Protozoa and Helminth

• What is the ecological term for a way of life involving parasites?

  Parasitism
• How are parasites evolutionarily related?

  Parasites are not evolutionarily related
• What are the three types of symbiotic relationships?

  • Commensalism
  • Mutualism
  • Parasitism
• What is commensalism?

  One species benefits, the other is unaffected
• What is mutualism?

  Both species benefit from the relationship
• What defines parasitism?

  One species lives at the expense of another
• What are the two types of human parasites?

  • Ectoparasites: live on the host
  • Endoparasites: live in the host
• What are protozoa?

  Unicellular eukaryotes with animal-like behavior
• What is the size range of protozoa?

  10-130 µm
• How many species of protozoa are there?

  Over 65,000 species
• Where are protozoa widely distributed?

  Freshwater, marine water, and soil
• How do protozoa obtain energy?

  They are heterotrophic, obtaining energy from organic carbon
• What distinguishes algae from protozoa?

  Algae are photoautotrophic
• What is the role of molds in the ecosystem?

  They are saprophytic, digesting dead organic matter
• What do protozoa primarily consume?

  Other unicellular organisms like bacteria and algae
• What are the life cycle stages of protozoa?

  • Trophozoites: active, feeding stage inside host
  • Cysts: dormant stage outside host
• What happens during the trophozoite stage?

  Active cells feed, are motile, and proliferate
• What is the function of cysts in protozoa?

  Protect against desiccation and lack of nutrients
• How are protozoan parasites classified?

  • Based on mode of motility:
  • Amoeba: move by pseudopods
  • Ciliates: move by cilia
  • Flagellates: move by flagella
  • Sporozoa: non-motile in a medium
• What diseases are caused by protozoan parasites?

  Intestinal, blood, and tissue diseases
• Which group of people is most affected by protozoan infections?

  People in developing countries
• What is the causative agent of malaria?

  Plasmodium spp.
• How is malaria transmitted?

  By Anopheles mosquitoes
• What percentage of the world's population lives in malaria-endemic areas?

  40%
• How many species of Plasmodium cause human malaria?

  Five known species
• Which Plasmodium species has the strongest pathogenicity?

  1. falciparum
• What was the number of malaria cases reported in 2024?

  263 million clinical cases
• How many deaths were attributed to malaria in 2024?

  597,000 deaths
• What is the life cycle of Plasmodium?

  1. Sporozoites injected into the host
  2. Sporozoites bind to hepatocytes
  3. Schizogonic proliferation begins
  4. Merozoites invade red blood cells
• What do hypnozoites do in P. vivax and P. ovale?

  They remain dormant in hepatocytes
• How do sporozoites enter hepatocytes?

  By binding with heparin sulfate proteoglycans
• What is the role of thrombospondin-related adhesive protein?

  It helps merozoites attach to red blood cells
• How does P. falciparum affect red blood cells?

  It remodels the RBC membrane
• What proteins does P. falciparum secrete into RBC cytosol?

  PfTRiC, PfEMP, and Maurer Cleft
• What is the purpose of knob formation in P. falciparum?

  To facilitate cyto-adherence and avoid clearance
• How do infected RBCs avoid clearance by the spleen?

  By binding with endothelial cells
• What is the historical treatment for malaria?

  Quinine
• How does quinine work against malaria?

  It inhibits hemozoin formation
• What is the action of primaquine?

  Kills dormant hypnozoites in hepatocytes
• What is the significance of artemisinin?

  It is specific for P. falciparum