Parasitology

• Parasitology is the area of biology concerned with the phenomenon of dependence of one living organism on another
• Medical Parasitology deals primarily with the animal parasites of man and their medical significance, as well as their importance in human communities
• Tropical Medicine deals with tropical diseases and other medical problems of tropical regions
• Parasite: Organisms depending on other living creatures for existence
• Host: An organism that supports or harbors a parasite
• Vector: Responsible for transmitting the parasite from one host to another
• Incidence: Number of new cases of infection in a population in a given period of time
• Exposure is the act or process of inoculation of an infective agent
• Infection is the establishment of the infective agent in the host
• Pathogen: Animal parasites which are harmful, frequently causing local and systemic damage of one type or another
• Incubation period is the period between infection and evidence of symptoms
• Ectoparasite: Parasite living outside the body of the host, living on the surface of the skin
• Endoparasite: Parasite living inside the body of the host, usually responsible for causing human infections
• Saprophytes live in organic substances in a state of decomposition
• Obligate parasite depends entirely upon their host for existence
• Facultative parasite can exist in a free-living state or become parasitic
• Accidental parasite 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 are free-living organisms in nature that are parasitic to others but not in humans
• Accidental host is a host other than the normal one that is harboring a parasite
• Definitive host harbors the sexual stage of parasites, where parasites complete their development
• Reservoir host allows the parasite to continue its life cycle and become an additional source of infection
• Intermediate host harbors the larval or asexual phase of the parasite
• Transport host is responsible for transferring a parasite from one location to another
• Carrier is a parasite-harboring host that is not exhibiting any clinical symptoms but can infect others
• Symbiosis is the living together of two unlike organisms whose dependence on each other is crucial for survival
• Commensalism is when two species live together, but one benefits from the relationship without harming or benefiting the other
• Mutualism is the living together of two unlike organisms whose dependence on each other is important for survival
• Parasitism is a type of relationship where one organism lives at the expense of the other
• Mechanical/Phoretic Vector: The parasite is only seen on the surface of this organism and there will be no development on the parasite
• Biological Vector: The parasite is seen inside the body of this organism and the parasite needs this organism for its development
• Modes of transmission include contaminated food or drink, hand-to-mouth transfer, insect bites, entry via drilling through the skin, unprotected sexual relations, mouth-to-mouth contact, eating raw or inadequately cooked foods, and contact with domestic animals
• Portals of entry include mouth, skin, percutaneous, inhalation, secretions, sexually transmitted, and congenital
• Parasitic life cycles range from simple to complex and have common components such as mode of transmission, morphologic form that invades humans, and forms that can be detected via laboratory retrieval methods
• Individuals at risk include those in underdeveloped areas and countries, refugees, immigrants, visitors from foreign countries, immunocompromised individuals, individuals living in close quarters, and children who attend daycare centers
• Treatment options include deworming, chemotherapy, surgical intervention, considering severity, duration, and intensity of infection, as well as the efficacy, availability, toxicity, and acceptability of the treatment
• Prevention methods include parasite awareness education programs, use of insecticides and other chemicals, protective clothing and netting, proper water treatment, good personal hygiene, sanitation practices, proper food handling, and avoiding unprotected sexual relations
• Sub-kingdom Protozoa includes Sarcomastigophora, further divided into Sarcodina, Mastigophora, Apicomplexa, Ciliophora, and Microspora
• Examples of species within Protozoa include Entamoeba histolytica, Giardia lamblia, Plasmodium falciparum, Balantidium coli, and Enterocytozoa bienusi