Original source: Isolated by B. M. McIntosh at S.A.I.M.R., Johannesburg, from 250 adult female Culex pipiens collected 8 January 1963 with solid CO2 baited traps at Olifantsvlei, Johannesburg, S. Africa, Lat. 26°S, Long. 28°E. Habitat: Grassland plateau, 1,500 m in elevation, with riverine reed bed at ground level. Storage: Frozen on dry ice.
Method of isolation in laboratory: Mosquitoes ground in 0.75% bovine albumin solution. Inoculated 0.02 ml ic into 2-day-old mice.
Validity of isolation: Reisolation not tried, but AR5 133 immunologically distinct from other viruses in laboratory; other isolations from mosquitoes made elsewhere in Africa.