Sero-prevalence of rickettsial infections in patients with Parkinson’s disease

Abstract

INTRODUCTION & OBJECTIVES: Role of infections in Parkinson’s disease (PD) pathogenesis has been proposed. A patient who had features of PD during scrub typhus infection fully recovered following treatment. Two years later, he developed features suggestive of early PD and raised the question, whether rickettsial infections could trigger development of PD. METHODS: In order to study the sero-prevalence of rickettsioses, a descriptive cross-sectional study was carried out in patients with diagnosed PD. Their IFA-IgG titres against O. tsutsugamushi (IFA-IgG-OT) antigens at 1:32 and 1:128 dilutions were compared with the population seroprevalence. Statistical analysis was performed using SPSS. RESULTS: A total of 35 patients; 20 (57.1%) males [mean age 62 years (SD 8.8)], 15 (42.9%) females [mean age 68.5 years (SD 7.4)]. Mean age at diagnosis of PD; males: 57.2 years (SD 9.7), females: 64.7 years (7.5). 10/35 (29.8%) had IFA-IgG-OT titre 1:32 (p=0.19 compared to population sero-prevalence of 19.8%) and one had a titre 1:128 (2.8% compared to population prevalence of 3.17%). At the time of assessment for sero-prevalence of rickettsioses, the mean (SD) duration of diagnosis of PD between IFA-IgG +ve vs IFA-IgG –ve were 4.3(3.9) vs 4.2(4.4) years. CONCLUSION: Although patients with PD had a higher percentage sero-prevalence compared to the population, it was not significantly different. The drawback of this study was the long duration of PD at the time IFA-IgG levels were done. Following up of patients who present with extrapyramidal features due to acute rickettsioses and assessing whether they later develop PD would help to arrive at conclusions.