Question

For this discussion, take on the role of one of the pathogens we learned about. Give us a narrative about what you are doing in the body from the pathogen's point of view. How did you get into the body? In other words, how did the body inherit you. How do you move through the body? What path of destruction are you on? How will you wage battle against the body? How do you plan to win that battle? What will the body try to do to stop you? How will you fight back? Who wins?

Answer 1

Pathogen: Corynebacterium diphtheriae.

Disease caused: Diphtheria

Three major clinical types have been described: anterior nasal, facial and laryngeal; however, the skin, conjunctiva, vulva and other parts of the body may be infected. The bacilli multiply locally, usually in the throat, and elaborate a powerful exotoxin which is responsible for:

• the formation of a greyish or yellowish membrane commonly over the tonsils, pharynx or larynx, with well defined edges and the membrane can't be wiped away
• Marked congestion, edema or local tissue destruction
• Enlargement of the regional lymph nodes
• Signs and symptoms of toxemia

C.diphtheriae is a gram positive, non motile organism. It has no invasive power, but produces a powerful exotoxin. The toxin can affect the heart leading to myocarditis or the nerves leading to paralysis.

Infective material: nasopharyngeal secretions, discharge from skin lesions, contaminated fomites and possibly infected dust

Period of infectivity: unless treated, the period of infectivity may vary from 14 to 28 days from the onset of the disease.

Affects particularly children aged 1-5years of both sex.

Mode of transmission: Droplet infection. It can also be transmitted directly to susceptible persons from infected cutaneous lesions. Transmission by objects contaminated by the nasopharyngeal secretions of the patient possible, but for only short periods.

Portal of entry: Respiratory route(respiratory tract) and non respiratory routes( cuts, wounds and ulcers on skin)

​​​​​​​Incubation period: 2-6days , occasionally longer.