The ethiopian

DISCUSSION

irrigation and lake ecologies pose considerable threats regarding transmission intensity and ecological health impacts. Although precise comparison of data is difficult due to the inequality of the sample populations studied in the three ecologies, it seems that infected individuals in the stream and irrigation transmission ecosystems have lower intensities of infections in terms of geometric mean egg output, despite relatively high infection rates in humans. In contrast, those from the lake ecology exhibited exceedingly high prevalence and intensity of infection. It was noted that geometric mean egg counts exceeded a thousand in the 15-19 age group among the inhabitants of the lake region, compared to about 400 eggs/g for the same age group among the inhabitants of the stream and irrigation settings. Ongom and Bradley (21), in their study of a fishing community of Panyagoro, West Nile (Uganda) observed extremely high human prevalence and intensity of infection which persisted throughout adult life similar to our Lake Zway community .

activities such as fishing may lead to heavy schistosomal transmission. In the lake regions of Ethiopia, including lake Zway, fishing is predominantly carried out by young male adults using locally made wooden or papyrus boats and nets. This may subject them to long hours of exposure to water. Hence, the high intensity of infection observed among the infected residents of the lake ecology should primarily be attributed to the intensity of human exposure to infective water. However , since S. mansoni transmission is effected by B. sudanica in the lake ecology and by B. pfeifferi in the others, possible occurrence of different parasite strains could be an additional factor resulting in different host-parasite relationships.

contamination of the environment more significantly than their counterparts in the other ecologies, owing to the reports of persistently high prevalence and intensity of infection among this age group in the area. This has significant implications in designing control measures. For instance, selected group chemotherapy of those below 20 years of age may be sufficient to significantly reduce morbidity and transmission in the stream and irrigation ecologies while, for similar purposes, mass chemotherapy may be warranted in the lake ecology . Limited quantitative studies by Polderman (23), Hiatt (24), Hiatt and Gebre-Medhin (25) and Birrie (26) have shown low intensities of infection among subjects, including school children, living in stream environments despite high prevalence rates. In Chewahit (a northwestern Ethiopian community with prevalence of 42% ) Polderman (23) could neither observe high egg output, even among the school age children, nor relate tile presence/absence of eggs to human exposure to infective water. The absence of major illness among subjects living in stream ecologies have been shown by Jordan and Webbe (20). With the higher rates of prevalence in Chewahit (42%) (23) and Jigga (41% ) (in this study) higher levels of egg excretion would be expected. Therefore, the apparently light infections and absence of major illness characterizing stream-based mansoni transmission in this country remain unclear at the moment. However, our findings regarding the indices of infection in the irrigation ecology should be interpreted with caution. From being only a rare disease in the 1960 on (5-7), schistosomiasis mansoni has now surfaced as a serious health threat in the Metahara Sugar Estate. In the relatively older Wonji Sugar estate, alarming levels of prevalence and possible intensities of infection (24) have been registered. This means that it may be a matter of time for the situation in Metahara irrigation scheme to show a similar upswing. In general, whether these findings are representative of others in their respective ecologies or not should be resolved in the future through rigorous studies on the ecological basis of transmission, human water contact patterns, immunological status of infected subjects and the possible occurrence of different parasite strains in varying

ecological and cultural settings.

ACKNOWLEDGEMENTS

technical assistance.

REFERENCES

2.Lo, C. T , Hailu Birrie, and Teklemariom Ayele. Localities of Biomphalaria pfeifferi and Bulinus trancatus/tropicus -complex new for Ethiopia with epidemiological notes on new transmission foci of Schistosoma mansoni, S.haematobium and S.bovis. Unpublished data 1988.

3.TekLemariom Ayele. Distribution of schistosomiasis in Ethiopia. Results of 1978-82 survey. In proc. Schisto. Symp. Addis Ababa 1982; Nov. 1-4.

4. Teklemariam Yiman. Schistosomiasis at Wonji. Ethiop. Med. J., 1964; 2: 259.

5.Aklilu Lemma "Preliminary report on schistosomiasis survey at the HVA estate in Wonji". Institute of pathobiology. Unpublished data 1966.

6.Aklilu Lemma. 19 (b). "A report on schistosomiasis survey in Metahera " .Inst. of pathobiology, Int. report 1966.

7.Aklilu Lemma. "Studies on Bilharziasis in Wonji, Shos and Metahera sugar plantations, with recommendations for possible control measures to be taken by HVA company". Inst. of psthobiology. Int. report. 1968.

8.Aklilu Lemma. Bilharziasis in the Awash Valley: an epidemiological study with special emphssis on ita possible future economic and public health importsnce. Ethiop. Med. J., 1969; 7: 147-176.

9.Duncon, I., Aklilu Lemma. Investigation into the control of schistosomiasis at the HVA Wonji-Shoa Sugar Estates in Ethiopia. I. Initiation of the project. Ethiop. Med. J., 1976; 14: 3-15.

10.Kloos, H., Aklilu Lemma. Bilharziasis in the Awash valley. n. Molluscan fauna in irrigation farms and agriculture development. Ethiop. Med. J., 1974; 12: 157-173.

11.Kloos, H., Aklilu Lemma. Bilherzies in the Awash valley, ill. Epidemiological studies in Nura Era, Abedir Melka Sedi, and Amibera irrigation schemes. Ethiopi. Med. J., 19770; 15:

161-168.

13.ReddaTeklehaimanotand Goll, P.H. Investigationation the control of achil10aomiaail at the HV A Wonji-Shoa eltAtea in Ethiopil. 2. Interirn evaluation of the project. E/hip. Med. J., 1978; 16: 115-121.

14.BNijing, C.F.A. Bilharziasia in irrigation achemcs in Ethiopia. Trop. Geogr. Med., 1969; 21: 28().292.

15.Fekade Tsegaye, Getahun Abebe. preliminary shcistosome survey in Zway, Arossi, report 10 the Ministry of Health (mimeographed document) 1968.

16.Zaphiropoulol, D.M. Preliminary observations on bilharziasil in Lake Tana, Ethiopil and on the treatment of Schistosome mansonl infectiona with Miracle. Gonder Hlth. Ser. Tech. Rep., 1963; 7: 27-33.

17.Polderrnan, A.M. Intc8Iinal achil10aomiasil north and west of Lake Tana, Elbiopil. Trop. Geogr. Med., 1974; 26: 170-177.

18.Tcklemariam Ayele and Tesfamichael Tesfa Yobannes. Epidemiology of Schistosoma mansonl around Lake Zway and its islands, Ethiopia. Ethiop. Med. J., 1982; 25: 133-139. 19.Petera, PS, EJ-A1amy, M. and Warren K.S. Quick Kalo smear for field quntitation of Schilloaomc manaoni eggs. Am. J. Trop. Med. Hya., 1980; 29, 217-219.

20.Jordan, P. and Webbe, G. Schistosomiasis; Epidemiology, Treatment and control. Williham Heincma Medical Books Lld., wndon 1982. (361 Pp).

21.Ongom, V.L, and Bradley, D.J. The epidemiology and consequence. of Bchlstosoma mansoni infectiona in West Nile, Uganda. I. Field studies of a community at Panyagora. Trans. Roy. Soc. Trop. Med. Hyg., 1972; 66: 835-851.

22.Kloctzcl, K. Spleno~..lyin achil10aomiasilmanaoni. Am. J. Trop. Med. Hya., 1962; 11: 472-47

23.Polderrnan, A.M. The tranamission of inteltinal achil10aomiasil in Bcgemnder Province, Ethiopil. Final report- Lab. of parasilology, Lcidcn, Netherlands 1975. (159 Pp)

24.Hiatt,RA. Morbidity from Schil10aoma manaoni infectiona: and epidemiologioal study based on quantitative analysis of egg excretion in two highland Ethiopiln villages. AM. J. Trop. Med. Hyg., 1976; 25: 808-817.

25.Hiltt, R.A, 8nd Mehari Gebremedhin. Morbidity from Schistoaoma manaoni infectiona: an epidemiological study based on quantitative elg excretion in Ethiopil. Am. J. Trop. Med. Hyg., 1977; 2: 473-481.

26.Hailu Birrie. Survey of SChislosomlasls mansoni in the Borkena river basin, Ethiopia. Elhlop. Med. J., 1986; 24: 159- 167.

27.Daniel Fedade, Feksdu Abebe, Hailu Birrie, Shibru Tedla, and Teklemariam Ayele. A community based morbidity study of achilloaomias; naoni in relation 10 intenaity of infection in Jigga, Ethiopil. Institute of Pathobiology. Unpublished data 1988.

COMPOSITE FLOUR DEVEWPMENT FOR INJERA
Haregewoin Cherinet, S.R.N, BSc, MPH
ABSTRACT: A composite flour has been developed to simulate an expensive cereal grain, tef (Eragrostis tef) for making injera, by incorporating cheaper grains. Sixty four combinations were baked, their physical characteristics and shelf-life tested. The results were statistically analyzed using mean scores of texture, elasticity , and reconstitution properties. The triangle and duo-trio tests were used for panel selection; paired

comparison preference and declared control difference tests were employed for sensory evaluation, and the best composite flour to imitate tef was a combination of [tef 35% wheat (Triticum durum) 25% and sorghum (Sorghum vulgare) kafir group 40%]. The nutritive value of the new product correspond with that of tef and a 27% cost reduction was accomplished for each injera. [Ethiop. J. Health Dev. 1993;7(2):71-77]