Organic arsenicals

Question 1

Use?

Answer 1

• Feed additives to improve wt. gain and feed efficiency and to control enteric infections in swine and poultry
  
  • Arsanilic acid mainly used in swine
  • Roxarsone mainly used in poultry

Question 2

Sources?

Answer 2

• Overdosage or prolonged use
• Recommended concentrations in debilitated, dehydrated, or sick animals

Question 3

T/F: Organic arsenicals are phenylarsonic acid (benzenearsonic acid) derivatives

Answer 3

TRUE

Question 4

What state is organic arsenic in?

Answer 4

Pentavalent oxidation state

Question 5

T/F: Organic pentavalent arsenicals are more toxic than inorganic arsenic

Answer 5

FALSE–organic pentavalent arsenicals are less toxic

Question 6

What is the recommended concentration of arsanilic acid in swine and poultry?

Answer 6

Recommended concentration as growth promoter is 50-100ppm

Question 7

What is the recommended concentration to control swine dysentery?

Answer 7

250-400 for 5-6 days

Question 8

What level causes toxicosis in swine?

Answer 8

500ppm for 7-10 days

Question 9

Recommended concentration of roxarsone as a growth promoter?

Answer 9

Poultry = 25-50ppm

Swine = 25-37.5ppm

Question 10

Recommended concentration of roxarsone to control swine dysentery?

Answer 10

200ppm for 5-6 days

Question 11

What levels of roxarsone causes toxicosis in swine?

Answer 11

250ppm for 7-10 days

Question 12

What enhances toxicity of organic arsenicals?

Answer 12

Dehydration, water deprivation, and renal insufficiency

Question 13

Absorbance, distribution, and excretion of organic arsenicals?

Answer 13

• Small amount is absorbed from GI tract
• Distributed throughout body
• Excreted unchanged in urine

Question 14

What is the mechanism of action?

Answer 14

Unknown

Peripheral nerve demyelination and axonal damage very similar to vitamin B deficiency

Question 15

Clinical signs of arsanilic acid toxicosis in swine?

Answer 15

• Onset of acute toxicosis is 3-5 days
• Signs are incoordination, ataxia, then partial paralysis but they still have a good appetite
• Blindness may develop with arsanilic acid but not with roxarsone
• May be erythema with sensitivity to sunlight
• In chronic toxicosis, gradual onset of blindness and partial paralysis but pigs still eat and drink

Question 16

Clinical signs of arsanilic acid in poultry?

Answer 16

Anorexia, depression, coma and death

Question 17

Clinical signs of roxarsone toxicity in swine?

Answer 17

• Sudden onset
• Marked hyperexcitability
• Tremors
• Collapse
• Coma
• Possible death
• No blindness

Question 18

Clinical signs of roxarsone toxicity in poultry?

Answer 18

Incoordination and ataxia

Question 19

What lesions are seen in swine?

Answer 19

• Possible erythema in light-skinned pigs
• May be muscle atrophy in chronic cases
• Microscopically: peripheral nerve and optic nerve degeneration, demyelination, and gliosis

Question 20

What specimens are used for chemical analysis?

Answer 20

Suspected feed, liver, and kidney

Question 21

Diagnosis?

Answer 21

• History of exposure to organic arsenicals
• Clinical signs
• No gross lesions
• Microscopic peripheral nerve demyelination
• Chemical analysis

Question 22

DDx for arsanilic acid toxicosis in swine?

Answer 22

• Subacute selenium toxicosis (paralysis w/o blindness)
• Organic mercury (seizure)
• Vitamin B complex deficiency
• Infectious diseases

Question 23

DDx for roxarsone toxicosis in swine?

Answer 23

• Pesticides
• Water deprivation/Na ion toxicosis

Question 24

Treatment?

Answer 24

• No specific antidote
• W/drawal of organic arsenicals
• Supportive therapy
  
  • Plenty of water or fluid therapy
  • Multiple vitamins
  • Antibiotics to prevent bac. infections

Question 25

How long might recovery take?

Answer 25

2-4 weeks