Toxoplasmosis-related Psychological, Behavioral, Neurological, and Hormonal Changes: A Literature Review

Abstract

Toxoplasma gondii is an intracellular parasite responsible for causing toxoplasmosis, a disease that infects approximately one-third of the global population. It is crucial to note that this parasite can infect both mammals and birds. Furthermore, it can be transmitted to humans through different transmission routes. Vertical transmission from an infected pregnant woman to her fetus and horizontal transmission via contaminated or infected raw food or drinks are the most prevalent modes of transmission. While most cases of the disease area symptomatic or develop flu-like symptoms, it can lead to severe manifestations in fetuses, infants, and individuals with compromised immune systems. During the latent phase of the disease, numerous cysts form throughout the patient's body, with the brain being the most significant site for cyst development. The occurrence of these cysts in the brain and their long-term existence have sparked extensive investigation, leading to various hypotheses and recent experiments exploring their impact on behavioral, psychological, and neurological alterations such as schizophrenia, depression, bipolar disorder, Alzheimer's disease, and autism. Furthermore, emerging studies and research have revealed the parasite's ability to trigger hormone and neurotransmitters secretion in the host, including dopamine and sex hormones, with testosterone being particularly noteworthy. This study aimed to shed additional insight into the significance of this parasite in these alterations. It also aimed to shed insight into the mechanisms this parasite employs in creating these changes. This study clearly indicates, as numerous other studies and research have, that this parasite plays a major role in several behavioral, neurological, psychological, hormonal, and neurotransmitters abnormalities in infected individuals.