Biopharmaceutical Solutions

Background information

• What is Dengue Fever?
  Dengue fever (DF) is a viral, mosquito-borne disease that can cause severe, flu-like symptoms with high fever and extreme muscle and joint pain. Dengue hemorrhagic fever (DHF), a more dangerous form of the disease associated with increased blood vessel permeability, can be fatal. 
• Global Burden
  There are an estimated 50 million new dengue infections each year, and more than 2.5 billion people are at risk for the disease. Approximately 500,000 cases of DHF require hospitalization each year, the majority of whom are children, resulting in more than 20,000 deaths. Without proper treatment, DHF case fatality rates can exceed 20 percent.
• Geographic Distribution
  DF is endemic in 100 countries throughout the Americas, Southeast Asia, the Western Pacific Islands, Africa, and the eastern Mediterranean. Southeast Asia and the Western Pacific are most seriously affected. Dengue cases have also been reported in Hawaii, Texas, and Puerto Rico.
• Causative Agent/Transmission
  The dengue virus is a member of the family Flaviviridae, which includes the viruses that cause yellow fever, Japanese encephalitis, and West Nile disease. There are four known serotypes. The viruses are transmitted by Aedes aegypti mosquitoes, subgenus Stegomyi.

Presentation

DF is a severe, incapacitating, flu-like illness that affects infants, young children, and adults, but seldom causes death. In older children and adults, DF symptoms include sudden onset of high fever, severe
headache, muscle and joint pain, and rash. With palliative care, these symptoms typically resolve within weeks, but complete convalescence  may require additional time.

Less than 1 percent of patients infected with dengue develop DHF, which is characterized by low platelet counts and blood iron imbalance that may be accompanied by bleeding, enlarged liver, and circulatory failure. Without proper treatment, DHF case fatality rates can exceed 20 percent. However, modern intensive supportive therapy such as intravenous fluid replacement can reduce case fatality rates to less than 1 percent.

Exposure to one dengue serotype provides permanent immunity against that serotype, but subsequent infections by a different serotype increase the likelihood that the patient will develop DHF.

Trends

Due to the deforestation, development, and urbanization of tropical regions, breeding grounds for A. aegypti have expanded. As a result, human-vector contact has increased, and infection rates are on the rise.

The A. aegypti habitat is not limited to the developing world, and dengue cases have recently occurred in Puerto Rico, Singapore, Hawaii, and the southern United States.

A dengue epidemic in Brazil that started in early 2008 caused over 55,000 infections over four months in Rio de Janeiro alone.

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