Question

A young man went to his doctor's office with a fever, wide-spread rash, severe muscle pain, and malaise. The symptoms had begun with a mild headache three days previously. He reported being bitten by a tick one week prior to that. The doctor correctly diagnosed Rocky Mountain Spotted fever and prescribed tetracycline. The rash and other signs and symptoms disappeared in a couple of days, but he continued on his antibiotic therapy for two weeks.

Draw a graph showing the course of the disease and the relative numbers of pathogens over time, starting with the tick bite, and ending with the end of antibiotics. Label the stages of the disease.

Answer 1

Answer :

Graph is drawn with pathogen load in Y axis and phase of infection in X axis.

We can see its almost a bell shaped curve.

The point A is tick bite and transfer of few microbes for rocky mountain spotted fever.

At the point B patient starts symptoms.

The distance between A and B is incubation period. This is one week in this case. On third day of symptoms he started treatment.

In a few days of treatment he became asymptomatic. The distance of B and C is infectious period.

Continued treatment for few more weeks in view of subclinical infection. This is distance between C and D. Treatment should extend at least few days after the last pathogen otherwise disease may recur. This is D and E.

Please see picture attached.