Disturbance of any of the "vital signs" can indicate serious illness. Use your common sense though, if someone looks obviously unwell or is in great distress, s/he may need urgent medical attention. The following are not in order of priority - the presence of one or more of any of these should prompt you to seek medical advice from a doctor.
Many detainees, including children, get malaria in their home country having been removed from the UK without having been provided with adequate or any anti-malarials. People lose their immunity after about 3 months of being away from their home country where malaria exists.
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