Medical Microbiologists are often required to give advice on measures that can be taken to reduce the risk of toxoplasma infection. This is particularly important in
clinical groups where acute toxoplasma infection can result in severe or life-threatening symptoms, e.g. in HIV/AIDS, the profoundly immunosuppressed, or during pregnancy. The purpose of these notes is to review,
briefly, potential sources and routes of infection and to summarise current advice aimed at reducing such risks.Ingestion is by far the most common route of infection (others including tissues/organs from
infected donors during organ transplantation, and accidental inoculation by needlestick injury during vaccination of sheep or laboratory work with live parasites). Ingested toxoplasma will be in the form of either
oocysts, primarily from hands or foodstuffs contaminated with infected cat faeces (e.g. after gardening, playing in sand-pits, eating insufficiently washed vegetables, etc.) or tissue cysts in infected, undercooked meat
(or from raw meat contaminating hands or work-surfaces during food preparation).
Based on this information, the risk of infection can be reduced by advising susceptible patients (eg pregnant women,
immunocompromised, etc.) to:-
1. not empty cat litter trays - if this is unavoidable wear rubber gloves and wash gloves and hands afterwards
2. disinfect cat litter trays daily with boiling water for five minutes to prevent sporulation
3. not eat undercooked or raw cured meat, only eat meat that has been thoroughly cooked
4. wash hands well after handling raw meat
5. wash kitchen surfaces and utensils thoroughly after contact with raw meat
6. wash fruit, vegetables, and lettuce thoroughly before consumption
7. not drink unpasteurised goats' milk or eat dairy products made from it
8. wear gloves for gardening and wash hands after touching soil
9. cover children's sandpits after use so preventing access to cats
10. Be wary of any unfamiliar foodstuffs that might contain uncooked meats, e.g. when traveling abroad.
Those involved directly in sheep farming or exposed to sheep during lambing face additional risks. Additional measures to prevent transmission from sheep to susceptible patients in an agricultural
environment include:-
1. Do not handle lambing ewes
2. Do not bring lambs into the house
3. Ensure that spouses/partners attending lambing ewes observe full hygiene procedures
3.1 Shower or bathe thoroughly including hair, after handling lambing ewes
3.2 Wash hands thoroughly and scrub nails
3.3 Launder clothes separately. Susceptible patients should
not handle dirty/contaminated overalls worn during lambing
3.4 If it is impossible to clean thoroughly in the night, separate bedrooms are advised
