The United Nations and international agencies are warning more than half the world’s population is at risk from the growing threat of vector borne diseases.  In advance of World Health Day, the agencies are urging nations to act to contain these often fatal, debilitating diseases.
One bite of a mosquito, a sandfly, a blackfly or a tick can be more than annoying. It can be fatal. 
 
Every year, the World Health Organization reports, more than one billion people are infected and more than one million die from vector-borne diseases, such as malaria, dengue, Lyme disease, and yellow fever.
 
The WHO is focusing on the threat posed by dengue, which it says is the most rapidly spreading vector-borne disease in the world. The International Federation of Red Cross and Red Crescent Societies is also campaigning to get governments to address what it calls a silent disaster.
 
Red Cross Senior Emergency Health Officer Amanda McClelland said dengue is a neglected disease, which mainly affects the poorest, most vulnerable members of society.
 
“We have seen the expansion of dengue from 15,000 cases in 1960 to over 380-, 390-million possible cases right now...  Families that are already close to the poverty line, families that are already affected by heavy disease burdens cannot afford to get this disease. And, they cannot afford for multiple people in their families to get this disease. And this is why the Red Cross is focusing specifically on dengue for the next 12 months and beyond,” said McClelland. 
 
The World Health Organization says during the past 50 years, the disease has spread to more than 100 countries, putting more than 2.5 billion people at risk.  About 75 percent of those at risk are found in the Asia-Pacific region. 
 
Meanwhile, WHO Vector Ecology and Neglected Tropical Diseases Department Director Raman Velayudhan notes, even developed countries such as those in Europe, Australia, and the United States are at risk from this vector-borne disease.
 
Velayudhan told VOA the spread of dengue is caused by environmental changes and increased international travel. He said the free movement of people and goods in Europe and elsewhere also enables the free movement of mosquitoes and other vectors.
 
"In terms of climate change, essentially we do not have strong scientific bases yet to establish that. But having said that, theoretically any increase in temperature helps multiplication of mosquitoes and the virus within the body of the mosquito. So, for example, the mosquito life-cycle may take 20 days when the temperature is 15 degrees, but when the temperature reaches 25 degrees, it will hatch in seven days,” said Velayudhan. 
 
Dengue is a severe flu-like illness with no vaccine or cure.  But, the WHO and the Red Cross say, the disease can be managed and prevented by using insecticide-treated mosquito nets, improved sanitation and the reduction of mosquito breeding sites.