History of Dengue

The origins of dengue and its pathway to the present day are the subject of much debate. While debate does exist, agreement is made that both the virus and its primary vector, the Aedes aegypti mosquito had their origins in either Africa or Asia.

The Aedes aegypti mosquito is often referred to as a “New World” mosquito. This species is thought to have made its way out of Africa on slave ships during the 17th, 18th and 19th centuries. By 1800 it was well established in many large tropical cities, especially those with very active shipping ports. The mosquito population remained stable in these areas for many years before experiencing a growth explosion during and after World War II.

The name ‘dengue’ is thought to have origins in the Swahili language. The Swahili name “Ki-Dinga pepo” was used to describe a dengue-like illness reported in Africa during the 19th century.

The dengue virus had its origins in the jungles, evolving from a mosquito virus to one capable of causing disease in lower primates and humans. Development of the environment by humans through the establishment of settlements and deforestation helped to move the dengue virus out of the jungle to the rural environment. Commerce and economic development then moved people from rural areas to towns and cities, thus introducing the virus to another new environment. Transmission cycles in Asia were kept alive by a native mosquito species, the Aedes albopictus. When the virus was introduced to areas that had become infested with the Ae.aegypti mosquito, epidemics occurred.

The name ‘dengue’ is thought to have origins in the Swahili language. The Swahili name “Ki-Dinga pepo” was used to describe a dengue-like illness reported in Africa during the 19th century. This name gave birth to the terms denga and dinga which, along with the Ae.aegypti mosquito traveled with the slave trade to the New World. From these terms, the modern day nomenclature ‘dengue’ evolved. During the 19th century the disease also went under the fanciful name ‘The Dandy’ or ‘Dandy fever’.

The World War II Phenomenon

World War II had a major effect not only on the spread of the disease but also on scientific understanding. The war caused massive demographic changes and ecologic disturbances in the Asia region. While these changes were disruptive for the human population, they provided ideal conditions for mosquito breeding and virus transmission. Key factors include the disruption to water supplies, an increase in the number of suitable breeding sites for mosquitoes (for example abandoned weaponry and equipment) and the increased mobility of people throughout the region. Following the war the region saw massive urbanization projects as people moved towards cities seeking work, food and shelter. With little time to plan for this massive influx of people, cities grew haphazardly with inadequate water supply and waste disposal systems, creating ideal breeding grounds for mosquitoes and the transmission of viruses.

Dengue was a cause of severe morbidity for troops deployed in the Asia region. This motivated scientific research by both the American and Japanese military. Both of these countries established commissions that were successful in isolating the virus, with the first strain (from Hawaii) labeled as Dengue 1. An antigenically distinct strain (from New Guinea) was also isolated and labeled as Dengue 2. Over a decade later, during an epidemic in the Philippines in 1956, the Dengue 3 and Dengue 4 serotypes were isolated, completing the serotype family. Thousands of dengue viruses have been isolated since then with all isolates fitting into one of the four serotypes.

References

Gubler  DJ (1997). Dengue and Dengue Hemhorrhagic Fever: It's history and resurgence as a global public health problem, p1-22. In (ed.) Gubler  DJ and Kuno G Dengue and Dengue Hemhorragic Fever. (AB International, Wallingford, United Kingdom)