Dengue fever, filariasis and malaria

Global and regional situation summary

Global situation summary


Approximately, 40% of the world’s population, mostly those living in the world’s poorest countries are at risk of malaria. Every year, more than 500 million people become severely ill with malaria. Most cases and deaths are in sub-Saharan Africa. However, Asia, Latin America, the Middle East, parts of Europe and two of the Pacific countries are also affected.

A few facts:

  • Malaria is both preventable and curable.
  • A child dies of malaria every 30 seconds
  • More than one million people die of malaria every year, mostly infants, young children and pregnant women and most of them in Africa.


The global prevalence of dengue has grown dramatically in recent decades. The disease is now endemic in more than 100 countries in Africa, the Americas, the Eastern Mediterranean, South-east Asia and the Western Pacific. South-east Asia and the Western Pacific are most seriously affected. Before 1970 only nine countries had experienced DHF epidemics, a number that had increased more than four-fold by 1995.

Some 2500 million people (two fifths of the world's population) are now at risk from dengue. WHO currently estimates there may be 50 million cases of dengue infection worldwide every year. In 2001 alone, there were more than 609 000 reported cases of dengue in the Americas, of which 15 000 cases were DHF. This is greater than double the number of dengue cases which were recorded in the same region in 1995.

Not only is the number of cases increasing as the disease is spreading to new areas, but explosive outbreaks are occurring. In 2001, Brazil reported over 390 000 cases including more than 670 cases of DHF. The spread of dengue is attributed to expanding geographic distribution of the four dengue viruses and of their mosquito vectors, the most important of which is the predominantly urban species Aedes aegypti. A rapid rise in urban populations is bringing ever greater numbers of people into contact with this vector, especially in areas that are favourable for mosquito breeding, e.g. where household water storage is common and where solid waste disposal services are inadequate.

Regional situation summary


Malaria is still endemic in 10 countries of the Western Pacific Region, associated with poverty and retarding progress towards economic well-being among the affected communities.

In the past decade, national health authorities in several of these endemic countries have made considerable progress in reducing malaria morbidity and mortality. Resistance to chloroquine and other commonly available antimalarial drugs is a major issue in malaria control in the Region, as it is worldwide. The problem is most critical in the countries of the Mekong region, where it is aggravated by the increasing proliferation of low-quality and counterfeit drugs, and widespread irrational drug use in the private sector.


Dengue fever is a growing problem in the Western Pacific Region. Unprecedented rapid urbanization has resulted in an increasing number of people living in poor housing with lack of proper waste disposal and inadequate drainage, creating favorable breeding conditions for the mosquito vectors of dengue. Dengue occurs in most of the countries in the Region, inflicting severe health and financial tolls on the populations affected. In 2004, more than 160 000 cases of dengue and dengue haemorrhagic fever were reported in the Region. Despite its significance, dengue prevention and control activities are under-funded in many countries. With appropriate levels of support, the risk of transmission can be reduced and with it the associated morbidity and mortality.