Morphometrics analysis and molecular identification of the Trypanozoon from Indonesia

Morphologically, the species within the subgenus Trypanozoon cannot be clearly distinguished.

To identify and characterize trypanosome species in Indonesia through a molecular algorithm that was carried out in stages using four pairs of primers to confirm and distinguish between species of the subgenus Trypanozoon.

A total of 28 trypanosome isolates were examined microscopically, and their morphobiometrics were observed. The isolates were also identified molecularly with an identification algorithm involving four pairs of primers in a hierarchical manner, namely, ITS1, ESAG6/7, minicircle, and maxicircle.

Morphologically, Indonesian trypanosomes are characterized by a long, slender shape, small kinetoplasts located below the posterior terminal end, and free flagella with conspicuous undulating membranes. Screening using ITS1 and ESAG6/7 showed a single band at 480 and 237 bp, which indicates the subgenus Trypanozoon species identification using minicircle primer followed by maxicircle primer showed that Indonesian trypanosomes are Trypanosoma (Trypanozoon) evansi (T. evansi) and Trypanosoma (Trypanozoon) equiperdum (T. equiperdum). Indonesian T. evansi has a total body length of 26.45 μm (22.79-29.04 μm) with the kinetoplast positioned at 1.73 μm from the posterior end, while Indonesian T. equiperdum has a body length of 26.41 μm (22.83-30.89 μm) and the kinetoplast positioned at 1.91 μm from the posterior end.

Molecular identification algorithms can distinguish species of the subgenus Trypanozoon more accurately than morphobiometric observations. Trypanozoon species found in Indonesia include Trypanosoma evansi and Trypanosoma equiperdum.

The minicircle and maxicircle primers are the key to species identification of Trapanozoon which can be applied to overcome the identification difficulties that have been experienced so far.