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Bioterrorist Weapons - Symptoms in Farm Animals
Posted by: JimEdwards on Mar 20, 2003 - 04:21 PM
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by Dr. Mike Meredith, Pig Disease Information Centre
March 19th 2003
Biological Terrorism is the threatened use or use of a microorganism or toxin derived from living organisms to induce death or disease in people, animals or plants.
Dr. Jacob Casper, Coordinator of Disaster Services at Maryland Department of Agriculture and Past President of the American Academy on Veterinary Disaster Medicine has brought together a team of experts to prepare an authoritative account of bioterrorist agents affecting animals. Contributors include Prof. Tam Garland, Diplomat of the American Board of Veterinary Toxicology, Dr. Joanne Howl, Secretary of the American Academy on Veterinary Disaster Medicine and Prof. Martin Hugh-Jones, Coordinator of the WHO Anthrax Research & Control Working Group.
General Suspicious Signs of Bioterror Weapon Activity:
1. Increased morbidity or mortality.
2. Disease in a species not normally manifesting the disease.
3. Disease at unusual time of year.
4. Disease in areas where not normally found.
5. Lack of response to the usual treatment.
Anthrax
Bacillus anthracis infects humans, ruminants, horses, swine, dogs and wildlife. Inhalation anthrax is the primary bioterrorist concern. The incubation period is generally between 1-6 days in both people and animals. Animal and human vaccines are available.
Initial cases are usually found dead, in a bloated 'saw horse' posture and without rigor mortis; blood may be found at the mouth, anus, vagina, or penis. Peracute inhalation anthrax may manifest as staggering, difficult breathing, trembling, collapse, convulsive movements and death. Acute anthrax presents with fever (up to 107 degF) and a period of excitement followed by staggering, convulsions and death. Chronic anthrax is the most familiar form in swine with local lesions on tongue and oropharynx. Cutaneous anthrax can occur in animals after contamination of wounds with spores. Clinical symptoms in humans are fever, malaise, fatigue, cough and chest discomfort progressing to severe respiratory distress, cyanosis and shock.
Foot and mouth disease
Although not included in the Maryland review, FMD is probably the greatest bioterrorism threat faced by farmers and the food chain. Typical signs are: sudden lameness, lying down, blisters on the upper edge of the hoof, where skin and horn meet, and on the heels and in the cleft of the foot. Blisters may also develop on the nose or tongue.
Influenza viruses
Poultry and pig farms are especially susceptible to epidemics following infection with 'flu viruses. Pigs and humans can be infected with the same virus strain. see www.aasv.org/news/story.php?id=504
Plague
As well as humans, Yersinia pestis can affect cats, wild cats, dogs, rabbits, hares, rodents flying squirrels, but it is not a likely agent to be used against food animals.
Ricin
A terrorist laboratory producing ricin was found in London recently. However the toxin is not passed between living animals and so farm animals are an unlikely target.
Smallpox
Does not affect farm animals.
Staphylococcal enterotoxin B (SEB)
This toxin can be encountered by exposure to toxin-producing strains of Staphylococcus aureus e.g. by food-borne proliferation of a toxigenic strain, or by exposure to the purified toxin. SEB was weaponized for use as a biologic agent by the U.S. in the 1960's. Swine are less susceptible than other farm animals and humans.
Trichothecene mycotoxins
These agents are toxic to farm animals, especially pigs. Toxicity can occur via oral, parenteral ,dermal or aerosol exposure. The mycotoxin T-2 (yellow rain), has been weaponized for aerosol distribution. After oral ingestion effects are seen in 3-12 hours, dermal contamination produces toxicity after 6-12 hours; ocular exposure within 2-5 minutes. Respiratory doses are toxic in less than one hour. Intoxication usually manifests as feed refusal, but vomiting and dermal necrosis are also common. Regardless of route of exposure, intoxication includes hematopoietic and immunosuppressive effects, central nervous effects, and vascular effects leading to hypotension and shock. Local route-specific effects may include: oral exposure with lesions to the upper gastrointestinal tract; dermal exposure with local cutaneous necrosis and inflammation; and ocular exposure with corneal injury. Human beings suffering exposure have skin pain, pruritus, redness, vesicles, necrosis and sloughing of the epidermis. Effects on the airway include pain in the throat and nose, nasal discharge, itching and sneezing, cough, dyspnea, wheezing, hemoptysis and chest pain. Severe intoxication has resulted in prostration, weakness, ataxia, collapse, shock and death.
References & Resources
"Bioterrorism agents: implications for animals" published by The Maryland Department of Health and Mental Hygiene (DHMH).
U.S. farms placed on a "Level Orange" bioterrorism alert
The Veterinary Role in Bioterrorism Surveillance
Bioterrorism Threat - FMD Defense Simulation
Facing the Threat of Emerging Diseases and Bioterrorism
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Souce: VETLIB-L@LISTSERV.VT.EDU
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