Association Between Infection and Serum Neurotransmitter Levels in Major Depressive Disorder Patients: A Case-Control Study in Bangladesh

() is an obligate, intracellular, neurotropic protozoan parasite. After primary infection, parasite undergoes stage conversion from fast-replicating tachyzoites to slow-replicating dormant bradyzoites, particularly in the brain, and persists for a lifetime of an individual. In this study, the impact of infection in individuals with psychological disorder, that is, major depressive disorder (MDD) has been studied. Ninety-five MDD ( = 95) patients were enrolled with age and sex-matched healthy controls (HCs, = 90). The seroprevalence of infection among these individuals was determined using the TOXO IgM/IgG Rapid Test Cassette that determines the anti- IgM and IgG antibodies in the serum samples. Furthermore, to understand the impact of in developing major depression, the serum level of neurotransmitters (i.e., dopamine, adrenaline, and noradrenaline) was determined using an enzyme-linked immunosorbent assay (ELISA). Our data suggest that anti- IgG was slightly higher in MDD patients than in HCs. The level of dopamine was significantly lower in -infected MDD patients than in HCs. However, adrenaline and noradrenaline levels showed increasing levels in -infected MDD patients. The level of neurotransmitters was correlated with the DSM-D scores of MDD patients. These data, nevertheless, confirm that might affect the level of neurotransmitters in MDD patients. However, whether the reduced level of dopamine and increased level of adrenaline and noradrenaline act as contributing factors for the development of MDD is yet to be known.