Dengue in the Pacific

Dengue fever is a tropical disease caused by the dengue virus. The virus is transmitted by several mosquito species from the genus Aedes.

There are four different virus types known as serotypes that cause dengue fever; DEN-1, DEN-2, DEN-3, and DEN-4. If an individual is infected by any one of the four virus serotypes, they develop immunity to that specific type that they were infected with. This means that there is no cross immunity between the serotypes, so for example if an individual is infected by DE-1, they will develop immunity for DEN-1 but NOT DEN-2, DEN-3, and DEN-4.

Dengue fever dates back in the 1700 but increase number of cases have been observed since the 1960’s with the disease being endemic to over 110 countries and infecting close to 100 million people every year.

What are the symptoms of dengue fever;

-fever

-headache

-muscle and joint pains

-a characteristic skin rash that is similar to measles

- Sometimes a more severe form of the disease may occur, these include dengue haemorrhagic fever which includes symptoms such as bleeding, low levels of blood platelets and blood plasma leakage.  Another severe form of the disease is dengue shock syndrome where the blood pressure drops dangerously low.

Dengue fever is ranked by the World health organization as one of the neglected diseases.

The incidence of dengue fever has increased over the years, the increase has been attributed to urbanization, population growth, increased in international travel and global warming.

In this article I will discuss some of the countries that have been affected by Dengue with increased international travel as one of the contributing factors.

In the pacific island countries and territories (PCITs), dengue is not endemic but several outbreaks have occurred over the years. The largest number of epidemics observed have been due to DEN-1 and DEN-2 serotypes.  DEN-1 affected 16 PCITs between 2000 and 2004.

From the beginning of May 2012, a dengue outbreak has been declared in some of the PICTs including New Caledonia, Kiribati, and Cooks Islands.

What are the factors facilitating dengue outbreaks in the PCITs?

Some of the factors that have been put forward to facilitate these outbreaks include;

1.       Lack of effective prevention activities in many PICTs.

2.       Inadequate diagnosis

3.       Limited surveillance for cases and the vector (the mosquito that transmits the virus).

4.       Lack of capacity to respond to outbreaks due to insufficient trained personnel and resources to implement control and prevention plans.

Sequencing of the dengue virus has been done and sequences are available for researchers for reference as they compare various outbreaks and the responsible virus serotype.