Clinical Biochemistry of Domestic Animals (Sixth Edition) - UMK ...

IX. Toxins Affecting the Nervous System
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TABLE 27-8 Toxins Affecting the Nervous System
Toxins Disease Onset Geography Species Affected
Asclepias spp. (milkweed) Acute N AM All
Aspergillus clavatus Acute UK, S AFR B, O
CO Acute Worldwide All
Centaurea spp. Chronic US E
Cyanide Acute Worldwide All
Cycadales Chronic AUS, DOM REP, US B
Eupatorium rugosum (white snakeroot) Acute to chronic US B
Fluoroacetate Acute AUS, S AFR B, Cn, Cp, F, O
Fumonisin ( Fusarium moniliforme ) Chronic Worldwide E
Hepatic encephalopathy Chronic All
Hexachlorophene Chronic Worldwide All
Halogenated salicylanilide Chronic Worldwide Cp, O
Helichrysum spp. Acute to chronic AUS, S AFR B, Cp, O
Karwinskia humboldtiana (coyotillo) Chronic US All
Kochia scoparia (fireweed) Chronic US B
Lead Chronic Worldwide All
Lolium perenne (perennial ryegrass) Acute Worldwide B, E, O
Nitrate/nitrite Acute Worldwide B, Cp, O
Organophosphates Acute to chronic Worldwide All
Phalaris Chronic AUS, NZ, S AFR, US B, O
Renal encephalopathy Chronic All
Selenium Acute to chronic Worldwide P
Solanum spp. Chronic Worldwide B
Strychnine Acute Worldwide All
Stypandrol Acute to chronic ASIA, AUS B, Cp, O
Swainsonine Chronic AUS, N AM B, Cp, E, O
Thiaminase Chronic Worldwide B, Cn, E, F, O,
Trachyandra spp. Chronic AUS, S AFR Cp, E, O, P
Abbreviations: B, bovine; Cn, canine; Cp, caprine; E, equine; F, feline; O, ovine; P, porcine.
detected as reduction of plasma or whole blood cholinesterase
activity.
Subacute selenium intoxication in pigs exposed to complete
rations containing 9.7 to 27 ppm selenium for 45 days
is manifested as a central nervous system disorder characterized
initially by hind limb ataxia progressing to posterior
paralysis. The clinical syndrome is associated with
focal symmetrical poliomyelomalacia of the ventral horns
of the cervical and lumbosacral intumescences ( Casteel
et al. , 1985 ). Hoof separation at the coronary band also
occurs. The clinical pathological alterations were consistent
with dehydration from inability to reach water sources.
Iatrogenic disease in the dog may result from parenteral
administration of selenium preparations ( Turk, 1980 ).
Solanum kwebense , S. dimidiatum , and S. fastigiatum
produce neuronal vacuolation resembling a lysosomal
storage disease. The biochemical basis of this lesion is
unknown.
Swainsonine is an indolizidine alkaloid produced by
certain species of the plants genera Astragalus, Oxytropis,
and Swainsona . This toxin inhibits lysosomal alphamannosidase
resulting in a lysosomal storage alteration
that affects cells in many organs but is often lethal because
of its neurological effect.
Thiaminases that may induce polioencephalomalacia in
herbivores are present in Equisetum arvense and Pteridium
aquilinum . Many uncooked fish species also contain thiaminase,
which may produce encephalopathy affecting