Week 2: Introduction to Parasitology Flashcards
It is the area of biology concerned with the phenomenon of dependence of one living organism on another
Parasitology
is concerned primarily with parasites of humans and their medical significance, as well as their importance in human communities
Medical Parasitology
It is a branch of medicine that deals with tropical diseases and other special medical problems of tropical regions
Tropical Medicine
is an illness, which is indigenous to or endemic in a tropical area but may also occur in sporadic or epidemic proportions in areas that are not tropical
Tropical disease
Biological Relationships
- Symbiosis
- Phoresis
- Mutualism
- Commensalism
- Parasitism
It is the living together of unlike organisms. It may also involve protection or other advantages to one or both organisms
Symbiosis
It exists when two symbionts are merely “traveling together,” and there is no physiological or biochemical dependence on the part of either participant
Phoresis
It is a symbiosis in which two organisms mutually benefit from each other
Mutualism
It is a symbiotic relationship in which two species live together and one species benefits from the relationship without harming or benefiting the other
Commensalism
It 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
Parasitism
Two types of Parasites: According to Habitat
Endoparasite and Ectoparasite
A parasite living inside the body of a host.
Endoparasite
The presence of an endoparasite in a host is called an __________.
infection
A parasite living outside the body of a host.
Ectoparasite
The presence of an ectoparasite on a host is called an __________.
infestation
According to Relationship between Host and Parasite
- Obligate
- Facultative
- Accidental
- Permanent
- Temporary
- Spurious
They need a host at some stage of their life cycle to complete their development and to propagate their species
Obligate
May exist in a free-living state or may become parasitic when the need arises
Facultative
When a parasite enters or attaches to the body of a species of host different from its normal one
Accidental
It remains on or in the body of the host for its entire life
Permanent
It lives on the host only for a short period of time
Temporary
It is a free-living organism that passes through the digestive tract without infecting the host
Spurious
It is known as the organism that provides physical protection and nourishment to the parasite
Hosts
Types of Host
- Definitive Host
- Intermediate Host
- First Intermediate Host
- Second Intermediate Host
- Paratenic Host
- Reservoir Host
It is one in which the parasite attains sexual maturity
Definitive Host
It harbors the asexual or larval stage of the parasite
Intermediate Host
Harbors the early larval stage of parasite
First Intermediate Host
Harbors the infective larval stage of parasite
Second Intermediate Host
It is one in which the parasite does not develop further to later stages. However, the parasite remains alive and is able to infect another susceptible host
Paratenic Host
Any animal that harbors an infection that can be transmitted to humans, even if the animal is a normal host of the parasite
Reservoir Host
Life Cycle of Protozoan
- Encysting protozoans
- Non-encysting protozoans
- Egg laying nematodes
Infective stage is called cyst.
Encysting protozoans
Infective stage is called the trophozoite.
Non-encysting protozoans
Infective stage is called the embryonated egg.
Egg laying nematodes
Egg laying Nematodes:
__________ and __________ are examples of soil helminthes that infect host through ingestion of embryonated egg
Ascaris lumbricoides and Trichuris trichiura
Egg laying Nematodes:
__________ is a contact-transmitted parasite whose embryonated eggs can be either ingested or inhaled
Enterobius vermicularis
__________ are responsible for transmitting the parasite from one host to another.
Vector
Vector Transmitted Parasites
- Mechanical
- Biological
Vector Transmitted Parasites:
If the arthropod is simply an instrument of passive transfer.
Mechanical
Vector Transmitted Parasites:
It transmits the parasite only after the latter has completed its development within the host.
Biological
It results when an infected individual becomes his own direct source of infection
Autoinfection
It happens when the already infected individual is further infected with the same species leading to massive infection with the parasite
Superinfection
Sources of Infection:
The most common sources are contaminated __________and __________.
soil and water
Sources of Infection:
Ascaris lumbricoides, Trichuris trichiura, Strongyloides stercoralis, and hookworm - contaminated __________
soil
Sources of Infection:
Cysts of amebae or flagellates, as well as cercariae of Schistosoma - contaminated __________
water
Modes of Transmission:
The most likely portal of entry is the __________
mouth
Modes of Transmission:
Taenia solium, Taenia saginata, and Diphyllobothrium latum - harboring the infective __________ stages
eating food, larval
Modes of Transmission:
Entamoeba histolytica and Giardia lamblia - __________ contaminated with __________
drinking water, cysts
Modes of Transmission:
Clonorchis, Opistorchis, and Haplorchis - ingesting __________or improperly cooked freshwater __________
raw, fish
Prevention & Control
- Morbidity control
- Information-education-communication
- Environmental management
- Environmental sanitation
- Sanitation
It is the avoidance of illness caused by infections. It may be achieved by periodically deworming individuals or groups, known to be at risk of morbidity
Morbidity control
It is a health education strategy that aims to encourage people to adapt and maintain healthy life practices
Information-education- communication
It is the planning, organization, performance, and monitoring of activities for the modification and/or manipulation of environmental factors or their interaction with human beings with a view to preventing or minimizing vector or intermediate host propagation and reducing contact between humans and the infective agent
Environmental management
It involves interventions to reduce environmental health risks including the safe disposal and hygienic management of human and animal excreta, refuse, and waste water
Environmental sanitation
It is the provision of access to adequate facilities for the safe disposal of human excreta, usually combined with access to safe drinking water
Sanitation
It is the use of anthelminthic drugs in an individual or a public health program
Deworming
Deworming:
What drug is use for Parasite Group?
Representative anti-parasitic drugs
Deworming:
What drug is use for Protozoan?
Metronidazole
Deworming:
What drug is use for Nematode?
Mebendazole
Deworming:
What drug is use for Platyhelminthes: trematodes & cestodes?
Praziquantel
Treatment
- Cure rate
- Egg reduction rate
- Selective treatment
- Targeted treatment
- Universal treatment
- Preventive Chemotherapy
It refers to the number (usually expressed as a percentage) of previously positive subjects found to be egg negative on examination of a stool or urine sample using a standard procedure at a set time after deworming
Cure rate
It is the percentage fall in egg counts after deworming based on examination of a stool or urine sample using a standard procedure at a set time after the treatment
Egg reduction rate
It involves individual-level deworming with selection for treatment based on a diagnosis of infection or an assessment of the intensity of infection, or based on presumptive grounds
Selective treatment
It is group-level deworming where the (risk) group to be treated (without prior diagnosis) may be defined by age, sex, or other social characteristics irrespective of infection status
Targeted treatment
It is population-level deworming in which the community is treated irrespective of age, sex, infection status, or other social characteristics
Universal treatment
It is the regular, systematic, large-scale intervention involving the administration of one or more drugs to selected population groups with the aim of reducing morbidity and transmission of selected helminth infections
Preventive Chemotherapy
It is defined as a permanent reduction to zero of the worldwide incidence of infection caused by a specific agent, as a result of deliberate efforts
Disease eradication
It is a reduction to zero of the incidence of a specified disease in a defined geographic area as a result of deliberate efforts
Disease elimination
__________ parasites are provided with a nucleus or nuclei, cytoplasm, an outer limiting membrane, and cellular elaborations called organelles
Protozoan
Classification of protozoa: Protozoa
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- Sarcomastigophora
- Ciliophora
- Apicomplexa
- Microspora
Classification of protozoa: Protozoa
Sarcodina: Amoeba: Equipped with pseudopods (‘false feet’)
Mastigophora: Flagellates: Equipped with flagellum, whip-like
Sarcomastigophora
Classification of protozoa: Protozoa
Ciliata: ciliates: equipped with cilia, hair-like structures
Ciliophora
Classification of protozoa: Protozoa
Parasites that are not equipped with definite locomotor appratus.
Apicomplexa
Classification of protozoa: Protozoa
Consists of spore-forming parasites of both vertebrates and invertebrates
Microspora
Classification of protozoa: Metozan
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- Platyhelminthes
- Nemathelminthes
- Arhtropoda
Classification of protozoa: Metozan
Trematoda: flukes: leaf-shaped or elongated, slender organisms
Cestoda: tapeworm: elongated, ribbon-like, segmented body
Platyhelminthes
Classification of protozoa: Metozan
Nematodes: roundworms: elongated, cylindrical worms
Nemathelminthes
Classification of protozoa: Metozan
composed of bilaterally symmetrical organisms with segmented and jointed appendages
Arhtropoda
