Signs and symptoms: Exposure causes skin pain, pruritus, redness, vesicles, necrosis and sloughing of epidermis. Effects on the airway include nose and throat pain, nasal discharge, itching and sneezing, cough, dyspnea, wheezing, chest pain and hemoptysis. Toxin also produces effects after ingestion or eye contact. Severe poisoning results in prostration, weakness, ataxia, collapse, shock, and death.
Diagnosis: Should be suspected if an aerosol attack occurs in the form of "yellow rain" with droplets of yellow fluid contaminating clothes and the environment. Confirmation requires testing of blood, tissue and environmental samples.
Treatment: There is no specific antidote. Superactivated charcoal should be given orally if the toxin is swallowed.
Prophylaxis: The only defense is to wear a protective mask and clothing during an attack. No specific immunotherapy or chemotherapy is available for use in the field.
Isolation and Decontamination: Standard Precautions for healthcare workers. Outer clothing should be removed and exposed skin should be decontaminated with soap and water. Eye exposure should be treated with copious saline irrigation. Once decontamination is complete, isolation is not required. Environmental decontamination requires the use of a hypochlorite solution under alkaline conditions such as 1% sodium hypochlorite and 0.1M NAOH with 1 hour contact time.
The trichothecene mycotoxins are low molecular weight (250-500 daltons) nonvolatile compounds produced by filamentous fungi (molds) of the genera Fusarium, Myrotecium, Trichoderma, Stachybotrys and others. The structures of approximately 150 trichothecene derivatives have been described in the literature. These substances are relatively insoluble in water but are highly soluble in ethanol, methanol and propylene glycol. The trichothecenes are extremely stable to heat and ultraviolet light inactivation. Heating to 1500o F for 30 minutes is required for inactivation, while brief exposure to NaOCl destroys toxic activity. The potential for use as a BW toxin was demonstrated to the Russian military shortly after World War II when flour contaminated with species of Fusarium was unknowingly baked into bread that was ingested by civilians. Some developed a protracted lethal illness called alimentary toxic aleukia (ATA) characterized by initial symptoms of abdominal pain, diarrhea, vomiting, prostration, and within days fever, chills, myalgias and bone marrow depression with granulocytopenia and secondary sepsis. Survival beyond this point allowed the development of painful pharyngeal/laryngeal ulceration and diffuse bleeding into the skin (petechiae and ecchymoses), melena, bloody diarrhea, hematuria, hematemesis, epistaxis and vaginal bleeding. Pancytopenia, and gastrointestinal ulceration and erosion were secondary to the ability of these toxins to profoundly arrest bone marrow and mucosal protein synthesis and cell cycle progression through DNA replication.
HISTORY AND SIGNIFICANCE
Mycotoxins allegedly have been used in aerosol form ("yellow rain") to produce lethal and nonlethal casualties in Laos (1975-81), Kampuchea (1979-81), and Afghanistan (1979-81). It has been estimated that there were more than 6,300 deaths in Laos, 1,000 in Kampuchea, and 3,042 in Afghanistan. The alleged victims were usually unarmed civilians or guerrilla forces. These groups were not protected with masks or chemical protective clothing and had little or no capability of destroying the attacking enemy aircraft. These attacks were alleged to have occurred in remote jungle areas which made confirmation of attacks and recovery of agent extremely difficult. Some investigators have claimed that the "yellow clouds" were, in fact, bee feces produced by swarms of migrating insects. Much controversy has centered upon the veracity of eyewitness and victim accounts, but there is evidence to make these allegations of BW agent use in these areas possible.
T-2 and other mycotoxins may enter the body through the skin and digestive or respiratory epithelium. They are fast acting potent inhibitors of protein and nucleic acid synthesis. Their main effects are on rapidly proliferating tissues such as the bone marrow, skin, mucosal epithelia, and germ cells. In a successful BW attack with trichothecene toxin (T-2), the toxin(s) can adhere to and penetrate the skin, be inhaled, or can be ingested. Clothing would be contaminated and serve as a reservoir for further toxin exposure. Early symptoms beginning within minutes of exposure include burning skin pain, redness, tenderness, blistering, and progression to skin necrosis with leathery blackening and sloughing of large areas of skin in lethal cases. Nasal contact is manifested by nasal itching and pain, sneezing, epistaxis and rhinorrhea; pulmonary/tracheobronchial toxicity by dyspnea, wheezing, and cough; and mouth and throat exposure by pain and blood tinged saliva and sputum. Anorexia, nausea, vomiting and watery or bloody diarrhea with abdominal crampy pain occurs with gastrointestinal toxicity. Eye pain, tearing, redness, foreign body sensation and blurred vision may follow entry of toxin into the eyes. Skin symptoms occur in minutes to hours and eye symptoms in minutes. Systemic toxicity is manifested by weakness, prostration, dizziness, ataxia, and loss of coordination. Tachycardia, hypothermia, and hypotension follow in fatal cases. Death may occur in minutes, hours or days. The most common symptoms are vomiting, diarrhea, skin involvement with burning pain, redness and pruritus, rash or blisters, bleeding, and dyspnea.
Rapid onset of symptoms in minutes to hours supports a diagnosis of a chemical or toxin attack. Mustard agents must be considered but they have an odor, are visible, and can be rapidly detected by a field available chemical test. Symptoms from mustard toxicity are also delayed for several hours after which mustard can cause skin, eye and respiratory symptoms. Staphylococcal enterotoxin B delivered by an aerosol attack can cause fever, cough, dyspnea and wheezing but does not involve the skin and eyes. Nausea, vomiting, and diarrhea may follow swallowing of inhaled toxin. Ricin inhalation can cause severe respiratory distress, cough, nausea and arthralgias. Swallowed agent can cause vomiting, diarrhea, and gastrointestinal bleeding, but it spares the skin, nose and eyes. Specific diagnosis of T-2 mycotoxins in the form of a rapid diagnostic test is not presently available in the field. Removal of blood, tissue from fatal cases, and environmental samples for testing using a gas liquid chromatography-mass spectrometry technique will confirm the toxic exposure. This system can detect as little as 0.1-1.0 ppb of T-2. This degree of sensitivity is capable of measuring T-2 levels in the plasma of toxin victims.
Use of a chemical protective mask and clothing prior to and during a mycotoxin aerosol attack will prevent illness. If a soldier is unprotected during an attack the outer uniform should be removed within 4 hours and decontaminated by exposure to 5% hypochlorite for 6-10 hours. The skin should be thoroughly washed with soap and uncontaminated water if available. The M291 skin decontamination kit should also be used to remove skin adherent T-2. Superactivated charcoal can absorb swallowed T-2 and should be administered to victims of an unprotected aerosol attack. The eyes should be irrigated with normal saline or water to remove toxin. No specific antidote or therapeutic regimen is currently available. All therapy is supportive.
Physical protection of the skin and airway are the only proven effective methods of protection during an attack. Immunological (vaccines) and chemoprotective pretreatments are being studied in animal models, but are not available for field use by the warfighter.
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