Epidemics
There have been two epidemics of o’nyong’nyong fever. The first occurred from 1959 to 1962, spreading from Uganda to Kenya, Tanzania, Zaire (Democratic Republic of the Congo), Malawi and Mozambique, and affecting over two million people. This was one of the largest arbovirus epidemics recorded. The first virus isolates were obtained during this outbreak from mosquitoes and human blood samples collected from Gulu in northern Uganda in 1959.
The second epidemic in 1996-1997 affected 400 people and was confined to Uganda. The 35-year hiatus between the two outbreaks and evidence of an outbreak in 1904-1906 in Uganda indicate a 30-50 year cycle for epidemics.
Read more about this topic: O'nyong'nyong Virus