Background
Listeria monocytogenes usually transmitted via contaminated food, occasionally direct person to person.
- Rising incidence (17 cases recorded in Ireland 2007)
- Pregnant women have x20 times the risk of infection
- With risk of: abortion, premature delivery, stillbirth, neonatal infection
- Severe in immunocompromised (including diabetics) and elderly
- Significant cause of food poisoning deaths (mostly infants and elderly)
- Incubation: 3 - 70 days (most <3 weeks)
- May remain infectious for months
Foodstuff
Listeria monocytogenes is widespread in environment (soil, water, vegetables
- Sensitive to adequate heat and pasteurisation
- Can multiply at low temperatures
- Non-pasteurised milk products
- Soft cheeses, coleslaw
- Raw vegetables, smoked salmon, pâté
Symptoms Listeriosis
- Asymptomatic ! (particularly pregnant women)
- 'Flu (mild fever, myalgia, nausea)
- Headache, meningism, convulsions
Diagnosis
- Blood or CSF culture
- Serology not useful
Treatment
- Penicillin ± aminoglycosides or
- Co-trimoxazole or erythromycin
Prevention
- Hand-washing
- Wash raw vegetables and kitchen surfaces
- Separate raw and cooked meat
- Avoid unpasteurised milk etc
- Ensure microwave food is heated properly (stir 1/2 way through cooking)
For high risk people
As left and (esp. pregnant women):
- Avoid ripe soft cheese, pâté or smoked fish
- Avoid lambing or milking ewes
- Be very careful if caring for someone with diarrhoea (hand washing ++)