Parasitology Lecture 1 PDF

  The study of parasites affecting human  An organism that lives in or on another organism (host)  Gets its food from or at the expense of its host.  The organism in or on which a parasite lives. ❶  Can’t complete their life cycle without a suitable host.  Org...

  The study of parasites affecting human  An organism that lives in or on another organism (host)  Gets its food from or at the expense of its host.  The organism in or on which a parasite lives. ❶  Can’t complete their life cycle without a suitable host.  Organism that lives independent of a host but may ❷ occasionally be parasitic under certain conditions. ❸  Parasites which live outside the body of the host (Infestation). ❹  Parasites which live inside the host (Infection).  That attack or establish themselves in unusual hosts (hosts that ❺ they do not normally parasitize).  A parasite that feeds on and then leaves its host (such as a ❻ biting insect). ❼  Affects specific host species.  The parasites which pass through digestive tract without ❽ infecting the host.   The organism wherein the parasite reaches its mature form. ❶  The parasite at this stage is typically capable of reproduction.  It is that host that harbors the non-sexual (reproductively/ ❷ sexually immature) phases of the parasite.  Site of asexual reproduction for the parasite.  An animal that harbors the parasite. ❸  Acts as continuous source of human infection.  Organism that harbors the sexually immature parasite but is not ❹ necessary for the parasite's development cycle to progress  A host from which infectious agents are not transmitted to ❺ other susceptible hosts.  An arthropod that harbors the parasitic stages and transmit ❻ them from one host to another.   Association between two different organisms where one ❶ benefits at the expense of the other.  All infectious agents causing illness belong to this category  Both organisms live together and the commensal organism benefits without causing harm to the other. ❷  Association between two organisms in which one derives benefit from the other without causing it any harm.  Both organisms benefit from the relationship. ❸  Non permanent, commensalistic interaction in which one organism (a phoront or phoretic) attaches itself to another (the host) solely for the purpose of transport  Example: Dientameoba fragilis on Enterobius egg) ❹  (plural zoonoses or zoonotic diseases)  Infectious disease transmitted from animal (usually vertebrate) to a human. ① Anthropozoonosis:  Zoonosis maintained in nature by animals and transmissible to humans ② Zooanthroponosis:  Parasitic infections naturally maintained by human but can be transmitted to other vertebrates  Diseases transmissible from human to human (only human species).  Trichomoniasis. ① ACCORDING TO THE SOURCE OF INFECTION  The source of infection is a wild animal with no close relationship to man.  Humans become exposed to infection in the course of hunting  The source of infection is man's own domesticated animals ② ACCORDING TO THE METHOD OF  Infection is directly transmitted from the reservoir host to man  infection is transmitted from the reservoir host to man via arthropod  infection is transmitted via a non animal developmental site as the soil and water  THE STUDY OF PARASITES AFFECTING HUMAN  Protozoa & Helminthes are Endoparasites.  Arthropods is Ectoparasite. ① Parasites that attack or establish themselves in unusual hosts: a) Specific parasite b) Incidental parasite c) Facultative parasite d) Temporary parasite ② A host from which infectious agents are not transmitted to other susceptible hosts: a) Intermediate host b) Definitive host c) End host d) Reservoir host