What Is the History of Dengue Fever Outbreaks?
Dengue fever is endemic in tropical and subtropical areas. Dengue fever is estimated by the World Health Organization (WHO) to cause about 50-100 million infections per year worldwide. The U.S. Centers for Disease Control and Prevention (CDC) considers dengue fever to cause the majority of acute febrile illnesses in travelers returning to the U.S. The first clinical report of dengue fever was in 1789 by B. Rush, although the Chinese may have described the disease associated with "flying insects" as early as 420 AD. Africans described "ka dinga pepo" as cramp-like seizure caused by an evil spirit. The Spanish may have changed "dinga" to dengue since it means fastidious or careful in Spanish, which describes the gait of people trying to reduce the pain of walking.
Unfortunately, the disease incidence seems to be increasing. Researchers suggest the surge in dengue fever may be due to several factors:
- Increased urban crowding with more sites for mosquitoes to develop
- International commerce that contains infected mosquitoes, thus introducing the disease to areas previously free of the disease
- Local and world environmental changes that allow mosquitoes to survive the winter months
- International travelers who carry the disease to areas where mosquitoes have not been previously infected
Although dengue is one of the tropical diseases, it has spread widely throughout the world; the CDC distribution map (available at https://wwwnc.cdc.gov/travel/yellowbook/2018/infectious-diseases-related-to-travel/dengue) shows that dengue fever mainly occurs in tropical and subtropical areas. In the U.S., dengue fever has been detected in California, Florida, Texas, and Hawaii. Other areas where it has been detected or there has been an outbreak of the disease include the Philippines, Taiwan, Samoa, South America (Brazil), Puerto Rico, Costa Rica, Southeast Asia, Thailand, and New Delhi. However, as climates warm, experts suggest dengue will become more prevalent.
In 2015, an outbreak of dengue fever occurred in New Delhi, the worst in the previous five years. Over 10,000 people tested positive for dengue fever; there have been at least 32 deaths attributed to this outbreak. State-run hospitals were so overcrowded that patients were sharing beds. An independent group (Brandeis University) suggests the actual numbers of people in India with dengue are "vastly underreported."
A 2017 outbreak of dengue in Sri Lanka reported over 107,000 infections, an unprecedented outbreak. Flooding early in 2017 allowed the mosquito population to flourish and spread the disease; this was a major factor contributing to this outbreak. Sri Lanka's hospitals are converting maternity and other wards to dengue wards, but many are running out of room to treat patients.