When 44-year-old Tokyo resident Isao was struck down by chronic diarrhea in June earlier this year, AIDS was the furthest thought from his mind. "I just thought I had a regular illness," said Isao, who asked for his surname to be withheld.

However, the craftsman suspected his illness was more serious after he started losing a large amount of weight, dropping from 60 kg to 45 kg in just two months.

Isao visited a doctor and was given a prescription for anti-diarrheal medicine. Nevertheless, his condition continued to worsen.