PARASITOLOGY

• Parasitology is the area of biology concerned with the phenomenon of dependence of one living organism on another
• Medical Parasitology is concerned primarily with the animal parasites of humans and their medical significance, as well as their importance in human communities
• Parasites are defined as organisms that live on or in other living organisms, at whose expense they gain some advantage
• A Parasitologist is someone who studies parasites
• Host is the one that harbors the parasite
• Entomology is the study of insects and other arthropods, with insects having a head, thorax, abdomen, and arachnids having a cephalothorax and abdomen
• Helminthology is the study of worms
• Protozoology is the study of protozoa
• Tropical Medicine deals with tropical diseases and other special medical problems of tropical regions
• Tropical disease is an illness indigenous to or endemic in a tropical area but may also occur in sporadic or epidemic proportions in areas that are not tropical
• Symbiosis is the living together of unlike organisms, which may involve protection or other advantages to one or both partners
• Commensalism is a symbiotic relationship in which two species live together and one species benefits from the relationship without harming or benefiting the other
• Mutualism is a symbiosis in which two organisms mutually benefit from each other, like termites and the flagellates in their digestive system
• Parasitism is a 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
• Parasites are often described according to their habitat or mode of development
• Obligate parasites need a host at some stage of their life cycle to complete their development and to propagate their species
• Facultative parasite may exist in a free-living state or may become parasitic when the need arises
• Accidental or Incidental parasite is a parasite which establishes itself in a host where it does not ordinarily live
• Permanent parasite remains on or in the body of the host for its entire life
• Temporary parasite lives on the host only for a short period of time
• Spurious parasite is a free-living organism that passes through the digestive tract without infecting the host
• Intermittent parasites simply visit the host during feeding time
• Periodic parasites are parasites whose larval and adult stages are passed in two different hosts
• Transitory parasites are parasites whose larval stage is passed in a host while the adult is free-living
• Zoonotic parasites are non-human parasites that may cause human infections
• Pseudoparasite is an artifact that may be mistaken for a parasite
• Definitive or Final host is one in which the parasite attains sexual maturity
• Intermediate host harbors the asexual or larval stage of the parasite
• Paratenic host is one in which the parasite does not develop further to later stages, but remains alive and is able to infect another susceptible host
• Reservoir hosts allow the parasite’s life cycle to continue and become additional sources of human infection
• Vectors are responsible for transmitting the parasite from one host to another
• Pathogens are majority of animal parasites, which are harmful and frequently cause mechanical injury to their hosts
• Carrier harbors a particular pathogen without manifesting any signs and symptoms
• Exposure is the process of inoculating an infective agent
• Infection connotes the establishment of the infective agent in the host
• Incubation period (Clinical incubation period) is the period between infection and evidence of symptoms
• Pre-patent period (Biologic incubation period) is the period between infection or acquisition of the parasite and evidence or demonstration of infection
• Autoinfection results when an infected individual becomes his own direct source of infection
• Superinfection or hyperinfection happens when the already infected individual is further infected with the same species leading to massive infection with the parasite
• Factors involved in the Transmission of Parasites are the source of infection, the mode of transmission, and the presence of a susceptible host