My son who is 18 years old suffered what we thought was a virus on return from Spain about a month ago. He had a high-ish temperature for about 3 days on and off. Since then he is completely lethargic (more so than usual), has lost his big appetite , is losing weight, always wants to sleep, looks extremely pale and interesting and has a persistent tickly cough, not chesty. He is starting to look quite thin from being a strapping 6 footer. We didn t consult a Doctor at any time during this illness . Any ideas?