Evidence shows human infection with Toxoplasma gondii is continuously increasing.

There is no vaccine or approved treatment to fight against this successful parasite.

The mental effects of toxoplasmosis are still debated, but the physical harm is confirmed and serious.

For a few years now, health organizations have been warning that Toxoplasma gondii infection in humans has reached dangerous levels [1], but newer statistics and projections point to some pretty alarming numbers. It looks like in some regions (Italy and Pakistan, for example), more than a third of the population is infected with this parasite, and overall, it has infected around a billion people worldwide, though the burden is unevenly distributed. Because of this, it could fairly be called the most common parasitic infection in humans [2].

Once someone is infected, the parasite stays with them for the rest of their life; there is no effective drug to fully clear it, and no vaccine has been developed to prevent it either. Given the evidence, even if still limited, of its clinical effects, and given how widespread it already is (and will almost certainly become more so), people and health organizations around the world need to pay much closer attention to this issue.

Toxoplasmosis life cycle

Toxoplasma gondii is a parasite that absolutely needs cats to complete its reproductive cycle. The only place where it can reproduce sexually is inside a cat’s gut. The cat sheds these microscopic eggs (oocysts) in its feces, and that’s where the trouble starts. Those eggs get into soil, water, or food. A mouse comes along, nibbles on something contaminated, and then becomes infected.

Once inside the mouse, the parasite does not waste time. It converts into a fast-growing form called tachyzoites, which multiply like crazy and invade all sorts of tissues. The immune system eventually fights back, but the parasite has a backup plan: it transforms into a slow-growing form (bradyzoites) and forms cysts, mostly in the brain........

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