Toxoplasmosis Flashcards
Toxoplasmosis
Type of organism and route of transmission
Obligate intracellular parasite
Ingestion of uncooked meat - infected with oocysts
Ingestion of oocysts from cat faeces - litter, soil, unwashed produce
Transplacental
Toxoplasmosis
Features of maternal infection
90% asymptomatic/subclinical Malaise, fever, cervical lymphadenopathy If severe - disseminated - Chorioretinitis - Encephalitis
Toxoplasmosis
Features of neonatal infection
Preterm birth 4x Low birthweight Hepatosplenomegaly Intracranial calcification Hydrocephaly or microcephaly 10% chorioretinitis Blindness Deafness Learning difficulty
Toxoplasmosis
Risk of transmission
T1 - 4-15% low
More severe - miscarriage
T2 - 25-44% intermediate
Intermediate risk damage
T3 - 30- 75% high
Lower risk damage 4-17%
Asymptomatic
Toxoplasmosis
Investigation
IgM +ve within 10days, -ve within 3 months. MAY be lifelong
IgG +ve within 2-3weeks, lifelong
IgA +ve = infection <3months
IgG avidity
Fetal USS +/- MRI
Amniocentesis - PCR
- do >18weeks and >4weeks after infection
Toxoplasmosis
Management
Spiramycin - maternal infection to prevent transmission. Doesn’t cross placenta.
Pyrimethamine + sulfadiazine + folinic acid - if fetal infection suspected or >18weeks regardless of fetal affect
As fetal transmission risk high
RCT showed reduced fetal anomalies
USS
Offer TOP if severe anomaly
Toxoplasmosis
At birth
Infant IgM, IgA, IgG
Placental histology PCR
Blood or CSF PCR
Full clinical review, ophthalmology + audiology exam, cerebral USS +/- MRI or CT
If +ve: treat with pyrimethamine + sulfadiazine. Monitor hearing, vision, neurodevelopment
If -ve: IgM 3months, IgM and IgG 6, 12, 18months
Toxoplasmosis
Prevention
Wash hands after handling raw meat and veggies and after gardening
Cook meat to safe temperature
Avoid emptying cat litter tray or wear gloves
Wash and dry hands well after cleaning up after animals
No vaccine
No role for screening antibody status in low prevalence areas
