Prior to travelling to Laos, do make sure you have received medical vaccinations for the following diseases including Japanese encephalitis, tuberculosis, Hepatitis E, Hepatitis B, and dengue fever. Do keep in mind that dengue fever is a very common affliction in this part of the world, so it's best to be aware of the symptoms, so early treatment is a possibility. Dengue is a mosquito-borne disease, and symptoms include, muscle and joint ache, high fever, severe headaches, and vomiting. Stay safe by opting to wear long-sleeved cotton shirts and t-shirts, and spraying insect repellent on yourself liberally every time you step outdoors.