Fluoride Toxicity in Waterfowl and Lagomorphs

Summary Information

Diseases / List of Toxic Diseases / Disease summary
Alternative Names Fluoride Poisoning
Disease Agents
  • In waterfowl: Fluoride, found as a by-product of boron production (B15).
  • In rabbits: Excessive fluoride in compounded food: food contained 310 - 550 mg/kg feed (maximum permitted 150 mg/kg). Also excessive vitamin A in one feed (34,235 IU/kg, normal 6,000 - 12,000 IU/kg). (J26.44.w2)
Infectious Agent(s) --
Non-infectious Agent(s)
Physical Agent(s) -- Indirect / Secondary
General Description
Clinical signs
In waterfowl
  • Bloody discharge from cloaca. (B15)
In rabbits
  • Apathy, reluctance to move, extremities swollen and painful. (J26.44.w2)
  • Examination: painful, hard thickenings of the distal limbs. (J26.44.w2)
  • Reduced body condition. (J26.44.w2)
  • Clinical pathology: Increased alkaline phosphatase in one rabbit. (J26.44.w2)
  • Radiography: "multifocal periosteal and endostial hyperostoses." (J26.44.w2) 
Pathological findings
In waterfowl

Gross post mortem findings

  • Gastro-intestinal tract - Small intestines dilated, with extensive sloughing and haemorrhage of mucosa, lumen containing bloody fluid or mucus. (B15)


  • Gastro-intestinal tract - superficial necrosis and haemorrhage. (B15)
  • Liver - lipidosis, haemorrhage. (B15)

Toxicological Examination - Tissue levels of fluoride increased, e.g. in affected geese:

  • liver - 84. 6mg/kg (healthy controls, 0.4mg/kg); (B15)
  • brain - 23.1mg/kg (healthy controls, 0.3mg/kg). (B15)
In rabbits

Gross post mortem findings

  • Skeletal: hyperostoses, particularly on the radius, ulna and metacarpals or the front legs and the tibia, fibula and metatarsals of the hind legs. Mandible also affected - on the caudal ventral surface, bulging osseous proliferation. (J26.44.w2)
  • Gastro-intestinal tract: in the stomach (fundic and pyloric glandular area) and the duodenum, multifocal mucosal proliferation; in sever cases this appeared as button-like projections of the mucosa. (J26.44.w2)
  • Note: teeth were normal. (J26.44.w2)


  • Skeletal: hyperostoses on the long bones were mainly periosteal, with "a prominent proliferation of woven bone and periosteal fibroblasts and a loss of preexisting lamellar bone", also moderate multifocal endosteal hyperostoses and mild myelofibrosis. (J26.44.w2)
  • Gastro-intestinal tract: Gastric mucosa thickend with mild to severe adenomatous proliferation; "branching villous projections covered by a hyperplastic columnar mucus-producing surface epithelium". In the duodenum, adenomatous proliferations and mild hyperplasia of goblet cells. In the lamina propria of the stomach and duodenum, mild to moderate diffuse inflammatory cell infiltration. (J26.44.w2)

Toxicological Examination

  • Long bones (tibia/fibula) of affected rabbits contained 12,700 and 15,000 g fluoride per gram bone ash, compared with 550 g/g in normal rabbit bone. (J26.44.w2)
Further Information
In waterfowl
  • Birds may have drunk from contaminated waste lagoons when other waters in the area were frozen (B15).
In rabbits
  • Once the feed ration was changed, no further clinical signs of osteofluorosis were noted. (J26.44.w2)
  • It is not known whether the chronic proliferative gastroduodenopathy was associated with the fluoride toxicity or was an incidental finding of unknown aetiology. (J26.44.w2)
Techniques linked to this disease
WaterfowlINDEXDisInvTrCntr.gif (2325 bytes)
Host taxa groups /species
Disease has been reported in either the wild or in captivity in the following species: Snow geese Anser caerulescens and a scaup (B15).
Disease has been reported in free-ranging populations of the following species: Snow geese Anser caerulescens and a scaup (B15).
Disease Author Dr Debra Bourne MA VetMB PhD MRCVS (V.w5)
Referees John Chitty BVetMed CertZooMed MRCVS (V.w65); Sharon Redrobe BSc(Hons) BVetMed CertLAS DZooMed MRCVS, RCVS Specialist in Zoo & Wildlife Medicine (V.w92)

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