Control of Biomphalaria pfeifferi population and schistosomiasis transmission in Ethiopia using the soap berry endod (Phytolacca dodecandra), with special emphasis on application methods.

The endod (Phytolacca dodecandra)-based schistosomiasis mansoni control project was implemented in Ethiopia between 1994 and 1999. The aim was to develop an effective, cheap and sustainable method of controlling schistosomiasis. First, different formulations of the Ethiopian endod strain 44 (E-44) were compared for potency in the laboratory. Secondly, spray and drip-feeding methods were compared for simplicity and effectiveness in the field. Lastly, the efficacy of endod powder soap was compared with the endod spray method. In Bati stream, endod powder soap was distributed to the residents every weekend at laundry sites. In Worke stream, endod was sprayed along a 1-km stretch of the stream at 3-month intervals. No endod was applied in Harbu stream. The immediate and long-term effects of endod application on the snail population and schistosomal infection were determined. Using the spray method, 100% snail mortality could be obtained, and it was simpler and more effective than the drip-feeding method. Snail mortality ranged from 20 to 100% using endod soap. There was a progressive decline in the snail population and infection in Bati stream compared with Worke stream, mainly due to sustained use of endod soap. The advantages and disadvantages of the different endod delivery systems are discussed.

The use of DNA hybridization for the detection of Leishmania aethiopica in naturally infected sandfly vectors.

Hybridization with kinetoplast deoxyribonucleic acid (kDNA) probes was used to detect Leishmania aethiopica in naturally infected sandflies in south-west Ethiopia, an endemic area for cutaneous leishmaniasis. 396 sandflies were dissected; microscopy revealed flagellates in the midgut of 5 Phlebotomus pedifer. The infecting flagellates were confirmed as L. aethiopica by isoenzyme typing. Gut specimens for all dissected sandflies were hybridized with total L. aethiopica kDNA as well as with a cloned kDNA probe specific for L. aethiopica. Samples from sandflies which were found to be infected microscopically also hybridized with the L. aethiopica kDNA probes. One additional sandfly hybridized but was not shown to be infected by microscopical examination. Hybridization experiments with 65 whole squash-blotted sandflies gave results that correlated very well with results obtained using microscopy. Our results indicate that DNA probing is a useful method to detect Leishmania infection in sandfly midguts as well as in whole squash-blotted sandflies, and can be used to follow changes of infection rate. DNA probing is therefore an alternative to microscopy in large-scale epidemiological studies as well as monitoring control programmes aimed at human leishmaniasis.

Cutaneous leishmaniasis in south-western Ethiopia: Ocholo revisited.

The borough of Ocholo, on the western side of the Ethiopian Rift Valley, is an endemic focus for Leishmania aethiopica infection and has been surveyed thrice between 1987 and 1990. In 1989, 3022 inhabitants (> 95% of the population) were interviewed and examined. The overall prevalence of localized cutaneous leishmaniasis (LCL) was 3.6-4.0%, with a peak value of 8.5% in the 0-10 years old age group. In half of the patients the active disease was estimated to last for 9.6 +/- 6 months; in 10%, it exceeded 3 years. Scars of LCL were present in 34.3% of the residents. Leishmanin skin tests were positive in 54% of 120 school-children without signs of the disease. Therefore, in Ocholo a minimum of 71.6% of the population has been exposed to L. aethiopica infection. Two cases of the diffuse form of cutaneous leishmaniasis were observed. In this highland biotope, Phlebotomus pedifer was found to be the major, and possibly the only, vector for L. aethiopica.

Detection of Plasmodium falciparum sporozoites in naturally infected anopheline species using a fluorescein-labelled DNA probe.

A dot blot hybridization method was developed to detect Plasmodium falciparum sporozoites in naturally infected mosquitoes. A fluorescein-labelled oligomer was used as a probe. Initial non-specific hybridization was found to correlate with the presence of blood in the mosquitoes. This was eliminated by allowing digestion of the engorged blood by keeping the mosquitoes in cages for 48 h before processing. The limit of detection of the hybridization assay was estimated to be about 500 sporozoites. The assay was evaluated on 198 indoor resting blood fed female Anopheles gambiae s.l mosquitoes collected from three malaria hypo- and meso-endemic areas in Ethiopia. An application of the polymerase chain reaction (PCR) amplifying a fragment of the K1-14 gene of P. falciparum was used as a reference method. P. falciparum sporozoites were detected in four specimens (2%) by hybridization assay and by PCR alike. The results of this study indicate that the hybridization method can be potentially valuable in large scale epidemiological studies for detection of P. falciparum sporozoites in naturally infected anopheline species.

Praziquantel side effects and efficacy related to Schistosoma mansoni egg loads and morbidity in primary school children in north-east Ethiopia.

A total of 611 Schistosoma mansoni infected primary school children from three schools in north-east Ethiopia were treated with praziquantel at 40 mg/kg body weight in a single dose. Pre-treatment, 40.4% had no presenting symptoms and 30-40% had nausea, abdominal cramps and/or bloody-mucoid diarrhoea. None of the pre-treatment symptoms was related to nutritional status, intensity of S. mansoni egg excretion, or to the presence of other concomitant intestinal parasitic infections. During the first 4-6 h post-treatment observation period, 90 (14.7%) children self-presented with severe gastro-intestinal symptoms. Children who self-presented with severe symptoms had a higher mean age and mean S. mansoni egg excretion compared with children who did not self-present. The following day a total of 529 (86.6%) children, including all who self-presented during the first 4-6 h post-treatment, reported for clinical check-up and were subjected to a structured questionnaire interview on symptoms they had experienced over the time lapse following treatment. Among these, 91.5% reported one or more treatment related symptoms which were at times severe. Abdominal cramps (86.9%), diarrhoea with blood and/or mucus (49.5%), dizziness (31.2%) and vomiting (24.9%) were the most common treatment related symptoms. Skin rash with oedema were observed in four cases. Among treatment related symptoms, the combination of abdominal cramps with vomiting, bloody diarrhoea, vomiting alone and general weakness were significantly higher among the malnourished. A proportion of these symptoms increased with increasing categories of S. mansoni egg excretion before and after adjusting for nutritional status and concurrent intestinal parasitic infections. Overall, the cure rate of praziquantel, among 541 children who had stool examination 5 weeks after treatment was 83.2% and this rate decreased with increasing pre-treatment egg counts. In conclusion, most of the treatment related symptoms were mild. However, some of the objective symptoms were at times severe and may reduce drug compliance in primary health care based population chemotherapy.

Transmission of intestinal schistosomiasis in Addis Ababa, Ethiopia.

Malacological and parasitological surveys were made in Bole-Kotobe area in Addis Ababa in April 1996 to investigate the transmission of intestinal schistosomiasis. Malacological survey conducted in Kotobe river showed Schistosoma mansoni cercarial infection rate of 2.6% (one out of 38) in Biomphalaria pfeifferi. In a total of 197 stool specimens from school children examined using Kato thin smear method in Misrak Bar Number 1 and Wondirad Elementary and Junior Secondary Schools, the overall prevalence rate of Schistosomas mansoni was 4% and 10%, respectively while the intensity of infection was 66 and 37 eggs per gram (EPG) of stool, respectively. Out of the 13 children found infected in the two schools, nine gave a history of having swam in Kotobe river and had never been outside of Addis Ababa since birth. The collection of B. pfeifferi infected with S. mansoni, the establishment of the isolated S. mansoni in laboratory mice and the finding of schistosome infected children who had never been outside of Addis Ababa confirmed that transmission of intestinal schistosomiasis is actually taking place in Addis Ababa. Further surveys in other water-bodies in the city for mapping of schistosomiasis infection sites and transmission foci are recommended to enable immediate control measures before the situation gets out of control.

Crohn's disease: report of seven cases from Ethiopia.

Crohn's disease is rare in Africa. We present the clinical features, surgical management and the histopathological findings of surgical specimens of seven cases of Crohn's disease.

Use of Leishmania major derived leishmanin for skin test surveys of visceral leishmaniasis in Ethiopia.

The potential use of Leishmania major derived leishmanin in surveys of visceral leishmaniasis (VL) was examined. The study was conducted in Konso sub-district, southwest Ethiopia involving 51 VL patients, 18 VL contacts, four localised cutaneous leishmaniasis (LCL) cases and 15 healthy controls. Sixty three percent of treated VL patients, 44.4% of VL contacts, all of LCL cases and none of untreated VL patients were positive to the test. Leishmanin skin test (LST) induration sizes of 41 treated VL patients were in the ranges of 0 to 10 mm, with a mean of 4.9 mm. The mean induration size and the positive LST rates in female patients were found to be significantly lower than in males. The major drawback of the antigen in the survey was the relatively smaller and flatter indurations. The relationship of LST to gender and leishmanial disease variant is discussed.

Control of Schistosoma mansoni by the soapberry Endod (Phytolacca dodecandra) in Wollo, northeastern Ethiopia: post-intervention prevalence.

OBJECTIVES: To record the effect of Endod soap and spraying of soaked Endod suspension on the prevalence of human schistosomiasis. DESIGN: A cross-sectional epidemiological study in which pre- and post-intervention parasitological results were compared. SETTING: Kemise, Bati and Harbu towns in northeastern Ethiopia. SUBJECTS: The study subjects included all members of the five per cent households systematically selected from the three towns. RESULTS: In Kemise town, where suspension of ground Endod was sprayed on the stream containing infected snails, the prevalence of the disease was reduced from 59% to 53% and the mean intensity of infection was reduced from 239 eggs per gram (EPG) of faeces to 99 EPG (p < 0.05). In Bati town where Endod soap approach was used, the respective reduction in the prevalence and intensity of infection was from 51% to 43% and from 195 EPG to 162 EPG (p < 0.05). There was also a significant reduction of the disease in the control town probably due to the effects of praziquantel treatment and other factors. CONCLUSION: The reduction achieved in the prevalence and intensity of schistosomiasis after an intervention period of four years was limited. This observation corroborates the fact that molluscicides must always be considered as supplementary to chemotherapy in the control of schistosomiasis. Although both approaches can be used, the spraying approach appears to be simpler and more feasible because two or three times yearly application of Endod suspension would suppress snail population and reduce transmission. Nevertheless, the choice as to what approach to use must be made on the basis of community preference, and for some soap-effect of Endod would be attractive

Epidemiology of schistosomiasis mansoni in three endemic communities in north-east Ethiopia: baseline characteristics before endod based intervention.

As part of a pre-intervention baseline data collection the epidemiological characteristics of schistosomiasis mansoni were studied in 3 endemic communities (Kemise, Harbu and Bati towns) in northeast Ethiopia in April and May 1994. The objective was to generate data based on which post-intervention differences (in changes), if any, in transmission level could partly be explained for the 3 towns. After calculating the sample size required for each town 132, 75, 158 households were selected by systematic random sampling from Kemise, Harbu and Bati, respectively and all members of the selected households stool was examined by the Kato's thick smear method. Eighty eight and 85% of the houses harboured one or more cases of Schistosoma mansoni in Kemise and in Bati, respectively, all members of the households being positive in 27% in Kemise and in 28% in Bati. The overall prevalences were 59%, 33% and 51% in Kemise, Harbu and Bati, respectively, with the corresponding geometric mean egg counts (epg) of 240, 123 and 195 for positives and 26.5 and 15 for the whole populations. All ages combined, there were no significant differences due to sex both in prevalence and intensity of infection. By age, children in the 10-14 years age group were most affected (p = 0.007), their prevalences reaching 86%, 52% and 66% in Kemise, Harbu and Bati, respectively and their corresponding geometric mean epg being 377, 157 and 401, respectively. Heavy infection (> 100 epg) reached 42%, 32% and 16% in Kemise, Bati and Harbu, respectively, reaching an average of 55% among the 10-14 years of age. The implications of the epidemiological findings and the possible use of the household approach for rapid assessment of schistosomiasis magnitude in an area are discussed.