By Patti Wilson, Contributing Editor

Anthrax has raised its ugly head once again, this time in Wyoming where several herds in Carbon County have been affected this fall.

Why do these outbreaks always make the news? It’s because anthrax is one unique and deadly organism in livestock. Also, because it affects humans as well. Finally, because it can be grown in a lab and used as a biological weapon.

What Is It?

Anthrax is an infection caused by the bacterium Bacillus anthracis. It is contracted through the skin (think cuts and scrapes), inhalation or gut absorption (by mouth). It may take anywhere from one to more than 60 days for symptoms to occur, making it difficult to identify the source of infection. Anthrax is a clostridial bacteria – a spore producer – making it closely related to blackleg.

A Short History

According to the Centers for Disease Control and Prevention, the first clinical description of cutaneous anthrax was recorded by a fellow named Maret in 1752 and Fournier in 1769. Robert Koch, a Prussian scientist, was the first to identify Bacillus anthracis as the bacterium that causes the disease. This discovery came in 1875 when debates took place over “spontaneous generation” of disease vs. cell theory. Koch later won the 1905 Nobel Peace Prize in Physiology and Medicine for his discovery of the bacterium causing tuberculosis.

Though Koch made the greatest strides in understanding anthrax, most researchers were concerned with the practical slide of prevention. It was soon understood that much of the blame lay in handling of livestock products, such as wool and hides.

Louis Pasteur, seemingly ever-present in this age of medical breakthroughs, was enlisted to produce a vaccine for livestock. In May of 1881, he prepared two groups of 25 sheep, one goat and several cattle. One group was vaccinated with anthrax vaccine and boosted at 15 days. The control group was left unvaccinated. Thirty days later, both groups were injected with live anthrax bacteria. All the animals in the unvaccinated group died; all the vaccinated animals survived. The results were considered a triumph.

The human vaccine for anthrax became available in about 1954. It differed from Pasteur’s live-cell version. An improved vaccine was released in 1970.

Where Does It Strike?

Although considered a rare disease, it is present worldwide. Asian and African countries are major reservoirs of the bacterium. It is also reported in many locations of Europe, Australia and the United States. What may be considered “hot spots” for anthrax are endemic and generally localized. The Texas A&M Agrilife website reports on the endemic area it refers to as the Texas “Anthrax Triangle.” It is bordered by Uvalde, Ozona and Eagle Pass. This area has soil conditions and weather patterns that make it anthrax prone. In 2019, there were 23 confirmed positive cases in several species of livestock and wild game. In more typical years, two or three cases may surface in the area.

There are 89 known strains of anthrax. Although this number is sufficient to scare the socks off most folks, it should be noted that in the United States, fewer than a dozen people per year are affected.

Livestock Are More at Risk

Why are livestock more at risk for contracting anthrax? It is primarily because they are grazers, and disease spores live in the soil. Thus, exposure to anthrax is increased exponentially. In addition, sheep and cattle, logically, are most susceptible to infection. Dust, forages and water can carry spores that may remain viable for more than 100 years, in optimum conditions.

The Journal of Advanced Veterinary and Animal Research website explains the inevitable outbreaks of anthrax that occur worldwide. Blame is paced on “significant climate changes like heavy rain after a prolonged drought, dry summer months after prolonged rain, late in the dry season after a prolonged drought or warm weather.” It goes on to say that “Outbreaks are related to the neutral or alkaline soil rich in calcium and nitrogen and temperatures above 59.9° F.

Symptoms and Treatment

Livestock can appear healthy but die within a few hours. Consequently, one simply finds dead stock. Fever, disorientation, labored breathing and muscle tremors plague those that area still alive.
Deceased livestock generally have blood that has failed to clot. Eyes, mouth, nostrils and anus may exude these fluids, which carry the anthrax bacterium. Once the bacterium is exposed to the environment, they produce spores that perpetuate contamination of an area. The spores are resistant to heat, cold, chemical disinfection, salting and irradiation.

Human morbidity is mostly of the cutaneous nature, up to 95 percent. This variety is most easily cured. Infection of humans through inhalation or digestive tract is extremely rare in the United States, perhaps only two per year, depending on the source of information.

Cutaneous symptoms include skin lesions or a small blister with surrounding red swelling. These are painless and will progress into a “eschar,” a black ulcer. Nearby lymph nodes may also become infected. Complete recovery may take several weeks.

Early treatment in animals is essential to survival. Penicillin and oxytetracycline are most effective in the field, although six other antibiotics are acceptable.
Humans, as well, need early treatment. Large doses of IV and oral antibiotics are recommended. Vaccination is appropriate for livestock and high-risk humans in affected areas.

Bioterrorism

Perhaps the kneejerk reaction elicited from the word anthrax is tied not only to the deadly nature of the spore, but to the threat of biological warfare.

Easily grown in a lab, anthrax spores have, in the past, been used during times of war. Beginning in 1916, Germany used anthrax spores in Finland against the Russian Imperial Army. Japan tested the bacterium on prisoners of war in 1930’s Manchuria. Allies pondered the use of the disease against Germany in World War II before scrapping the idea; conventional methods of warfare already had Germany on its knees. Most scary is the stockpile of 100 to 200 tons of anthrax spores hoarded by the Soviet Union at Kantubek on Vozrozhdeniya Island; they were abandoned in 1992 and destroyed in 2002.

President Nixon ordered the dismantling of U.S. biowarfare programs in 1969 and the destruction of all existing stockpiles of bioweapons as part of the worldwide Biological Weapons Convention.
Most famously, concentrated anthrax spores were used in a 2001 attack in the United States, delivered by mailing postal letters containing spores. They were sent to two news media offices and two U.S. senators. As a result, 22 people were affected and five died. The Department of Justice determined a senior biodefense researcher employed by the U.S. Government was responsible, using only a few grams of spores. Total cleanup/disinfection of this incident took a combined $157 million and 26 months.

The Soviet Union had its own embarrassing scandal in 1979 when an accidental release of anthrax spores poured over an area about 850 miles east of Moscow. At least 94 people were infected, of whom at least 68 died. An extensive government cover-up continued until 1992, when President Boris Yeltsin admitted that he was “absolutely certain” that rumors about the Soviet Union violating the 1972 Bioweapons Treaty were true.

We can only be grateful that this onerous disease is relatively rare and that we live in a time of modern medicine.