1. *Host is a person or other living animal that affords subsistence or lodgment to an infectious agent. *Pathogen is a microorganism if it is capable of causing an infectious disease. *The definition of endemic is the occurrence in a community or region of cases of an illness (or an outbreak) clearly in excess of expectancy. *Virulence is the organisms that can cause disease when introduced into the host, even in small numbers. *Infectious agents usually must enter a host’s body through Portals of entry and proliferate in order to initiate an infection.
*Infection is the entry and development or multiplication of an infectious agent in the body of man or animals. *Incubation Period is the time interval between initial contact with an infectious agent (exposure) and the first apperance of symptoms associated with the infection. *Pathogenicity is the ability of a pathogen to cause disease in a susceptible person. *The definition of Pandemic is the widespread occurrence in a region or sometimes worldwide with high occurrence of an infection.
*Carrier is a person or animal that harbors a specific infectious agent in the absence of discernible clinical disease and serves as a potential source of infection. 2. Neurotoxin binds to receptors of pre-synaptic membrances of motor neurons. It inhibtis the release of Acetylcholine and lead to paralysis. Examples: Botulinum toxins caused by Cl. Botulinum Tetanus toxin caused by Cl. Tetani Enterotoxin performed in contaminated food causing diarrhea and vomiting. It attaches to the mucosal receptors on the epithelial cell membrane. It activates adenylyl cyclase that increases intracellular cAMP. It will increase the secretion of electrolytes and water by the epithelial cells.
Therefore it causes watery diarrhea. Examples: S. aureus and Vibrio cholerae Cytotoxin cause necrosis of epithelial cells, so the patient have watery or bloody diarrhea. Examples: Toxin A and B caused by Cl. difficile 3. For animal reservoirs, cats and Toxoplasma gondill cause Toxoplasmosis. Many wild and domestic animals such as poultry are the resevoirs of Salmonella spp. and cause Salmonellosis. Rabies are caused by Rabies virus in many wild and domestic animals such as dogs. For human reservoir, Staphylococcus aureus cause many different infections.
Neisseria meningtidis cause Meningococcal infections. Neisseria gonorrheae cause gonorrhea. Mycobacterium leprae cause leprosy. Vibrio cholerae cause cholera. 4. There are three class of indirect transmission. First one is Vehicle-Borne transmission. It caused by contaminated inanimate objects and the infectious agent is transported and introduced into a host through a suitable portal of entry. For example, water, food and toys. Second one is Vector-Borne transmission. It cause by living transmitter. Mechanical vector such as cockroach and fly. Biological vector such as Plasmodia in mosquito for malaria.
The third one is Airborne Transmission. It classify droplet nuclei such as M. tuberculosis and dust such as Aspergillus of fungal spores. 5. (a) Streptococcus pneumoniae of Gram-positive cocci cause pneumonia. Haemophilus influenzae, Legionella pneumophila, Pseudomonas aeruginosa of Gram-negative bacilli cause pneumonia. (b) Staphylococcal toxic shock syndrome appears high fever, vomiting, diarrhea, myalgia, shock with cardiac and renal failure and it has a high mortality rate. Its causative agent is Staphylococcus aureus of Gram-positive Cocci. 6. F 7. T 8. T 9. T 10. F 11. T 12. F 13. T 14. T 15. F