The phrase "obvious signs of illness" refers to any clear indications that a person is sick or unwell. These may include physical symptoms such as fever, coughing, sneezing, fatigue, and weakness; behavioral changes like listlessness, irritability, or lack of appetite; and other observable signs like difficulty in breathing, rashes, or swelling. In short, it refers to any noticeable indications that a person is not well and may require medical attention.