Organochlorine Insecticide

Question 1

What are the three classes of insecticide and examples of each?

Answer 1

Diphenylaliphatic compounds - DDT, methoxyclor

Arylhydrocarbon compounds - Lindaine, mirex, kepone

Cyclodiene insecticide - aldrin, chlordane, toxaphene

Question 2

How many months withdrawal for these chemicals?

Answer 2

2 months

Question 3

Which 2 are approved with limited use?

Answer 3

methyoxyclor and lindaine

Question 4

What should organochlorines not be confused with?

Answer 4

other chlorinated hydrocarbons

Question 5

Why have organochlorines been banned?

Answer 5

bioaccumulation, environmental persistance, estrogenic activity, endocrine discruption, egg shell thining, learning disorders, enzyme induction

Question 6

What is the absorption and distribution?

Answer 6

water insoluble and have low volatility
through skin and MM. poorly through lungs and GIT

accumulate in lipid tissues
- detect in liver, kidney, brain and fetus

Question 7

What is the metabolism and excretion?

Answer 7

slowly de chlorinated in the liver (metabolites are also toxic)

• excreted primarily through the bile
• enterohepatic recycling can occur
• rapid mobilization of fat can enhance toxicity

Question 8

Although not fully understood what is the general MOA?

Answer 8

CNS excitation

Question 9

What is the MOA of DDT?

Answer 9

K efflux hindered
NA depolarization prolonged
= decrease transmembrane resting potential
= decrease firing threshold
= tremors or convulsions

Question 10

What other MOA are involved and what does this cause?

Answer 10

1. increased synaptic activity
2. increase NT release
3. inhibition of gamma (GABA)

affect all neurons releaseing both inhibitory and excitatory
= variety of neurological problems
variable and dose dependent

Question 11

what animals are very susceptable?

Answer 11

sheep and cats

Question 12

What is the onset of clinical manifestations? toxic dose?

Answer 12

min to days depending on dose

15-100mg/kg in most species

Question 13

What are the 4 main clinical signs?

Answer 13

behavioural aberrations
nervous phenomena
autonomic manifestations
locomotor disturbances

Question 14

What are the behavioural aberrations?

Answer 14

anxiety, apprehension, frenzy
belligerance, aggression
head between legs
jumping over unseen objects
licking excessively

Question 15

What is the nervous phenomena?

Answer 15

hypersensitivity
muscle twitching, jaw champing
clonic tonic (stiff paddle)
tremors (increase temp)
opisthotonus
not blind

Question 16

What are the autonomic manifestations?

Answer 16

emesis in some
salivation
diarrhea
heart rate variable
dyspnea

Question 17

What are the locomotor disturbances?

Answer 17

stiff gait
incoordintation, atazia
possible circling to side of lesion

Question 18

What are the chronic manifestations of the poisoning?

Answer 18

similar but lesser

estrus cycling, decreased milk production or egg production

Question 19

does permanent damage occur in nervous system? can they recover?

Answer 19

if they survive acute yes

no permanent damage

Question 20

what are the PM findings?

Answer 20

can have non at all

non-specific:
mild hemorrhage and congestion in GI
mild fatty degeneration or cloudy swelling in liver and kidney
degenerative changes in thyroid, pancreas, testis or adrenal gland

Question 21

What is the Dx?

Answer 21

Hx, herd outbreaks, CNS manifestations with no PM finding

analysis of fat, milk, liver, kidney or GI contents recommended

Question 22

What is the treatment?

Answer 22

kill em
dermal - wash
GL
AC
mineral oil
sedation
reduce nutrition to lower fat
lipid emulsion

Question 23

What are the economic impacts?

Answer 23

milk residues

reproductive, carcinogenic and immunosuppressive effects in food animals