Visual impairment: a correctable global problem.
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Biomedical subjects
Publications and source records attributed to S M Sulaiman.
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The Marrara syndrome, like Halazoun in Lebanon, is a hypersensitivity reaction of the upper respiratory tract and buccopharyngeal mucosa to nymphs of Linguatula serrata. The condition follows the consumption of Marrara which consists of raw liver, lungs, trachea and rumen of goats and sheep infected with larvae of L. serrata. The adult worm is found in the nasal passages of dogs. Sheep and goats are infected by eggs from infected dogs. A survey that included 240 adult individuals in a village of endemic L. serrata infection in the Sudan showed that 20% experienced symptoms of allergic nasopharyngitis (Marrara syndrome) following the consumption of raw viscera of goats or sheep at least once in their life. In a prospective study of 24 patients who reported to hospital with the Marrara syndrome, the clinical features included itching in the throat and nose, unilateral conductive deafness, tinnitus and facial palsy. Secondary bacterial infection caused suppurative otitis media. Adult L. serrata parasites were found in the nasal passages of 56 and 47% of male and female dogs in the endemic area. Nymphs were recovered from the mesenteric lymph nodes, lungs and livers of goats in the area.
The present work was a longitudinal study on Schistosoma mansoni infection in occupationally hyperexposed canal cleaners in the Sudan and the influence of therapy on the parasitological and humoral immune parameters. Chronically infected canal cleaners (n = 28) were more resistant to reinfection (Fisher's exact test, P < 0.05) than newly recruited canal cleaners (n=17). Chronically infected canal cleaners had a significantly higher degree of Symmers' fibrosis (chi2 = 19.1, P < 0.0001), significantly larger portal vein diameter (P < 0.05) and enlarged spleen (chi2 = 4.2, P < 0.05) than recently infected, newly recruited canal cleaners. ELISA was used to detect IgG, IgA and IgM in response to whole worm homogenate (WWH) and cercarial homogenate (CH). Chronically infected canal cleaners had significantly higher IgG to WWH antigen than newly recruited canal cleaners and normally exposed individuals (P < 0.05), while both chronically infected and newly recruited canal cleaners had higher IgG levels to CH antigen than normally exposed individuals (P < 0.05). The newly recruited canal cleaners had a significantly higher IgM level to CH antigen than chronically infected canal cleaners (P < 0.05). The IgG level to WWH antigen increased significantly after treatment in newly recruited canal cleaners and normally exposed individuals (P < 0.05). The IgA level to CH antigen increased significantly after treatment in the chronically infected group (P < 0.05). Comparison of the serological parameters between the different study groups with regards to infection and treatment is discussed.
The present work comprises a longitudinal study of Schistosoma mansoni infection in occupationally hyper-exposed canal cleaners in the Sudan and the influence of chemotherapy on humoral immune parameters. The study groups included chronically infected canal cleaners (n = 19), newly recruited canal cleaners (n = 17), normally exposed adults (n = 31), school children (n = 46) and Sudanese negative controls (n = 48). Previous studies of the same canal cleaners have demonstrated that chronically infected canal cleaners were more resistant to reinfection than newly recruited canal cleaners. ELISA was used to detect specific IgE and IgG subclasses in response to whole worm antigen (WWH) and soluble egg antigen (SEA) before and 3 months after praziquantel treatment in the groups of canal cleaners and before and 1 year after treatment in normally exposed adults. When intensity of infection was correlated with IgE antibody response, the resistant group of canal cleaners (those who stopped passing ova after treatment) showed a significant positive correlation between intensity of infection and specific IgE to WWH (Spearman's correlation coefficient = 0.49, P < 0.05) compared with a highly significant negative correlation in the susceptible group (acquired new infection after treatment, Spearman's correlation coefficient = -0.94, P < 0.01). Normally exposed adults and school children had significantly less specific IgE to WWH than canal cleaners, while chronically infected canal cleaners had significantly higher levels of specific IgG1 to WWH than newly recruited canal cleaners and school children, and significantly higher levels of specific IgG4 to WWH than school children. There was a significant increase in specific IgG1 and IgG4 to WWH, 3 months after treatment, in newly recruited canal cleaners and a significant decrease, 1 year after treatment, in normally exposed adults. None of the groups studied after treatment showed a significant change in their specific IgE to WWH. Normally exposed adults had significantly lower levels of specific IgE to SEA than newly recruited canal cleaners, and significantly lower levels of specific IgG1 to SEA than other infected groups. Both newly recruited canal cleaners and school children had significantly higher levels of specific IgG2 to SEA than persons in other groups. Only small differences between groups were observed with regard to specific IgG3 and IgM to SEA. Specific IgG4 to WWH and SEA showed different patterns after treatment between the resistant and susceptible groups of canal cleaners. The resistant group maintained the same level of IgG4 to WWH after treatment compared with a significant increase in the susceptible group. On the other hand, levels of specific IgG4 to SEA showed a highly significant decrease after treatment in the resistant group. In contrast, the same antibody subclass increased after treatment in the susceptible group. Generally, results show an association between IgE and IgG1 responses to WWH and resistance to reinfection. In contrast, an association was observed between IgG2 and IgM responses to SEA and susceptibility to reinfection.
A cross-sectional survey of schistosomiasis was carried out in five villages around the Elziedab irrigation scheme, in the north, and three villages in the Gezira-Managil area in central Sudan. Stools and urine from 53% (2832 individuals) and 72% (3684 individuals) of the population of these villages, respectively, were examined using the modified Kato thick smear for stools and sedimentation for urine. Clinical history and examination were done on 2832 subjects (53%) in Elziedab and on 893 (18%) randomly selected samples in Gezira-Managil. Prevalence of Schistosoma mansoni was 36% in Elziedab and the mean egg count was 150 eggs per gram of faeces (e.p.g.). Prevalence of bloody diarrhoea was 6%, hepatomegaly 6% and splenomegaly 10%. There was a significant association between these parameters and infection in the age group 10-24 years. Prevalence and intensity in Gezira-Managil area were significantly higher than in Elziedab, 52% and 234 e.p.g. Prevalences of bloody stool 29%, hepatomegaly 17% and splenomegaly 15% were also significantly higher than in Elziedab. These parameters were unrelated to the presence of eggs in the stool. Advanced hepatosplenic schistosomiasis is less than 1% in both areas. While S. haematobium was not found in Elziedab, its prevalence varied from 10 to 15% in Gezira-Managil area. In conclusion, S. mansoni is much less prevalent in Elziedab than Gezira, signs and symptoms are much less prominent in Elziedab, and most of the symptoms are unrelated to the presence of eggs in the stool.
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A cross-sectional study was performed in a Sudanese village endemic for intestinal schistosomiasis and not located in a control area. Immunological and parasitological diagnosis were compared in 156 individuals. Sera were tested with defined diagnostic Schistosoma mansoni antigens (Sm 31/32, i.e. hemoglobinase and cathepsin), and repeated stool examinations were performed. In immunoblots, 98% of the egg excretors were correctly identified. On the other hand, 75% of the parasitologically negative individuals had anti-Sm 31/32 antibodies. Cross-reactivity of these antigens with other parasites was excluded earlier, and the patients had not received previous chemotherapy. It is concluded that the sensitivity of these defined antigens to detect immunologically infections with S. mansoni compares favourably with stool examinations.
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Some compounds of the class 9-acridanone-hydrazones have recently been developed by Hoffmann-La Roche (Basel-Switzerland) and were shown to have antischistosomal effects. One of these compounds (RO 15-5458/000) was administered at two dose levels (25 mg and 15 mg/kg body-weight) to S. mansoni (Gezira strain-Sudan) infected vervet monkeys. The faecal egg-output was terminated, worm-burden killed and tissue egg-counts were greatly reduced as compared with the untreated control monkey. Severe necrotic changes were seen around dead worms in sections from treated animals' livers. The efficacy of this compound as an antischistosomal is encouraging and deserves further studying.
The long-term infection with Schistosoma mansoni (Gezira strain--Sudan) was studied in the Nile rat (Arvicanthis niloticus) to investigate the 'self cure' phenomenon. The results indicated that while a considerable number of worms and eggs were still recovered by week 28 post-infection, elimination of some of the worms occurred by week 20.
Ultrasonography was used in a village in the Gezira-Managil scheme in the Sudan to identify patients with Symmers' fibrosis. In a random sample from patients with active Schistosoma mansoni infection, 238 patients were found to have no liver involvement while 59 had Symmers' periportal fibrosis. Patients were treated with a single dose of 40 mg/kg body weight of praziquantel. Six months after dosing, 51% and 58% were cured of the infection with 81% and 84% reduction in egg burden in the Symmers' and non-Symmers' patients, respectively. The drug was equally well tolerated by the two groups. It is concluded that patients with Symmers' fibrosis respond to praziquantel and tolerate the drug in a similar manner to patients without Symmers'.
In a previous study it was demonstrated that the concentration of oltipraz in the plasma of human volunteers was significantly elevated when administered with food. In this study we attempted to determine if this food-induced increase was associated with an increase in the drug's anti-schistosomal activity. The drug was administered with and without food to two groups of patients infected with Schistosoma mansoni. The concentration of oltipraz in the plasma of these patients was measured at varying intervals after dosing. Results indicate that the food-induced increase in the bioavailability of oltipraz in patients with S. mansoni produces a significant increase in the drug's anti-schistosomal activity.
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The comparative susceptibility of Biomphalaria snails from Gezira and Jebel Marra to S. mansoni (Gezira) was investigated. Groups of laboratory-bred snails from the two localities were exposed to 0, 1, 2, 3 and 4 miracidia. The growth rate of the snails was followed over the experimental period by measuring the snails' shell size. Sub-groups of infected snails were examined for daughter sporocyst counts by crushing of the snails. Other groups of exposed snails were maintained until cercariae were shed. The exposed snails grew faster than the controls and growth was not dependent on the number of infecting miracidia. Jebel Marra snails grew faster than the Gezira snails and development of the daughter sporocysts within the snails was temperature dependent. Daughter sporocysts were first found on day 19 after exposure when the laboratory temperature ranged between 18 and 25 degrees C and on day 10 at a range of between 28 and 30 degrees C. Daughter sporocysts and cercarial counts overlapped in numbers per snail exposed to 1, 2, 3 and 4 miracidia for both Gezira and Jebel Marra snails. Nine out of 78 Jebel Marra snails were negative for daughter sporocysts, while all of the Gezira snails were positive. This might indicate greater susceptibility of the Jebel Marra snails to the parasite. Our experiments showed that snails from Jebel Marra are capable of supporting an S. mansoni infection from the Gezira until cercariae are shed. The epidemiological significance of the migrant labourers to the Gezira area in the transmission and spread of intestinal schistosomiasis in Jebel Marra is discussed.
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The bioavailability of the new antischistosomal agent, oltipraz, was examined under three different dietary conditions in seven healthy males. Oltipraz tablets (500 mg) were administered in single doses (25 mg/kg) under fasting conditions, with a low fat meal (less than 5% fat) and a high fat meal (24% fat). The extent and rate of oltipraz bioavailability were significantly increased by concurrent administration of the drug with food, as demonstrated by the increase in the plasma peak concentration, the area under the plasma concentration vs. time curve and the absorption rate constant. The plasma peak concentration was also reached earlier. Oltipraz plasma concentrations, following its administration under fasting conditions, were almost negligible. The likely mechanisms underlining oltipraz-food interaction are discussed.
Oral coadministration of oltipraz, an antischistosomal compound, with cysteine to green monkeys (Cercopithecus aethiops) led to a marked increase in both the extent and rate of oltipraz bioavailability. The drug blood levels were monitored using a single extraction gas-liquid chromatographic assay. When 6 healthy adult animals were given oltipraz together with cysteine in a crossover study, peak serum concentrations, areas under the curve and absorption rate constants of oltipraz were on average 7 times greater than when the drug was administered alone. Oltipraz peak serum concentrations were reached 1 h earlier as a result of cysteine administration (2 h after dosing). At present, the mechanisms responsible for the effect(s) of cysteine on oltipraz bioavailability have not been identified. The marked increase in oltipraz bioavailability produced by coadministration of cysteine, irrespective of the exact mechanisms involved, may have significant clinical implications with regard to the treatment of schistosomiasis. Our results also indicate that oltipraz blood levels seem to be influenced by some sex-related factors. Male monkeys had higher oltipraz blood levels than females. These sex-induced differences were more evident in oltipraz-cysteine-treated monkeys.
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