Mathematical morphology for counting Trypanosoma cruzi amastigotes

The hemoflagellate protozoan parasite Trypanosoma cruzi is the causative agent of the Chagas disease. The two drugs used clinically have a high level of toxicity and are active only during the acute phase of the disease, making it urgent the development of new safe and effective treatment. The first step in the screening of new compounds is to identify their effectiveness by manual microscopic counting of the intracellular parasite form (amastigotes), which is a slow and tedious methodology. This paper presents an approach for the automatic counting of intracellular parasites using watershed transform with internal and external markers as segmentation technique, and connected components labeling for subsequent counting. The contrast against the classic counting, conducted by experts in the field, validated the technique, showing that the proposal is very efficient and with a low error rate.