Parasites ,Fungi, Viruses

Parasites Are eukaryotes that depend on another host for their nutrients and metabolic activities. Divided to 1-Protozoa: Unicellular. 2-Helminths: Multicellular. 3-Arthropods: Multicellular.

Protozoa 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

Protozoa Protozoa move by : Psuedopod: (extending part of protoplasm towards direction of movement) Example: Entamoeba species Flagella : Example: Trypanosoma species, Giardia Lamblia

Protozoa Cilia: Example: Balantidium coli non motile: Example : Plasmodium species

Entamoeba Trophozoite Cyst

Protozoa Trypanosoma

Protozoa Balantidium coli cyst

Protozoa Ring stage))Plasmodium

Helminths(worms) 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 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

Helminths Ascaris lumbricoides egg

Helminths Tenia saginata adult and ova

Helminths Schistosoma ova

Arthropods Are insects such as bugs ,fleas, biting flies, mosquitoes etc. Harmful effects of parasites Discomfort, transmission of diseases( malaria, yellow fever, typhus), cause disease(amoebic dysentery, bilharzias), damage to crops.

Fungi Heterotrophic eukaryotes Saprophytes: obtain nutrients from dead organic material Nucleated achlorophyllous organisms Reproduce sexually and asexually Surrounded by true cell wall 2 groups Yeast and mold

Fungi Grow within a wide range pH(acidic-alkaline) Grow at room temperature (can grow at cold temp) Prefer moist or humid atmospheres Can be cultured in Sabouraud Dextrose agar media (SDA) or potato dextrose agar (PDA) that contains a source of protein (peptone) and a source of carbohydrate (dextrose)

Fungi The commonest microscopic examination of fungi is LACTO-PHENOL- COTTON BLUE tease mount or reagent (LPCB) Benefits of fungi: important in baking , pharmaceutical(antibiotic),brewing industries. Also as saprophytes and as food. Harmful effects: cause a lot of diseases in skin, hair, nail and systemic diseases.

Fungi Yeast Unicellular, round or oval( tear drop)shape Multiply asexually by budding resulting in production of 2 cells Molds Multicellular branching hyphea forming a mycelium.

Fungi Molds using LPCB x40 Alternaria species

Fungi Molds using LPCB x40 Penicillium

Fungi Molds using LPCB x40 Aspergillus species

Fungi Yeast LPCB x40

Fungi /Molds on SDA

Tools used for fungi Iron needles made from iron because fungi dig into agar thus it is difficult to culture them with wire loop

Viruses Virus in Latin means poison All viruses are obligate intracellular parasites( can multiply only in living cells) Possess 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)

Viruses Vary in size from 20-300nm Cannot be seen by bright field microscope Can be examined by Electron microscope Can infect humans, animals, plants and bacteria Viruses that infect bacteria are called bacteriophages

Viruses Isolation of viruses : a- animal inoculation b- embrynoted egg inoculation c- cell culture Cytopathic effects are morphological changes in cell lines due to virus infection.