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Por meio de revisão da literatura pertinente foram coligidos e são apresentados os principais dados relativos à intoxicação por selênio em animais domésticos. Foram abordados e discutidos os aspectos epidemiológicos, clínicos, anátomo e histopatológicos e patogenéticos atribuídos a Alkali Disease, Blind Staggers, intoxicação aguda e poliomielomalácia simétrica focal dos suínos. O trabalho tem como objetivo esclarecer pontos obscuros relativos à intoxicação por selênio, bem como alertar para os riscos que a suplementação com esse elemento pode representar.

Selenium in certain soils may be taken up by plants in amounts to render them toxic. Seleniferous forage can be found in most of the western states. Intoxication of livestock by seleniferous plants has been classified as acute and chronic. Acute poisoning results from consumption of plants having high levels of Se; chronic Se poisoning has been described in two forms— alkali disease and blind staggers. Alkali disease is said to result from the consumption of seleniferous grains and grasses, and is manifest by loss of hair, lameness, and loss of weight. Blind staggers is slid to result from the consumption of Se indicator plants and is manifest by wandering, circling, loss of ability to swallow, and blindness. Some research casts doubt on the above classification of Se poisoning. Research using pigs (Sus scrofa domesticus) indicates that the source of Se does not alter the type of lesion or signs of poisoning observed. There are data available that suggest that blind staggers is not related to Se poisoning.

I. ABSTRACT Soils in some areas of the world contain such high concentrations of selenium that they produce plants toxic to livestock. Some plants grow only in these seleniferous soils, are referred to as primary selenium indicators, and concentrate high levels of the element in their tissues. Others, referred to as secondary selenium absorbers, can accumulate rather high concentrations of the element when growing on seleniferous soils. A third class of plants, grasses, and grains as well as many others, absorb less selenium, but still often contain enough to be toxic. Three major types of selenium toxicosis have been described. “Blind staggers” is suggested as a chronic type toxicosis resulting from long-term ingestion by sheep and cattle of the primary indicators or secondary absorbers in less than acutely toxic amounts. There is some reason to question the role of selenium in causing this syndrome. “Alkali disease ” occurs in poultry, swine, cattle, and horses that consume grains, forages, or pasture plants containing usually less than 50 but more than 5 parts per million of the element over a period of many weeks or months. Acute selenium toxicosis results when grazing animals consume the primary selenium indicators in amounts sufficient to cause a very rapid toxicosis. Control in all types of selenium toxicoses requires avoidance of seleniferous feeds.

Humboldt, Tenn., April 8, 1905. To the Editor: —I have just read Dr. Albert's letter inThe Journal, April 8, p. 1132, on the identity of meningitis in animals and man. This is an interesting and important subject, especially as the question of contagion is beginning to receive the attention it should have had long ago. I am not familar with the disease in the cow, but I have seen a few cases in man and in horses and have long been impressed with the idea that the disease is the same in both. The disease in the horse is known in this locality as "blind staggers" and there is a popular impression that the horse contracts the disease from eating the "chaff" of old corn, and as it is undoubtedly more common about the time the farmers are cleaning out the corn-cribs preparatory to housing the new crop, it