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• Protozoa – free living. Some are clinically relevant as they cause diseases.

  They are unicellular and are motile at one point of their life cycle with locomotor organelles. They have heterotrophic nutrition and can survive harsh conditions.
• Motility – cilia are tiny fibers on the cell surface which beat in a regular continuous pattern like flexible oar.

  Flagella – long thread like structures extending from cell surface which moves in a whip like motion and propels the organism around

  Amboeid movement – the organism moves by sending out pseudopodia which fill up with cytoplasm to help the organism move.

  Clinically important protozoas – flagellates, amoeboids and protozoans.
• Protozoa reproduction – through mitosis – budding, longitudinal binary fission and schizogony.

  It is usually asexual reproduction even if it can be sexual.
• Flagellates – trypanosomes: human blood parasite.

  It has a single flagellum at the front which runs along the cell and creates an undulating membrane. In life cycle, it goes thorugh an ameboid phase.

  Disease caused sleeping sickness in africa. Causes lethargy and eventual coma. Host is tsetse fly.
• Other flagellates – intestinalis and trichomas vaginalis.
• Amoeboids – they are shape shifiting. They are known for their pseudopods (false feet) for lcoomotion and feeding.

  Majority are free living and some are endoparasitic.

  Reproduction sexually is rare but asexually through transverse binary fission.
• Parasitic amoeba: entamoeba histoytica – causes asymptomatic infection and ameoba dysentry.

  Contract from contaminated water sources and it invades the colonic mucosa.

  Entamoeba gingivalis – causes ginigvitis. No cysts formed. Feeds on red and white blood cells in the mouth.
• Facultative amoebas – free living in soil and enter nasal cavity and reaches brains neuroepithelium causing ameobic meningitisencephalitis (brain eating ameoba).

  Risks – swimming in freshwaters, swimming pools and to prevent this avoid swimming in freshwater.
• Sporozoans – haemosporidia plasmodia

  They are obligate endoparasites. Have 2 host life cell cycle involving a mosquito and a vertebrate. These attack red blood cells and cause malaria. It can be identified through tertian fever spikes every 48 hours and quartan fever spikes every 72 hours.

  Malaria can be benign and non fatal whereas other forms can be malignant and fatal.
• Plasmodium species causing malaria – plasmodium malariae, vivax, ovale, falciparum and knowlesi
• Malaria – caused by the plasmodium species and transmitted by the female anopheles mosquito. The parasite multiplies in the liver and then infect red blood cells.