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Human trypanosomiasis in Ethiopia
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TRYPANOSOMIASIS SEMINAR
Mallam YESUFU has made further studies on the influence of the donor host on the ability oftrypanosomes to grow in artificial media, using 6 strains of T. congolense isolated from cattle in the course of a field survey. The donor animals were infected by syringe passage from the original rats inoculated in the field or from rats subinoculated from them. T h e following species were investigated: albino rats, albino mice, guinea-pigs, rabbits, dogs, sheep, goats and domestic pigs. There appeared to be no direct relationship between the infectivity and pathogenicity of the strains in the donor host and their ability to grow in culture. All 6 strains were infective to rats and mice, causing heavy infections in both species, and also to rabbits, sheep, goats and dogs. Only 3 were infective to guinea-pigs and 2 to domestic pigs. On sowing into artificial media, 5 of the 6 strains grew from rats and rabbits, 3 from mice and dogs and 2 and 1 from sheep and goats respectively. All 3 strains from guinea-pigs grew, as did both strains from pigs.
Human trypanosomlasis in Ethiopia* J. R. BAKER London School of Hygiene & Tropical Medicine AND
E. M c C O N N E L L U.S. Naval Medical Research Unit No. 3, Addis Ababa, Ethiopia Human trypanosomiasis had not been reported from Ethiopia until March 1967, when Dr. R. H. Marion and Dr. Assefa Tekle found 2 cases from the Akobo river west of Maji, in south-western Ethiopia. In December 1967 2 infections were diagnosed in persons living near Gambela on the river Baro, about 160 miles north-north-west of Maji, one by the U.S. Naval Medical Research Unit No. 3 (NAMRU-3) and the other at Pokwo Mission Hospital. Subsequently (March-Aug. 1968) 7 more persons from the same general area have been found to be infected. Two strains were isolated in rats by NAMRU-3 and stored at -70°C. : both were virulent to rats, pleomorphic with many posteronuclear forms, and resistant to tryparsamide (single inoculations to rats of 80 and 160 mg. per kg. body weight). This suggested that the infective organisms were Trypanosoma brucei rhodesiense. The only species of tsetse fly found around Gambela was Glossina morsitans: in this area most of the inhabitants live in a strip of cultivated land along the river banks, which has been cleared of the tsetse-infested woodland (mainly Acacia and Combretum spp,). Further south, between the Gilo and Akobo rivers, where most of the known infections were probably acquired, the vegetation is denser forest and G. pallidipes predominates, together with s o m e G. fgscipes and G. morsitans. The sporadic nature of the human infections and the ecology of the area, especially around Gambela, suggest that the disease is at present a zoonosis. 430 people living near Gambela were examined by the East African Trypanosomiasis Research Organization, by means of thick blood films, and the collection of blood on filter paper for the determination of IgM content and for indirect fluorescent antibody tests IFAT. No overt trypanosome infection was found: 129 specimens (30%) had raised IgM levels and 23 of these (5%) gave high titres in the IFAT. A fuller account of this work is in preparation. *These opinions and assertions are private to the authors, and are not tO be construed as official, or as reflecting the views of the Department of the Navy or of the naval service at large.
TRYPANOSOMIASIS SEMINAR
Mallam YESUFU has made further studies on the influence of the donor host on the ability oftrypanosomes to grow in artificial media, using 6 strains of T. congolense isolated from cattle in the course of a field survey. The donor animals were infected by syringe passage from the original rats inoculated in the field or from rats subinoculated from them. T h e following species were investigated: albino rats, albino mice, guinea-pigs, rabbits, dogs, sheep, goats and domestic pigs. There appeared to be no direct relationship between the infectivity and pathogenicity of the strains in the donor host and their ability to grow in culture. All 6 strains were infective to rats and mice, causing heavy infections in both species, and also to rabbits, sheep, goats and dogs. Only 3 were infective to guinea-pigs and 2 to domestic pigs. On sowing into artificial media, 5 of the 6 strains grew from rats and rabbits, 3 from mice and dogs and 2 and 1 from sheep and goats respectively. All 3 strains from guinea-pigs grew, as did both strains from pigs.
Human trypanosomlasis in Ethiopia* J. R. BAKER London School of Hygiene & Tropical Medicine AND
E. M c C O N N E L L U.S. Naval Medical Research Unit No. 3, Addis Ababa, Ethiopia Human trypanosomiasis had not been reported from Ethiopia until March 1967, when Dr. R. H. Marion and Dr. Assefa Tekle found 2 cases from the Akobo river west of Maji, in south-western Ethiopia. In December 1967 2 infections were diagnosed in persons living near Gambela on the river Baro, about 160 miles north-north-west of Maji, one by the U.S. Naval Medical Research Unit No. 3 (NAMRU-3) and the other at Pokwo Mission Hospital. Subsequently (March-Aug. 1968) 7 more persons from the same general area have been found to be infected. Two strains were isolated in rats by NAMRU-3 and stored at -70°C. : both were virulent to rats, pleomorphic with many posteronuclear forms, and resistant to tryparsamide (single inoculations to rats of 80 and 160 mg. per kg. body weight). This suggested that the infective organisms were Trypanosoma brucei rhodesiense. The only species of tsetse fly found around Gambela was Glossina morsitans: in this area most of the inhabitants live in a strip of cultivated land along the river banks, which has been cleared of the tsetse-infested woodland (mainly Acacia and Combretum spp,). Further south, between the Gilo and Akobo rivers, where most of the known infections were probably acquired, the vegetation is denser forest and G. pallidipes predominates, together with s o m e G. fgscipes and G. morsitans. The sporadic nature of the human infections and the ecology of the area, especially around Gambela, suggest that the disease is at present a zoonosis. 430 people living near Gambela were examined by the East African Trypanosomiasis Research Organization, by means of thick blood films, and the collection of blood on filter paper for the determination of IgM content and for indirect fluorescent antibody tests IFAT. No overt trypanosome infection was found: 129 specimens (30%) had raised IgM levels and 23 of these (5%) gave high titres in the IFAT. A fuller account of this work is in preparation. *These opinions and assertions are private to the authors, and are not tO be construed as official, or as reflecting the views of the Department of the Navy or of the naval service at large.