O'nyong-nyong fever: An epidemic virus disease in East Africa

1) The virus responsible for the epidemic of o'nyong-nyong (ONN) fever has been isolated from the serum of a febrile patient. 2) Using 1-day-old mice, isolation was achieved by inoculation of diluted serum and diluted brain passage material. 3) O'nyong-nyong virus is an arthropod-borne virus belonging to the Group A of Casals and Brown, and is closely related to chikungunya virus. 4) Plaque inhibition tests in tissue culture have shown it to be distinct from chikungunya virus. 5) A patchy alopecia was noticed in some of the inoculated mice, and was shown to be associated with ONN virus infection; it is suggested that such hair changes in mice may be of value as indications of other arthropod-borne virus infections.