Pentachlorophenol

Question 1

What are fungicides?

Answer 1

Chemicals used to prevent or treat fungal infections in plants

Question 2

T/F: Generally, fungicides have low toxicity to animals if properly used

Answer 2

TRUE

Question 3

Uses of pentachlorophenol (PCP)?

Answer 3

• Only used by certified applicators as a wood preservative (to protect limber from fungal rot and wood-boring insects)
• No longer found in wood-preserving solutions or insecticides and herbicides for home/garden use

Question 4

4 sources of PCP toxicosis?

Answer 4

• Vapors can penetrate intact skin–dermal exposure is the most toxic route of exposure, esp to newborns
• Inhalation of toxic amounts from treated walls in sheds and barns (even if applied months-years before), esp with poor ventilation
• Licking wood treated w/ PCP
• Ingestion of contaminated feeds or water with spills of PCP

Question 5

What is PCP?

Answer 5

Chlorinated hydrocarbon insecticide and fungicide

Question 6

Solubility (salts and solution)?

Answer 6

• Solution not very soluble in water, but soluble in oils and organic solvents
• Salts are soluble in water

Question 7

Stability?

Answer 7

PCP is volatile and can give off toxic vapors in toxic conc. esp. in high ambient temp

Question 8

Persistence?

Answer 8

Not persistent in water, sewage, or soil b/c of bac. composition

Question 9

Is PCP an irritant?

Answer 9

Yes–to mm, resp tract, and skin

Question 10

What do older preparations contain?

Answer 10

Dioxins–carcinogenic and teratogenic

Question 11

Acute oral (dermal LD₅₀) toxicity?

Chronic toxicity?

Answer 11

• Acute oral in domestic animals ranges from 100-200 mg/kg
• Chronic toxicity ranges from 40-70mg/kg

Question 12

Factors increasing toxicity?

Answer 12

• High ambient temp
• Oily or organic solvent vehicles
• Previous exposure
• Poor condition
• Newborn
• Hyperthyroidism

Question 13

Factors decreasing toxicity?

Answer 13

• Cold temp
• Antithyroid drugs
• Presence of body fat

Question 14

Where is PCP readily absorbed from? Where is it distributed?

Answer 14

• Readily absorbed from GI tract, by inhalation, and from intact skin
• Distributed throughout the body w/ some accumulation in body fat

Question 15

Half-life?

Answer 15

1.5-2 days in various species

Question 16

What is PCP metabolized by?

Answer 16

Conjugation to glucuronic acid

Question 17

How is PCP excreted?

Answer 17

Excreted as glucuronides or unchanged in urine

Question 18

Residues?

Answer 18

Residues in tissues and fat are depleted from the body w/in 1 week of exposure

Question 19

Mechanism of action?

Answer 19

• Uncouples oxidative phosphorylation and blocks or decreases ATP
• Increases oxygen demand in an effort to produce ATP
• Oxygen demand > oxygen supply
• Resulting in overheating, metabolic acidosis, and dehydration

Question 20

Effects on the body?

Answer 20

• Irritation of eye, GI mucosa, resp, and intact skin
• Decreased cellular energy may cause neurotoxic and other effects (wt. loss, dec. milk prod., repro problems)
• High exposures may lead to signs of CNS stimulation or seizures

Question 21

Clinical signs of acute toxicosis?

Answer 21

• Onset and duration may be so fast that no signs are seen
• Hyperthermia, tachycardia, dyspnea, cyanosis, seizures, collapse, death
• Newborn pigs show hyperthermia, skin irritation, and rapid death

Question 22

Clinical signs of chronic toxicosis?

Answer 22

• Wt. loss, dec. milk production, anemia, fetal malformations, and poss. abortions
• Fever and resp distress may be absent

Question 23

What are the lesions of PCP toxicosis?

Answer 23

• Rapid rigor mortis
• Local irritation of skin and mm
• Pulmonary congestion and edema
• Degenerative changes in liver, kidney, and brain
• Dark blood (oxygen deprivation)
• Hyperkeratosis of skin and villous like hyperplasia of urinary bladder mucosa in chronic cases

Question 24

Laboratory diagnosis: live vs. dead animal?

Answer 24

• Live animal–chemical analysis in blood and urine
• Dead animal–chemical analysis of kidney and skin

Question 25

Diagnosis

Answer 25

* History of exposure * Signs of rapid overheating and resp distress * Lesions of rapid rigor mortis and dark blood * Chemical analysis

Question 26

DDx

Answer 26

* Heat stroke (history) * Toxicants causing resp insufficiency * Nitrate (brown blood, no fever) * CO (bright red blood, no fever) * Pesticides (marked neuromuscular signs, autonomic signs) * Peracute infectious diseases

Question 27

Is there a specific antidote?

Answer 27

Of course not

Question 28

Detoxification?

Answer 28

* Emetics or gastric levage w/ 5% sodium bicarbonate * Activated charcoal or mineral oil * Soap and water bath (**use gloves**)

Question 29

Supportive/symptomatic therapy?

Answer 29

* Oxygen therapy * Lower body temp--apply cold water to skin, ethanol * IV fluids (**no glucose**) and electrolytes for dehydration and metabolic acidosis * Prophylactic use of antibiotics and mult vitamins may be used to prevent secondary bac. infections (due to liver, kidney, and intestinal damage)

Question 30

Prognosis?

Answer 30

If animal survives for 24hrs, chances for complete recovery are fair