Tropical diseases are illnesses that are caused by viruses, bacteria, or parasites and are found in tropical and subtropical regions. Dengue is a mosquito-borne viral infection that can cause severe flu-like symptoms and can even be fatal. Beriberi is a vitamin B1 deficiency caused by a lack of thiamine in the diet, which can lead to neurological and cardiovascular problems. MALARIA is a parasitic infection spread by mosquitoes that can cause fever, chills, and anemia. SPRUE is an intestinal disorder caused by a sensitivity to gluten, which can lead to malabsorption of nutrients.