Lecture: Intro to Parasitology Flashcards
The science that deals with the study of living organism that depends on another organism for the purpose of procuring food and securing protection.
Parasitology
Organisms that obtain its food and shelter from another organism and derive all the benefits from the association.
Parasites
Organism that provides physical protection and nourishment to the parasites.
Host
Harbors the adult/sexual stage of the parasites.
Final or Definitive Host
Harbors part or all the larval stages of the parasites.
Intermediate Host
Harbors the early larval stages of the parasites.
First Intermediate Host
Harbors the infective larval stage of the parasite.
Second Intermediate Host
These hosts ensure the continuity of the life cycle of the parasites and act as additional source of infection.
Reservoir Host
Harbors the parasite in an arrested state of development. However, the parasite is capable of continuing its life cycle in a suitable host.
Paratenic Host
A process by which one organism, the parasite, living for or part of its life cycle on or within another, the host, obtains its energy or sustenance from the latter while producing effects that range from no demonstrable effect to severe pathology and death.
Parasitism
A close association between two organisms that is permanent wherein one cannot exist independently.
Symbiosis
An association that is beneficial to both the parasites and the host in which one can still survive even without the other.
Mutualism
Only the parasite benefit from the association while the host is unaffected.
Commensalism
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
These parasites require further development in the soil before they become infective.
Soil-Transmitted Group (Soil-Transmitted Helminths, STH)
These group requires further development within the body of snail which serves as their intermediate host before they can become infective.
Snail-Transmitted Group
Some species of insects act as vectors of parasitic diseases such as mosquitoes, sandfly and Tsetse fly
Arthropod-Transmitted Group
Organisms that transmit parasites to man and may serve as intermediate host or definitive host to some parasite.
Vectors
Vector that is essential in the life cycle
Biological Vector
Vector that is inessential in the life cycle
Mechanical/Phoretic Vector
These group requires further development in the flesh of some animals that man consume.
Animal/Food-Transmitted Group
Person to person transmission, wherein the parasites require no further development and are readily infective.
Contact-Transmitted Group
In this case, the infected person is his own source of re-exposure.
Autoinfection (One’s self)
Parasites that are ingested in its infective stage.
Cyst of Entamoeba histolytica
Embryonated egg of Ascaris lumbricoides
Trichuris trichiura