The Archives of General Psychiatry has published two studies from Denmark demonstrating the relationship between toxoplasmosis and suicide. Especially violent suicide. Toxoplasma parasities hide within neurons and glial (supporting brain cells) in cystic forms.
Toxoplasma are persistent brain parasites. The immune system is unable to eradicate them. No effective antimicrobial therapy is available. As with Lyme infection, the organisms manipulate the immune system and are associated with alterations in cytokine levels including interleukin 6. Toxoplasma infection and Lyme also impacts metabolic pathways which lead to the production of kynurenic acid and quinolinic acid from tryptophan.
Elevated quinolinic acid levels has been associated with neuroborreliosis in at least one frequently cited study. These neuro-active substances are associated with glutamic acid excito-toxicity.
Toxoplasma infection has been long associated with depression, schizophrenia, autism, congenital disorders and many other brain disorders.
Toxoplasma infection is common, infecting up to 1/3 of the world's population.
As the microbiome projects has shown. Microorganisms inhabit communities within special niches. Many bacteria commonly found in places as prosaic as the skin remain unknowns. It is clear our bodies are loaded with unknown "mystery bugs."
Perhaps the brain also frequently hosts communities of microbes: Toxoplasmosis, Lyme, other spirochetes. Of course, only those in the Lyme community think of Lyme, Babesia, Bartonella and other co-infections as frequent denizens of the human brain.
An unknown, perhaps endogenous, protozoan has been observed within human cells and the nervous system (unpublished) with genetic/morphological features borrowed from both Malaria and Toxoplasma. (We may all be born infected with this unknown parasite). This is all I can say regarding this topic at the present time).
One investigator has suggested such organisms could even be symbiotic? mutalistic at times. This is certainly the case with many other microbial communities, natural flora. At times usually beneficial organisms, under the right opportunistic conditions can become troublesome.
Most Toxoplasma infected individuals have no symptoms or apparent ill effects. The same is likely true for most individuals harboring brain infection with many of the other microbes listed here.
Why or when infected individuals is unpredictable. Experience has shown that other infection, trauma or stress can provoke illness with Lyme. It does seem clear that mixes of co-infection increase the severity of Lyme syndromes including neuroborreliosis. One could postulate that at times Toxoplasmosis acts a co-infection.
Many patients with extensive, systemic Lyme seem to have immune dysfunction. Many have subtle decreases in varying IgG subclasses. This may turn out to be a key factor.
From a treatment perspective, anti-Babesia drugs are used for chronic forms of the disease. It should be noted that many anti-psychotic medications also have anti-parasitic properties.
The authors note that two other studies have shown the association of toxplasmosis with suicide, one in Maryland, my home state. Great.