<s>[INST] Who should be especially careful about dengue? [/INST] People living in and traveling to an endemic area (an area where dengue occurs regularly) during an epidemic are at increased risk of being infected with the virus. Persons who were previously infected with one or more types of dengue virus, who are very young or old, or who have a weak immune system are thought to be at greater risk for developing dengue hemorrhagic fever. Source: TEXAS HEALTH AND HUMAN SERVICES. Link: https://www.dshs.texas.gov/mosquito-borne-diseases/dengue/dengue-faqs. Field: Infectious Disease. Disease: Dengue </s>