Introduction to Parasitology

• What is clinical parasitology?

  It is the study of organisms living permanently or temporarily on or within another organism.
• What does clinical parasitology focus on?

  It focuses on the study of parasites, their hosts, and the relationship between them.
• What are the three main branches of clinical parasitology?

  Protozoology, Helminthology, and Medical Entomology.
• What is protozoology?

  • Study of protozoans
  • Small, unicellular organisms
  • Contain nucleus and functional organelles
• What is helminthology?

  • Study of worms
  • Larger, multicellular organisms
  • Normally visible to the naked eye in their adult form
• What does medical entomology study?

  • Study of insects and arthropods
• What is medical parasitology concerned with?

  It is primarily concerned with parasites that affect humans and their medical significance.
• What is tropical medicine?

  It is a branch of medicine that deals with tropical diseases and medical problems in tropical regions.
• What defines a tropical disease?

  A tropical disease is indigenous to or endemic in tropical areas but may occur sporadically in non-tropical areas.
• What is a parasite?

  A parasite lives on or in a host, usually a larger organism, providing physical protection and nourishment.
• What is a host in the context of parasitology?

  A host harbors a parasite and provides nourishment.
• What are the types of symbiotic relationships in parasitology?

  • Symbiosis: Living together of unlike organisms
  • Mutualism: Beneficial to both organisms (e.g., termites and flagellates)
  • Commensalism: One benefits without harming the other (e.g., Entamoeba coli)
  • Parasitism: One organism benefits at the expense of the other (e.g., Entamoeba histolytica)
• What are ectoparasites?

  Ectoparasites live outside the body of the host.
• What are endoparasites?

  Endoparasites live inside the body of the host.
• What is the difference between facultative and obligate parasites?

  Facultative parasites can live outside or inside the host, while obligate parasites are completely dependent on the host for existence.
• What is an accidental or incidental parasite?

  An accidental or incidental parasite establishes itself in a host in which it does not ordinarily live.
• What are saprophytes?

  Saprophytes live in organic substances in a state of decomposition.
• What are zoonotic parasites?

  Zoonotic parasites are animal parasites that may cause infections in humans.
• How are parasites classified according to the duration of parasitism?

  • Temporary parasites: Free living during part of existence
  • Permanent parasites: Remain on the host throughout their life cycle
• How are parasites classified according to their pathological locations?

  • Spurious/Coprozoic: Passes through the digestive tract without infecting
  • Coprophilic: Multiply in fecal matter outside the body
  • Hematozoic: Lives inside red blood cells
  • Cytozoic: Lives inside cells or tissues
  • Coelozoic: Lives in body cavities
  • Enterozoic: Lives in the intestine
• What is a definitive host?

  A definitive host harbors the adult and sexually mature form of the parasite.
• What is an intermediate host?

  An intermediate host harbors the larvae or asexual stage of the parasite.
• What is a reservoir host?

  A reservoir host is an animal that harbors the same parasite as humans.
• What is a paratenic host?

  A paratenic host harbors a stage of the parasite where no further development takes place.
• What are pathogens?

  Pathogens can be animal parasites that are harmful and frequently cause mechanical injury to their host.
• What is the difference between pathogenic and non-pathogenic organisms?

  Pathogenic organisms can cause diseases, while non-pathogenic organisms cannot.
• What is a carrier in parasitology?

  A carrier harbors a particular pathogen without manifesting signs and symptoms.
• What is the incubation period?

  The incubation period is the time between infection and the evidence of symptoms.
• What is the pre-patent period?

  The pre-patent period is the time between infection and the demonstration of the parasite.
• What is autoinfection?

  Autoinfection occurs when an infected individual becomes their own direct source of infection.
• What is superinfection or hyperinfection?

  Superinfection occurs when an already affected individual is further infected with the same species, leading to massive infection.
• What is co-infection?

  Co-infection is the simultaneous infection of a host by two or more parasites.
• What are the sources of infection for parasites?

  • Contaminated soil and water
  • Food containing immature stages of parasites
  • Arthropods and blood-sucking insects
  • Another person
  • One's self (autoinfection)
• What is a biological vector?

  A biological vector is an organism that harbors the parasite inside its body and is necessary for the parasite's development.
• What is a mechanical vector?

  A mechanical vector is responsible for transporting the parasite without any development occurring in the parasite.
• What are the modes of transmission for parasites?

  • Soil transmitted
  • Arthropod/vector transmitted
  • Food-borne
  • Water-borne
  • Skin penetration
  • Congenital transmission
  • Direct contact
• What are the portals of entry for parasites?

  • By mouth: common for intestinal protozoa
  • Skin penetration
  • Intranasal: inhalation of eggs
  • Transplacental during pregnancy
  • Transmammary during breastfeeding
  • Sexual intercourse
• What are the portals of exit for parasites?

  • Stool
  • Urine
  • Sputum
  • Blood
  • Tissue aspirates and biopsy
  • Orifice swab
  • Discharges
• How are scientific names of parasites formatted?

  • Latinized names
  • Italicized or underlined
  • Generic names: initial capital letter
  • Specific names: small letter
• What are the life stages of a parasite?

  1. Ova
  2. Egg
  3. Larva
  4. Trophozoite
  5. Cyst
  6. Adult