Malaria, diarrhoea and pneumonia are preventable childhood diseases that are major causes of death in young children. They’re transmitted largely in and around the home, where children spend most of their time. For example, of malaria transmission in Africa occurs when people are bitten by malarial mosquitoes indoors at night. Diarrhoea results usually from food and water that’s been contaminated by faeces. It can also be spread through poor hygiene.