Two human cases of anthrax in Florida are making headlines across the United States and the world. While some experts doubt that anthrax could be used as a biological weapon in this country, other experts are warning that hunters--especially those in Southwest Texas--should take precautions against a disease that is as old as time itself.
Even before the Florida cases, many people in Texas were familiar with anthrax, because an outbreak in deer and cattle in Southwest Texas this summer killed hundreds of animals and left two men hospitalized. The outbreak was localized in the Del Rio and Uvalde area.
"As far as anthrax goes--in these endemic areas--it's been here since the beginning of time," said Dr. James Lenarduzzi of Beeville, veterinarian with the Texas Animal Health Commission. Usually four to six counties are affected in these localized outbreaks, he said.
"Because of the climatic conditions and the soil conditions, it will probably remain here forever."
Still, he said, there is no danger with most activities, such as biking, fossil hunting or camping, and even hunting.
"There's not any danger of getting anthrax by camping out or by having campfires or having any type of activity out here in this part of the world. As long as you're not getting the blood of an infected animal on your skin, you're just as safe here as anywhere else," Lenarduzzi said.
Hunters in upper South Texas or the southwestern part of the Edwards Plateau should exercise caution. Rick Taylor of Uvalde, wildlife biologist with Texas Parks and Wildlife Department, said, "If you come across carcasses--dead deer bones, skulls, skeletons--you should leave them alone. Don't touch them, just leave them alone."
One confirmed and one suspected case cutaneous anthrax were reported in the Uvalde area after contact with infected animals and animal products.
The men were treated in the hospital and recovered.
Anthrax is a bacterial disease that occurs in humans and in a wide range of livestock and animal species, according to Dr. Bruce Lawhorn of College Station, veterinarian with Texas Cooperative Extension and College of Veterinary Medicine department of large animal medicine and surgery. It is endemic to several southern states, including Texas, Louisiana and Arkansas, and many other countries throughout the world, Lawhorn said.
The disease usually occurs most commonly after periods of drought or flooding, Lawhorn said.
Anthrax occurs in one of two forms: The vegetative type is actually the form that multiplies in the animal; the spore type is the dormant form found in the environment.
Animals primarily become infected by grazing and picking up the microscopic spores from the soil. The spores enter the blood stream through cuts and abrasion in the mouth, said Dr. Floron "Buddy" Faries of College Station, Extension veterinarian.
The spores, when exposed to body fluids and the warmth of body temperatures, transform to vegetative form, and as the vegetative form multiplies, toxins that destroy tissues and organs, cause shock and death are released.
Any animal that grazes and swallows the spores--whether it is a cow, sheep, goat or deer--are susceptible. The severity of the disease varies somewhat within species. Coyotes and domestic dogs are not very susceptible; however, they can contract a chronic form of the disease.
With canines, "It's not a quick death, maybe some swollen lymph nodes in the neck. They get sick and they may be diagnosed as having some bacterial sickness. The vet then possibly diagnoses anthrax," he said. Domestic dogs can be treated with antibiotics.
Potentially, feral pigs can be infected with the chronic form and are more likely to recover without treatment than other animals, Lawhorn said.
Hunters in endemic Texas counties should be careful when field--dressing feral pigs because lymph nodes in the head and neck can be full of anthrax organisms; another disease called brucellosis--a bacterial disease that can affect certain organs in the body--is also a slight risk. Lawhorn suggests hunters wear latex disposable gloves when field-dressing feral swine.
There are several forms of anthrax in humans, Lawhorn said. One is the cutaneous: a form when spores are introduced into the body through a cut or abrasion. Symptoms appear two to five days later. The first symptom is a red, raised lesion that may be mistaken for an insect bite that later develops into a blister. This area becomes swollen, and the swelling may spread to other areas, he said.
The second--the inhalation form--is the type suspected in the Florida cases. The spores are inhaled, and symptoms usually appear one to seven days later. It mimics many other common respiratory infections with fever, malaise, muscle pain and coughing. But instead of recovering as with a common cold, the patient suddenly develops respiratory distress, sweating, cyanosis and shock. Victims usually die within 24 hours.
"This form of anthrax is almost always fatal, if left untreated," Lawhorn said.
The third form--ingested--comes from eating contaminated meat. Patients develop fever, vomiting, bloody diarrhea and malaise. If untreated, the death rate can be as high as 50 percent.
Penicillin is the preferred antibiotic for treating anthrax in humans, Lawhorn said. Tetracycline and erythromycin also are effective if used early in patients with a penicillin allergy, he said.
Generally, anthrax in livestock and deer dies down in the cooler months, Lenarduzzi said.
"I haven't seen or heard of any cases reported in deer in October. Usually, it will taper off in late August. Anthrax is a disease that likes the summer time," he said.
"And as soon as the first cool weather begins, anthrax disappears. And so, starting in October, November and into those months--as a general rule--anthrax will not be present in the wildlife population. That's not to say it's impossible, but it's very unlikely."
Hunters still should be concerned about any wildlife disease, Lenarduzzi explained.
"They should have a look at what they are going to shoot. Look at the animal first of all, of course, from a safety standpoint and be sure of what they're shooting. But they should also look at the general health and condition of the animal," he said.
He advised hunters not to shoot any animal that appeared sick or abnormal.
Cutaneous anthrax can be contracted through contact with antlers, pelts and bones, so Lenarduzzi advised hunters not to pick up antlers that have fallen this year in Southwest Texas.
As far as anthrax being used as a biological warfare method, Lenarduzzi acknowledged that was a possibility but not a probability.
The delivery method is what causes the difficulty in using anthrax as a biological weapon, he said.
"They have to have a system that delivers it in high--enough concentrations and the right spot to where it's transmitted to whomever they're trying to transmit it to."