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Professor Simon Hay, a Wellcome Trust Senior Research Fellow at the University of Oxford explained that he and his team created the first detailed and up-to-date map of global dengue fever distribution, making it possible for researchers now to accurately estimate how many humans are infected with the virus worldwide, regionally and nationally.

 

The authors added that their study findings will help public health authorities and agencies when deciding on vaccine, drug and vector control strategies.

 

Dengue is today the world's fastest-spreading tropical disease. There are no licensed vaccines for dengue, nor are there any specific treatments. Scientists at Sanofi Pasteur, however, believe a dengue vaccine is in sight. Despite considerable efforts to control mosquito populations, dengue fever has emerged, spread and established itself rapidly.

 

Dr Samir Bhatt, who was in charge of modeling the study, said:

 

"Our aim was to take all of the evidence that is currently available on the distribution of dengue worldwide and combine it with the latest in mapping and mathematical modelling to produce the most refined risk maps and burden estimates.

 

We then hope to use this knowledge to help predict the future burden of the disease."

 

 

The researchers found that dengue is present throughout the tropics. How common it is depends primarily on a region's:

Rainfall

Temperature

Degree of urbanization - however, in a study reported in PLoS Medicine (August 2011 issue), researchers from the Nagasaki Institute of Tropical Medicine in Japan wrote that people living in rural areas have a higher risk of dengue virus infection than city dwellers.

Professor Hay and colleagues estimate that there are approximately 390 million human dengue infections annually around the world. Ninety-six million people reach "any level of clinical or subclinical severity". This is a much higher figure than WHO's 50 to 100 million annual infections.

 

Prof. Hay said:

 

"We found that climate and population spread were important factors for predicting the current risk of dengue around the world. With globalization and the constant march of urbanization, we anticipate that there could be dramatic shifts in the distribution of the disease in the future: the virus may be introduced to areas that previously were not at risk, and those that are currently affected may experience increases in the number of infections.

 

We hope that the research will initiate a wider discussion about the significant global impact of this disease."

 

 

Seventy percent of the 96 million apparent infections occur in Asia, with India making up one third of the total.

 

Approximately 16 million people are estimated to become infected with dengue fever in Africa each year, much higher than previous estimates; about the same as the total in the Americas.

 

The researchers believe that the African figure was underestimated because dengue fever has signs and symptoms that can lead misdiagnoses - there are other illnesses in Africa with similar symptoms to dengue. Two other factors that probably led to the low previous figure in the continent were under-reporting and "highly variable treatment-seeking behavior".

 

Prof. Hay and team have created a map with estimates that will now become the benchmark for dengue fever, said Prof. Jeremy Farrar, Director of the Wellcome Trust Vietnam Research Program and Oxford University Clinical Research Unit Hospital for Tropical Diseases in Vietnam.

 

Prof. Farrar said:

 

"This is the first systematic robust estimate of the extent of dengue. The evidence that we've gathered here will help to maximise the value and cost-effectiveness of public health and clinical efforts, by indicating where limited resources can be targeted for maximum possible impact.

 

With endemic transmission in Asia and the Americas, recent outbreaks in Portugal, the ever-increasing incidence in Africa, and the challenges of making an effective dengue vaccine or controlling the vector, Professor Farrar stresses: "This really does represent a crucial period in the global spread of dengue."

 

 

Head of International Activities at the Wellcome Trust, Jimmy Whitworth believes that this new comprehensive map of the global dengue fever burden will also help in determining which control measures work best in reducing the incidence of the disease. "Without a vaccine or specific treatment options, it's crucial that we understand where best to direct the limited resources available for preventing this resurgent disease."

What is Dengue Fever

 

Dengue fever, also referred to as breakbone fever is a mosquito-borne infection that causes flu-like illness.

 

Dengue fever can be caused by four different types of viruses, which are spread mainly by the Aedes aegypti mosquito and more rarely by the Aedes albopictus mosquito. Aedes aegypti originated in Africa, but can currently be found in all tropical areas of the world - it thrives in areas of human population.

 

 

Dengue can vary from mild to severe. Severe forms of dengue include dengue shock syndrome and DHF (dengue hemorrhagic fever) - in such cases patients need to be hospitalized.

 

The only way to prevent from becoming infected and developing dengue fever is to avoid being bitten by the mosquito. There is no specific treatment for Dengue fever. However, if caught early on, it is easier to prevent complications.

 

According to WHO:

About two-fifths of the world's population (2.5 billion people) are currently at risk of dengue fever

Dengue fever is endemic in more than 100 countries

About 1 in every 40 patients with DHF die from the disease

If left untreated, approximately 20% of people with DHF die from the infection

 

Source:http://www.medicalnewstoday.com/articles/258735.php