Hypothermia and frostbite should be prevented by not allowing the body core or extremities to drop in temperature. Common hiking injuries in the Himalayas can put you at risk, as help may be days away. It's best to hike with caution, in groups of 3 or more, so if an injury arises, one person can go for help while the second stays with the injured. Ankle twists are common, as are sprains, strains, cuts and scrapes. Make sure to have a good first aid kit and someone on board who has basic first aid training or knowledge.
Worms are a concern, so wear shoes or sandals at all times, especially in the showers.
Stomach or intestinal problems can debilitate you for days. As you're sure to be served uncooked food somewhere along the trail, do your best to make sure all you eat is fully cooked or washed with treated water. Make sure to have plenty in your first aid kits. Water must be treated, for drinking and brushing but not for washing. Iodine tablets or drops are popular, as they don't take up much space and won't be used long enough to cause liver damage.