Toxoplasma Gondii Avoiding Toxoplasmosis in Pregnancy

Toxoplasmosis an infection caused by the obligate intra-cellular parasite Toxoplasma gondii. Infection in most immunocompetent people leads to little or no symptoms. Infection while pregnant, however, can lead to severe congenital complications for the baby.

It is useful to know something about the life cycle of Toxoplasma gondii, as it will aid the pregnant mother in avoiding infection. The parasite can infect many mammalian and bird species but its primary hosts are members of the cat family both large and small.

It is only within the gut of the cat that Toxoplasma can breed sexually; the resultant oocysts pass out of the cat in the feces. The oocysts become infectious between one and four days after being shed from the cat. Toxoplasma oocysts are very resilient and can remain viable for over a year in warm damp environments. An infected cat can excrete millions of oocysts on a daily basis for one to three weeks after primary infection after which the cat is immune and ceases to shed the oocysts.

If an animal ingests a viable oocyst, they can develop Toxoplasma. The oocysts break down in the gut to release tachyzoites and these can travel around the body via the blood and lymph systems. A tachyzoite can infect any cell within the body, which will later release more tachyzoites. This is the primary or acute stage of Toxoplasma infection.

During the acute phase of infection, some of the tachyzoites become encapsulated in tissues to form cysts known as bradyzoites. Bradyzoites persist in tissues for the rest of the host’s life they rarely cause any symptoms unless reactivated by immuno-suppression of the host.

In addition to oocysts, Toxoplasma is transmissible in both the tachyzoite and bradyzoite form by ingestion of undercooked infected meat products. A fetus acquires the infection by tachyzoites, which can cross the placenta during the acute phase of the mother’s infection.

To avoid infection a susceptible mother must take certain precautions.

Avoiding infection via oocysts: –

* Get someone else to change cat litter trays

* If having to change litter trays use latex gloves and wash hands thoroughly afterwards.

* Avoid contact with stray cats and kittens.

* Wear gloves while gardening and wash hand thoroughly afterwards.

* Wash or peel all fruit and vegetables prior to eating.

Avoiding infection via tachyzoites or bradyzoites: –

* Do not eat raw or undercooked meats.

* Avoid eating raw eggs.

* Avoid drinking un-pasteurized milk.

* Avoid eating cheeses or other milk products made from un-pasteurized milk.

* Thoroughly clean surfaces and utensils used to prepare uncooked meat.

* Freeze un-cooked meat for a few days before cooking.

If a mother suspects she may have been exposed, a quick laboratory diagnosis and start of treatment is required. If a mother is infected in the first trimester and the infection is not treated, approximately seventeen percent of fetuses are infected, and disease in the infant is usually severe. If a mother is infected in the third trimester and the infection is not treated, approximately sixty-five percent of fetuses are infected, and involvement is mild or unapparent at birth. Although the condition may not be apparent at birth many Toxoplasma infected babies will develop chorioretinitis or mental disorders as they grow up.