By

Assist. Prof. of Parasitology, Zoology Department,

Damietta Faculty of Science, Mansoura University

TopicsNO. of hoursDate

1Parasitology and Parasitism122 Sept.

2Protozoan Parasites129 Sept.

3Protozoan Parasites16 Oct.

4Protozoan Parasites113 Oct.

5Protozoan Parasites120 Oct.

6Worm Parasites127 Oct.

7Worm Parasites13 Nov.

8Revision110 Nov.

9Worm Parasites117 Nov.

10Worm Parasites124 Nov.

11Worm Parasites11 Dec.

12Worm Parasites18 Dec.

13Worm Parasites115 Dec.

14Revision122 Dec.

15Final Exam1

**Dr. Ola Abdell Halim Abu SamakDr. Ola Abdell Halim Abu Samak**Office hoursOffice hours::

**Phone: 0572403981-168Phone: 0572403981-168**Email: Email: olasamak@mans.edu.egolasamak@mans.edu.eg

11 hourhour *Lecture*Lecture::**Labs: 2 hoursLabs: 2 hours

Parasites and ParasitismParasites and Parasitism

Lecture 1Lecture 1

Aim of the lectureAim of the lecture

Increasing the familiarity with the Increasing the familiarity with the parasites and host relations parasites and host relations

Recognizing the parasitism among the Recognizing the parasitism among the other biological relationshipsother biological relationships

Comparing between different biological Comparing between different biological relationships and monitoring in the relationships and monitoring in the surrounding environmentsurrounding environment

Identifying the biological relationshipsIdentifying the biological relationships

Do Parasites Rule the WorldDo Parasites Rule the World??Do Parasites Rule the WorldDo Parasites Rule the World??Parasites are often occupying the 3Parasites are often occupying the 3rdrd great great environment (aquatic-terrestrial-parasitic)environment (aquatic-terrestrial-parasitic)

*Traditionally, only considered to be protists, *Traditionally, only considered to be protists, worms, and arthropods.worms, and arthropods.

*Now known to encompass everything from *Now known to encompass everything from prokaryotes up to the diversity of metazoans.prokaryotes up to the diversity of metazoans.

*One of the most common lifestyles in existence, *One of the most common lifestyles in existence, with an estimate 1/3 of life being parasitic (Price with an estimate 1/3 of life being parasitic (Price 1980).1980).

*In fact, of the 35 animal phyla, only echinoderms, *In fact, of the 35 animal phyla, only echinoderms, chordates, and a few minor phyla do not have chordates, and a few minor phyla do not have representative parasitic members.representative parasitic members.

Organismal AssociationsOrganismal AssociationsAny 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

SymbiosisSymbiosis

PhoresisPhoresis CommensalismCommensalism ParasitismParasitismMutualismMutualism

PhoresisPhoresis

Two organisms simply travel together

Neither organism is helped or harmed

Usually one is transporting the other

Barnacles on a whaleBarnacles on a whale

Burrs attached to fur of mammalsBurrs attached to fur of mammals

Or your socks and shoe lacesOr your socks and shoe laces

Dematobia Dematobia (bot fly) eggs on mosquito(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 flyFungal spores on legs of house fly

Examples of PhoresisExamples of Phoresis

CommensalismCommensalism

One benefits but the other isn’t harmed One benefits but the other isn’t harmed and receives no benefitsand receives no benefits

Usually one feeds off the “wastes” of the Usually one feeds off the “wastes” of the other partner.other partner.

Commensalism ExamplesCommensalism ExamplesRemoras and sharks Remoras and sharks

**Feed on scraps left by shark

Humans have many commensalsHumans have many commensals

**Intestinal protozoans and bacteri

*Entamoeba Gingivalis Amoeba in the mouth

*Eyelash mites

MutualismMutualism

Both organisms benefit from the relationshipBoth organisms benefit from the relationship

Usually obligatoryUsually obligatory

Both partners realy on the relationship and can’t live Both partners realy on the relationship and can’t live without the other.without the other.

Mutualism ExamplesMutualism ExamplesCoral and ZooxanthelleCoral and Zooxanthelle

Termites and bacteriaTermites and bacteria

Bacteria digest woodBacteria digest wood

Cleaner fish and the fish they Cleaner fish and the fish they cleanclean

Leeches and bacteriaLeeches and bacteria

Bacteria digest bloodBacteria digest blood

Humans and bacteriaHumans and bacteria

Bacteria make vitamins out Bacteria make vitamins out of our wastesof our wastes

ParasitismParasitismOne organism benefits while the other organism is One organism benefits while the other organism is harmedharmed

The amount of harm can varyThe amount of harm can vary

-Mosquito bite causes minor irritation-Mosquito bite causes minor irritation

-Some parasites steal nutrients-Some parasites steal nutrients

-Some cause major damage that can result in death -Some cause major damage that can result in death of other organismof other organism

Parasite is in wrong hostParasite is in wrong host

Parasites in large numbersParasites in large numbers

SymbiosisSymbiosis

The line between some the categories may The line between some the categories may be difficult to draw.be difficult to draw.

A parasite in one organism may be a A parasite in one organism may be a commensal in another organism.commensal in another organism.

How much “harm” is necessary before a How much “harm” is necessary before a commensal becomes a parasite?commensal becomes a parasite?

PredationPredation

Predation is frequently viewed as a Predation is frequently viewed as a symbiosissymbiosis

Interaction between two organismsInteraction between two organisms

One organism dies at the end of the One organism dies at the end of the interaction.interaction.

The interaction occurs over a very short The interaction occurs over a very short timetime

Predation vs. ParasitismPredation vs. ParasitismPredation and parasitism may seem to be the Predation and parasitism may seem to be the same.same.

One organism benefits, other is harmedOne organism benefits, other is harmedBoth can result in an evolutionary arms raceBoth can result in an evolutionary arms race

The host/prey gets better at avoiding the The host/prey gets better at avoiding the parasite/predator so the parasite/predator must adaptparasite/predator so the parasite/predator must adapt

But there are significant differencesBut there are significant differences..Predation results in the death of one of the Predation results in the death of one of the organism.organism.

Parasites usually try to keep host alive.Parasites usually try to keep host alive.

Predator is larger than the prey.Predator is larger than the prey.Parasites are usually smaller than host.Parasites are usually smaller than host.

Predator preys on many individuals in a lifetime.Predator preys on many individuals in a lifetime.Parasite usually spends entire life in one or two hostParasite usually spends entire life in one or two host

ParasitologyParasitology

Usually restricted to protozoans and Usually restricted to protozoans and multi-cellular animals that are parasitic multi-cellular animals that are parasitic on other animals, particularly humans.on other animals, particularly humans.

Does not include Does not include

bacteria and virusesbacteria and viruses

parasites on plantsparasites on plants

Our Focus in ParasitologyOur Focus in Parasitology

Learn the taxonomic groups of parasitesLearn the taxonomic groups of parasites

Recognize life cycles for important parasitesRecognize life cycles for important parasites

Identify diseases associated with particular Identify diseases associated with particular parasites, and how to recognize themparasites, and how to recognize them

Parasites or notParasites or not??

If an animal lives inside another, but is not If an animal lives inside another, but is not actively causing harm, is it a parasite?actively causing harm, is it a parasite?

If an animal temporarily feeds upon If an animal temporarily feeds upon another, but leaves its prey alive, is it a another, but leaves its prey alive, is it a parasite?parasite?

If an animal lays its eggs in another, and the If an animal lays its eggs in another, and the young consume the host from the inside-out, young consume the host from the inside-out, is it a parasite?is it a parasite?

A simple viewA simple view

In a straight forward situation a small In a straight forward situation a small organism (Parasite) has the potential to organism (Parasite) has the potential to harm a larger organism (Host), and relies on harm a larger organism (Host), and relies on said host for nutrients and shelter (a Niche). said host for nutrients and shelter (a Niche).

The parasite generally has a much higher The parasite generally has a much higher reproductive capability compared to its reproductive capability compared to its host.host.

Unfortunately, parasitism is seldom this Unfortunately, parasitism is seldom this clear cut.clear cut.

Endoparasite vs EctoparasiteEndoparasite vs EctoparasiteLiving inside or outside the hostLiving inside or outside the host

What about What about Pneumonyssus simicolaPneumonyssus simicola that infest nasal passages and lungs? that infest nasal passages and lungs?

Temporary vs PermanentTemporary vs PermanentOnly on host to feed or only off the host to Only on host to feed or only off the host to dispersedisperse

Obligate vs FacultativeObligate vs FacultativeMust have the host to complete life cycle or free-Must have the host to complete life cycle or free-living organism capable of infesting a host under living organism capable of infesting a host under the right conditions.the right conditions.

Types of ParasitesTypes of Parasites

Types of ParasitesTypes of Parasites 11 - -LocationLocation

EndoparasiteEndoparasiteLives inside the body of the host may be just Lives inside the body of the host may be just

under the surface or deep in the bodyunder the surface or deep in the bodyTapeworms, flukes, protozoansTapeworms, flukes, protozoans

EctoparasiteEctoparasiteStays on outside surface of the hostStays on outside surface of the host

Mosquitoes, leeches, ticks, fleas, brood Mosquitoes, leeches, ticks, fleas, brood parasitesparasites

22 – – Required or notRequired or not

Obligate ParasiteObligate Parasite Requires finding and invading the Requires finding and invading the host to complete its life cycle host to complete its life cycle

Most of the parasites we will cover Most of the parasites we will cover are obligate parasitesare obligate parasites

Facultative ParasiteFacultative Parasite May become parasitic if it is given May become parasitic if it is given the chance but does not require a host.the chance but does not require a host.

Types of ParasitesTypes of Parasites

33 - -Amount of time spentAmount of time spent

Permanent ParasitePermanent Parasite Lives entire adult life stage on or in a Lives entire adult life stage on or in a hosthost

Usually endoparasitesUsually endoparasites One exception is eyelash miteOne exception is eyelash mite

Temporary ParasiteTemporary Parasite Spends only a short time on a hostSpends only a short time on a host

Usually ectoparasitesUsually ectoparasites

Types of ParasitesTypes of Parasites

Types of HostsTypes of HostsDefinitive HostDefinitive Host

Host where sexual reproduction (or Host where sexual reproduction (or any other gene shuffling) takes place.any other gene shuffling) takes place.

In the few parasites with only asexual In the few parasites with only asexual reproduction, it is the host most reproduction, it is the host most important to humans.important to humans.

Intermediate HostIntermediate Host Required in the life cycle of parasite.Required in the life cycle of parasite.

No reproduction or asexual No reproduction or asexual reproduction takes place.reproduction takes place.

Paratenic or Transport HostParatenic or Transport Host No development occurs but parasite No development occurs but parasite remains aliveremains alive May go dormantMay go dormant May cause damageMay cause damage

Accidental or Incidental HostAccidental or Incidental Host Parasite is in the “wrong” species.Parasite is in the “wrong” species. Parasite usually wanders around and Parasite usually wanders around and causes great damage because it doesn’t know causes great damage because it doesn’t know where to go then dies.where to go then dies.

Types of HostsTypes of Hosts

Reservoir HostReservoir HostAny animal that carries a parasite that can cause Any animal that carries a parasite that can cause infections in humans.infections in humans.

Even if it is the normal host for that parasite.Even if it is the normal host for that parasite.Related to the medical perspective of parasitologyRelated to the medical perspective of parasitology

VectorVectorAny organism that transmits infections to humans.Any organism that transmits infections to humans.Broader because it includes organisms that carry Broader because it includes organisms that carry parasites, bacteria, and viruses.parasites, bacteria, and viruses.Frequently, it is an obligate host for a parasite.Frequently, it is an obligate host for a parasite.

Types of HostsTypes of Hosts

Life CyclesLife Cycles

Tritrichomonas foetusDirect life cycle

Direct life cycleDirect life cycleTransmitted from one Transmitted from one

host to another through the host to another through the air, by a fomite, or in air, by a fomite, or in contaminated food or contaminated food or water.water.

Indirect life cyclesIndirect life cycles requires a vector or requires a vector or

intermediate host to intermediate host to

reproduce or grow inreproduce or grow in..

Indirect life cycleIndirect life cycle

How are Parasites StudiedHow are Parasites Studied??Need to be familiar with invertebrate and Need to be familiar with invertebrate and

vertebrate zoologyvertebrate zoology

Taxonomy and systematicsTaxonomy and systematics

Histology and cytologyHistology and cytology

ImmunologyImmunology

Molecular biologyMolecular biology

Vector Biology and the study of life cyclesVector Biology and the study of life cycles

Our Focus in ParasitologyOur Focus in ParasitologyLearn the taxonomic groups of Learn the taxonomic groups of

parasitesparasites

Recognize life cycles for important Recognize life cycles for important parasitesparasites

Identify diseases associated with Identify diseases associated with particular parasites, and how to particular parasites, and how to recognize themrecognize them