Parasitology Lab

• Parasitology is the science that deals with the study of living organism that depends on another organism for the purpose of procuring food and securing protection
• Parasite


  Organisms which are usually smaller and weaker than the other organism, that obtain its food and shelter from another organism and derive all the benefits from the association
• Host


  The organism that provides physical protection and nourishment to the parasites
• Types of host


  • Final or Definitive host
  • Intermediate host
  • First intermediate host
  • Second intermediate host
  • Reservoir host
  • Paratenic host
• Final or Definitive host


  Harbors the adult/sexual stage of the parasites
• Intermediate host


  Harbors part or all the larval stages of the parasites

  
• First intermediate host


  Harbors the early larval stages of the parasites

  
• Second intermediate host


  Harbors the infective larval stage of the parasite

  
• Reservoir host


  Other animals that harbors the same species as that of man, ensuring the continuity of the life cycle of the parasites and acting as additional source of infection
• Paratenic host


  Harbors the parasite in an arrested state of development, but the parasite is capable of continuing its life cycle in a suitable host

  
• Parasitism


  Any association in which an organism depends upon another organism for its existence
• Symbiosis


  A close association between two organisms that is permanent wherein one cannot exist independently
• Mutualism


  An association that is beneficial to both the parasites and the host in which one can still survive even without the other
• Commensalism


  An association where only the parasite benefits while the host is unaffected
• Infection


  Connotes a "take" in which the infective agent becomes established in the host, associated with endoparasitism
• Infestation


  Associated with ectoparasitism
• Parasitic infection


  The host usually shows mild symptoms and suffers a little damage

  
• Parasitic disease


  The host develops pathologic changes and exhibit symptoms of varying degree

  
• Factors affecting transmission of parasites

  • The source of infection
  • An effective mode of transmission and portal of entry
  • The presence of a susceptible host
  • Successful entry of the infective stage of the parasite

  
• Sources of exposure to infection

  • Soil-Transmitted Group (STH)
  • Snail-Transmitted Group
  • Arthropod-Transmitted Group
  • Animal/Food-Transmitted Group
  • Contact-Transmitted Group
  • One's self (autoinfection)
• Biological vector


  Essential in the life cycle of the parasite

  
• Mechanical/Phoretic vector


  Not essential in the life cycle of the parasite

  
• Portals of entry and modes of transmission

  • Mouth
  • Skin
  • Genitals
  • Nose/Intranasal cavity
  • Transplacental
• Clinical Incubation Period


  The interval between exposure to the parasites and the appearance of the earliest signs and symptoms

  
• Biological Incubation Period/Prepatent Period


  The development of the parasite in a particular host and demonstration of the stages of the parasites in the different specimens

  
• Life cycle


  The development of a parasite which involves the survival and development in the external environment and in one or more hosts

  
• Types of life cycles

  • Those with definitive host and without intermediate host
  • Those with definitive host and one intermediate host
  • Those with definitive host and with two intermediate hosts
• Methods of diagnosis


  • Clinical Diagnosis
  • Laboratory diagnosis
• Epidemiology


  The body of knowledge that concerns diseases in human population or communities rather than in individuals
• Distribution of diseases


  • Endemic
  • Epidemic
  • Hyperendemic
  • Sporadic
  • Pandemic
• Procedures for prevention and control

  • Reduction of the sources of infection in human beings by therapeutic measures
  • Education in personal prophylaxis to prevent dissemination of infection and to reduce opportunities for exposure
  • Sanitary control of water, food and proper waste disposal
  • Destruction or control of reservoir hosts and vectors
  • Erection of biologic barriers to the transmission of parasites
• Classification of parasites


  • According to habitat
  • According to its effects to the host
  • According to mode of living

  
• Endoparasite


  Those that live within the body of the host
• Ectoparasite


  Those that live outside or on the surface of the body of the host
• Pathogenic


  Cause injury by its mechanical, traumatic or toxic activities
• Non-pathogenic


  Derives benefits from the host without causing any considerable damage or harm
• Obligate


  Takes up a permanent residence and is completely dependent upon its host for existence throughout its life
• Facultative


  Capable of leading both free and parasitic existence under favorable or appropriate circumstances
• Incidental


  One that establishes itself in a host in which it does not ordinarily lives
• Temporary


  Free living during part of existence and seeks only its host intermittently to obtain nourishment