RIYADH — Saudi Arabia will on Monday observe World Health Day 2014, which will be held under the theme, "Small Bite, Big Threat". The Ministry of Health announced that during 2012 Saudi Arabia had 2,788 cases of malaria, up by about 22 percent over the previous year. The ministry said schistosomiasis was contained more than 20 years ago but added that diseases caused by insects, flies and mosquitoes are difficult to contain. It warned that these diseases might recur many times. According to WHO, as many as 660,000 people died from malaria in 2010, the majority of them children from the African continent. The organization said the most common diseases caused by insects, flies and mosquitoes are malaria, dengue fever, Rift Valley fever, leishmania and schistosomiasis.