April 7 is World Health Day and the theme this year is 'Vector-borne disease - small bite big threat'. More than half the world’s population is at risk from diseases such as malaria dengue leishmaniasis Lyme disease schistosomiasis and yellow fever carried by mosquitoes flies ticks water snails and other vectors. Every year more than one billion people are infected and more than one million die from vector-borne diseases. This World Health Day – 7 April – WHO is highlighting the serious and increasing threat of vector-borne diseases with the slogan ‘Small bite big threat’. Take part in our quiz to