O'nyong‐nyong Fever in South‐Central Uganda, 1996–1997: Description of the Epidemic and Results of a Household‐Based Seroprevalence Survey

Abstract

O'nyong-nyong (ONN) fever, an acute, nonfatal illness characterized by polyarthralgia, is caused by infection with a mosquito-borne central African alphavirus. During 1996-1997, south-central Uganda experienced the second ONN fever epidemic ever recognized. During January and early February 1997, active case-finding and a household cluster serosurvey were conducted in two affected and two comparison areas. A confirmed case was defined as an acute febrile illness with polyarthralgia occurring within the previous 9 months plus serologic confirmation or isolation of ONN virus from blood. In affected (n=129) and comparison (n=115) areas, the estimated infection rates were 45% and 3%, respectively, and the estimated attack rates were 29% and 0%, respectively, for an apparent:inapparent infection ratio of nearly 2 in affected areas. In villages sampled near Lake Kijanebalola, Rakai District, the estimated infection and attack rates were 68% and 41%, respectively, and 55% of sampled households had >/=1 case of ONN fever. In conclusion, this epidemic was focused near lakes and swamps, where it was associated with high infection and attack rates.

The Role of Innate versus Adaptive Immune Responses in a Mouse Model of O'Nyong-Nyong Virus Infection

“…[1][2][3][4][5][6] O'nyong-nyong virus has caused three major outbreaks of disease in Africa. [7][8][9][10] The first occurred in Uganda in the late 1950s and early 1960s and affected over 2 million people. 7 The last two outbreaks occurred in 1996 and 2003, affecting tens of thousands of people.…”

“…7 The last two outbreaks occurred in 1996 and 2003, affecting tens of thousands of people. [8][9][10][11] O'nyong-nyong virus causes a similar syndrome to CHIKV, Ross River virus (RRV), and other Old World arthritic alphaviruses, characterized by fever, rash, debilitating arthralgia, and myalgia. [7][8][9][10][11] The disease is self-limiting and lasts a few days, though some patients have more persistent arthrlagia.…”

“…[8][9][10][11] O'nyong-nyong virus causes a similar syndrome to CHIKV, Ross River virus (RRV), and other Old World arthritic alphaviruses, characterized by fever, rash, debilitating arthralgia, and myalgia. [7][8][9][10][11] The disease is self-limiting and lasts a few days, though some patients have more persistent arthrlagia. 12 In contrast to CHIKV, which has recently been shown to produce neurologic manifestations and death in some individuals, ONNV is not known to cause fatal disease.…”

“…Furthermore, it is difficult to distinguish antibodies generated in response to ONNV versus CHIKV infection because of nearly complete cross-reactivity. 9,13 This difficulty with serodiagnosis is particularly important because control measures differ for ONNV and CHIKV as a result of the different genera of mosquitoes that serve as vectors.…”

O'nyong-nyong Virus, Chad

“…ONNV (family Togaviridae, genus Alphavirus) was first isolated from human blood and anopheline mosquitoes in Gulu, Uganda, in 1959 (4) and has been responsible for several outbreaks in humans that occurred in East Africa (Kenya, Uganda, Tanzania, Malawi, Mozambique). Fever, headache, joint pains, and rash were the principal signs and symptoms (5,6). Virus isolations from human and animal sera as well as from Anopheles funestus and A. gambiae have been reported in East Africa (7,8).…”