Biological Terrorist Agents Part I – Bacterial Agents

In January 2002, anthrax was covered in detail in the Hazmat Studies column. This column will cover other potential biological agents that could be used by terrorists. Biological terrorist agents are microorganisms or toxins derived from living...


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Q-Fever is generally a self-limiting illness and will clear up without treatment. Antibiotics given during the illness can shorten the period of incapacitation. Tetracycline is the antibiotic of choice and when given during the incubation period may delay the onset of symptoms. The usual dosage is 500 mg every six hours (or doxycycline, 100 mg every 12 hours). Use of antibiotics will shorten the duration of the illness. Antibiotic treatment should be continued for five to seven days.

The disease is remarkably resistant to heat and drying and is stable under diverse environmental conditions. It can survive for months and even years in the environment. It also survives in dried sputum for 30 days, in dust for up to 120 days, in dried urine for 49 days, in the feces of ticks for 586 days, in milk for 42 months at 45 degrees Fahrenheit and in wool for 12 to 16 months, also at 45F. Vaccines for humans are in the development stages, although tests have shown promise.

Cholera (vibrio cholera) is a bacterial disease contracted through the ingestion of contaminated water or food, but it does not spread easily from person to person. It can be spread through ingestion of food or water contaminated with flies, feces or vomit of patients, by dirty water or hands contaminated with feces.

Cholera is an acute infectious disease, represented by a very sudden onset of symptoms. Victims may experience nausea, vomiting, profuse watery diarrhea with a "rice water" appearance, the rapid loss of body fluids, toxemia and frequent collapse. Not everyone exposed will show symptoms. In some cases there may be as many as 400 people without symptoms for every patient showing symptoms. When cases go untreated, the death rate can be as high as 50%. With treatment, the death rate drops to below 1%.

Cholera itself is not lethal, but the breakdown of medical treatment systems in large outbreaks can result in many deaths from dehydration, hypovolemia (loss of body fluid) and shock. Fluid loss can be as much as five to 10 liters per day and IV fluids used to replenish fluids can be in short supply. The incubation period varies from 12 to 72 hours, depending on the dose of ingested organisms. An infectious dose is greater than 108 organisms to a healthy individual through ingestion.

Treatment involves antibiotic and IV fluid therapy using tetracycline (500 mg every six hours for three days). Doxycycline (300 mg once or 100 mg every 12 hours for three days), IV solutions of 3.5 g NaCl, 2.5 g NaHCO3, 1.5 g KCl and 20 g glucose per liter are also appropriate treatments. Cholera shows a significant resistance to tetracycline and polymyxin antibiotics. Ciprofloxacin (500 mg every 12 hours for three days) or erythromycin (500 mg every six hours for three days) can be used as substitutes.

Cholera is very sensitive to cold temperatures. Bacteria can remain active in dust for 3 to 16 days; feces up to 50 days; in glass up to 30 days; on metal coins for 7 days; on finger tips for 1 to 2 hours; and in soil for 16 days. It also survives well in water depending on the temperature. A vaccine is available for prevention, however it has not proven very effective. It offers only 50% protection for up to six months.

Brucella (brucellosis), also called undulant fever and Bang's disease, is a bacterial disease caused by any of four species of coccobacilli. They are naturally occurring diseases in cattle, goats, pigs, swine, sheep, reindeer, caribou, coyotes and dogs. The organisms can be contracted by humans through ingestion of unpasteurized milk and cheese or from inhalation of aerosols generated on farms and in slaughterhouses. Skin lesions on persons who have come in contact with infected animals can also spread infection. The disease is also common in populations who eat raw caribou. When the animal population has a high rate of infection, the rate of disease occurrence is also higher in humans.

The infectious dose of brucella is unknown. Symptoms are nonspecific and insidious upon onset (the disease is well established when the symptoms appear). Symptoms include intermittent fever, headache, weakness, profuse sweating, chills, arthralgia and localized suppurative (pus-forming) infections are frequent. Incubation periods vary from five to 30 days, and in some cases, many months. Evidence of human-to-human transmission of the disease has not been documented. Death is uncommon even in the absence of treatment.

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Photo by Robert Burke
Hospitals should be prepared to decontaminate victims of known dissemination of biological agents, the deadliest substances known to man.