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| | ==Description== | | ==Description== |
| − | Clastridiurre perfringens type A causes
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| − | enterotoxemia, or yellow lamb disease,
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| − | which occurs primarily in the western US
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| − | (McGowan et al., 1958). Depression, anemia,
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| − | icterus and hemoglobinuria, are followed
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| − | by death after a clinical course of
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| − | 6-12 h, and large numbers of C. perfringen.
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| − | s are found in intestinal contents. A
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| − | similar condition occurs in goats (Russell,
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| − | 1970), and type A probably also causes
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| − | tympany, sometimes accompanied by
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| − | hemorrhagic, necrotic abomasitis in calves.
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| − | Gram-positive bacilli are demonstrable on
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| − | the mucosa and in the submucosa and a
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| − | toxin is found in intestinal contents
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| − | (Roeder et al., 1988). Intravascular hemolysis,
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| − | capillary endothelial damage, platelet
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| − | aggregation, shock and cardiac effects in
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| − | natural infections are predictable systemic
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| − | actions of a hemolytic toxin (Stevens et
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| − | al., 1988; Timoney et a]., 1988). Chymotrypsin
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| − | resistance of a toxin from
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| − | enterotoxemia isolates may allow accumulation
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| − | in the gut and entry to circulation
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| − | (Ginter et al., 1995).
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| | C. pgheernfrsi type B is frequently isolated | | C. pgheernfrsi type B is frequently isolated |
| | from cases of dysentery in newborn | | from cases of dysentery in newborn |
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| | of type B infections may be due to | | of type B infections may be due to |
| | additive or synergistic effects of a, p and | | additive or synergistic effects of a, p and |
| − | c toxins. | + | c toxins |
| − | Neonates of most species are highly
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| − | susceptible to infection by C. perfringen.s
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| − | type C (MacKinnon, 1989) (table ll), and
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| − | colonization in advance of normal intestinal
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| − | flora or alteration of flora by dietary
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| − | changes are significant factors in pathogenesis
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| − | (Timoney et al., 1988). In lambs,
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| − | type C infection resembles lamb dysentery,
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| − | and may be accompanied by nervous
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| − | signs, including tetany and opisthotonus.
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| − | Peracute death, occasionally without other
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| − | clinical signs, is not uncommon, but the
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| − | clinical course may also extend to several
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| − | days. Young ewes and other adult sheep
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| − | can also develop type C enterotoxemia, a
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| − | condition known as ’struck’, in which the
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| − | clinical disease occurs so rapidly that it
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| − | often suggests that the animal has been
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| − | struck by lightning. Mucosal damage, perhaps
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| − | caused by poor quality feed, facilitates
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| − | abomasal and small intestinal multiplication
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| − | of organisms, with resulting
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| − | mucosal necrosis. Fluid accumulation in
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| − | the peritoneum and thoracic cavity suggest
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| − | toxemia, and enteric lesions, dysentery
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| − | and diarrhea are often absent (Sterne
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| − | and Thomson, 1963). Similarities of cpb,
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| − | the (3 toxin gene, to the genes for staphylococcal
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| − | a and y toxins and leukocidin
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| − | (Hunter et al., 1993), strengthen suggestions
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| − | that (3 toxin may affect the CNS
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| − | (Jolivet-Reynaud et al., 1986; McDonel,
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| − | 1986). However, hemorrhagic enterotoxemia
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| − | has not been reproduced in lambs by
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| − | inoculation with cell-free culture supernatant
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| − | fluid (Niilo, 1986).
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| − | Enterotoxemia (’overeating’) in sheep
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| − | of all ages except newborns is caused by
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| − | C. perfrivgetes type D (table II) (Timoney
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| − | et al., 1988). Lambs 3-10 weeks old, suckling
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| − | heavily lactating ewes, are commonly
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| − | affected, as are feedlot animals up to 100
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| − | months of age. Upsets in the gut flora, following
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| − | sudden changes to a rich diet, continuous
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| − | feeding of concentrates (Popoff,
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| − | 1984), and the presence of excess dietary
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| − | starch in the small intestine are often
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| − | involved. e toxin facilitates its own absorption
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| − | (Niilo, 1993), resulting in toxemia
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| − | with little or no enteritis. Some animals
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| − | display dullness, retraction of the head,
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| − | opisthotonus and convulsions (Niilo, 1993;
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| − | Popoff, 1984), but sudden death is common.
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| − | Degeneration and necrosis in the
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| − | CNS is typical (Buxton and Morgan,
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| − | 1976), and focal encephalomalacia is a
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| − | chronic neurological manifestation of nonfatal
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| − | disease (Griner, 1961; Buxton and
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| − | Morgan, 1976). The extent of incoordination
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| − | and convulsions is directly related to
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| − | the severity of lesions (Griner, 1961). Peritoneal
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| − | and pericardial effusions are typical
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| − | in sheep, and glycosuria is pathognomonic
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| − | (Gardner, 1973; Niilo, 1993). The common
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| − | name ’pulpy kidney’ derives from
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| − | the post mortem autolysis of hyperemic,
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| − | toxin-damaged tissue.
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| − | Goats develop catarrhal, fibrinous, or
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| − | hemorrhagic enterocolitis. The condition
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| − | is often chronic, and pulpy kidney is
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| − | absent (von Rotz et al., 1984; Blackwell
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| − | and Butler, 1992).
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| − | C. perfringens type E is an apparently
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| − | uncommon cause of enterotoxemia of
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| − | lambs (table II), and recent isolates have
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| − | been obtained from calves with hemorrhagic
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| − | enteritis, in the western and midwestern
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| − | US (Meer and Songer, 1997).
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| − | However, type E remains of uncertain
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| − | overall importance in animal disease.
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| − | An increasing body of evidence suggests
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| − | a role for enterotoxigenic strains,
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| − | particularly of type A, in the etiology of
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| − | diarrheal conditions in several animal
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| − | species (Estrada-Correa and Taylor, 1989;
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| − | Niilo, 1993). In one study, CPE production
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| − | was observed in 12 % of isolates from cattle,
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| − | sheep and chickens with enteritis
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| − | (Niilo, 1978), and in another, genotyping
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| − | revealed that about 5 % of isolates are
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| − | enterotoxigenic, with most of these being
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| − | type A (Songer and Meer, 1996; Meer and
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| − | Songer, 1997).
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| − | CPE is weakly immunogenic when
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| − | administered via the intestinal tract. Disease
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| − | gives rise to serum antibodies in
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| − | sheep and other domestic species, but antibodies
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| − | produced following parenteral inoculation
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| − | are not protective (Niilo and Cho,
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| − | 1985; Estrada-Correa and Taylor, 1989).
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| − | The best target for immunoprophylaxis
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| − | may be the toxin’s membrane binding
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| − | event (Hanna et al., 1989; Mietzner et al.,
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| − | 1992).
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| − | Immunoprophylaxis is a control measure
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| − | of paramount importance, due to the
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| − | rapid and frequently fatal course of disease
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| − | caused by the various types of C. perfringens.
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| − | Lambs born to ewes vaccinated
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| − | against types B, C or D are protected
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| − | against dysentery (Smith and Matsuoka,
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| − | 1959; Kennedy et al., 1977; Odendaal et
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| − | al., 1989), and may be immunized at 3
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| − | days of age (Kennedy et al., 1977). Enterocolitis,
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| − | but not toxemia, may occur in
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| − | vaccinated goats (Blackwell et al., 1991;
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| − | Blackwell and Butler, 1992).
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| | Infection with Clostridium perfringens types B and C causes severe enteritis, dysentery, toxemia, and high mortality in young lambs, calves, pigs, and foals. Types B and C both produce the highly necrotizing and lethal β toxin that is responsible for severe intestinal damage. This toxin is sensitive to proteolytic enzymes, and disease is associated with inhibition of proteolysis in the intestine. Sow colostrum, which contains a trypsin inhibitor, has been suggested as a factor in the susceptibility of young piglets. Type C also causes enterotoxemia in adult cattle, sheep, and goats. The diseases are listed below, categorized as to cause and host. C perfringens also has been associated with hemorrhagic enteritis in dogs. (See also intestinal diseases in horses, Intestinal Diseases in Horses and Foals: Introduction.) | | Infection with Clostridium perfringens types B and C causes severe enteritis, dysentery, toxemia, and high mortality in young lambs, calves, pigs, and foals. Types B and C both produce the highly necrotizing and lethal β toxin that is responsible for severe intestinal damage. This toxin is sensitive to proteolytic enzymes, and disease is associated with inhibition of proteolysis in the intestine. Sow colostrum, which contains a trypsin inhibitor, has been suggested as a factor in the susceptibility of young piglets. Type C also causes enterotoxemia in adult cattle, sheep, and goats. The diseases are listed below, categorized as to cause and host. C perfringens also has been associated with hemorrhagic enteritis in dogs. (See also intestinal diseases in horses, Intestinal Diseases in Horses and Foals: Introduction.) |