system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
Seasonal trends is shown by-
assistant
The correct answer is  .seasonal trend is a well known characteristic of many communicable diseases such as varicella,cerebrospinal meningitis,upper respiratory infections,malaria etc.varicella is usually at its height in early spring and so is measles. ref:parks textbook ,22nd edition,pg no 62