Altitude and tropical diseases each have their own playbook, and both reward preparation over improvisation. For high-altitude destinations, roughly above two and a half thousand meters, the symptoms to respect are headache, nausea, dizziness, poor sleep and unusual breathlessness; mild versions are common and pass with rest, but worsening symptoms, confusion, or a wet cough are danger signs that mean descend immediately. The golden rules are ascending gradually, resting on arrival, hydrating well, and avoiding alcohol the first days. Preventive medication for altitude exists and is commonly prescribed for rapid ascents, so discuss it with a travel doctor beforehand.
In tropical zones, the watchwords are fever and mosquitoes. Any fever during or after tropical travel deserves prompt medical attention, since malaria and dengue both start like flu. Malaria prophylaxis is advised for many regions, and the right drug depends on local resistance patterns, another travel-clinic conversation. Dengue has no preventive pill, making repellent, long sleeves at dawn and dusk, and screened rooms your real defense.
A pre-trip consultation four to six weeks out covers both scenarios properly, and your government's travel health guidance lists which precautions apply to your exact route.