The contaminated letters recently sent as biological weapons produced America's first human anthrax cases in …
The answer, "c," might not be so surprising to ranchers and residents in parts of the country who have lived amid anthrax all their lives — but rarely have gotten sick.
"There are certain things that a rancher knows about raising cattle," said Ed Curlett, a spokesman for the Department of Agriculture's Animal and Plant Health Inspection Service. "How to deal with anthrax is one of those things."
In a case this summer in western Texas, a man contracted the skin form of anthrax, apparently after attempting to skin a bison that had died of the disease, state health officials said. He was treated with antibiotics.
Found In Nature
"It's not a bioterroristic, intentionally criminal act," said Doug McBride, a spokesman for the Texas Department of Health. "Anthrax is found in nature in parts of the country, including parts of Texas. The organism itself in spore form can stay in soil for years."
Anthrax appears sporadically around the country, mostly along old cattle trails that ran from Texas to Canada, where health officials speculate anthrax from dead cattle settled in the soil. When conditions are right — such as when hot, dry weather follows cool, wet weather — the anthrax can reemerge and infect grazing animals that consume the spores. Anthrax usually occurs only in the summer.
This year, an estimated 1,600 animals in Texas — including about 1,200 wild white-tailed deer — are believed to have died from anthrax in what was a particularly bad season, state health officials said. Dozens of animals also died of apparent anthrax this summer in Minnesota, and 21 cattle died between Oct. 20 and 28 on a ranch in Santa Clara County, Calif.
Anthrax emerges so often in the part of western Texas where this year's human case occurred, the area around the towns of Del Rio, Rocksprings and Uvalde is known locally as the "anthrax triangle."
"It's just another one of the things we deal with, like a rabies outbreak or something like that," Carl Hellums, a rancher from Uvalde, told the ABC station WFAA-TV in Dallas.
Ranchers in the "anthrax triangle" often vaccinate their livestock against anthrax, which is recommended by state health officials and the U.S. Department of Agriculture for areas prone to the disease.
Human Cases Dwindling in Wild
But despite the occasional appearance of the disease among animals in some areas, human cases from natural sources are increasingly rare in the United States. There have been only three human cases in Texas since 1967, state health officials said. Nationwide, a skin anthrax case last year in North Dakota was America's first since 1992, according to a Centers for Disease Control and Prevention report.
In the North Dakota case, a man successfully was treated with antibiotics after handling five cows he believed died of anthrax (see Web link, in right column).
The human risk in the United States has gone down considerably since the early 1900s, when there were approximately 200 human anthrax cases from sources in the wild, according to the CDC. The last of 18 20th-century human cases of the frequently fatal inhalational form of anthrax occurred in 1976.
Several experts speculate that anthrax in the wild — though the same disease that has been mailed as a deadly biological terror agent — rarely causes human inhalation cases because anthrax in soil may clump together in larger chunks, rather than in minute particles that can be easily spread through the air. Even plowing possibly anthrax-contaminated soil, which kicks up dust, "does not seem to be a problem," said Julie Rawlings, epidemiologist for the Texas Department of Health.
Ranchers Know What to Do
Another reason for the low human rate of infection in the wild may be that most ranchers recognize the signs of anthrax in animals.
"It's usually fairly obvious when you know what to look for," said Martin Hugh-Jones, a veterinarian at Louisiana State University who monitors anthrax. "[Animal victims] bloat up fairly quickly. … You get blood coming out of the nose and anus in some cases and they don't have rigor mortis."
When ranchers see the signs, most know to avoid infected blood or tissue, to wash up after animal contact and to use other techniques to avoid infection, experts say.
"Rather than fooling with the animal carcasses, it's highly recommended that they burn that animal on site rather than dragging it from one area to another," said Terry Conger, a veterinarian who is Texas' state epidemiologist for animal cases. "If they bury the animal, that will only preserve the organism deep within the soil."
Fear Among Hunters
While most ranchers know what to do, some hunters in the area seem unduly alarmed this year by the corresponding natural and terrorist-driven anthrax scares, Conger said.
"A day doesn't go by that I don't receive three or four calls from deer hunters who have always hunted deer in that part of the state and this year wonder what their risk is," he said. "Deer are exceedingly susceptible to the disease. They typically die 12 hours after exposure. So the odds of a deer hunter coming into contact with a deer between the time of exposure and death is kind of rare.
"Also, deer season occurs in the fall of the year after it's cooled off," he added. "It's very, very rare that we have an anthrax case after Oct. 1."
ABCNEWS' Shelley Kofler in Uvalde, Texas, contributed to this report.