The Importance of Veterinary Toxicology for Animal Agriculture and the Food Supply

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The Importance of Veterinary Toxicology for
Animal Agriculture and the Food Supply

• Birgit Puschner
• DVM, PhD, Dipl. ABVT
• California Animal Health and Food Safety
  Laboratory System
• School of Veterinary Medicine
• University of California, Davs

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Belgium PCB and Dioxin Incident

• In January, 1999, 500 tons of animal feed were
  contaminated with
• 50 kg of PCBs and
• 1 gram of dioxin
• ?Distributed to animal farms in Belgium

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1 storage tank of fat
2140 pork, poultry and beef farms
10 livestock feed manufacturers
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Timeline of events

• Feed contamination January, 1999
• Early Feb, 1999 Veterinarian diagnosed chicken
  edema disease ? prompted investigation
• Mid March, 1999
• Feed and animal tissues were sent for tox testing
• Veterinarian considered fat in animal feed the
  most likely source
• April 26, 1999 Dioxin and PCB contamination
  confirmed by laboratory

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60 billion Belgian francs or 1.5 billion U.S.
dollars
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Lesson learned

• Animal agriculture is an easy target
• Toxicants can be widely distributed
• Veterinarians may be the first responders
• Veterinary toxicology laboratories are crucial in
  investigations
• ? Toxicology Case Studies

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Poisoning Case in Dairy Cows

• 22 24 lactating cattle died over a period of 9
  days in a herd of 300 cows
• Affected cattle in one pen
• Clinical signs
• Reduced or no rumen motility
• Lethargic and hunched up
• Decreased milk production
• Increased respiratory rate and effort

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• ? Tongue tone
• ? Palpebral reflex

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Timeline

• Consultation with herd vet Day 1
• Necropsies Day 2
• Hold placed on milk and milk products Day 2
• Awaiting toxicology results
• Awaiting possible danger to the food supply
• Toxicology testing Day 3-5

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Toxicological Analyses

• Oleander
• OP and carbamate insecticides
• Ionophore antibiotics (monensin, etc.)
• Toxic plants tree tobacco, jimsonweed, poison
  hemlock, yews, larkspurs, lupine, foxglove,
  rhododendrons
• Hypocalcemia
• Hypomagnesemia

• Lead
• Arsenic, Mercury, Cadmium
• Copper
• Selenium
• GC/MS screen pesticides, drugs, natural products
• FERN LC/MS screen a large variety of chemicals
  that may result in high morbidity or mortality
• Rat poisons

Decision with regards to safety of milk dairy
products
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Final Diagnosis Day 7

• Diagnosis of Botulism Type C Source
• Challenges
• Vagueness of clinical signs
• Tests for botulinum toxin not sensitive enough
• Tox testing crucial!
• Source of toxin

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March 2006
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47th and Stockton blvd
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Cooked mushroom samples positive for alpha- and
beta- amanitin.
Mushroom pieces
Onions
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Toxicology Involvement

• Soup available for testing rapid diagnosis
• New methodology (LC/MS)

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Poisoning Case in Dairy Cows

• 6 lactating cattle (total in pen 16) died
  within 24 hours in a herd of 600 cows
• Just found dead
• Other information
• All animals are off feed a little
• All animals on dairy get the same ration TMR
  (corn silage and premix, top-dressed with hay)
• Owner washed a spray tank the day before

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Diagnostic Work-up

• Necropsies cardiotoxic event
• Toxicology testing oleandrin
• GI contents, liver, muscle feed
• Serum, urine, milk

Results within a few hours (LC/MS)
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Benefit of Toxicology Testing

• Rapid diagnosis
• Testing of milk and meat

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Perchlorate
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Perchlorate

• Developed LC-MS/MS method in 2 weeks
• Method detection limit 0.8 ppb
• 46 milk samples
• All samples were positive
• 1.54 ppb to 20 ppb

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Perchlorate Interlab Comparison Study
Sample No. FDA/CFSAN IC-MS/MS CAHFS HPLC-MS/MS
Milk 1 5.21ppb 5.83 ppb
Milk 2 4.59 ppb 5.28 ppb
Milk 5 4.66 ppb 5.28 ppb
Milk 7 4.70 ppb 4.85 ppb
Milk 8 4.59 ppb 5.82 ppb
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Perchlorate Regulatory Issues

• NAS recommendation 0.7 µg/kg/day
• Drinking water equivalent level (DWEL)
• 24.5 ppb for an adult
• 4 ppb for infants
• CA - Public health goal 6 ppb

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Perchlorate, Dairy Cattle and Human Health

• Human health
• WHO iodine deficiency
• Rapid transfer of dietary perchlorate to milk
• Perchlorate in dairy cows
• Ruminants biofilters?
• Perchlorate intake and milk iodide
• Goal limit perchlorate content
• of the dairy cows diet

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Insecticide Cases

• Humans
• Thai food restaurant
• 107 affected people
• Methomyl exposure

• Cattle
• Phorate
• 167 deaths
• Diagnosis established within hours
• Analysis of milk and fat within hours

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Methomyl

• Testing of food, and food ingredients (oil, salt,
  herbs)

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Mycotoxins

• Aflatoxins
• Fumonisins
• Ochratoxin
• Tricothecene mycotoxins
• Penitrem A
• Zearalenone

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Algal Toxins

• Saxitoxins
• Anatoxins

• Microcystins

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Importance

• Testing for toxicants in a large number of
  matrices
• Diagnosis of intoxications
• Prevention of intoxications
• Ensuring food safety
• Assisting with risk assessments
• Providing information to regulatory agencies

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www.cahfs.ucdavis.edu
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CAHFS Toxicology Laboratory

• Member of FERN
• Received funding through the Homeland Security
  Department
• Largest Vet Tox Lab in the Country
• ? Highly trained personnel
• ? Continuous method development and expansion of
  existing testing