INVISIBLE ENEMIES IN THE HUMAN BODY: BIOLOGICAL CHARACTERISTICS OF PARASITIC PROTOZOA
Keywords:
Parasitic protozoa, molecular mimicry, antigenic variationAbstract
Infections caused by parasitic protozoa remain a significant global public health challenge. This study analyzes the ultrastructural modifications, metabolic dependency, and immune evasion strategies of obligate intracellular pathogens, including Plasmodium, Toxoplasma, Leishmania, and Trypanosoma, at the molecular level. As a result of evolutionary genome reduction, these parasites have lost several autonomous biochemical pathways, including purine biosynthesis, and exhibit a strong dependence on the host cell’s metabolic resources. Their immune evasion mechanisms are not limited to passive concealment; rather, they involve molecular mimicry, antigenic variation, and modulation of the intracellular environment of macrophages, including pH and redox balance. Certain pathogens may also activate Toll-like receptor (TLR) signaling pathways, leading to dysregulated cytokine production that contributes to tissue damage and inflammatory imbalance. At the same time, the dependence of parasites on host metabolic and oxidative stress systems represents a key vulnerability and a potential therapeutic target. In particular, antioxidant systems such as iron superoxide dismutase (Fe-SOD) and membrane transport proteins (ENTs) are considered promising targets for future drug development. Modern therapeutic strategies should therefore focus not only on direct parasite elimination but also on disrupting their metabolic supply chains.
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