A 38-year-old man who had stayed in Brazzaville, Congo from 19 January, 1970 to 28 December, 1970 developed fever with chills on 14September. Anti malarial drugs had been prophylactically adminstered regularly during his stay in Congo and for a month after his return to Japan.
On 17 August 1971, he was admitted to our hospital for the operation of a pituitary tumor. He was operated on 20 August, and received irradiation since 1 September. On 14 September noticed chills and fever after two days' diarrhea. From 15 September he repeated febrile episodes, of so-called tartian-like type. On 20 September, thin blood smears stained with Wright at pH 6.4 revealed malarial parasites.
These parasites occupied about one half of the host erythrocytes. Schizont contained five merozoites on the average. The shape of the host erythrocytes were typically oval or fimbriaten. The typical Schüffner's dots were not clearly observed, but the over-stained films with the same Wright proved the existence of stipplings with dark colour in host erythrocytes. Though these dots may be disputed, these observations strongly suggested the diagnosis of plasmodium ovale. Parasitemia count was 13560/cmm. Erythrocyte count was 339 × 10⁴/cmm, Hb was 11.2 g/dl. CRP was 21.5 mg/dl. The urinalysis showed strongly positive reaction of urobilinogen. After chloroquine therapy (total 1500mg base) and sulfamonomethoxine (total 5 g), parasitemia disappeared. Radical cure with primaquine 15 mg/day and sulfamonomethoxine 1 g/week was continued for 4 weeks.
He was transfused at his operation, but the donors had not been exposed to malaria.
A case of ovale malaria at the Tenri Hospital acquired in West Africa was described. Delayed primary attack occurred 8 months after his exposure to malaria. Four cases of P. ovale have been published in Japan. Three cases were concerned with malaria acquired in Korea before the World War II, and a case acquired in New Guinea after the World War II.
As far as west african ovale malaria is concerned, the case reported herein is probably the first in Japan.