Ultrasonography in schistosomiasis in Africa.

Approximately 50 publications have become available in the international literature on ultrasonography in schistosomiasis in Africa. Geographically these cover Congo, Egypt, Kenya, Mali, Mauritius, Niger, Senegal, Sudan, Tanzania and East African Islands as well as Zimbabwe. Further studies are ongoing in many countries, such as Burundi, Ghana, Madagaskar and Uganda. It was shown that ultrasonography is useful in the detection of morbidity induced by schistosomiasis on an individual basis and on the community level. There is indication for varying morbidity patterns in different African foci. Post-treatment monitoring has provided evidence for reversibility of pathological lesions induced by Schistosoma (S.) haematobium and S. mansoni, even though evidence for reversibility of periportal fibrosis in adults is not yet satisfactorily substantiated. A standardized set of criteria for ultrasonographical observations has been worked out and is presently in the process of being refined. It is thus hoped that standardization will contribute to render studies in different endemic settings comparable on a global basis.

Ultrasonography of ureteric abnormalities induced by Schistosoma haematobium infection before and after praziquantel treatment.

OBJECTIVE: To describe the ultrasonographic appearance of ureteric lesions due to Schistosoma haematobium infection and to report prevalence rates of such lesions in endemic communities in Mali before and after praziquantel treatment. SUBJECTS AND METHODS: The total population (n = 961) of three S. haematobium-endemic villages in Mali was examined ultrasonographically to detect urinary tract morbidity. Urine was tested for S. haematobium ova and for haematuria. An identical follow-up study was performed 1 year after mass treatment with praziquantel. RESULTS: Prevalence rates of S. haematobium infection in the three villages were 53%, 72% and 73%. Ultrasonography revealed dilatation of the ureters in 143 subjects (15%). In 20 of these, mainly children and adolescents, thickening and irregularities of the ureteric wall with distal ureter obstruction were directly visualized on ultrasonography. Within the bladder of two others, an intraluminal structure of ureterocele-like appearance was seen. None of these alterations has been previously described as an ultrasonographic feature of schistosomal uropathy. Active S. haematobium infection and microhaematuria were found in 21 and 20 of these 22 subjects respectively. Significant renal obstruction was present in 10 of them. One year after treatment, an entirely normal urinary tract was found in 85% of 104 re-examined individuals who had had ureter dilatation. Ureteric wall thickening or ureterocele-like lesions had disappeared in 95% of subjects. CONCLUSIONS: The role of ultrasound in the evaluation of schistosomal uropathy is confirmed. Ureteric wall abnormalities causing strictures and ureterocele-like lesions of the ostium must be regarded as further ultrasonographic features of this condition. The study documents the excellent reversibility of ureteric abnormalities after antischistosomal treatment in children and adolescents, thus emphasizing the need for early and efficient medical treatment of the infection.

Urban Schistosoma mansoni near Enyau river in Arua town, Uganda.

Using the Kato Katz method for quantification of parasitic eggs in faeces, 500 individuals aged between 4 and 50 years, living along River Enyau, half a kilometre from Arua town, were studied to assess the prevalence of Schistosoma mansoni in the population. The overall prevalence of Schistosoma mansoni infection was 62%. The infection was highest among school children (71.1%, i.e. 199 out of 280). Villagers who lived along the immediate vicinity of the river had a 62.8% prevalence of infection (98 out of 156). School teachers and the members of their families had the lowest infection rate (20.3% i.e. 13 out of 64). The geometric mean egg output for males and females in the community studied was 203 and 179 eggs per gram of stool, respectively. 206 (41%) out of 500 individuals had mixed infections of S. mansoni and hookworms. The rate of orally transmitted intestinal helminths like Trichuris trichiura was very low (0.8%). Ascaris lumbricoides eggs were not found.

Evidence for the occurrence of Schistosoma intercalatum at Albert Nile in northern Uganda.

During a field investigation in Rhino Camp at Albert Nile in northern Uganda, 77.8% of 636 persons excreted Schistosoma mansoni ova that were detected by the Kato-Katz method. Six patients, 8-17 years of age, had terminally spined schistosome eggs in their stools. These findings were confirmed when preserved specimens were examined at the Institute of Medical Parasitology in Bonn using a concentration technique. The mean +/- SD length of 36 terminally spined eggs was 156 +/- 6 microns and the mean +/- SD width was 59 +/- 3.6 microns. Urine filtration in the study patients revealed no schistosome eggs in the urine. It is concluded that these findings provide evidence for the occurrence of S. intercalatum at Albert Nile in northern Uganda.

Sonographical morphometrical findings of the liver and spleen in Sudanese patients with Schistosoma mansoni induced periportal fibrosis.

Sonographic measurements of the liver, spleen and related blood vessels were performed in 87 healthy controls and in 50 patients with periportal fibrosis (pF) as well as in 52 patients with pF and at least one episode of gastro-oesophageal bleeding due to chronic Schistosoma mansoni infection. There was a progressing shrinkage of the liver paralleled by an increasing rate of patients with a larger left than right liver lobe as involvement of pF due to S. mansoni infection progressed. This was accompanied by an increasing percentage of pathological gallbladder wall enlargement, splenomegaly and an increasing portal vein diameter. It is suggested that organomorphometrical parameters of the liver and spleen can be used for sonographical evaluation of patients with S. mansoni infection as these may be useful for their clinical assessment of the progression of disease.

Transmission of Schistosoma mansoni in Rhino Camp, Uganda.

Non-participant observations totalling 204 hours relevant to the transmission of Schistosoma mansoni infection were carried out in Rhino Camp at the shores of Albert Nile in North Uganda. A cross-sectional study of 636 individuals from Rhino Camp revealed a prevalence of S. mansoni infection of 77.8%. Occupational and domestic purposes were the most important reasons for water contact, whereas recreational purposes ranked lower and mainly concerned children. Both sexes were equally active in water contacts. A distinct preference of Nile water was noted despite availability of borehole water in the area. It is concluded that control measures against schistosomiasis have to take into consideration that water contact for recreational purposes might be minimized, whereas it is expected to be extremely difficult to reduce occupational and domestic water contacts.

PIP: Rhino Camp is one of the most important fishing and farming villages along the shores of Albert Nile in West Nile Province, Uganda. Ajagoro and Diova water contact sites were selected to observe water contact activities in November 1991 for 17 days during the rainy season. Cumulatively, 204 hours of observations during all times of the day were done by 2 experienced persons. The observation period covered 12 hours a day. Water contact activities were recorded up to 10 times per hour, 11-20 times per hour, and more than 20 tines per hour. A total of 157 individuals, 5-50 years old, were interviewed about tribal origin, reasons for water contact, previous status in exile, and attitudes towards Nile water. 636 individuals consisting of 155 school children, 208 fishermen and families, 247 individuals seeking admission to the study and 26 officials provided up to 2 stool samples. Fishing and water fetching was the most frequent reason for water contact at the sites. Water activities were highest in the morning and early afternoon and decreased markedly towards the evening. Children, fishers, subsistence cultivators, business people, and civil servants were involved in water activities. Children 5-9 years old were few, but individuals 10-39 years old had the highest frequencies of water contacts. A considerable proportion of observed water contacts were made by people who had been exiled from Zaire or Sudan. Individuals 10-39 years old made water contacts almost exclusively for domestic and economic reasons. Those below 5 years old came for recreational purposes. Prevalence of S. mansoni infection was 77.8% in the cross-sectional survey performed in 636 individuals. 5.5% of those had more than 500 eggs per gram stool. Little is known about the impact of water contact activities on the intensity of schistosomiasis in the area. Therefore, further ecological research is needed for future control of schistosomiasis at the community level along the river Nile.

Epidemiology, immunology and chemotherapy of Schistosoma mansoni infections in a recently exposed community in Senegal.

Schistosoma mansoni was introduced in the Richard Toll area (Senegal) around 1988, probably due to man-made ecological changes in the Senegal river basin. Since 1991, we investigate the community of Ndombo, close to Richard Toll. Four random population samples of approximately 400 subjects are surveyed, starting at 8 months intervals. Each cohort is examined parasitologically (Kato-Katz), clinically, serologically (circulating antigen and antibody profiles); treated with praziquantel 40 mg/kg; and followed up 6-12 weeks, 1 and 2 years after treatment. Water contact patterns and snail densities are longitudinally surveyed. In the first cohort, prevalence of infection was 91%, with 41% excreting over 1000 eggs per gram (epg); the mean egg count was 646 epg, individual counts up to 24,000 epg. Prevalences remained almost 100%, but egg counts declined strongly in adults, in spite of continued exposure and the supposed lack of acquired immunity. Antigen detection in serum and urine confirmed that the egg counts genuinely reflect variations of worm burdens. Serum circulating anodic antigen (CAA) provided intriguing epidemiological information on worm burdens, while circulating cathodic antigen (CCA) showed promise for non-invasive diagnosis and screening. So far, similar epidemiological results were found in subsequent cohorts, although some variations were observed, possibly due to seasonal transmission fluctuations. IgE levels increased with age, while IgG4 peaked in the age-group 10-19 years. IgE and IgG4-levels against adult worm antigen (AWA) and soluble egg antigen (SEA) increased between cohort 1 and cohort 3 in almost all age-groups. In all 3 cohorts examined so far a strong correlation between IgG4 and pre-treatment egg-load was observed. Further follow-up and analysis, and comparison with chronically infected populations will provide insight in the development of acquired immunity. Abdominal discomfort was reported by 61% and diarrhoea by 33% of the subjects in the first cohort; mild hepatomegaly was found in 16%, splenomegaly in 0.5%. There was no correlation between frequency of symptoms and egg counts. This low morbidity, in spite of intense infections, was confirmed by ultrasound, and may be due to the recent nature of the focus. In the first cohort, 82% of treated subjects still excreted eggs 12 weeks after treatment, though egg counts declined strongly. Antigen detection confirmed these results. Parasitological negativation rates in subsequent cohorts, followed up sooner after treatment, improved but remained remarkably low. The low drug efficacy may be due to very rapid reinfection (though further reinfection after one year was limited), and/or to the lack of immunity in the population. Reduced susceptibility of the local schistosome strain can not be excluded, however. Praziquantel treatment provoked impressive but transient side effects (colics, vomiting, urticaria, oedema), the frequency of which correlated with intensity of infection.

Scaly skin alterations and plasma fatty acids in Congolese children.

Scaly skin alterations on the surface of the legs are frequently found in African children. Because similar signs occur in essential fatty acid deficiency, the fatty acid status of a group of African children with (n = 10) and without (n = 27) such skin alterations was determined. Analysis of the fatty acid composition of the plasma phospholipid and cholesterol ester fractions as well as clinical examinations were performed. Constantly low levels of linoleic acid and arachidonic acid were not associated with the occurrence of scaly skin alterations, which were also found in children with normal values for these polyunsaturated fatty acids. It is suggested that scaly skin alterations in Congolese children are not a sign of essential fatty acid deficiency.

Ultrasound versus clinical examination as indication for Schistosoma mansoni associated morbidity in children.

In order to compare clinical versus ultrasound based diagnosis of Schistosoma mansoni induced periportal fibrosis (pF) 536 infected Sudanese schoolchildren underwent clinical and sonographical examination. A liver exceeding 3 cm in sternal line and a palpable spleen were considered pathological. Ultrasound criteria for age dependent organometry of a Central European cohort were used as reference. Based on clinical criteria 190 children (35.4%) had hepatomegaly, whereas according to ultrasound results the rate was only 11.4%. Splenomegaly was detected in 77 cases (14.4%) by clinical means, but in 196 by ultrasound (36.6%). The sensitivity of clinical parameters as indication of pF was around 50%. Results for ultrasound detected organomegaly were only slightly better. It was concluded that assessment of liver and spleen sizes was of limited value as an indication for pF and that a considerable discrepancy existed between clinical and ultrasound based assessment of hepato- and splenomegaly.

Hepatosplenic schistosomiasis: comparison of sonographic findings in Brazilian and Sudanese patients--correlation of sonographic findings with clinical symptoms.

Twenty-seven Brazilian and 32 Sudanese patients with hepatosplenic schistosomiasis from areas where the disease is endemic were examined with ultrasound (US). Hyperechoic periportal areas indicating periportal fibrosis (PPF) were present in all patients irrespective of their origin. Nonspecific findings were splenomegaly (all patients), gallbladder wall thickening (81% and 92%, respectively, in Brazilian and Sudanese patients), portal vein (74% and 87%, respectively) and splenic vein (59% and 70%, respectively) enlargement, and portosystemic vascular shunts (62% and 61%, respectively). The hepatic alterations were congruent and the frequency of their occurrence was similar in both patient groups. With a standardized grading system, it was shown that grade of PPF was significantly correlated with a history of bleeding from endoscopically proved esophageal varices and with distention of the portal vein as measured with US. It was concluded that sonographic grading may be used in patients with hepatosplenic Schistosoma mansoni infection who originate from completely different endemic areas.

Ultrasonography as a diagnostic aid for a district hospital in the tropics.

To improve diagnostic capabilities, an ultrasound unit was installed at a major hospital in Wad Medani, Sudan. During the implementation period (October 1986 to March 1987) of ultrasound service, 863 patients were examined cooperatively by Sudanese and German physicians. The service covered internal medicine (47.5%), obstetrics and gynecology (31.6%), surgery (12.5%), and pediatrics (8.4%). Pathologic findings were seen in 75% of the patients. In obstetrics, the rate of pathologic findings was 40%. Five hundred eighty-three pathologic findings were detected in organ systems that constituted the primary indication for ultrasonography (of a total of 1,009 indications). The clinical benefit of ultrasonography was evaluated in 289 randomly selected patients in a standardized questionnaire completed by the attending physicians. The final clinical diagnosis was established or substantially revised in 21.5% of the patients, based on the ultrasonographic report. The previously reported diagnosis was supported in 69.5% of the patients. Medical management was directly influenced in 26% of the patients. We conclude that the clinical benefit of ultrasonography at a district hospital in the tropics is substantial, providing cost-effective, immediate therapeutic benefits in 25% of the patients examined. The technique thereby contributes to better and more rational patient management in institutions with limited resources.

Inter-observer variance in ultrasonographical assessment of Schistosoma mansoni-related morbidity in young schoolchildren.

49 Sudanese schoolchildren aged 6-9 years with Schistosoma mansoni infection were ultrasonographically examined by two independent observers in a double-blind fashion. The first observer recorded normal appearance of the liver in 23 cases, whereas the second observer recorded the appearance as normal in 33 cases. There were 23 concordant observations. For Grade I periportal fibrosis (PF), 13 observations were concordant. PF Grade II was rarely observed (2 versus 3 cases), and Grade III was not recorded at all. In total, 38 out of 49 observations were concordant (77.5%). These preliminary data from two ultrasound observers, from observations on a limited number of patients, can be seen as an indication of a potential inter-observer variation of around 20% for the distinction between the absence of PF and a low level of PF.

Ultrasonographical investigation of periportal fibrosis in children with Schistosoma mansoni infection: reversibility of morbidity twenty-three months after treatment with praziquantel.

In February 1987, 322 Sudanese school children were diagnosed for Schistosoma mansoni infection and treated randomly with praziquantel (either 20 mg/kg or 40 mg/kg body weight). A followup of these subjects was carried out in January 1989. This treatment resulted in a substantial reduction of egg output. Patients underwent complete abdominal ultrasonography and periportal fibrosis of the liver was graded into three degrees of severity. The proportion of patients with periportal fibrosis decreased from 36.6% in February 1987 to 21.7% in January 1989. At the time of followup, higher grades of periportal fibrosis (grades II and III) were encountered in only 4.3% and 0.3% of these patients, respectively, compared with 21.1% and 5.9%, respectively, before therapy. This was paralleled by a significant decrease in hepatomegaly from 10.9% to 7% of the patients. In contrast, the rate of splenomegaly showed a slight increase during the period of observation. The different dosage regimens of praziquantel did not result in a significantly different reversibility of periportal fibrosis or a decrease in egg excretion. The reversibility of specific liver lesions 23 months after antischistosomal therapy with praziquantel was substantial. The improvement was greater at 23 months than that obtained seven months after treatment.

Urine test strips: reliability of semi-quantitative findings under tropical conditions.

Semi-quantitative urinalysis with urine reagent strips (URS) for erythrocyturia (EU), leucocyturia (LU) and proteinuria (PU) was performed in Congolese and Sudanese school children with Schistosoma haematobium and/or S. mansoni infection. Quantitative urinalysis was performed on the same specimen using microscopy and a Neubauer counting chamber for EU and LU and the Coomassie blue dye-binding assay for PU. Microscopically detectable EU of more than 10 cells/microliters was found in 63% of all samples and LU of more than 20 cells/microliters was found in 60% of all samples. With the Coomassie blue method, PU of more than 150 mg/l was detected in 51% of all samples. URS gave positive results of grade 1-3 for EU in 69% of all samples, for LU in 63% of all samples and for PU in 66% of all samples. The sensitivity and specificity of URS compared with standard reference methods were as follow: EU 95% and 75%, LU 81% and 81% and PU 90% and 56%. When the results of all three test were combined, URS differentiated abnormal from normal urine specimens with a sensitivity of 94% and a specificity of 70%. Median quantitative results showed a good correlation with semiquantitative URS readings for all parameters, but there was a wide range of URS scores. We concluded that URS sensitivity detect urinary abnormalities and thus may be used as a general screening method under field conditions when more specific methods cannot be performed.(ABSTRACT TRUNCATED AT 250 WORDS)

Ultrasonographical investigation of periportal fibrosis in children with Schistosoma mansoni infection: reversibility of morbidity seven months after treatment with praziquantel.

Five hundred thirty six Sudanese schoolchildren with Schistosoma mansoni infection were treated at random with either 20 mg or 40 mg/kg praziquantel. Seven months later 420 children could be reinvestigated by ultrasonography. Reduction of egg excretion and reversibility of sonographically-proven periportal fibrosis (PF) was not significantly different in the two groups. Schistosoma mansoni-induced PF grade II decreased from 22.9% to 6.7% and grade III from 5.2% to 1.6%. An increased prevalence of PF grade I, from 10% to 29.8% of the investigated patients, was observed. This increase was caused partly by a downshifting of patients who had PF II (n = 45) and PF III (n = 8) before therapy, but also by patients who developed PF I in the seven months after therapy (n = 56). The overall percentage of patients with PF before and after treatment was 38.1%. Of 420 children, 17.4% increased in their PF grade, 55% remained at the same level and 27.6% improved. Children younger than 11 years of age had a higher rate of complete reversibility than older ones. The percentage of patients with hepatomegaly decreased significantly (11.6% to 6.9%; p = 0.001). The rate of splenomegaly remained unchanged. It was concluded that within seven months therapy with praziquantel resulted in a considerable qualitative improvement of PF in Sudanese schoolchildren with S. mansoni infection.

Ultrasonographical investigations of onchocerciasis in Liberia.

The efficiency of ultrasonography (US) for the diagnosis and clinical characterization of onchocerciasis was evaluated. US was performed on 120 probands in Liberia. Ninety-two patients had generalized onchocerciasis, 21 patients suffered from the chronic hyperreactive form of onchocerciasis (sowda), and 7 probands served as controls. Patients were examined by US with linear (7.5 MHz and 5 MHz) and sector (3.5 MHz) scanners. US results were evaluated by examination of extirpated nodules. The US structure of nodules revealed a typical pattern consisting of a homogeneous echogenicity with small echodense particles and a lateral acoustic shadow, and differentiation from lymph nodes, lipoma, or fibroma was achieved. Within the onchocercomata, calcifications or fluid were identified. Regarding the estimation of the worm burden, it is important to note that in 24 patients, additional nodules not previously palpated were found by US. Also, the number of worm centers in palpable conglomerate nodules were determined more exactly by US than by palpation. In 4 of 16 sowda patients, impalpable nodules were found by US. In 13 patients with positive microfilaria counts, no nodules could be detected. The highly characteristic ultrasonographical pattern of onchocercomata may serve as a basis for further US investigations in onchocerciasis.

Results of echocardiographic examinations in a regional hospital of central Sudan.

Sixty-seven patients were examined with a small portable echocardiograph in Wad Medani Teaching Hospital in central Sudan. The cardiac alterations detected in the referred patients, namely valvular disease and pericardial effusion, suggested a high prevalence of inflammatory heart disease in this area. Other findings were dilatative cardiomyopathy, congenital heart disease, mitral valve prolapse and a cardiac mass. Echocardiographic examination of patients with advanced hepatosplenic schistosomiasis revealed no evidence of cardiac alterations or abnormal right heart function. For echocardiography a general purpose ultrasound scanner, as defined by the World Health Organization, was used, additionally equipped with M mode facilities. It was concluded that echocardiography is applicable even in remote tropical areas and that its value, considering costs, therapeutic consequences and clinical benefit in developing countries, can be substantial. It was particularly helpful with pericardial disease.

Ultrasonographical investigation of periportal fibrosis in children with Schistosoma mansoni infection: evaluation of morbidity.

Morbidity of Schistosoma mansoni infection was assessed in 536 infected Sudanese schoolchildren using an ultrasonographical staging system for periportal fibrosis of the liver. S. mansoni ova excretion in stools was mild in 28%, moderate in 58%, and severe in 14% of the patients. Grade 1 periportal fibrosis was found in 10.3% grade 2 in 23.1%, and grade 3 in 4.7% of S. mansoni-infected children. Girls and boys were equally affected. The distribution of periportal fibrosis compared to the age of patients was homogenous. There was no significant difference of the rate of periportal fibrosis in the 3 groups of intensity of infection. However, in the 204 patients who showed periportal fibrosis, there was a strong relation between severity of ultrasonographically detectable fibrosis with intensity of egg excretion. In 332 children, of which 73 had a heavy infection, no signs of periportal fibrosis were detected. Sudanese children show a variable susceptibility towards the development of S. mansoni-induced periportal fibrosis. High risk patients can be detected at a childhood stage by measuring the intensity of infection and investigating the liver by ultrasound.

Vitamin E status of Congolese children in a rural area.

The role of vitamin E in severe malnutrition is controversially discussed. In order to evaluate the vitamin E status of unselected African children the plasma tocopherol levels of 52 children from a village in the People's Republic of Congo were assessed by HPLC and related to the plasma lipid values. Although plasma concentrations of total tocopherols (mean 351.1 +/- 59.4 micrograms/dl) and alpha-tocopherol (mean 313.3 +/- 57.0 micrograms/dl) were found to be low, normal ratios of total tocopherols to total lipids (mean 0.99 +/- 0.17 mg/g) and alpha-tocopherol to total lipids (mean 0.89 +/- 0.09 mg/g) were estimated. It is concluded that plasma vitamin E levels should be related to plasma lipids if populations are monitored in which low lipid concentrations have to be expected. These data on Congolese children may be used for comparison if the vitamin E status in other agrogeographical areas of Africa or in clinically abnormal groups is investigated.