Malaria topped all diseases in 2016 as the leading cause of death, the UN has announced.

However, fewer cases of the disease were reported in 2016 compared to 2015.

According to a biweekly report of the UN Office for the Coordination of Humanitarian Affairs, the decline in malaria cases is due to an overall decline in reporting rate in 2016.

It says conflict spread to new areas and disrupted health services, therefore making it difficult to record cases.

OCHA says 2.2 million cases, including more than 500 deaths, were recorded last year, compared to almost 2.4 million cases, including 1,000 deaths in 2015.

Children under the age 5 remained the most affected by the disease, accounting for 71 per cent of all malaria deaths in 2016.

Malaria is a parasitic disease transmitted by bites from infected mosquitoes.

It can be prevented by sleeping under mosquito nets to avoid the bites.

OCHA says pregnant women and children under age 5 are especially vulnerable, with malaria during pregnancy potentially resulting in high maternal mortality, low birth weight and maternal anemia.

In 2016, partners responded to malaria by distributing protective insecticide treated nets, indoor spraying with insecticide in the IDP camps and, treatment for pregnant women and surveillance.