In a fairly large series in which a parasite resembling A. perstans was found, no serious lesions or effects were noted. The spinal fluid in 22 cases was normal in all respects. Joint pains were perhaps the most significant finding in the history. A skin test was carried out on 30 Africans with positive blood and found positive in all. There was eosinophilia in 80%, mostly mild to moderate in degree but in this environment its significance is uncertain. No variation in the number of parasites appearing in the peripheral blood could be elicited over a 48-hour period. Diethylcarbamazine and metronidazole did not affect the course of the parasitaemia in 2 patients carefully observed in Salisbury and removed from their original environment. © 1969 Oxford University Press.