PARASITOLOGY: Parasitology is a discipline that describes the relationships (whatever these may be) between two organisms, i.e. the host organism and the parasite. What is Parasitology ? Parasitology is the study of parasitism. Parasite: An organism that spends a significant portion of its life in or on the living tissue of a host organism and which causes harm to the host without immediately killing it. Host: An organism which provides shelter and food to other organisms. NB: Normally a true parasite does not kill its host

When one organism gives shelter and food to another organism two totally different situations may exist: Without any harm being done, where some hosts may benefit from the presence of a parasite, in which case we normally speak of: Mutualism: a situation where two organisms live in some contact and benefit from each others presence. They exchange food or provide shelter or protection, but may still be able to live an independent life. Symbiosis: a situation where two organisms live in close contact and benefit from each others presence. They have become dependent upon each others presence and are unable to survive independently.

PARASITOLOGY:  Parasite:  Host: Medical parasitologyVeterinary parasitology The study of parasites which cause economic losses in agriculture or aquaculture operations, or which infect companion animals.agriculture aquaculturecompanion animals Medical parasitology is the study of those parasites which infect humans.

HISTORY Upto the middle of the 17th century knowledge of parasitology was limited to recognition of the existence of a few self-asserting external parasites, Lice, fleas, and a few kinds of internal parasites such as Tape Worms, Ascaris, Pinworms & Guinea worms. were, however thought to be natural products of the bodies comparable to warts and boils. Grand father of parasitology Francesco Redi (1626). In the later half of the 17th century demonstrated that maggot developed from the eggs of flies and that even Ascaris has male & female and produced eggs.

He was the 1st genius parasites hunter. In the same half century Leeunven hock, perfected microscopes, which enabled protozoa in rain water. Saliva and feces. (Giardia). First protozoan recognized as human parasites was Balantidium coli (Malmsten in Sweden 1856) Rudolphi (1771-Stockholm worked in Germany) collected & classified all the parasites known up to his time.

 With harm being done. When one organism lives at the expense of its host we can distinct several situations: viral infections viral infections bacterial infections bacterial infections parasitic diseases parasitic diseases

PROTOZOA   Traditionally the animal kingdom has been divided into two subkingdoms;   Protozoa* and Metazoa*Protozoa*Metazoa*   Protozoa are the most abundant animals in the world in terms of numbers and biomass.   Their principal importance is as consumers of bacteria.   Bacteria play a vital role in maintaining the earth as a suitable place for inhabitation by other forms of life and protozoa play a vital role in controlling their numbers and biomass.   Protozoa are also important as parasites and Symbionts of multicellular animals.

Prokaryotic and eukaryotic cell  Protozoa are single-celled eukaryotic* organsims (Organisms whose cells characteristically contain a cell-bound nucleus* or nuclei.) eukaryotic*nucleus*eukaryotic*nucleus*

Protozoology branch of biology concerned with the study of protozoans The science had its beginnings in the latter half of the 17th centuryscience when Antonie van Leeuwenhoek of the Netherlands first observed protozoans by means of microscope.Antonie van Leeuwenhoek Protozoans are common, and they are of particular interest to man because they cause such diseases as malaria, amoebic dysentery, and African trypanosomiasis (sleeping sickness). Babesiasis, Theilleriasis. Protozoans also serve as experimental organisms in many studies of cell and molecular biology

Associations  Symbiosis/Mutualism, highly interdependent association.  Commensalism involves one way benefit.  Parasitism.  Predation.  Phoresis

Key terms in Parasitology Protozoa, Helminthes, Arthropods Nematodes Cestodes Trematodes Parasite, Host Obligate parasite 1.Definitive Host: Facultative parasite 2.Intermediate Host: Temporary Parasite: 3.Normal Host:. Constant Parasite 4.Abnormal Host: Occasional or accidental 5.Reservoir host: Aberrant parasite 6.Paratenic host/ Hyperparasite Transport host: LIFE CYCLES OF PARASITES: DIRECT LIFE CYCLE INDIRECT LIFE CYCLE

VECTOR: BIOLOGICAL VECTOR: MECHNICAL VECTOR: ZOONOSIS: Disease of animals that is transmissible to humans. Infection Infestation Macroparasites: Microparasites:

Relationships in Nature Relationships can be found throughout nature: Dependent and Independent Beneficial and Harmful Hosts and Parasites

What is symbiosis? What it means: Two organisms that live together Two organisms that live together Temporarily or for a longer time Temporarily or for a longer time At least one of the organisms benefits from the relationship At least one of the organisms benefits from the relationship Literal definition: the act of living together

What are the different kinds of symbiosis? MutualismParasitism Commensalism both organisms benefit one organism benefits one organism is unaffected one organism is harmed

Relationships   Symbiosis/Mutualism, highly interdependent association.   Commensalism :involves one way benefit.   Parasitism.   Phoresis   Predation.

Symbiosis Anemone fishes (sometimes called clownfishes) have close relationship with sea anemones. Living together A partnership Two different species Both partners benefit – mutual benefit – mutual benefit

Mutualism : both benefit Example 2: Moray Eel with Cleaner Fish Moray Eel gets a clean mouth Cleaner Fish gets a meal

 “eating together at the same table”  Only one member benefits sharing space, defense, shelter, food  Neither will die if relationship is ended  Shrimp & sea cucumber Commensalism

Commensalism: one benefits, one is unaffected Example 3: Cattle with cattle egrets Cattle stir up insects as they eat grass Egrets hang around and eat insects

  The Cattle Egret (Bubulcus ibis) forages in pastures and fields among livestock such as cattle and horses, feeding on the insects stirred up by the movement of the grazing animals. Buffalo & Oxpecker -Lets the bird eat -Eats ticks and other parasites off skin -Warns buffalo of danger

PARASITISM  Not symbiotic  Causes harm to host

Mosquito: Females ingest blood for the protein. Male mosquitos ingest plant juices.

Phoresis Phoresis New Latin, from Greek phorēsis act of carrying, from phorein to carry,   Loose association   One organism is smaller than other   Larger organism used for transport The term phoresis means “to carry” Historically, phoresy has been regarded as a type of symbiotic relationship in which one organism (the smaller phoront) is mechanically carried on or in another species (host) In this relationship, there is no physiological or biochemical dependence on the part of the host or symbiont

Predation A true predator is one which kills and eats another organism

LionLion and cub eating a Cape BuffaloCape Buffalo

Types of parasites 1. Endoparasites 2.Ectoparasites: Pediculus humanus (head louse) adult. Dirofilaria immitis: Heartworm of dogs,

KINDS OF PARASITES  Temporary Parasite: Visits its host for a short period e.g. warble files and ticks. warble files and ticks.  Constant Parasite: Leads parasitic life throughout the whole period of its life e.g. Cestodes period of its life e.g. Cestodes  Facultative Parasite: Lives a parasitic life when opportunity arises or which can live entirely as saprophyte. arises or which can live entirely as saprophyte.  Obligatory Parasite: Cannot exist without a parasitic life ‘  Occasional or Attacks an unusual host, in which they are Accidental Parasite: not usually found.  Aberrant Parasite: follows the unusual routes within the host body and die. body and die.  Hyperparasite :Parasite within a parasite i.e. malaria in mosquitos; mosquitos;

KINDS OF HOST: 1.Definitive Host: The organism which harbors the adult stage of the parasite or parasite or in which parasite reaches sexual maturity and reproduces. e.g. Man,Sheep. in which parasite reaches sexual maturity and reproduces. e.g. Man,Sheep. 2.Intermediate Host: Some development in host, but does not reach sexual maturity; often asexual stages. e.g. snails maturity; often asexual stages. e.g. snails 3.Normal Host: In which any particular species of parasite is usually parasitic e.g.E.histolytica. parasitic e.g.E.histolytica. 4.Abnormal Host: In which the parasite may be, but not usually found. 5.RESERVOIR HOST: 6.PARATENIC HOST/ TRANSPORT HOST: Intermediate hosts can be divided into two groups: Passive IH (molluscs in the case of Schistosoma) Active IH (tsetse fly in the case of trypanosomes)

LIFE CYCLES OF PARASITS:  DIRECT LIFE CYCLE: When a parasite requires only one species of host. e.g. Entamoeba histolytica  INDIRECT LIFE CYCLE: When two or more species of hosts are required, the life cycle is an indirect.

SIX ESSENTIAL ASPECTS TO A PARASITE LIFE CYCLE 1. Find a Host 2. Enter a Host 3. Overcome Host Defenses: 4. Derive Nutrients From Host 5. Reproduce More Individuals 6. Disperse Young to New Hosts

VECTOR: “a living carrier (e.g.an arthropod) that transports a pathogenic organism from an infected to a non-infected host”. A typical example is the female Anopheles mosquito that transmits malaria A female Anopheles mosquito taking a blood meal

BIOLOGICAL VECTOR: a host, usually an arthropod, in which the parasite undergoes a significant change and is actively transmitted to the next host, usually by a bite. Example: a mosquito picks up malaria from a bite, parasite undergoes reproduction, and is transmitted in a new bite of a human host

MECHNICAL VECTOR: Vector that transmits disease organism by mechanical means only

Zoonosis: “a parasitic disease in which an animal is normally the host - but which also infects man” or Disease of animals that is transmissible to humans Infection: Establishment of a parasite within a host. Infestation: Refers to the presence of external parasite.

Macroparasites: do not multiply in or on the host. e.g.Cestodes, adult Nematode, Trematodes and ticks. Microparasites: multiply within the host.i.e.Protzoa Mesoparasite: penetrates external openings – e.g. buccal cavity, cloaca, external ear.

THANKSTHANKSTHANKSTHANKS