An observational study in Toxoplasmosis and Rhd, sponsored by University of Zurich. Not yet recruiting. Open to participants aged 18 Years to 35 Years. Per ClinicalTrials.gov, last updated 2023-05-18.
Sponsored by University of Zurich · Observational
The investigators propose a fast and inexpensive procedure to determine the prevalence of the Toxoplasmosis infection (Toxoplasma Gondii) in the general population, using response times in a cognitive task instead of costly medical tests. Therefore, the investigators aim to measure the prevalence of Toxoplasmosis and its socio-economic consequences in the general population.
An estimated 2 billion humans worldwide are affected by the protozoan Toxoplasma gondii. The resulting Toxoplasmosis is considered one of the most important but most neglected parasitic infections. Toxoplasmosis has been linked to behavioral alterations in humans. While rarely resulting in an acute pathology, latent infections have been associated with non-clinical outcomes such as car accidents, impulsiveness, and suicides through the pathology's influence on personality and risk-taking behaviors.
Given the economic and social impact of these consequences, it is important to have reliable estimates of Toxoplasmosis prevalence. However, current methods involve costly, time-expensive medical tests, which are not always available, especially in developing countries. Therefore, simpler, inexpensive, and easily-scalable diagnostic methods would be highly valuable. For this reason, both the CDC and the WHO consider it a priority to improve diagnostic testing of Toxoplasmosis. This includes obtaining reliable and easily-implementable estimates at the population level, which is essential to gauge the magnitude of the problem and to inform and design health policy aimed at reducing the number of infections in the population.
Therefore, the investigators aim to determine the frequency of latent Toxoplasmosis infections in the general population in a simple, quick, and inexpensive way.
The key idea of simplifying the diagnosis of this infection is that Toxoplasmosis induces specific behavioral and physiological changes. It alters the levels of neurotransmitters such as dopamine and causes a delay in muscle response time. In particular, people with RhD-negative blood type become slower when afflicted by Toxoplasmosis, while the RhD-positive sub-population does not experience a change in response times. This relation is important because, while the distribution of blood types can be determined in an inexpensive way and is already commonly known at the aggregate level (RhD-negative are 15% in Caucasians, 8% in Africans, and 1% in Asians), the actual prevalence of the Toxoplasmosis infection is underinvestigated, and the respective tests are costly and not easily deployable in large numbers (especially in developing countries). The investigators aim to leverage on the differential effects of Toxoplasmosis on response times across blood types to estimate its latent diffusion.
Response times (RT) are known to be log-normally distributed [22]. This is crucial because mixtures of log-normally distributed variables are identifiable through standard statistical methods as e.g. finite mixture models [23]. The distribution of RTs in the population is a mixture of two different types, afflicted vs. non-afflicted, and the first group should show a systematic delay in RTs compared to the latter group. A finite mixture model can then be applied to a sample of RhD-negative individuals to estimate the characteristics of the two distributions and hence quantify both the magnitude of the delay in response times as well as the size of the afflicted group.
The investigators already obtained data showing that the proposed method is able to capture interesting and economically-relevant individual characteristics between those who are imputed to be afflicted by this parasite compared to those who do not. This first investigation also passed some preliminary validation. For example, those estimated to be afflicted by Toxoplasmosis are also those who are more likely to have a cat, which is the main vector of contagion for this parasite.
In this study the investigators propose a systematic validation of the proposed method. In particular, the investigators aim to compare it agrees with a standard medical test for Toxoplasmosis infection, e.g., compare it to the presence of Toxoplasma gondii IgG Antibodies. The latter medical test requires a blood sample.
29 studies on the registry are indexed under Toxoplasmosis; 8 are open to participants now.
This study's planned enrollment of 120 is above the median of 100 across 10 observational studies indexed under Toxoplasmosis.
Browse Toxoplasmosis studies →University of Zurich is the lead sponsor of 1,049 studies on the registry; 133 are open to participants now.
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Participants will be recruited among the student population of the University of Zürich according to the established procedures of the SNS Laboratory.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Autoimmune disease
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Healthy students with RhD-Negative blood with Toxoplasma gondii IgG Antibodies
Diagnostic Test: Presence of Toxoplasma gondii IgG Antibodies
Healthy students with RhD-Negative blood without Toxoplasma gondii IgG Antibodies
Diagnostic Test: Presence of Toxoplasma gondii IgG Antibodies
Testing for the presence of Toxoplasma gondii IgG Antibodies in participants blood.
Presence of Toxoplasma gondii IgG Antibodies
Presence of Toxoplasma gondii IgG Antibodies
Time frame: 6 months
Classified as afflicted by Toxoplasma gondii using response times
Classification based on a reaction-time task of whether the participant is considered as afflicted by Toxoplasma gondii.
Time frame: 6 months
Big 5 personality trait
Score in the Big 5 personality trait scale from Gosling et al. (2013). It is a 10-items scale subdivided in 5 traits (2 items for each trait): Extraversion, Agreeableness, Conscientiousness, Emotional Stability, and Openness to Experiences. Each item is evaluated using a 7-points Likert scale with the following labels "Disagree Moderately", "Disagree a little", "Neither agree not disagree", "Agree a little", "Agree moderately", "Agree strongly". For each trait one of the two items is reversely scored. For each of the 5 traits the score of the two items is added, hence it can go from 2 to 14. Higher scores on each of the scales correspond higher closeness to that personality trait, e.g., more agreeable.
Time frame: 6 months
Sensation Seeking scale
Score in the Sensation Seeking scale (Cook et al., 2015). This scale consists of 10 binary choices where participants are asked to choose which option best describes their likes or the way they feel. One of the two options is associated with a higher Sensation Seeking score. Items 2, 3, 5, 6, and 8 are reversely scored. The answers from the single items are added to obtain the total score, which can go from 0 to 10. Higher scores indicate more sensation seeking.
Time frame: 6 months
Cognitive Reflection Test
Score in the Cognitive Reflection Test from Toplak, West, and Stanovich (2014). In this 7-item scale each item asks for the answer to a mathematical or logical problem in an open-entry format or as multiple-choice question. The score for this scale is the sum of the correct answer to the 7 items, hence it goes from 0 to 7. Higher scores indicate higher cognitive reflections.
Time frame: 6 months
Risk aversion
Measure of risk aversion (number from 1 to 10, Falk et al., 2018). A single question asking the participants' attitude toward risk. 1 means "not willing to take risks" and 10 means "very willing to take risks". Higher values mean more risk tolerance.
Time frame: 6 months
Time preference
Measure of time preference (number from 1 to 10, Falk et al., 2018). A single question asking the participants' patience. 1 means "not willing to give up something today" and 10 means "very willing to give up something today". Higher values mean more patience.
Time frame: 6 months
Self-control
Score in the self-control scale from Tangney, Boone, and Baumeister (2018). It is a 13-item scale evaluated using a 5-point Likert scale with two labels at the extreme of the scale 1="Not at all" and 5="Very much". Items 2/5, 7, 9/11 are reversely scored. The score is obtained by adding the score of the single items. Higher values indicate more self control.
Time frame: 6 months
Field of study
Which major the participant studied.
Time frame: 6 months
Accidents
Number of accidents (work related or traffic accidents) the participant experienced.
Time frame: 6 months
Owning Pets
Which pets the participant owns or owned.
Time frame: 6 months
Income
The yearly income (in Swiss Francs).
Time frame: 6 months
Alcohol consumption
Average units of alcohol consumed in a week.
Time frame: 6 months
No study locations are listed for this record.
Plan to share: Undecided
No publications or documents are linked to this record.
Start is estimated for Jun 2023; primary completion for Jul 2023, 1 month later.
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This study is not yet recruiting, as verified in May 2023. You cannot join it, but the record below documents what was studied.
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