Additional Clinical Aspects
The CME article on toxoplasmosis in Germany (1) informs about clinical aspects and consequences of infection with Toxoplasma gondii. However, important clinical consequences of a chronic latent infection remain unmentioned, in particular the possible manifestation of neuropsychic disorders. Numerous epidemiological studies have shown an association between T. gondii seropositive status and mental illness (2).
A recently published study from Denmark (3) provides additional evidence for a causal relationship between the chronic latent infection with T. gondii and the occurrence of schizophrenia. As part of a Danish blood donor study involving more than 80 000 participants, a nested case-control study was conducted. Data analysis with exclusively newly occurring diseases took into account the temporal sequence of infection status and disease outcome and showed a statistically significant increase in the incidence rate ratio (2.78, 95% confidence interval: [1.27; 6.09]).
This result is consistent with previous studies and with already known neurobiological mechanisms (2, 4). Studies of mammals have shown that a chronic infection with T. gondii affects the regulation of neurotransmitters and in particular dopamine metabolism (4). In humans as host organisms, these changes could contribute to the increased incidence of mental disorders in chronically infected individuals.
Dr. med. Johannes Seydel
|1.||Pleyer U, Gross U, Schlüter D, Wilking H, Seeber F: Toxoplasmosis in Germany—epidemiology, diagnosis, risk factors, and treatment. Dtsch Arztebl Int 2019; 116: 435–44. VOLLTEXT|
|2.||Sutterland AL, Fond G, Kuin A, et al.: Beyond the association. Toxoplasma gondii in schizophrenia, bipolar disorder, and addiction: systematic review and meta-analysis. Acta Psychiatr Scand 2015; 132: 161–79 CrossRef MEDLINE|
|3.||Burgdorf KS, Trabjerg BB, Pedersen MG, et al.: Large-scale study of toxoplasma and cytomegalovirus shows an association between infection and serious psychiatric disorders. Brain Behav Immun 2019; 79: 152–8 CrossRef MEDLINE|
|4.||McConkey GA, Martin HL, Bristow GC, Webster JP: Toxoplasma gondii infection and behaviour—location, location, location? J Exp Biol 2013; 216: 113–9 CrossRef MEDLINE PubMed Central|