1. By General Parasitology Assist. Prof. of Parasitology,
Dr./ Ola Abdell Halim Abu Samak
Assist. Prof. of Parasitology,
Zoology Department,
Damietta Faculty of Science, Mansoura University

2. Syllabus of the Lecutures for 3rd year Students of Zoology Department
Topics
NO. of hours
Date 1
Parasitology and Parasitism
22 Sept. 2
Protozoan Parasites
29 Sept. 3
6 Oct. 4
13 Oct. 5
20 Oct. 6
Worm Parasites
27 Oct. 7
3 Nov. 8
Revision
10 Nov. 9
17 Nov. 10
24 Nov. 11
1 Dec. 12
8 Dec. 13
15 Dec. 14
22 Dec. 15
Final Exam

3. *Dr. Ola Abdell Halim Abu Samak *Office hours: *Phone: 0572403981-168 *
1 hour *Lecture:
*Labs: 2 hours

4. Parasites and Parasitism
Lecture 1

5. Aim of the lecture
Increasing the familiarity with the parasites and host relations
Recognizing the parasitism among the other biological relationships
Comparing between different biological relationships and monitoring in the surrounding environment
Identifying the biological relationships

6. Do Parasites Rule the World?
Parasites are often occupying the 3rd great environment (aquatic-terrestrial-parasitic)
*Traditionally, only considered to be protists, worms, and arthropods.
*Now known to encompass everything from prokaryotes up to the diversity of metazoans.
*One of the most common lifestyles in existence, with an estimate 1/3 of life being parasitic (Price 1980).
*In fact, of the 35 animal phyla, only echinoderms, chordates, and a few minor phyla do not have representative parasitic members.

7. Organismal Associations
Any association more or less permanent is called a symbiosis, with each member a symbiont.
Symbiosis is used as a n umbrella term for organisms that live together

8. Phoresis Two organisms simply travel together
Neither organism is helped or harmed
Usually one is transporting the other

9. Examples of Phoresis Barnacles on a whale
Burrs attached to fur of mammals
Or your socks and shoe laces
Dematobia (bot fly) eggs on mosquito
Female bot fly lays eggs on female mosquito
Eggs drop off when mosquito feeds
Fungal spores on legs of house fly

10. Commensalism
One benefits but the other isn’t harmed and receives no benefits
Usually one feeds off the “wastes” of the other partner.

11. Commensalism Examples
Remoras and sharks
*Feed on scraps left by shark
Humans have many commensals
*Intestinal protozoans and bacteri
*Entamoeba Gingivalis Amoeba in the mouth
*Eyelash mites

12. Mutualism Both organisms benefit from the relationship
Usually obligatory
Both partners realy on the relationship and can’t live without the other.

13. Mutualism Examples Coral and Zooxanthelle Termites and bacteria
Bacteria digest wood
Cleaner fish and the fish they clean
Leeches and bacteria
Bacteria digest blood
Humans and bacteria
Bacteria make vitamins out of our wastes

14. Parasitism One organism benefits while the other organism is harmed
The amount of harm can vary
-Mosquito bite causes minor irritation
-Some parasites steal nutrients
-Some cause major damage that can result in death of other organism
Parasite is in wrong host
Parasites in large numbers

15. Symbiosis
The line between some the categories may be difficult to draw.
A parasite in one organism may be a commensal in another organism.
How much “harm” is necessary before a commensal becomes a parasite?

16. Predation Predation is frequently viewed as a symbiosis
Interaction between two organisms
One organism dies at the end of the interaction.
The interaction occurs over a very short time

17. Predation vs. Parasitism
Predation and parasitism may seem to be the same.
One organism benefits, other is harmed
Both can result in an evolutionary arms race
The host/prey gets better at avoiding the parasite/predator so the parasite/predator must adapt
But there are significant differences.
Predation results in the death of one of the organism.
Parasites usually try to keep host alive.
Predator is larger than the prey.
Parasites are usually smaller than host.
Predator preys on many individuals in a lifetime.
Parasite usually spends entire life in one or two host

18. Parasitology
Usually restricted to protozoans and multi-cellular animals that are parasitic on other animals, particularly humans.
Does not include
bacteria and viruses
parasites on plants

19. Our Focus in Parasitology
Learn the taxonomic groups of parasites
Recognize life cycles for important parasites
Identify diseases associated with particular parasites, and how to recognize them

20. Parasites or not?
If an animal lives inside another, but is not actively causing harm, is it a parasite?
If an animal temporarily feeds upon another, but leaves its prey alive, is it a parasite?
If an animal lays its eggs in another, and the young consume the host from the inside-out, is it a parasite?

21. A simple view
In a straight forward situation a small organism (Parasite) has the potential to harm a larger organism (Host), and relies on said host for nutrients and shelter (a Niche).
The parasite generally has a much higher reproductive capability compared to its host.
Unfortunately, parasitism is seldom this clear cut.

22. Types of Parasites Endoparasite vs Ectoparasite Temporary vs Permanent
Living inside or outside the host
What about Pneumonyssus simicola that infest nasal passages and lungs?
Temporary vs Permanent
Only on host to feed or only off the host to disperse
Obligate vs Facultative
Must have the host to complete life cycle or free-living organism capable of infesting a host under the right conditions.

23. Types of Parasites 1- Location
Endoparasite
Lives inside the body of the host may be just under the surface or deep in the body
Tapeworms, flukes, protozoans
Ectoparasite
Stays on outside surface of the host
Mosquitoes, leeches, ticks, fleas, brood parasites

24. Types of Parasites 2 – Required or not Obligate Parasite
Requires finding and invading the host to complete its life cycle
Most of the parasites we will cover are obligate parasites
Facultative Parasite
May become parasitic if it is given the chance but does not require a host.

25. Types of Parasites 3- Amount of time spent Permanent Parasite
Lives entire adult life stage on or in a host
Usually endoparasites
One exception is eyelash mite
Temporary Parasite
Spends only a short time on a host
Usually ectoparasites

26. Types of Hosts Definitive Host
Host where sexual reproduction (or any other gene shuffling) takes place.
In the few parasites with only asexual reproduction, it is the host most important to humans.
Intermediate Host
Required in the life cycle of parasite.
No reproduction or asexual reproduction takes place.

27. Types of Hosts Paratenic or Transport Host
No development occurs but parasite remains alive
May go dormant
May cause damage
Accidental or Incidental Host
Parasite is in the “wrong” species.
Parasite usually wanders around and causes great damage because it doesn’t know where to go then dies.

28. Types of Hosts Reservoir Host Vector
Any animal that carries a parasite that can cause infections in humans.
Even if it is the normal host for that parasite.
Related to the medical perspective of parasitology
Vector
Any organism that transmits infections to humans.
Broader because it includes organisms that carry parasites, bacteria, and viruses.
Frequently, it is an obligate host for a parasite.

29. Tritrichomonas foetus
Life Cycles
Direct life cycle
Transmitted from one host to another through the air, by a fomite, or in contaminated food or water.
Indirect life cycles
requires a vector or intermediate host to reproduce or grow in.
Tritrichomonas foetus
Direct life cycle

30. Indirect life cycle

31. How are Parasites Studied?
Need to be familiar with invertebrate and vertebrate zoology
Taxonomy and systematics
Histology and cytology
Immunology
Molecular biology
Vector Biology and the study of life cycles

32. Our Focus in Parasitology
Learn the taxonomic groups of parasites
Recognize life cycles for important parasites
Identify diseases associated with particular parasites, and how to recognize them