Chapter 1 PARASITOLOGY Flashcards
- the area of biology concerned with the phenomenon of dependence of one living organism on another.
Parasitology
is a heterospecific type of an association between two individuals in which one of the partners called parasite is metabolically dependent on another referred to as host
Parasitism
Hosts that transmit parasites to man
vectors
are essential in
the lifecycle of a parasite
biologic vectors
are not essential to the life cycle of the parasites
phoretic or mechanical vectors
deals with the parasites which infect man, the diseases they produce, the response generated by him against them and various methods of diagnosis and prevention.
Medical parasitology
Historical Background of Parasitology
The first written records of what are almost certainly parasitic infections come from a period of Egyptian medicine from 3000 to 400 BC, particularly the ____ ____ of 1500 BC discovered at Thebes.
Ebers papyrus
Historical Background of Parasitology
1681 Antonie van Leeuwenhoek observed and illustrated ___ ___ and linked it to “his own loose stools”. This was the first protozoan parasite of humans that he recorded, and the first to be seen under a microscope
Giardia lamblia
Historical Background of Parasitology
1687, the Italian biologists Giovanni Cosimo Bonomo and Diacinto Cestoni published that scabies is caused by the parasitic mite ____ ___ , marking scabies as the first disease of humans with a known microscopic causative agent
Sarcoptes scabiei
Historical Background of Parasitology
In the same publication, Esperienze Intorno alla Generazione degl’Insetti (Experiences of the Generation of Insects), Francesco Redi also described ecto- and endoparasites, illustrating ticks, the larvae of ____, and sheep liver fluke. His earlier book in 1684 - Osservazioni intorno agli animali viventi che si trovano negli animali viventi (Observations on Living Animals found in Living Animals) described and illustrated over 100 parasites including the human roundworm. He noted that parasites develop from ____, contradicting the theory of spontaneous generation.
nasal flies of deer
eggs
1828, James Annersley described ____ – a protozoal infections of the intestines and the liver, though the pathogen, Entamoeba histolytica, was not discovered until 1873 by Friedrich Lösch
amoebiasis
1835, James Paget discovered the intestinal nematode _______ in humans
Trichinella spiralis
James McConnell described the ___ in 1875
human liver fluke
1876, Louis Alexis Normand, A physician at the French naval hospital at Toulon discovered the helminth that causes the disease ____ by studying the ailment of French soldiers returning from Vietnam
strongyloidiasis
Patrick Manson discovered the life cycle of ______, caused by nematode worms transmitted by mosquitoes, in 1877. Manson further predicted that the malaria parasite, ____, had a mosquito vector, and persuaded Ronald Ross to investigate. Ross confirmed that the prediction was correct in 1897–1898.
elephantiasis
Plasmodium
Giovanni Battista Grassi and his colleague described the malaria parasite’s life cycle stages in ____ mosquitoes. Ross was controversially awarded the 1902 Nobel prize for his work, while Grassi was not.
Anopheles
Major Types of Association in Animals
- First used by de Bary in 1879.
- It is an intimate or close association or relationship of two individuals in which both the partners are benefited like mutualism but in this the participating species are dependent on each other for existence and are obligatory.
Symbiosis
Major Types of Association in Animals
Examples of Symbiosis
Termites and their intestinal protozoa
Zoochlorella and Hydra Zoochlorella
Major Types of Association in Animals
- “eating at the same table”
- it is a loose association in which two animals or organisms of different species live together without either being metabolically dependent on the other although one animal may receive some benefit, but the other neither get benefit nor harm from the other. However, it is not obligatory for their existence.
Commensalism
Major Types of Association in Animals
Examples of Commensalism
- Entamoeba coli and Trichomonas sp. live in intestine
- Pilot fish and shark
- Remora and shark
- Crab and sea-urchin
Major Types of Association in Animals
- Latin word ______ means exchange
- It is an intimate association or relationship of two animals or individuals in which both the partners are benefited, However, this relationship is not permanent and obligatory. Either of the partners can break it without any loss to either of them.
mutuus
Mutualism
Major Types of Association in Animals
examples of mutualism
- Hermit crab and sea anemone
- herbivores ruminal flora
Major Types of Association in Animals
- “Traveling together”.
- temporary association between two
individuals or living beings in which where is no metabolic dependence
Phoresis
Major Types of Association in Animals
examples of phoresis
Bacteria and amoebae on the legs of fly or fungal spores on the legs of a beetle
Major Types of Association in Animals
It is an intimate association between two specifically distinct organisms in which one partner usually smaller lives on or within the other usually larger in order to obtain sustenance.
parasitism
Major Types of Association in Animals
– invertebrate animals with long, flat, round bodies.
Helminths
Major Groups of Parasites
Helminths
* Phylum Nemathelminthes
Class Nematoda: ________ (body round in cross section)
Examples: Ascaris lumbricoides (ascariasis)
a)
* Phylum Platyhelminthes”: ____
Class Cestoda: ______ (body flattened and segmented)
Examples: Taenia solium (cysticercosis)
b)
Class Digenea: ____ (body flattened, leaf-shaped, and nonsegmented)
Examples: Fasciolopsis buski (giant intestinal fluke)
c)
roundworms
Enterobius vermicularis (pinworm)
tapeworms
Echinococcus granulosus (hydatid disease)
trematodes, flukes
Fasciola hepatica (sheep liver fluke)
Major Groups of Parasites
– unicellular, eukaryotic microorganisms.
Protozoa
Major Groups of Parasites
Protozoa
A. Phylum Sarcomastigophora
1. Class ____: organisms that move by means of pseudopodia (ex. Entamoeba histolytic - amoebiasis)
2. Class ______: organisms that move by means of flagella (ex. Giardia lamblia - giardiasis)
B. Phylum Ciliophora
C. Phylum Apicomplexa
Lobosea
Zoomastigophorea
Protozoa
A. Phylum Sarcomastigophora
B. Phylum Ciliophora
. Class ____: organisms that move by means of cilia
Examples: __ (balantidiasis)
C. Phylum Apicomplexa
Kinetofragminophorea
Balantidium coli
Protozoa
A. Phylum Sarcomastigophora
B. Phylum Ciliophora
C. Phylum Apicomplexa
Class Sporozoa: organisms with both sexual and asexual life cycles; ___ seen with Electron microscope.
Examples: Plasmodium spp. (Malaria)
Babesia spp (Babesiosis)
apical complex
– hard exoskeleton, jointed appendages
Arthropods
Phylum Arthropoda
1. Class __: flies, mosquitoes, bugs, lice, fleas
2. Class __: ticks and mites
Hexapoda
Arachnida
Classification of Parasites
- inhabit only the body surface of the host without penetrating the tissue. (lice, ticks and mites)
- A parasite, which lives within the body of the host and is said to cause an infection. Most of the protozoan and helminthic parasites causing human disease.
Ectoparasites
Endoparasites
Categories of Endoparasites
- Parasite that do not exist without a host
- Either live as parasite form or as free-living form
- Parasites, which infect an unusual host
- Parasites, which infect a host where they cannot develop further
- Refers to nonparasitic stages of active existence, which live independent of the host
Obligate parasite
Facultative parasite
Accidental parasite
Aberrant/wandering parasites
Free-living parasites
Categories of Endoparasites
Examples:
1.Obligate:
2.Facultative:
3.Accidental:
4.Aberrant/wandering:
5.Free-living:
- Toxoplasma gondii and Plasmodium
- Naegleria fowleri
- Echinococcus granulosus infects man accidentally, giving rise to hydatid
- Toxocara canis (dog roundworm) infecting humans
- cystic stage of Naegleria fowleri
Life cycle of Parasites
- Parasite the requires only one host to complete its development
- Parasite that requires two hosts (one definitive host and another intermediate host)
- Direct/simple life cycle
- Indirect/complex life cycle
Examples of Parasites that exhibit Direct/Simple Life Cycle
Protozoans:
1. Entamoeba histolytica
2. Giardia lamblia
3. Trichomonas vaginalis
4.
5.
Helminths:
1. Hymenolepis nana
2. Ascaris lumbricoides
3. Trichuris trichiura
4.
5.
Protozoans:
4. Balantidium coli
5. Cryptosporidium parvum
Helminths
4. Enterobius spp.
5. Strongyloides spp.
Examples of Parasites that exhibit Indirect/Complex Life Cycle (Man acts as definitive host
Parasites – Intermediate Host
1. *Leishmania** spp. – sandfly
2. Trypanosoma bruzi – tsetse fly
3. Trypanosoma cruzi – reduviid bug
4. Schistosoma spp. – snail
5.
6.
7.
- Taenia saginata – cattle
- Trichinella spiralis – pig
- Filarial worms – mosquito
Examples of Parasites that exhibit Indirect/Complex Life Cycle (Man acts as Intermediate host
Parasites – Definitive host
1. Plasmodium spp. – mosquito
2. Babesia spp. – tick
3. Toxoplasma gondii – cat
4.
5
- Echinococcus granulosus - dog
- Sarcocystis lindemanni - cats and dogs
An organism which harbors the parasite and provides nourishment and shelter to latter and is relatively larger than the parasite
Host
Host can be
- Definitive host
- Intermediate host
- Paratenic host
- Reservoir host
- Accidental host
- Adult parasite lives and undergoes sexual (e.g. mosquito acts as def. host in malaria)
- Host, The larval stage of the parasite lives or asexual multiplication takes place
- Host in larval stage of the parasite remains viable without further development
- Parasitic infection is continuously kept up by the presence of a host, which harbors the parasite and acts as an important source of infection to other suscsptible hosts (e.g. dog is the reservoir host of hydatid disease
- One that harbors an organism which usually does not infect it.
First introduced by Rudolf Virchow in 1880 to include the diseases shared in nature by man and animals
- Later, in 1959, the WHO defined ____ as those diseases and infections, which are naturally tranamitted between vertebrate animals and man
Zoonosis
wonosis
Types of Zoonosis
- Protozoal zoonoses, e.g. toxoplasmic, leishmaniasis, balandiasis and cryptosporidiosis
- Helminthic zoonoses, e.g. hydatid disease, taeniasis
- Anthropozoonoses, infections transmitted to man from lower vertebrate animals, e.g. cystic echinococcosis
- Zooanthroponoses, infections transmitted from man to lower vertebrate animals, e.g. human tubercolosis to cattle
