Medical Parasitology

• area of biology concerned with the phenomenon of dependence of one living organism on another

  Parasitology
• concerned primarily with parasites of humans and their medical significance, as well as their importance in human communities

  Medical Parasitology
• the science that deals with all aspects of parasite-host relationships, including the ecological, biological, physiological, pathogenic, epidemiologic, clinical, diagnostic, therapeutic, preventive, and control aspects of these interactions.
• The term “parasite” is derived from the Greek word parastētēs meaning “one who eats at the same table.”
• A parasite is an organism that lives on or inside another organism (called host) and benefits by deriving nutrients at the expense of its host.
• Ectoparasites - Live outside the body of the host.
• a branch of medicine that deals with tropical diseases and other special medical problems of tropical regions

  Tropical Medicine
• an illness, which is indigenous to or endemic in a tropical area but may also occur in sporadic or epidemic proportions in areas that are not tropical

  tropical disease
• living together of unlike organisms. It may also involve protection or other advantages to one or both organisms

  Symbiosis
• a symbiotic relationship in which two species live together and one species benefits from the relationship without harming or benefiting the other

  Commensalism
• What form of symbiosis: Entamoeba coli in the intestinal lumen are supplied with nourishment and are protected from harm, while it does not cause

  Commensalism
• symbiosis in which two organisms mutually benefit from each other

  Mutualism
• What form of symbiosis: termites and the

  flagellates in their digestive system, which

  synthesize cellulase to aid in the breakdown

  of ingested wood.

  Mutualism
• symbiotic relationship where one organism, the parasite, lives in or on another, depending on the latter for its survival and usually at the expense of the host

  Parasitism
• What form of symbiosis:Entamoeba histolytica, which derives nutrition from the human host and causes amebic dysentery

  Parasitism
• Parasites are often described according to their habitat or mode of development.
• A parasite living inside the body

  endoparasite
• a parasite living outside the body of a host

  ectoparasite
• The presence of an endoparasite in a host is called

  infection
• the presence of an ectoparasite on a host is called

  infestation
• A parasite is considered erratic when it is found in an organ which is not its usual habitat.
• Most parasites are obligate parasites in that they need a host at some stage of their life cycle to complete their development and to propagate their species.
• A facultative parasite may exist in a free-living state or may become parasitic when the need arises.
• A parasite, which establishes itself in a host where it does not ordinarily live

  accidental or incidental parasite
• parasite remains on or in the body of the host for its entire life

  permanent parasite
• parasite lives on the host only for a short period of time

  temporary parasite
• a free-living organism that passes through the digestive tract without infecting the host.

  spurious parasite
• Hosts can be classified into various types based on their role in the life cycle of the parasite.
• one in which the parasite attains sexual maturity. In taeniasis, for example, humans are considered the definitive host


  definitive or final host
• harbors the asexual or larval stage of the parasite

  intermediate host