Parasitism

• Caur


  2
• In

  COMMON INFECTIOUS DISEASES AND MANAGEMENT
• PARASITIC DISEASES OF MAN

  Parim
• Symbiotic relationship


  Benefit to one party or symbiont (the parasite) at the expense of the other party (the host)
• Parasitic relationships are always considered detrimental to the host
• Parasites can be found in humans, animals, as well as giants
• Organisms that live on or in other living organisms (hosts)

  Deprive nutrients
• Parasites are considered detrimental to the host
• Ectoparasites


  Parasites that live outside the host's body
• Ectoparasites


  • Arthropods such as mites, ticks, and lice
• Endoparasites


  Parasites living inside the host
• Endoparasites


  • Parasitic protozoa and helminths
• Manner of Parasites to Cause Damage

  • Depends on the number of parasites present
  • Flagellates-whiplike flagella
  • Ciliates-hairlike cilia
  • Sporozoa-no pseudopodia, flagella, or cilia, exhibit no motility
• Process of Diagnosing Protozoal Infections

  1. Microscopic examination (body fluids, tissue specimens, or feces)

  2. Gram Staining

  3. Peripheral blood smears - Giemsa stain

  4. Fecal specimens are stained with trichome, iron hematoxylin, or acid-fast stains
• Trophozoites


  Motile, feeding, dividing stage in a protozoan's life cycle
• Oocysts


  Dormant stages
• Acquisition of Protozoal Infections

  • Ingestion
  • Inhalation of cysts, oocysts, or spores
  • Injection via the bite of an infected arthropod
• The number of helminths present is often referred to as the "worm burden"
• How Parasites Cause Damage

  • Produce toxins
  • Produce harmful enzymes
  • Invasive and migratory parasites cause the destruction of individual cells
  • Cause occlusion of blood vessels and other tubular structures
  • Interfere with vital processes of the host, whereas others deprive their host of essential nutrients
  • Host immune response to the presence of parasites or their products causes more injury than do the parasites themselves
• Protozoa


  Mostly are unicellular, but some are multicellular (colonial)
• Protozoa classification


  Taxonomically by their mode of locomotion
• Protozoa classification


  • Amebas - pseudopodia
• Leishmaniasis


  Protozoal infection of the skin
• Amastigote


  Nonmotile, intracellular form of the parasite
• Promastigote


  Motile, extracellular form of the parasite
• Leishmaniasis occurs in many regions of the world, including Pakistan, India, China, the Middle East, Africa, South and Central America, and Mexico
• Cutaneous Leishmaniasis


  Starts with a papule that enlarges into a craterlike ulcer, individual ulcers may combine or coalesce, causing severe tissue destruction and disfigurement
• Visceral leishmaniasis


  • Progressive thinning
• A vaccine for leishmaniasis does not exist
• Facultative Parasites


  Term used for amebas for they are capable of either a free-living or a parasitic existence