans are not contagious. It takes the ingestion of thousands of spores to become infected and we seldom see more that two or three animals die at a time from anthrax. Penicillin is the antibiotic of choice in treating anthrax in cattle but tetracycline has also proven effective. It is not uncommon for those of us in regular contact with infected livestock to be exposed to anthrax spores, usually cutaneous or respiratory, but I know of no human that has died from such anthrax exposure.''

Knox County Health Department Director Greg Chance shares the feelings of both Hoefling and Dyer that undue concern by the general public over the potential exposure to anthrax is unfortunate. Dyer and Chance noted that trace evidence of anthrax is not unusual in rural livestock-producing areas and not cause for alarm.

''The consensus among Illinois public health authorities is that we would not be a likely target of bioterrorism,'' stated Chance. ''The current evidence suggests that the anthrax spores involved in the Washington and New York incidents specially produced as a biological weapon to be very fine and almost aerosol in nature. Anthrax spores offer the advantage of persistence as a weapon but they are also a very difficult biological agent to use if one intends to inflict widespread casualties.''

Hoefling seconded Chance's point: ''There are very few researchers doing legitimate work with anthrax and it would require significant training in microbiology and bacteriology to work in this area safely. There are many technical challenges involved in using anthrax as an effective weapon and very few people are properly trained or equipped to produce effective aerosol agents like those discovered in Washington. Many of us in the field of disease prevention are more concerned over the potential of a number of other biological agents that could be employed much more easily than anthrax.''

The Illinois Department of Agriculture has warned the state's veterinarians of the '''dirty dozen' diseases believed most likely to be spread by biological warfare. As we have seen earlier this year, diseases like foot and mouth that are not a threat to humans, can still significantly alter the economy if it strikes a particular nation.''

The consensus of these experts is that the fear of anthrax is probably overblown. Humans are not easily infected with the disease and both treatments and vaccines already exist. The recent news accounts have focused on the drug Cipro®, manufactured and sold by Bayer, as treatment for anthrax. This is a costly antibiotic that also has a short shelf life and a bevy of side effects. As in animals, penicillin, tetracycline and other common, comparatively inexpensive antibiotics have also proven effective in the treatment of anthrax.

The IDPH reports that the anthrax vaccine ''is 93 percent effective but seldom used in this country because of the low risk of exposure.'' Manufactured by a Michigan company, this vaccine ''is a cell-free filtrate vaccine, which means it contains no dead or live bacteria in the preparation. Currently, anthrax vaccine is not recommended for the general public and is not available commercially.'' It has been mandated for all military personnel and is recommended for civilians who are at high risk of exposure to anthrax.

While the bioterrorism threat of anthrax is real, the probability of being exposed to a health-threatening amount of the spores is remote. The available evidence suggests that there have been a very few carefully targeted terrorist attacks using anthrax resulting in the death of only four persons.

Chance probably summed it up best: ''It is always wise to be vigilant and informed but the available evidence hardly merits either hysteria or a total overhaul of our mail system.''

Uploaded to The Zephyr Online November 14, 2001

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