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| *''L. monocytogenes'' and ''L. ivanovii'' are pathogens | | *''L. monocytogenes'' and ''L. ivanovii'' are pathogens |
| *Carried by sheep and goats and shed in faeces and milk especially during stress | | *Carried by sheep and goats and shed in faeces and milk especially during stress |
− | *Can cause septicaemia, encephalitis and abortion | + | *Can cause septicaemia, encephalitis, abortion and endophthalmitis in ruminants |
| *Outbreaks of listeriosis often linked to silage feeding | | *Outbreaks of listeriosis often linked to silage feeding |
| | | |
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| *Small Gram negative rods | | *Small Gram negative rods |
| *Catalase positive, oxidase negative | | *Catalase positive, oxidase negative |
− | *Motile | + | *Tumbling motility |
| *Facultative anaerobes | | *Facultative anaerobes |
| *''L. monocytogenes is haemolytic on blood agar due to a cytolytic protein, listeriolysin; grows at range of pH values and temperatures | | *''L. monocytogenes is haemolytic on blood agar due to a cytolytic protein, listeriolysin; grows at range of pH values and temperatures |
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| ===Clinical infections=== | | ===Clinical infections=== |
| + | |
| + | *Outbreaks of listeriosis caused by ''L. moncytogenes'' seasonal and linked to silage feeding |
| + | *Replicates in poor quality silage where the pH excedes 5.5 |
| + | *Animals highly susceptible during pregnancy due to lowered cell-mediated immunity |
| + | *Neural listeriosis: |
| + | **Incubation period 14-40 days |
| + | **Dullness, circling, head tilt, facial paralysis, drool saliva, droop of eyelid and ear |
| + | **Exposure keratitis |
| + | **Fever during early stages |
| + | **Recumbency and death within a few days in sheep and goats |
| + | **Abortion up to 12 days after infection in cattle |
| + | *Septicaemic listeriosis: |
| + | **Incubation perios 2-3 days |
| + | **Lambs and occasionally pregnant sheep |
| + | **Occurs in newborn piglets, foals, poultry, adult sheep |
| + | *Keratoconjunctivitis in cattle and sheep - direct contact with silage via eye |
| + | |
| + | *''L. ivanovii causes sporadic abortion in sheep and cattle |
| + | *''L. innocua'' rarely causes ovine meningoencephalitis |
| + | |
| + | |
| + | ===Diagnosis=== |
| + | |
| + | *Specimens should include CSF in neural cases, cotyledons in abortion, liver, spleen and blood in septicaemia |
| + | *Immunofluorescence using monoclonal antibodies |
| + | *Histology of brain demonstrates microabscesses and lymphocytic cuffing in brainstem |
| + | *Smears of cotyledons |
| + | *High protein and cell counts in CSF |
| + | *Isolation on blood and MacConkey agar |
| + | |
| + | |
| + | ===Treatment and control=== |
| + | |
| + | *Ampicillin or amoxycillin in early stages of septicaemic listeriosis |
| + | *Sub-conjuntival antibiotics and corticosteroids for ocular listeriosis |
| + | *Avoid poor quality silage and discontinue silage-feeding in an outbreak |