Travelers to the Dominican Republic should be aware of several endemic infections, primarily those transmitted by mosquitoes or contaminated water. Dengue fever is the most common vector-borne illness, with sporadic outbreaks occurring year-round, particularly in urban areas. Malaria is also present, though its risk is generally lower and concentrated in specific rural provinces like San Juan. Zika virus and Chikungunya have been reported in the past, so pregnant women are often advised to take extra precautions. Waterborne illnesses such as Leptospirosis can be a concern, especially after heavy rainfall or flooding when soil and water become contaminated with animal urine. While the country has made strides in public health, travelers are still susceptible to "traveler's diarrhea" caused by bacteria like E. coli or parasites in untreated water. As of early 2026, health authorities have also increased surveillance for respiratory viruses like Influenza and keep a watchful eye on international alerts such as the Nipah virus, although no cases of the latter have been detected within the territory.