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| | ==Diagnosis== | | ==Diagnosis== |
| | ===Clinical Signs=== | | ===Clinical Signs=== |
| − | T
| + | |
| − | et al., 2000). The incubation period in individual
| + | Although the incubation period for classical swine fever is generally less than ten days, in the field it may take up to four weeks for clinical signs to become apparent in a population. Disease severity varies with virulence, immune status and the age of the animal: this means that although acute, chronic and congenital forms of the disease can be appreciated, there is no "classic" disease presentation. |
| − | animals is about one week to 10 days. Under field
| + | |
| − | conditions, symptoms may only become evident in a
| + | In the acute form, animals are almost always pyrexic. In piglets under 12 weeks old the fever may exceed 40°, but in adults |
| − | holding 2–4 weeks after virus introduction, or even
| + | |
| − | later (Laevens et al., 1999). The severity of clinical
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| − | signs mainly depends on the age of the animal and
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| − | the virulence of the virus, and in older breeding pigs
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| − | the course of the infection is often mild or subclinical.
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| − | The virulence of a CSF virus isolate is difficult
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| − | to determine on a rational basis (Mittelholzer
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| − | et al., 2000), as the same CSF virus isolate can cause
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| − | different forms of CSF depending on age, breed and
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| − | immune status of the host animal (Floegel-Niesmann
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| − | et al., unpublished observation).
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| − | Acute, chronic and prenatal forms of CSF can be
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| − | distinguished, and there is no array of classical
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| − | symptoms that is invariably associated with the disease.
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| | Piglets up to 12 weeks of age most often display | | Piglets up to 12 weeks of age most often display |
| | the acute form. A constant finding is pyrexia, usually | | the acute form. A constant finding is pyrexia, usually |