pathogens

• Pathogen: Number of pathogens, Pathogenicity • Host: Defence capabilities of host, Immunocompromised

• Infectious agent that is capable causing disease

• Any organism that carries another organism

• A disease that is caused by a pathogen or infectious agent and can be transmitted from one organism to another

• Contains DNA or RNA • Intracellular obligate pathogen E.G. Influenza

• Virus targets a specific cell • Viral genetic material inserted into host cell • Genetic material replicate in DNA replication • Cell lysis • Virus spread to more cells

• Misfolded protein 1. Abnormal prion induced misfolding in normal prions 2. Damages the nervous tissue 3. Transmissible spongiform encephalopathy E.G. Kuru Disease

• Prokaryotic organism • Can be intracellular or extracellular • Treated with antibiotics and disinfectant 1. Rapidly multiply by binary fission 2. Release mycotoxins 3. Toxin cause disease E.G. Samonella

• Unicellular eukaryotes E.G. Malaria

• Attaches to intestine • Prevents nutrient absorption

• Unicellular eukaryotes E.G. Athletes Foot

• Survive on surface of skin • Release mycotoxins

• Multicellular eukaryotes • Can be pathogens and vectors E.G. Tapeworm, Aphids

• Vector transmission • Contact with infected surfaces • Contaminated food and water

• Contaminated surgical tools • Eating meat containing abnormal protein • Inheritance

• Widespread occurrence of an infectious disease in a community at a particular period of time

• Direct Contact • Indirect Contact • Vector Transmission

• Vertical Transmission: Genetic • Horizontal Transmission: Anything else E.G. touching, kissing, bitin

• Fomites E.G. Airborne, surgical equiptment

• Disease is spread through another animal

• Suspected causative agent must be absent from all healthy organisms but present in all diseased organisms • Suspected causative agent must be isolated from the diseased organism and grown in pure culture • Suspected causative agent must cause the same disease when inoculated in a healthy organism • Suspected causative agent must then be reisolated from the inoculated diseased organism