Chapter 1 PARASITOLOGY

Question 1

• the area of biology concerned with the phenomenon of dependence of one living organism on another.

Answer 1

Parasitology

Question 2

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

Answer 2

Parasitism

Question 3

Hosts that transmit parasites to man

Answer 3

vectors

Question 4

are essential in
the lifecycle of a parasite

Answer 4

biologic vectors

Question 5

are not essential to the life cycle of the parasites

Answer 5

phoretic or mechanical vectors

Question 6

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.

Answer 6

Medical parasitology

Question 7

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.

Answer 7

Ebers papyrus

Question 8

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

Answer 8

Giardia lamblia

Question 9

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

Answer 9

Sarcoptes scabiei

Question 10

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.

Answer 10

nasal flies of deer
eggs

Question 11

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

Answer 11

amoebiasis

Question 12

1835, James Paget discovered the intestinal nematode _______ in humans

Answer 12

Trichinella spiralis

Question 13

James McConnell described the ___ in 1875

Answer 13

human liver fluke

Question 14

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

Answer 14

strongyloidiasis

Question 15

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.

Answer 15

elephantiasis
Plasmodium

Question 16

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.

Answer 16

Anopheles

Question 17

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.

Answer 17

Symbiosis

Question 18

Major Types of Association in Animals

Examples of Symbiosis

Answer 18

Termites and their intestinal protozoa
Zoochlorella and Hydra Zoochlorella

Question 19

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.

Answer 19

Commensalism

Question 20

Major Types of Association in Animals

Examples of Commensalism

Answer 20

• Entamoeba coli and Trichomonas sp. live in intestine
• Pilot fish and shark
• Remora and shark
• Crab and sea-urchin

Question 21

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.

Answer 21

mutuus
Mutualism

Question 22

Major Types of Association in Animals

examples of mutualism

Answer 22

• Hermit crab and sea anemone
• herbivores ruminal flora

Question 23

Major Types of Association in Animals

• “Traveling together”.
• temporary association between two
  individuals or living beings in which where is no metabolic dependence

Answer 23

Phoresis

Question 24

Major Types of Association in Animals

examples of phoresis

Answer 24

Bacteria and amoebae on the legs of fly or fungal spores on the legs of a beetle

Question 25

# 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.

Answer 25

parasitism

Question 26

# Major Types of Association in Animals – invertebrate animals with long, flat, round bodies.

Answer 26

Helminths

Question 27

# 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)

Answer 27

roundworms *Enterobius vermicularis* (pinworm) tapeworms *Echinococcus granulosus* (hydatid disease) trematodes, flukes *Fasciola hepatica* (sheep liver fluke)

Question 28

# Major Groups of Parasites – unicellular, eukaryotic microorganisms.

Answer 28

Protozoa

Question 29

# 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**

Answer 29

Lobosea Zoomastigophorea

Question 30

Protozoa **A. Phylum Sarcomastigophora B. Phylum Ciliophora** . Class ____: organisms that move by means of cilia Examples: __ (*balantidiasis*) **C. Phylum Apicomplexa**

Answer 30

Kinetofragminophorea *Balantidium coli*

Question 31

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)*

Answer 31

apical complex

Question 32

– hard exoskeleton, jointed appendages

Answer 32

Arthropods

Question 33

Phylum Arthropoda 1. Class __: flies, mosquitoes, bugs, lice, fleas 2. Class __: ticks and mites

Answer 33

Hexapoda Arachnida

Question 34

# Classification of Parasites 1. inhabit only the body surface of the host **without penetrating the tissue**. (lice, ticks and mites) 2. 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.

Answer 34

Ectoparasites Endoparasites

Question 35

# Categories of Endoparasites 1. Parasite that **do not exist without a host** 2. Either live as **parasite form or as free-living form** 3. Parasites, which **infect an unusual host** 4. Parasites, which infect a host where they **cannot develop further** 5. Refers to **nonparasitic stages** of active existence, which live independent of the host

Answer 35

Obligate parasite Facultative parasite Accidental parasite Aberrant/wandering parasites Free-living parasites

Question 36

# Categories of Endoparasites Examples: 1.Obligate: 2.Facultative: 3.Accidental: 4.Aberrant/wandering: 5.Free-living:

Answer 36

1. *Toxoplasma gondii* and *Plasmodium* 2. *Naegleria fowleri* 3. *Echinococcus granulosus* infects man accidentally, giving rise to hydatid 4. *Toxocara canis* (dog roundworm) infecting humans 5. cystic stage of *Naegleria fowleri*

Question 37

# Life cycle of Parasites 1. Parasite the requires only one host to complete its development 2. Parasite that requires two hosts (one definitive host and another intermediate host)

Answer 37

1. Direct/simple life cycle 2. Indirect/complex life cycle

Question 38

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.

Answer 38

Protozoans: 4. *Balantidium coli* 5. *Cryptosporidium parvum* Helminths 4. *Enterobius spp.* 5. *Strongyloides spp.*

Question 39

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.

Answer 39

5. *Taenia saginata* -- cattle 6. *Trichinella spiralis* -- pig 7. Filarial worms -- mosquito

Question 40

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

Answer 40

4. *Echinococcus granulosus* - dog 5. *Sarcocystis lindemanni* - cats and dogs

Question 41

An organism which harbors the parasite and provides nourishment and shelter to latter and is relatively larger than the parasite

Answer 41

Host

Question 42

# Host can be 1. Definitive host 2. Intermediate host 3. Paratenic host 4. Reservoir host 5. Accidental host

Answer 42

1. **Adult parasite** lives and undergoes sexual (e.g. mosquito acts as def. host in malaria) 2. Host, The larval stage of the parasite lives or **asexual multiplication takes place** 3. Host in larval stage of the parasite remains viable **without further development** 4. 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 5. One that harbors an organism which **usually does not infect it**.

Question 43

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

Answer 43

Zoonosis wonosis

Question 44

# Types of Zoonosis

Answer 44

1. Protozoal zoonoses, e.g. toxoplasmic, leishmaniasis, balandiasis and cryptosporidiosis 2. Helminthic zoonoses, e.g. hydatid disease, taeniasis 3. Anthropozoonoses, infections transmitted to man from lower vertebrate animals, e.g. cystic echinococcosis 4. Zooanthroponoses, infections transmitted from man to lower vertebrate animals, e.g. human tubercolosis to cattle