Introduction
Pathogens including viruses and parasites manipulate the host’s system to enhance their ability to be infectious. One such parasite, T. gondii, a protozoan, is often associated with neurological disorders such as Parkinson’s disease (PD) in its host (Xiao et al. 2010). Though it is known that T. gondii affects the central nervous system, the mechanism of transmission is not well understood. The objective of this study is to investigate the correlation between T. gondii antibodies and PD and find out the effects of T. gondii on Parkinson’s disease.
Discussion
The study involved a total of 105 PD samples obtained from infected rats. Of the 105 samples, 20 PD samples were positives representing a positivity rate of 19%. In contrast, the positivity rates of the control groups, sera and plasma samples, were 11% and 13% respectively. In a comparable study by Miman et al. (2010), of the 52 PD patients, 22 were positive for T. gondii antibodies representing a seropositivity rate of 42.3%. When compared to the control group, this rate was found to be statistically significant (p = 0.006). The study also found a significant correlation between T. gondii infection and PD.
In a similar study, seropositivity rates in psychiatric and healthy (control) groups were found to be 12.5% and 11.3% respectively (Xiao et al. 2010). The sero-positivity between the two groups was found to be statistically insignificant (p > 0.005). However, male and female groups showed statistically significant sero-positivity (p = 0.004). These results imply that men are less susceptible to T. gondii infection compared to women.
In this study, anecdotal evidence indicates that there is a connection between the control (sera and plasma) groups and the PD group. Fisher’s exact test (2-tail) gives a p-value of 0.05781. Generally, a p-value of 0.005 or less indicates that the test is significant and the null hypothesis (Ho) should be rejected (Simundic 2008). Thus, the p-value of 0.05781 obtained in this study implies that the result is not significant and thus the Ho is not rejected. This means that there is no difference in sero-positivity rates between the healthy and PD groups. Similarly, in this study, the positivity between the sera and plasma control groups is not statistically significant (p = 0.5212). In contrast, an odds ratio (OR) of 1.855 implies that there is a significant correlation between T. gondii antibodies and the first group (PD group). The odds ratio also implies that there is no significant correlation between the control groups (sera and plasma).
The results further show that there is no statistical significance between the sera and the plasma controls (p > 0.005). Serum, unlike plasma, lacks clotting agents and fibrinogen. In this study, the results suggest that there is no significant correlation between plasma and serum levels of T. gondii antibodies. This implies that the storage and laboratory preparations did not affect the level of T. gondii antibodies in the serum samples.
Conclusion
The results of the Brian cyst counting in Toxoplasma-positive mice reveal that the subpallidum, which makes up 5.4% of the brain, was the most affected region followed by the olfactory region with a 20% cyst infection rate. The corpus callosum and the colliculus-superior regions, which constitute 2.5% and 1.8% of the brain respectively, had a cyst infection rate of 15% each. Thus, the cyst infections were prevalent in the subpallidum, corpus callosum and colliculus-superior regions of the brain. This implies that T. gondii is specific to these regions. On the other hand, the thalamus, which constitutes 8.1% of the brain, was the least affected part with only 7.5% cyst infection rate. 25% of all cyst infections affected unknown regions of the brain.
References
Miman, O, Kusbeci, Y, Aktepe, O, & Cetinkaya, Z, 2010, ‘The probable relation between Toxoplasma gondii and Parkinson’s disease’, Neuroscience Letters, vol. 475, no. 5, pp. 129-131.
Simundic, A, 2008, ‘Confidence Interval’, Biochemia Medica, vol. 18, no. 9, pp. 154-161.
Xiao, Y, Yin, J, Jiang, N, Hao, L, Lu, H, Sang, H, 2010, ‘Seroepidemiology of human Toxoplasma gondii infection in China’, BMC Infectious Diseases, vol. 10, no. 4, pp. 471-473.