The WHO is sharing the actual early warning signs of Chagas disease, a parasitic infection spread by triatomine bugs. Most people infected don't notice symptoms or have only mild ones, but fever, headache, muscle pain, and pale skin can appear early, sometimes with a distinctive purple swelling around one eye. This matters because about 8 million people worldwide carry the infection often without knowing it — early diagnosis lets doctors treat it effectively with antiparasitic drugs before it causes heart damage.