[Best of 2019] Billions are infected by a cat poop brain bug, but studying it is vexing researchers

Toxoplasmais closely related toPlasmodium, the parasite that causes malaria.

It muscles its way into just about any jot down of cell.

But its also very hard to isolateToxoplasmafrom the cells that it infects.

So Im trying to find a method to increase the amount ofToxoplasmaparasite in samples.

Once infected, you will never get rid of your new silent buddy.

But humans are not actually the parasites natural host.

Normally itcyclesbetween cats both domestic and wild and the animals they eat.

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Cats release the equivalent ofToxoplasmaeggs, known as oocysts, in their faeces.

There they will wait quietly for years, until their host is eaten by a cat.

Once inside their final host, the parasite wakes up again and starts dividing.

Its not only through cat faeces thathumans can become infected, however.

In fact, the most common method of infection isthrough consuming undercooked or rare meatcontaining the parasite.

Infection can also happen in the womb, or through an organ transplant from an infected person.

At worst, a typicalToxoplasmainfection (known as toxoplasmosis) feels like a light flu.

The parasite doesnt want to kill its intermediate host (us) after all.

It can be particularly dangerous for a woman to get toxoplasmosis during pregnancy.

A developing infant is protected only by its mothers antibodies that cross the placenta.

This is because T cells would act as if the developing child were a huge parasite and destroy it.

Maternal antibodies do a good job against a flu virus, butcant protect againstToxoplasma.

ForToxoplasma, the fetus would need its own inflammatory T cells to drive the parasites back into their oocysts.

But fetuses dont have their own T cells either.

Investigating effects

Due to this unique behavior,Toxoplasmahasbeen widely investigatedby parasitologists, biologists and psychiatrists.

Researchers have found that theToxoplasmaparasites mayaffect human behavior and personality, for example.

Studies have also suggested a link withschizophreniaandbipolar disorder.

In women, the shift in these two factors is the opposite.

They appear to be more warm-hearted, outgoing and easygoing than women without the parasite.

It is very difficult to isolateToxoplasmafrom human DNA, and the parasite can only grow within other living cells.

So unlike bacteria, it cannot be easily cultured in the lab.

In addition, unlike many other disease-causing microbes,Toxoplasmais typically found in very low numbers within clinical samples.

My current research is focused on increasing the number of parasites to obtain high quality samples.

And will assist indeveloping new treatments, methods of surveillance and strategies to stop people getting infected.

This article is republished fromThe ConversationbyJustyna Anna Nalepa-Grajcar, PhD Researcher,Aberystwyth Universityunder a Creative Commons license.