Are eukaryotes that depend on another host for their nutrients and metabolic activities.

Divided to 1-Protozoa: Unicellular. 2-Helminths: Multicellular. 3-Arthropods: Multicellular.

ParasiteParasite

Common stages of life cycle 1- Trophozoite: active growing stage 2- Cyst: resting non active stage.

Can infect all major tissues and organs of the body.

Transmission of protozoan parasites by 1- injection via bites of blood sucking insects. 2- ingestion of infective stages.

protozoaprotozoa

Protozoa move byProtozoa move by ::

Psuedopod: (extending part of protoplasm towards direction of movement)

Example: Entamoeba species.

Flagella : Example: Trypanosoma

species, Giardia Lamblia

Cilia: Example: Balantidium coli

non motile: Example : Plasmodium species (ring stage)

EntamoebaEntamoeba

Trophozoite Cyst

ProtozoaTrypanosoma

ProtozoaBalantidium coli cyst

Multicellular organisms with organ systems as digestive, nervous , excretory system.

Have complicated life cycle. Mostly have different stages of life cycle

which are: ova(egg), larvae (Adult). Adult worms can measure centimeters or

even meters long. Extracellular parasites.

Helminths(worms)Helminths(worms)

Are classified according to shape into: 1- Nematodes (round worms) cylindrical

thin Example: Ascaris lumbricoides.

2- Cestodes ( tape worms)flat long worms Example: Tenia saginata,tenia solium.

3- Trematodes( Flukes)leaf like flat worms Example: Schistosoma species.

HelminthsHelminths

HelminthsHelminthsAscaris lumbricoides eggAscaris lumbricoides egg

HelminthsHelminthsTenia saginata adult and ovaTenia saginata adult and ova

HelminthsHelminthsSchistosoma ovaSchistosoma ova

Are insects such as bugs ,fleas, biting flies, mosquitoes etc.

Harmful effects of arthropods: 1) Discomfort, transmission of diseases

( malaria, yellow fever, typhus). 2) cause disease (amoebic dysentery,

bilharzias).

ArthropodsArthropods

Fungi: Group of Heterotrophic Eukaryotes cells.

Fungi are called Saprophytes because they obtain nutrients from dead organic material. Some fungi can absorb organic nutrients from living tussue.

Classification of Fungi:1.Yeast.2.Mold.

1)Yeast: Oval, spherical, tear drop shape. Single cell (unicellular). One nucleus. Multiply asexual by budding resulting in

production of two cells.

2)Mold:

Consist of branching hyphae forming mycelium.

Multicellular. Multinucleated cell. Reproduce sexually and asexually.

1) PH: Grow within a wide range pH especially acidic (4-6).

2) Temp: • Room temperature: superficial infections.• 37C: Systemic infection (pathogenic Fungi).• Cold temp: Spoilage of food.

3) Humidity: Prefer moist or humid atmospheres.

4) Media:

• Sabouraud Dextrose agar media (SDA).Contains: source of protein ----(peptone).source of carbohydrate ---(dextrose).

• Potato Dextrose Agar (PDA).made from potato and dextrose

Yeast Mold

LACTO-PHENOL-COTTON BLUE (LPCB): Reagent used to stain fungi for microscopicexamination.

Why do we cultivate?1.Diagnosis2.Research3.Production of vaccines

Benefits of fungi:Baking: by using yeast.

Antibiotic: penicillin extracted from penicillium.

Saprophytes: Breaking down of dead organic material.

Wine production.

Harmful effects:

cause a lot of diseases in skin, hair, nail and systemic diseases.

Alternaria species

Penicillium

Aspergillus species

Iron needles: made from iron because fungi dig into the

agar.

Viruses are obligate intracellular agents: can multiply only in living cells.

Consist of a single type of nucleic acid either DNA or RNA (Ss or Ds).

Nucleic material is enclosed in a protein coat called capsid.

both capsid and nucleic acid are called nucleocapsid.

Some viruses are enveloped others are naked.

Vary in size from 20-300 nm

Viruses are examined only by Electron microscope.

Viruses Can infect humans, animals, plants and bacteria.

Viruses that infect bacteria are called bacteriophages.

Cultivation of viruses :

A) Animal inoculation eg: mice

b) Embryonated egg inoculation.

C) Tissue cell culture (see CPE).

Cytopathic effects (CPE):Is the morphological changes in cell caused by theviral infection.

Figure:a. Monolayer of normal fetal tonsil cells. b. tonsil cells with adenovirus.c. tonsil cells with herpes simplex infection and monolayer destroyed.