Analysis of the activity of toxoplasma invasion in elderly and old people

Introduction. Persons of the older age group, due to weakened immunity, are at risk for toxoplasmosis: with age, the level of seropositivity and the risk of reactivation of infection in people with chronic infection increases. But in clinical and epidemiological terms, this group has not been sufficiently studied.

Purpose of the study. Determination of the level of seropositivity and the degree of activity of toxoplasma invasion in persons of the older age category without pathology, as well as in combination with psychoneurological symptoms or transplantation of solid organs.

Materials and methods. The ELISA method was used to determine various classes of antibodies to T. gondii in the blood sera of 614 people aged 60 to 93 years (conditionally healthy individuals, patients with neuropsychiatric pathology, with cognitive decline, after organ transplantation).

Results. IgG antibodies to T. gondii were detected in 51,5 % of the examined people. There was a trend of increasing infection from the age of 60-64 years to 75-79 years. Very few cases of acute toxoplasmosis have been identified; more significant was the detection of IgA antibodies, a reactivation marker, in 10,1 % of the examined antibodies. The largest number of individuals with IgA was observed in patients after transplantation, with neuropsychiatric pathology and cognitive decline.

Discussion. Since toxoplasmosis is a latent infection of the brain and its association with a number of mental and neurodegenerative diseases has been proven, the high T. gondii infection in elderly people and the presence of reactivation markers in them suggests systematic monitoring of invasion, especially when combined with CNS pathology and reduced immunity. People aged "60+" with a certain clinical history are at risk in the presence of a parasite in the body.

Conclusion. Finding an association between toxoplasmosis and psychiatric disorders in immunocompetent individuals is the basis for further monitoring of such associations with a view to their prevention and treatment.

1. Xiao J., Prandovszky E., Kannan G., Pletnikov M.V., Dickerson F., Severance E.G., Yolken R.H. Toxoplasma gondii: Biological Parameters of the Connection to Schizophrenia // Schizophr Bull. 2018;44(5):983–992. DOI: 10.1093/schbul/sby082.

2. Roe K. The Symptoms and Clinical Manifestations Observed in COVID-19 Patients / Long COVID-19 Symptoms that Parallel Toxoplasma gondii Infections// J Neuroimmune Pharmacol. 2021;16(3):513-516. DOI 10.1007/s11481-021-09997-0.

3. Cicero C.E., Allibrio F.E., Giuliano L., Luna J., Preux P-M., Nicoletti A. Toxoplasma gondii and multiple sclerosis: A systematic review and metaanalysis // Eur J Neurol. 2021;28(12):4251-4257. DOI: 10.1111/ene.15055.

4. Dhakal R., Gajurel K., Montoya J.G. Toxoplasmosis in the non-orthotopic heart transplant recipient population, how common is it? Any indication for prophylaxis? // Curr Opin Organ Transplant. 2018;23(4):407-416. DOI: 10.1097/MOT.0000000000000550.

5. Brandsma D., Bromberg J.E.C. Primary CNS lymphoma in HIV infection // Handb Clin Neurol. 2018;152:177-186. DOI: 10.1016/B978-0-444-63849-6.00014-1.

6. Kovaleva V.A., Goncharov D.B., Zhuravlev A.Yu., Abbazova E.V., Titova I.V. Shizophrenia and toxoplasmosis: analysis of their association // Epidemiology and infectious diseases. Current items. 2020;10(4):88-92. (in Russian) DOI: 10.18565/epidem.2020.10.4.88-92.

7. Wilking H., Thamm M., Stark K., Aebischer T., Seeber F. Prevalence, incidence estimations, and risk factors of Toxoplasma gondii infection in Germany: arepresentative, cross-sectional, serological study // Sci Rep. 2016;6:22551. DOI: 10.1038/srep22551.

8. Uttah E., Ogban E., Okonofua C. Toxoplasmosis: A global infection, so widespread, so neglected // International Journal of Scientific and Research Publications. 2013; V. 3; I. 6.

9. Goncharov D.B., Abbazova E.V., Kovaleva V.A., Maracusha B.I., Titova I.V. Strategy for the diagnostics of toxoplasmosis in different population groups // Med parazitol. 2021;1:29-36. (in Russian). DOI:10.33092/0025-8326mp2021.1.29-36.

10. Virus M.A., Ehrhorn E.G., Lui L.M., Davis P.H. Neurological and Neurobehavioral Disorders Associated with Toxoplasma gondii Infection in Humans // J Parasitol Res. 2021:6634807. DOI: 10.1155/2021/6634807.

11. Mewara A., Singh S., Khurana S., Gupta P., Sehgal R. Seroprevalence of Toxoplasmosis at a Tertiary Care Centre in North India from 2004 to 2014 // Indian J Med Microbiol 2019;37(3):351-357. DOI: 10.4103/ijmm.IJMM_19_327.

12. Stepanova E.V., Kondrashin A.V., Sergiev V.P., Morozova L.F., Turbabina N.A., Maksimova M.S., Brazhnikov A.I., Shevchenko S.B., Morozov E.N. Significance of chronic toxoplasmosis in epidemiology of road traffic accidents in Russian Federation // PLoS One. 2017;12(9):e0184930. DOI: 10.1371/journal.pone.0184930.

13. Goncharov D.B., Ievleva E.S., Krupenio T.V., Pchelkina D.S., Saitgareev R.Sh.,Gabrielyan N.I. On the problem of toxoplasmosis during organ transplantation// Epidemiology and infectious diseases. Current items. 2015;4:34-38 (in Russian).

14. Willemssen R., Falkenstein M., Schwarz M., Müller T., Beste C. Effects of aging, Parkinson’s disease, and dopaminergic medication on response selection and control // Neurobiol Aging. 2011;32(2):327-35. DOI: 10.1016/j.neurobiolaging.2009.02.002.

15. Yolken R., Torrey E.F., Dickerson F. Evidence of increased exposure to Toxoplasma gondii in individuals with recent onset psychosis but not with established schizophrenia // PLoS Negl Trop Dis. 2017;11(11):e0006040. DOI:10.1371/journal. pntd.0006040.

16. Stepanova E.V., Kondrashin A.V., Maksimova M.S., Turbabina N.A., Morozova L.F., Morozov E.N., Kinkulkina M.A., Lazareva A.V., Brazhnikov A. .Yu., Sergiev V.P. Latent chronic toxoplasmosis and schizophrenia // Medical parasitology and parasitic diseases. 2019;1:18-24 (in Russian)]. DOI: 10.33092/0025-8326mp2019.1.18-24

17. Passos ADC, Bollela VR, Furtado JMF, de Lucena MM, Bellissimo-Rodrigues F, Paula JS, Melo LVL, Rodrigues MLV. Prevalence and risk factors of toxoplasmosis among adults in a small Brazilian city// Rev Soc Bras Med Trop. 2018; 51(6):781-787. doi: 10.1590/0037-8682-0214-2017.

18. Flegr J, Prandota J, Sovičková M, Israili ZH. Toxoplasmosis - a global threat. Correlation of latent toxoplasmosis with specific diseases burden in a set of 88 countries// PLoS One. 2014; 9(3): e90203. doi: 10.1371/journal.pone.0090203.

19. Prandota J. Solving the Old Puzzle 1862-2021: Pathophysiology and Pathomechanisms of Raynaud’s Phenomenon. Key Role of Acute and Chronic Latent T. gondii Infection in these Clinical Events and their Potential Link with COVID-19 Pandemic// Int. J. of Radiology. 2021; 8(1): 270-325. doi: 10.17554/j.issn.2313-3406.2021.08.88.