Clinical Trial Details
— Status: Not yet recruiting
Administrative data
| NCT number |
NCT05860998 |
| Other study ID # |
2023-00366 |
| Secondary ID |
|
| Status |
Not yet recruiting |
| Phase |
|
| First received |
|
| Last updated |
|
| Start date |
June 26, 2023 |
| Est. completion date |
July 30, 2023 |
Study information
| Verified date |
May 2023 |
| Source |
University of Zurich |
| Contact |
Carlos Alós-Ferrer, PhD |
| Phone |
798667160 |
| Email |
carlos.alos-ferrer[@]econ.uzh.ch |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Observational
|
Clinical Trial Summary
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.
Description:
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.
