Living in the Shadow of Dengue
I had never considered how much of a threat dengue posed until my daughter and I became infected.
For the past six years, as part of my role with Charles River, I have been based in Southeast Asia, in counties where dengue fever is endemic. Dengue is not just a problem in Asia, it is also widespread in Latin America, and cases have been reported in Hawaii.
Dengue is caused by a virus spread primarily by the bite of the Aedes aegypti mosquito. The World Health Organization reports that there may be in the region of 390 million infections per year and half of the world's population is now at risk!
Yet despite the presence of dengue where I live, I had never really considered how much of a threat it posed. Naturally, my family and I took the usual precautions to minimise mosquito contact: screens on windows and doors, removing potential breeding sites within our properties and using mosquito repellents, though it is never practical to completely remove all contact with mosquitoes.
My views of dengue changed during last September when I developed a fever and some body pain. At first I thought it was possibly just a flu-like illness until the pain became worse and my 8-year old daughter also started showing the same symptoms. A visit to the clinic and blood tests confirmed that we were both infected with the dengue virus and we were both admitted to hospital.
As there is no drug available, treatment consisted of an IV drip to keep us hydrated and regular blood tests to assess platelet levels and check for internal bleeding. I remained in hospital for several days with no further complication. My daughter was not so lucky. She developed the more severe form of the illness (often known as dengue hemorrhagic fever), which required platelet transfusions to stem the internal bleeding. It was only through the dedication and tenacity of her medical team that they eventually managed to get two IV lines into her veins, which had become seriously contracted due to the virus, to deliver enough platelets and fluids. I later learned from one of her doctors, that another child in the same hospital had not been as lucky earlier that day and passed away.
Both my daughter and I are completely recovered, although she is now terrified of mosquitoes! And we're not completely immune to dengue. Previous infection with dengue provides only immunity against the particular serotype transmitted; it offers no protection against the other three serotypes of the virus that also cause dengue and which also circulate where we live. Indeed it is known that once infected, further infection by any of the other serotypes, paradoxically, can increase the risk of developing the severe form of the disease.
However, there is hope. In December the first dengue vaccine was approved for human use. It is reported to be effective against all four serotypes and in human trials showed a big reduction in the likelihood of the disease progressing to the severe form. The vaccine has just become available where I live and two weeks ago the whole family was vaccinated! Several other vaccines are also in development.
While drug companies continue with their efforts to find ways to combat tropical diseases such as dengue, with some success, the emergence of the Zika virus, which is spread by the same mosquito, is causing concern as infection during pregnancy can lead to a serious birth defect, microcephaly. Although it is not a new virus, a widespread outbreak of Zika virus is underway in South and Central America. Although presently not endemic where I live in Southeast Asia, previous outbreaks have been reported and currently several travel-related cases are known. The environment and widespread presence of the Aedes mosquito could mean that it is only a matter of time before the locally transmitted Zika infections are seen.
Hopefully our drug discovery community will be able to respond to this new challenge as well as continuing in the fight against other tropical diseases.
How to cite:
Hill, Richard. Living in the Shadow of Dengue. Eureka blog. June 22, 2016. Available: https://eureka.criver.com/living-in-the-shadow-of-dengue/