Organochlorine Insecticide Flashcards
What are the three classes of insecticide and examples of each?
Diphenylaliphatic compounds - DDT, methoxyclor
Arylhydrocarbon compounds - Lindaine, mirex, kepone
Cyclodiene insecticide - aldrin, chlordane, toxaphene
How many months withdrawal for these chemicals?
2 months
Which 2 are approved with limited use?
methyoxyclor and lindaine
What should organochlorines not be confused with?
other chlorinated hydrocarbons
Why have organochlorines been banned?
bioaccumulation, environmental persistance, estrogenic activity, endocrine discruption, egg shell thining, learning disorders, enzyme induction
What is the absorption and distribution?
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
What is the metabolism and excretion?
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
Although not fully understood what is the general MOA?
CNS excitation
What is the MOA of DDT?
K efflux hindered NA depolarization prolonged = decrease transmembrane resting potential = decrease firing threshold = tremors or convulsions
What other MOA are involved and what does this cause?
- increased synaptic activity
- increase NT release
- inhibition of gamma (GABA)
affect all neurons releaseing both inhibitory and excitatory
= variety of neurological problems
variable and dose dependent
what animals are very susceptable?
sheep and cats
What is the onset of clinical manifestations? toxic dose?
min to days depending on dose
15-100mg/kg in most species
What are the 4 main clinical signs?
behavioural aberrations
nervous phenomena
autonomic manifestations
locomotor disturbances
What are the behavioural aberrations?
anxiety, apprehension, frenzy belligerance, aggression head between legs jumping over unseen objects licking excessively
What is the nervous phenomena?
hypersensitivity muscle twitching, jaw champing clonic tonic (stiff paddle) tremors (increase temp) opisthotonus not blind
What are the autonomic manifestations?
emesis in some salivation diarrhea heart rate variable dyspnea
What are the locomotor disturbances?
stiff gait
incoordintation, atazia
possible circling to side of lesion
What are the chronic manifestations of the poisoning?
similar but lesser
estrus cycling, decreased milk production or egg production
does permanent damage occur in nervous system? can they recover?
if they survive acute yes
no permanent damage
what are the PM findings?
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
What is the Dx?
Hx, herd outbreaks, CNS manifestations with no PM finding
analysis of fat, milk, liver, kidney or GI contents recommended
What is the treatment?
kill em dermal - wash GL AC mineral oil sedation reduce nutrition to lower fat lipid emulsion
What are the economic impacts?
milk residues
reproductive, carcinogenic and immunosuppressive effects in food animals
