GENEVA - The UN says new disease outbreaks are being reported across the Horn of Africa with an estimated 10,000 people hit by dengue fever in the Kenyan town of Mandera.

The UN's Office for the Coordination of Humanitarian Affairs reported Tuesday that outbreaks of malaria and dengue fever are increasing in northern Kenya.

Malaria infections are caused by mosquitoes breeding in standing water left by the heavy seasonal rains and dengue fever, a tropical disease, also is spread by mosquito bites.

OCHA said cases of measles also are rising in the Dadaab refugee camp, a sprawling expanse of temporary homes for almost 500,000 Somalis in eastern Kenya.

It said an estimated 7,000 to 8,000 cases of measles also are being reported in central and southern Somalia.