Dengue Fever

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The mosquito Aedes aegypti feeding on a human host

 

 

The first record of a case of probable dengue fever is in a Chinese medical encyclopedia from the Jin Dynasty (265-420 CE) which referred to a “water poison“ associated with flying insects.

 

The primary vector, A. aegypti, spread out of Africa in the 15th to 19th centuries due in part to increased globalization secondary to the slave trade. There have been descriptions of epidemics in the 17th century, but the most plausible early reports of dengue epidemics are from 1779 and 1780, when an epidemic swept across Asia, Africa and North America. From that time until 1940, epidemics were infrequent. In 1906, transmission by the Aedes mosquitoes was confirmed, and in 1907 dengue was the second disease (after yellow fever) that was shown to be caused by a virus. Further investigations by John Burton Cleland and Joseph Franklin Siler completed the basic understanding of dengue transmission. The marked spread of dengue during and after the Second World War has been attributed to ecologic disruption. The same trends also led to the spread of different serotypes of the disease to new areas, and to the emergence of dengue hemorrhagic fever. This severe form of the disease was first reported in the Philippines in 1953; by the 1970s, it had become a major cause of child mortality and had emerged in the Pacific and the Americas. Dengue hemorrhagic fever and dengue shock syndrome were first noted in Central and South America in 1981, as DENV-2 was contracted by people who had previously been infected with DENV-1 several years earlier.

 

The origins of the Spanish word dengue are not certain, but it is possibly derived from dinga in the Swahili phrase Ka-dinga pepo, which describes the disease as being caused by an evil spirit. Slaves in the West Indies having contracted dengue were said to have the posture and gait of a dandy, and the disease was known as “dandy fever“. The term “break-bone fever“ was applied by physician and United States Founding Father, Benjamin Rush, in a 1789 report of the 1780 epidemic in Philadelphia. In the report title he uses the more formal term “bilious remitting fever“. It was called “break-bone fever“ because it sometimes causes severe joint and muscle pain, that feels like bones are breaking. The term dengue fever came into general use only after 1828. Other historical terms include “breakheart fever“ and “la dengue“. Terms for severe disease include “infectious thrombocytopenic purpura“ and “Philippine“, “Thai“, or “Singapore hemorrhagic fever“.

 

 

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Figure 1. Average annual number of dengue fever (DF) and dengue hemorrhagic fever (DHF) cases reported to WHO and average annual number of countries reporting dengue (Source: World Health Organization).

 

Possible factors for dengue fever spread include:

 

1. Unplanned urban overpopulation of areas leading to inadequate housing and public health systems (water, sewerage and waste management)

2. Poor vector control, e.g., stagnant pools of water for mosquito breeding

3. Climate change and viral evolution (increased virus transmission has been linked to El Nino conditions)

Increased international travel (recreational, business or military) to endemic areas

All of these factors must be addressed to control the spread of dengue. Unplanned urbanization is believed to have had the largest impact on disease amplification in individual countries, whereas travel is believed to have had the largest impact on global spread.

 

Short, well explained video about dengue fever and a vaccine

 

Sanofi Pasteur dengue vaccine candidate clinical trials

 

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