  We report on a diffusive analysis of the motion of flagellate protozoa
species. These parasites are the etiological agents of neglected tropical
diseases: leishmaniasis caused by Leishmania amazonensis and Leishmania
braziliensis, African sleeping sickness caused by Trypanosoma brucei, and
Chagas disease caused by Trypanosoma cruzi. By tracking the positions of these
parasites and evaluating the variance related to the radial positions, we find
that their motions are characterized by a short-time transient superdiffusive
behavior. Also, the probability distributions of the radial positions are
self-similar and can be approximated by a stretched Gaussian distribution. We
further investigate the probability distributions of the radial velocities of
individual trajectories. Among several candidates, we find that the generalized
gamma distribution shows a good agreement with these distributions. The
velocity time series have long-range correlations, displaying a strong
persistent behavior (Hurst exponents close to one). The prevalence of
"universal" patterns across all analyzed species indicates that similar
mechanisms may be ruling the motion of these parasites, despite their
differences in morphological traits. In addition, further analysis of these
patterns could become a useful tool for investigating the activity of new
candidate drugs against these and others neglected tropical diseases.
