Intro to para

• Symbiosis -> Relationship -> unlike micrroorg exist together
• Three types of symbiotic relationships - (1)COMMENSALISM (2)MUTUALISM(3)PARASITISM
• Commensalism -> 2 live together - one organism benefits and the other is not harmed
• Commensalism -> example: human body and most normal flora in the body / whale shark covered with remora fish
• MUTUALISM -> two organism mutually benefit from each other
• MUTUALISM -> example : normal intestinal flora in HB produces vitamin k-> needed for clotting factors
• PARASITISM

  -> one party or symbiont (parasite) benefits to the detriment of the other (host)
• PARASITISM

  -> in most cases the parasite deprives the host of essential nutrients and produce disease in the host.
• PARASITISM

  -> Ex: Malnutrition caused by intestinal parasites
• Two important elements of parasitism

  1. Parasite
  2. host
• Classification of parasites:

  > Based on habitat

  > Based on the ability to live independently of the host

  > Based on mode of living
• Based on Habitat

  1. Ectoparasites
  2. Endoparasites
• Ectoparasites

  -> parasites that live outside the host's body
• ENDOPARASITES

  -> Parasites that live inside the body of the host
• Invasion of the body by endoparasites is called Infection
• Example of endoparasites

  > helminths or worms
• Invasion of the body by ectoparasites is called infestation
• example of enctoparasites:

  > fleas, lice
• Based on the ability to live independently of the host:

  1. Facultative parasites
  2. Obligate parasites
• Facultative parasites

  > Parasites that can live independently of the the host (free-living)
• Facultative parasites

  > These parasites do not have to live inside the host to complete their life cycle.
• Example of facultative parasites

  > Strongyloides stercoralis
• Obligate parasites

  > Parasites that must live inside a host to complete the life cycle
• Example of obligate parasites:

  1 Plasmodium

  2 Leishmania

  3 hookworms
• Majority of the parasites that infect humans are obligate parasites
• Based on mode of living

  1. Permanent parasites
  2. Intermittent parasites
  3. Incidental parasites
  4. Transitory parasites
  5. Erratic parasites
• Permanent parasites

  > Parasite that remain in a host from early life to maturity
• Example of permanent parasites: plasmodium
• Intermittent parasites

  > Parasites that simply visit the host during feeding time
• Examples of intermittent parasites

  Non pathogenic parasites

  Mosquitoes

  bedbugs
• Incidental parasites

  > Parasites that occur in an unusual host(dog tapeworm in humans)
• Examples pdf incidental parasites

  Rat tapeworms

  dog tapeworms
• Transitory parasites

  > Parasites whose larva develops in a host while the adult is free-living
• Example of transitory parasites

  Echinococcus granulosus or dog tapeworm
• Erratic parasites

  > Parasites that are seen in an unusual organ, different from that which it ordinarily parasitizes
• Example of erratic parasites

  Entamoeba histolytica in the liver or lung of humans