Heavy metal occurring in metallic form or as salts.


[affected.gif] Animals most affected
Cattle, sheep, ducks, geese, swans (other wild birds), dogs, (other species).



[etiology.gif] Etiology
Poisoning (termed saturnism or plumbism) occurs by:


(Note: the use of tetraethyl lead as an anti-knock agent in petrol contributes to atmospheric lead. However, the increased use of lead-free petrol should reduce the amount of lead from this source.) Pets and domestic animals may play a role as biological indicators of lead pollution. The contamination of land by lead also occurs in the immediate vicinity of motorways, busy roads and junctions.



[toxic.gif] Toxicity
Cumulative thiol-depriving poison, capable of blocking particular enzyme processes, notably those involved in haemopoiesis.

Toxic oral doses in mg/kg (lead acetate):
LD (single exposure):
cattle  
 
600-800
calves  
 
200-400
horses 400-600
pigs 800-1000
dogs  
 
800-1000
poultry 200-600
ducks 1 g/animal
LD (multiple exposures):  
cattle 6-10 mg/kg per day

Toxicity varies according to the different lead salts. Repeated doses of sufficient quantity may induce a syndrome of acute lead poisoning.


[clinical.gif] Clinical features
Acute intoxication
in ruminants
in dogs
in birds (swans, waterfowl)
 
  • anorexia, weight loss, ruffled dull feathers;
  • conjunctivitis, ataxia, immobility with intermittent periods of collapse and falling to the ground, convulsions, abnormal stance or postures (e.g. head on the ground);
  • may lead to a rapid death, generally occurring within a few hours of exposure.

Chronic poisoning
(Relatively uncommon in animals, or more correctly, more difficult to identify and to diagnose accurately.) The clinical features are non-specific, of variable intensity and are often transient:


[lesions.gif] Lesions

Not well characterized, but from observations made in veterinary practice:



[treatm~1.gif] Treatment

Antidotes

Symptomatic and supportive care


[labinv~1.gif] Laboratory investigations