Which of the following is a major issue addressed in medical ecology (epidemiology of disease)?

• A. Occurrence, cause, susceptibility (host), source of disease, transmission (mode and route), cost
• B. Occurrence
• C. Transmission (mode and route) and cost
• D. Susceptibility (host) only

Answer: (A)

Medical ecology looks at disease in populations by considering how often it occurs, why it occurs, who is at risk, where the infection comes from, how it spreads, and the economic impact. The best choice includes all of these elements: occurrence, cause, host susceptibility, source of disease, transmission, and cost. This comprehensive view lets us map disease patterns, identify who’s most at risk, locate reservoirs or sources, understand how transmission happens, and assess the financial burden of illness. The other options leave out one or more important aspects, making them incomplete for a full epidemiologic understanding.