Question

1. Describe the six links in the chain of infection 2. What are the stages of infection? 3. Explain acquired immunity, naturally acquired immunity, artificially acquired immunity, passively acquired immunity 4. What are the bodies first and second line of defense 5. What is another name for the common cold? 6. What would be the most useful strategy for avoiding getting another cold? 7. What is the portal of entry for influenza? 8. What is the most common approach to treating influenza? 9. What is Tuberculosis? 10. What is the mode of transmission for tuberculosis? 11. What is the standard treatment for mononucleosis? 12. What is West Nile and how is it transmitted to humans? 13. What is the vector for Lyme disease? 14. What is toxic shock syndrome and what is it most often linked to? 15. Explain what Hepatitis is and how it effects on the body 16. STI chart; what the cause, symptoms, is it curable, treatable, treatment method

Answer 1

1. The chain of infection, if we think of it as an actual chain, is made up of six different links: pathogen (infectious agent), reservoir, portal of exit, means of transmission, portal of entry, and the new host. Each link has a unique role in the chain, and each can be interrupted, or broken, through various means.

The first link is the pathogen itself. This is the disease-causing organism. For many illnesses and diseases this is a virus or bacterium. In order to break this link, various methods can be used, including the pasteurization of milk, the chlorination of drinking water, or the use of disinfectants.

The second link is the reservoir. This is the natural environment that the pathogen requires for survival. Reservoirs can be a person, an animal, or an environmental component, such as soil or water. This link can be broken through medical treatment and testing, insect and rodent eradication, or quarantine.

The third link is the portal of exit. This link is needed for the pathogen to leave the reservoir. If the reservoir is a human, then the portal of exit may be saliva, mucous membranes, feces, blood, or nose or throat discharges. By using barrier methods, such as condoms or masks, or covering the mouth while coughing, this link can be broken.

The fourth link is the means of transmission. The pathogen can be transmitted either directly or indirectly. Direct transmission requires close association with the infected host, but not necessarily physical contact. Indirect transmission requires a vector, such as an animal or insect. The link can be broken through hand washing, safe sex practices, or avoiding contact with infected individuals.

Link number five is the portal of entry. Entry of the pathogen can take place in one of three ways: penetration, inhalation, or ingestion. The level and severity of an infection may depend on the depth of penetration. Similar to the portal of exit, barrier methods, such as condoms or masks, can be used to break this link along with other methods, such as insect repellants.

The final link is the new host. Once in the new host, various factors influence the severity of infection, including the strength of the immune system and the reproductive rate of the pathogen. Immunization, health promotion, and medical treatment can be used to break this link in the chain.