Fun with Toxoplasmosis

Toxoplasma Gondii is a single-celled parasite that can only sexually reproduce in cat feces, infectious up to 12 months after expulsion.

T. Gondii life cycle

In a warm-blooded host like us, T. gondii will start out by entering all sorts of cell types and asexually reproducing in vacoules, virus-style. This will continue until the cell bursts, spreading toxoplasma all over the body and destroying cells in a domino of break in and explode out.

This stage ends when the host’s immune system kicks in. Then, toxoplasma will slowly replicate from within a cyst. These cysts can persist for a long time, eventually bursting and forming new cysts.

Humans end up contracting it a couple of ways: exposed to cat feces directly, dealing with it indirectly in dirt outside, or eating raw meat (especially free range and pig / boar) with cysts that contain the parasite. There are more people infected in France just because they eat more raw and undercooked meat.

If the host is not immunocompromised, there will usually be no symptoms. But some of the fun effects include increased mood disorders, Alzheimer’s, traffic accidents, and a 2.7x higher risk of schizophrenia.

I think a lot about how I can provide value to the places I’m going, and in a few months I’m going to a party in the woods. It would be beyond valuable to have a volunteer station that can provide tests for toxoplasmosis while there. It fits with the theme.

The CDC website describes a few screening methods:

  1. Screening blood for the genetic tissue of Toxoplasma gondii using PCR.
  2. Isolating and spotting the parasite directly via a tissue biopsy, blood, or other bodily fluids. Bronchoalveolar lavage is one invasive diagnostic technique for this.
  3. Testing relative levels of IgG and IgM to detect antibodies, present in blood, saliva, spinal fluid, and semen. This is the normal screening method.

Unfortunately, all of these require blood or similar. Fortunately, anyone can buy an IgG kit for $299.20 + shipping. The site doesn’t require any credentials. That’s under $4 per test. Downsides are needing a freezer and incubator, as well as needing 2 hours of waiting with steps to be done at very specific time intervals.

The test requires 100µl of serum. Serum is the liquid portion of blood, and to get it, we need a blood draw of 2-3ml, which we then allow to clot for 30 minutes. The clot is removed using a refrigerated centrifuge for 10 minutes. A good finger prick draw is right on the border of getting enough blood. I don’t know if it is possible to make serum from finger prick blood, because “milking” the finger causes blood cells to explode.

I reckon that it would be a bad idea to do a blood draw in my tent, primarily because I am an untrained phlebotomist. Setting up a sterile blood draw station in a van is relatively easy [citation needed], and following the directions to bind antigens seems simple enough. I also haven’t looked into what the law has to say about non-diagnostic blood draws and testing for fun.

Freezer, incubator, blood draws, centrifuges, and antigens, oh my. But perhaps this all might not be necessary. The older you are, the more certain it is that you have toxoplasmosis. Especially if you garden, have a cat, or eat raw meat.

Seroprevalence of Toxoplasma gondii, by age and sex, Third National Health and Nutrition Examination Survey, 1988–1994. □, men; ▪, women. Done in USA with around 17,000 samples. [Source]

So instead of a blood draw, maybe this is what must be done: “Doctors” helpfully offer free toxoplasma screening, doing saliva swabs of innocent party goers. The doctors then rip off their doctor outfit, revealing a cat costume underneath. Instead of being tested, surprise! they’ve been given toxoplasmosis by Big Feline. After all, if the infection rate is 100%, who needs screening?

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