Geometric Mean Egg Count Research Articles

Schistosoma mansoni infection in a rural area of the Jequitinhonha Valley, Minas Gerais, Brazil: Analysis of exposure risk

This study examines the relative contribution of age-specific total IgE levels, eosinophils and water contact behavior to the prevalence and intensity (geometric mean egg counts) of Schistosoma mansoni infection in the poor rural population of Virgem das Graças in northern Minas Gerais State. In bivariate analysis, age was strongly correlated with both prevalence and intensity of infection, while eosinophil levels with prevalence only ( p < 0.0001); IgE levels and 5 demographic and socioeconomic variables were moderately correlated with prevalence ( p < 0.05), as were number of persons per room and TBM (total body minutes) with egg counts. In multivariate analysis, after controlling for demographic and socioeconomic factors, only total IgE levels were significantly correlated with both prevalence ( p = 0.248, 95% CI = 1.01–1.11) and intensity ( p = 0.0217, 95% CI = 0.01–0.14) of infection and eosinophil levels with prevalence ( p = 0.0005, 95% CI = 1.07–1.24). Although any causal relationship cannot be confirmed by a cross-sectional study, we demonstrated an associated decrease in prevalence and intensity of S. mansoni infection with increased IgE levels.

Sequential analysis of helminth egg output in human stool samples following albendazole and praziquantel administration

Large-scale administration of anthelminthic drugs currently is the most widely used intervention for controlling morbidity due to schistosomiasis and soil-transmitted helminthiasis. An important issue is drug efficacy monitoring. However, the optimal time points post-treatment for assessing the efficacy of praziquantel against Schistosoma mansoni and albendazole against hookworm infections are not known. Forty-nine schoolchildren infected with S. mansoni and 52 infected with hookworm were treated with a single oral dose of praziquantel (40 mg/kg) and albendazole (400 mg), respectively. Stool samples were collected on 19 occasions over a 44-day post-treatment follow-up period, and two Kato-Katz thick smears per sample were examined at each time point. Both the mean egg counts and observed cure rates varied depending on the time point post-treatment. The highest reduction in the geometric mean egg counts (>97%) and the highest observed cure rate (>97%) of S. mansoni infections were found 15–20 days after praziquantel administration. Among the hookworm-infected children, egg counts decreased rapidly within the first week after albendazole administration (>95%), whereas infection rates showed high and heterogeneous (45.0–71.2%) levels at later time points. Both praziquantel and albendazole were highly efficacious in reducing the overall egg burden of S. mansoni and hookworm, respectively. We suggest that 15–20 days post-treatment is the most appropriate time point for efficacy evaluation of praziquantel against S. mansoni. Although no clear conclusion can be drawn for the optimal timing of efficacy evaluation of albendazole against hookworm, a 2–3-week time frame seems a reasonable compromise. This is justified on logistical grounds (i.e. collection of stool samples only once) and growing emphasis on integrating the control of schistosomiasis and soil-transmitted helminthiasis, including drug efficacy monitoring.

The Effects Of Season And Distance On The Prevalence And Intensity Rates Of Urinary Schistosomiasis In Agulu-Lake Area Of Anambra State, Nigeria

A survey of the effects of season, and distance to water source on the prevalence and intensity rates of Schistosoma haematobium infection in Agulu community of Anambra State was conducted using the primary schools in the town, using parasitological screening approach. Prevalence was similar in both the dry and rainy season months. Seven out of the 15 Primary schools surveyed had pupils with infection. Prevalence in schools with infection ranged from 4.1- 55.2 % during the dry season to 3.3-55.6 % during the rainy season. Prevalence and geometric mean egg count were highest in the 10-14 years age group in all the schools and in both dry and rainy seasons. Geometric mean of egg count / 10ml urine (intensity) decreased from 22.5 egg/10 ml in dry season to 10.7 egg/10 ml in wet season. Prevalence rates and intensity showed significant decrease with increase in the distance from the village to the lake. The implications of these are discussed .

Genitourinary schistosomiasis among pre-primary schoolchildren in a rural community within the Cross River Basin, Nigeria

In Africa, most schistosomiasis control programmes defined the age 5-19 years as the target population for nationwide control through the school systems, excluding the under fives. A study was therefore undertaken to determine the prevalence and intensity of genitourinary schistosomiasis in children aged 0-5 years (pre-primary) in Adim, a rural and endemic community within the Cross River Basin, Nigeria. Of the 126 children examined, 25 (19.8%) were infected with Schistosoma haematobium, with no significant difference (P > 0.05) in infection rates between boys (21.1%) and girls (18.2%). Both prevalence and intensity of infection increased significantly (P 0.05) between intensity in boys (6.2 eggs/10 ml urine) and girls (5.6 eggs/10 ml urine). A total of 32.5 and 27.8% of the children had haematuria and proteinuria, respectively; it was not gender specific (P > 0.05). Six species of snail were encountered, with Bulinus globosus being the most abundant and widespread. The results of this study have shown that pre-primary schoolchildren are a source of transmission of schistosomiasis in endemic communities and should be integrated into any control intervention.

Socioeconomic determinants of schistosomiasis in a poor rural area in Brazil

The objective of this paper is to identify and quantify socioeconomic determinants of Schistosoma mansoni infection in the rural area of Virgem das Graças in Minas Gerais State of Brazil. A cross-sectional study was carried out to examine the prevalence and intensity of schistosomiasis in relation to socioeconomic characteristics of the households. Log-binomial regression analysis was used to examine the data on both the household and individual levels, analyzing the prevalence ratios for the association of schistosomiasis and socioeconomic variables related to the head of the household. Multiple comparisons through mixed effect modeling were used to examine the relationship between intensity of infection (geometric mean egg counts) and different levels of socioeconomic variables, respectively. In the univariate analysis, place of residence, number of persons per room, and lack of motorized transport were associated with schistosomiasis at the household level and age and unsafe water contact at the individual level. Age, unsafe water contact, number of persons per room, household possessions and lack of education of head of household remained significant predictors of schistosomiasis in the multivariable analysis. Only age was significantly associated with intensity of infection of individuals. It is concluded that widespread poverty, the rural environment, and weak socioeconomic differentiation that result in intense contact with infective water appear to minimize the protective effect of piped water supply and other socioeconomic parameters on schistosomiasis found in other studies. The potential role of socioeconomic development in conjunction with schistosomiasis control is described and areas for further studies are identified.

Distribution and clustering ofOesophagostomum bifurcumand hookworm infections in Northern Ghana

Human Oesophagostomum infections are locally common in northern Ghana. The present study describes the results of a cross-sectional survey involving 1011 subjects, selected by a compound-based random sampling method from 1227 compounds in 24 villages. Selected persons were examined by both Kato and coproculture methods. Hookworm-like eggs, representing ova of Oesophagostomum bifurcum and hookworm were detected in 87.5% of the Kato smears. The geometric mean egg count of the infected subjects was 1018. Upon coproculture, third-stage larvae of O. bifurcum and hookworm were detected in 53.0% and 86.9% of subjects respectively. Oesophagostomum infections were clustered but no clear explanation for aggregation of infections could be found as yet. Subjects infected with hookworm had a 5-fold higher risk of being infected with O. bifurcum. Infection rates in adult women were higher than in adult men. No association was found with family size, level of hygiene or with the presence of animals in the compounds. Representatives of the Bimoba-tribe were significantly more infected than those of the other tribes. It appears, however, that this tribal association is a geographical phenomenon: Bimoba are mostly living in villages with the highest infection rates.

EFFICACY OF MYRRH IN THE TREATMENT OF HUMAN SCHISTOSOMIASIS MANSONI

Myrrh (Mirazid) has been produced and marketed as an antischistosomal drug since 2001. The current study was designed to assess the efficacy of a commercially available product of myrrh. One hundred four individuals, infected with Schistosoma mansoni, were randomized in two groups, one for myrrh and the second for praziquantel. Treatment-whether myrrh or praziquantel-was given twice with a 3-week interval. The cure rate with myrrh was very low, 15.6% after the first treatment, and 8.9% after the second treatment. Egg reduction among uncured persons was also very low, being 17.2% after the first treatment, and 28% after the second treatment. Praziquantel cure rate was 73.7% and 76.3%, and individuals still passing S. mansoni ova after praziquantel treatment showed a substantial reduction in the geometric mean egg counts (84% and 88.2% after the first and second treatments, respectively). When 34 individuals-uncured after two myrrh treatments-were offered praziquantel in the standard dose, 32 of them stopped passing S. mansoni eggs when tested 4 weeks post-treatment. The results of the current study raise serious doubts about the antischistosomal properties of Mirazid.

Control of endoparasites in horses with a gel containing moxidectin and praziquantel

A gel formulation containing moxidectin (20 g/kg) and praziquantel (125 g/kg) reduced the geometric mean faecal strongyle egg count in horses to below 100 eggs per gram of faeces (epg)...

The short-term impact of albendazole treatment on Oesophagostomum bifurcum and hookworm infections in northern Ghana.

In November-December 2002, stool samples from a random sample of the human population (N = 190) in the Garu area of northern Ghana were checked for intestinal helminths, using a single Kato smear and duplicate coprocultures for each subject. All 190 subjects were subsequently treated with a single, 400-mg dose of albendazole and 146 of them were successfully re-examined 21-28 days post-treatment. Prior to treatment, 75.5% of the Kato smears were found to contain 'hookworm-like' eggs (with a geometric mean egg count among the positives of 578 eggs/g faeces), and the third-stage larvae of Oesophagostomum bifurcum and hookworm were found in the cultures of stools from 34.2% and 77.4% of the subjects, respectively. Among the subjects who had positive Kato smears before treatment, albendazole treatment led to a cure 'rate' of 79.0% and an egg-reduction 'rate' of 73.5%. The results from the coprocultures indicated cure 'rates' of 98.0% for O. bifurcum but only 51.3% for hookworm. Only one subject was still positive for O. bifurcum after treatment. Among those still positive for hookworm after treatment, the larva-reduction 'rate' was 79.8%. The egg-/larva-reduction 'rates' among those with heavy infections prior to treatment were >90%, whether the data analysed came from the Kato smears or the coprocultures. It may be concluded that a single dose of albendazole is very likely to cure an O. bifurcum infection and to reduce greatly the intensity (but not the prevalence) of any hookworm infections.

Effectiveness of Myrrh in the Treatment of Schistosoma Mansoni Infection: A Controlled Trial

Chemotherapy is the main tool for control of schistosomiasis. Although praziquantel has high degree of efficacy and minimal side effects, yet concern was raised over possible low-level resistance. This necessitates search for new safe and effective drugs. The present study was implemented to evaluate the efficacy of Mirazid [oleo-resin extract of Myrrh obtained from the stem of Commiphora molmol]. 1184 recruits were parasitological screened using Kato-Katz technique and intensity of infection was classified into light, moderate, or heavy according to WHO Guidelines. Schistosoma mansoni infection was detected in 156 recruits [13.2%], they were equally allocated to one of three therapy groups either mirazid [600 mg] for 3 consecutive days, mirazid [600 mg] for 6 consecutive days, or single dose of praziquantel 40 mg/kgbw. Cure was monitored 3 and 6 weeks post-treatment by parasitological stool examination using quantitative Kato-Katz [4 slides/stool sample] and formol detergent techniques. Cure rate was [55.6%] for 3-days Mirazid, [45.8%] for 6-days Mirazid, and [94.3%] for praziquantel when assessed 6 weeks post-treatment. Results showed that cure rates decreased with increasing pre-treatment egg count for the 3 studied treatment groups. For the uncured subjects, the percent reduction in geometric mean egg count observed 6 weeks post-treatment was [-6%] for those who received 3-days Mirazid, [39.1%] for those who received 6-days Mirazid, and [97.2%] for those who received praziquantel. Based on the finding of this study, although Mirazid is a well-tolerated herbal drug with minimal side effects, yet if compared with praziquantel as an anti-schistosomal drug, it has a lower cure rate and is given in multiple doses with a compliance problem.

Endemicity of vesical schistosomiasis in the Ebonyi Benue River valley, South Eastern Nigeria

The investigation on the prevalence of patent and clinically severe infections with Schistosoma haematobium was carried out amongst inhabitants of Ebonyi Benue river valley, South Eastern Nigeria between August 2000 and June 2001. The inhabitants are predominantly farmers. Of the 3296 subjects examined from 15 randomly selected villages in the valley, 776 (23.5%) were excreting the eggs of S. haematobium in their urine. Infection rates varied between 18.9% and 30.6%. The severity of infection calculated by arithmetic mean egg counts (AMEC) and geometric mean egg counts (GMEC) varied significantly between the age groups and the villages (P<0.05). The prevalence and severity of infection increased with age from 0 to 25 years and decreased thereafter. Symptoms associated with the disease include visible hematuria (63.1%), suprapubic pain (10.3%) and stranguary (9.9%). While 65 positive persons had more than one symptom, 64 of the positive persons had no noticeable symptoms. Visible hematuria showed moderate sensitivity and high specificity for the disease. Female genital schistosomiasis (FGS) of the lower reproductive tract was recorded in 19 females of child bearing age that complained of severe suprapubic pain. Eight snail species were recorded in the stagnant ponds and both Bulinus globosus and B. truncatus were infected with schistosome cercariae. The factors contributing to these observations and feasible control measures are discussed.

Ascaris lumbricoides among children in rural communities in the Northern Area, Pakistan: prevalence, intensity, and associated socio-cultural and behavioral risk factors

The prevalence and intensity of Ascaris lumbricoides in 492 children from five rural villages in the Northern Area of Pakistan was examined. The overall prevalence of A. lumbricoides was 91% (95%CI 88.6–93.6) with geometric mean (GM) egg count intensities of 3985 eggs per g (epg). The most intense A. lumbricoides infections were found in children aged 5–8 years. We also investigated selected socio-cultural and behavioral variables for A. lumbricoides infections that might be relevant for the design of appropriate prevention and control programs. Univariate analysis associated A. lumbricoides intensity with age ( P=0.004), location of household ( P<0.01), defecation practices ( P=0.02), soil eating habit ( P<0.01), hand washing after defecation ( P<0.01), and living with children under 5 years old ( P=0.02). Multivariate analysis identified the children's age 5–8 ( P<0.01), location of household in Surngo, Askole, and Stakchun where the pilot health care model activities were not done ( P<0.01), and living with children under 5 years old ( P=0.03) as variables statistically associated with the intensity of A. lumbricoides. The results indicated that there were certain clear risk factors in A. lumbricoides transmission, and that its intensity was influenced by age-related behavioral and environmental factors that contribute to exposure.

Reduction in the prevalence and intensity of hookworm infections after praziquantel treatment for schistosomiasis infection

Praziquantel exhibits activity against all major human schistosome parasites and has become the cornerstone for treatment and morbidity control of schistosomiasis. Praziquantel is also active against a wide range of trematodes, human and veterinary cestodes and displays cysticidal effects. To the best of our knowledge anthelminthic properties have never been documented. Here, we report a study among 96 schoolchildren from an area highly endemic for Schistosoma mansoni and hookworm infection, and place particular emphasis on the effect of praziquantel on the prevalence and intensity of hookworm infections. Stool specimens were screened over several consecutive days prior and 4 weeks after systematic administration of praziquantel. We found a significant reduction in the prevalence of hookworm infection from 75.0 to 40.6% (odds ratio (OR)=0.21; 95% confidence interval (CI): 0.11–0.40). Infection intensities, expressed by geometric mean egg counts of all children, were also reduced significantly from 10.7 to 2.0 eggs per gram stool (paired t-test=7.78, P<0.001). If these findings are confirmed in other epidemiological settings – following a similarly sensitive diagnostic approach – they might become of considerable relevance. In areas where both schistosome and hookworm coexist, and praziquantel is being recommended for schistosomiasis control, large-scale application of this drug might also reduce the burden of hookworms.

Cyathostome fecal egg count trends in horses treated with moxidectin, ivermectin or fenbendazole

Commercial preparations of fenbendazole (Safe-Guard ®, Intervet), ivermectin (Eqvalan ®, Merial) or moxidectin (Quest ®, Fort Dodge) were administered once to horses scheduled for routine parasiticide treatment. In total, 93 horses from six cooperating farms were used in the study. Computer generated, random allocation of horses to treatment group was conducted at each farm. Fecal egg counts were determined for all horses on trial days 0, 56, 84 and 112, with corresponding calendar dates that were unique to each farm. Only strongyle egg counts from animals which were positive at day 0 were used for analysis of variance and comparisons. Counts for the three treatment groups were similar at day 0, moxidectin<ivermectin<fenbendazole for days 56 and 84, and moxidectin<ivermectin=fenbendazole on day 112 ( P<0.05). Reductions of geometric mean egg counts from day 0 levels were 99.1, 97.6 and 94.9% for moxidectin, 16.4, −27.0 and −32.0% for fenbendazole and 85.9, 24.2 and −8.1% for ivermectin on trial days 56, 84 and 112, respectively. Adverse reactions to treatment were not observed for any of the parasiticides.

Geographic differences in hepatosplenic complications of schistosomiasis mansoni and explanatory factors of morbidity.

In a study in three neighbouring villages of southern Madagascar, where Schistosoma mansoni is hyperendemic, ultrasound examination using the Niamey protocol showed marked differences in the burden of disease from one village to another. Hepatosplenic schistosomiasis was more frequent in the village with the highest geometric mean egg counts and the earliest onset of infections, demonstrating that the morbidity induced by S. mansoni may vary greatly within a given area. True representativeness of study populations, a keystone of epidemiological studies, is mandatory to obtain a clear picture of a wide area. Ultrasound examinations in a small number of villages, or even a single one, may be a questionable approach. Using logistic regression analysis, the explanatory variables found to be significantly associated with a risk of severe hepatosplenic disease in our study were sex, age, village of residence and S. mansoni egg counts. On the other hand, a concurrent infection with an intestinal helminth seems to reduce the risk of severe hepatosplenic disease. Further studies should assess the role and possible impact of intestinal helminths on S. mansoni associated-morbidity.

Intestinal helminths and schistosomiasis among school children in a rural district in Kenya.

To determine the extent of intestinal schistosomiasis, ascariasis, trichuriasis and hookworm infections among school children of Usigu and Bondo divisions of Bondo District. A cross sectional study. Fifty out of 130 primary schools in Usigu and Bondo divisions, Bondo District. Randomly selected school children (n= 3158) aged five to 20 years, were examined for intestinal helminths and schistosomiasis using Kato thick smear technique. The overall prevalence and geometric mean egg counts per gram/faeces for Schistosoma mansoni were 31.6% and 3.1; hookworm 36.8% and 4.1; Trichuris trichiura 21.8% and 1.5, and Ascaris lumbricoides 16.5% and 2.5. More girls (34.9%) than boys (28.6%) were infected with S. mansoni whereas more boys (39.0%) than girls (34.5%) were infected with hookworm. The prevalence of S. mansoni and hookworm infections increased with age but Ascaris and Trichuris infections decreased with age without any sex differences. Children under ten years of age tended to be more heavily infected with ascariasis, trichuriasis and hookworm than the older ones, while the intensity of S. mansoni increased gradually with age. There were positive relationships between different infections except for a significant negative correlation between Schistosoma mansoni and hookworm infections. Only four cases out of 789 had S. haematobium infection. CONCLUSION. Schistosoma mansoni and geohelminths were endemic in Bondo District, where two thirds of the school children suffered from these parasites. Polyparasitism was also common. There was a little overlap in the distribution of Schistosoma mansoni and hookworm, whereas ascariasis and trichuriasis were fairly distributed in the district.

The epidemiology of schistosomiasis in Egypt: Qena governorate.

Qena is the southernmost governorate of Egypt included in the Epidemiology 1, 2, 3 national study. A probability sample selected 17,822 individuals from 2,950 households in 34 ezbas and 10 villages from a total rural target population of 1,731,252 (based on the most recent 1986 census of the population by the Egyptian Central Agency for Public Mobilization And Statistics). Parasitologic examination of urine and stool were made for Schistosoma haematobium and S. mansoni, respectively, and physical and ultrasound examinations were made on a 20% subsample. The overall estimated prevalence of S. haematobium was 4.8 +/- 0.7% (+/-SE) and geometric mean egg count (GMEC) was 7.0 ova per 10 ml of urine. Considerable variation in prevalence was observed between the villages and ezbas, ranging from 0.0% to 20%, with the smaller ezbas having a slightly higher overall prevalence. The age- and sex-specific patterns of S. haematobium showed typical peak prevalence in early adolescence, with males having a higher prevalence than females. A history of hematuria was associated with current infection (odds ratio = 3.6, 95% confidence interval = 2.32-5.63). Hepatomegaly and splenomegaly determined by physical examination present in 7.9% and 3.0%, respectively. Ultrasonography-determined hepatomegaly of the left liver lobe was found in 10.1%. Ultrasonography-detected hepatomegaly in both the left and right lobes increased in prevalence from approximately 5% in children to 15-20% in adults. The prevalence of ultrasonography-detected splenomegaly increased slightly with age. Grade III periportal fibrosis was detected in only 2 individuals in the sample. Bladder wall lesions and obstructive uropathy were also very infrequent. Other associations with these measures are given. Most villages and ezbas had an S. mansoni prevalence of less than 1%. The exception was Nag'a El-Sheikh Hamad, where the prevalence was 10.3 +/- 0.5% (GMEC = 57.4 +/- 2.6). Two other communities also had a prevalence >1% (Ezbet Sarhan and Kom Heitin).

The epidemiology of schistosomiasis in Egypt: Fayoum Governorate.

Health questionnaires and parasitologic examinations of urine and stool were performed upon a stratified random sample of 7,710 individuals from 1,109 households in 21 rural communities in Fayoum Governorate, Egypt in 1992 to investigate the prevalence of, risk factors for, and changing pattern of, infection with Schistosoma sp. in the governorate. A subset, every fifth household, or 1,038 subjects, had physical and ultrasound examinations to investigate prevalence of, and risk factors for, morbidity. The prevalence of S. haematobium ranged from 0% to 27.1% and averaged 13.7%. The geometric mean egg count (GMEC) was 10.0 eggs/10 ml of urine. Age-stratified prevalence and intensity of infection were 18-25% and 10-15 eggs/10 ml of urine in those 5-25 years of age. Schistosoma mansoni were detected in inhabitants of 13 communities, but 78.5% of the infections were focally present in a group of 4 satellite hamlets around a single village. The overall prevalence of S. mansoni in the governorate was 4.3% and the GMEC was 44.0 ova/g of stool. Risk factors for infection with either species were male gender, an age <20 years, living in smaller communities, and exposures to canal water by males. Histories of burning micturation, blood in the urine, or prior schistosomiasis and reagent strip-detected hematuria and proteinuria were risks for S. haematobium, but not for S. mansoni. Both urinary tract and higher grades of hepatic morbidity were rare. Obstructive uropathy was present in 6.3% of the subjects and was more common in males and older people. Ultrasonography-detected bladder lesions were present in 5.2% and correlated with S. haematobium only in younger subjects and in those with hematuria and proteinuria. The prevalences of hepatomegaly, splenomegaly, and periportal fibrosis (PPF) were associated with each other and increased with age and in males. Ultrasonography-detected hepatomegaly and splenomegaly were weakly associated with S. mansoni infections only in children. The prevalence of PPF was greater in the 4 communities with >25% S. mansoni infection rates in comparison with the 17 other villages and ezbas. Transmission of S. mansoni is focally well established in Fayoum, which also has the highest prevalence of S. haematobium in the governorates surveyed by the Epidemiology 1, 2, 3 Project. However, both urinary tract and hepatic morbidity are relatively rare in the governorate. This probably results from the long-standing schistosomiasis control program in Fayoum, which suppressed intensity more than prevalence of infection, leading to less community morbidity.

The epidemiology of schistosomiasis in Egypt: Minya Governorate.

Risk factors, prevalence, and intensity of infection with Schistosoma sp. and prevalence and magnitude of morbidity caused by schistosomiasis was assessed in a stratified random sample of 16,433 subjects from 2,409 households in 33 rural communities in Minya Governorate, Egypt. The prevalence of S. haematobium ranged from 1.9% to 32.7% among the communities and averaged 8.9%. The average intensity of infection was a geometric mean egg count (GMEC) of 8.5 per 10 ml of urine and ranged from 1.6 to 30.9. Prevalence was maximum (18-20%) in those 10-20 years of age and higher in males than in females. Intensity of infection followed the same pattern. Infection with S. mansoni was present almost exclusively in a single village, confirming spread of this species up the Nile River and its focality in Minya. Risk factors for S. haematobium infection were an age from 11 to 20; male gender; males bathing in, women washing clothing or utensils in, and children swimming or playing in canals; and a history of, or treatment for, schistosomiasis. Recent history of burning micturition was associated with infection in children but not in adults, while a history of blood in urine correlated with S. haematobium infection in both age groups. Reagent strip-detected hematuria and proteinuria were highly associated, particularly in children, with S. haematobium infection. The presence of hepatomegaly or splenomegaly on physical examination was not associated with S. haematobium ova in the urine. Hepatomegaly, as measured by ultrasonography in the midclavicular line or the midsternal line, or ultrasonography-detected splenomegaly were not present more frequently in infected subjects than in uninfected subjects. Schistosoma ova were not detected more frequently in urine of subjects with ultrasonography-detected periportal fibrosis than in the urine from subjects without this finding. Ultrasonography-detected urinary bladder wall lesions were detected in only 6 (0.3%) subjects and obstructive uropathy was observed in 54 (2.7%) subjects. The absence of an association between prevalence of urinary tract morbidity and S. haematobium infections was surprising. Two possible explanations are 1) that repeated chemotherapy has reduced the prevalence of urinary tract morbidity and 2) that morbidity was not being detected by the ultrasonographic operators.

The epidemiology of schistosomiasis in Egypt: Ismailia governorate.

A multi-stage stratified sample of 12,515 individuals from 1,941 households in 42 villages in the Ismailia governorate of Egypt were surveyed for schistosomal infection. A subset of 2,390 subjects were surveyed for morbidity by physical and ultrasonographic examination. The prevalence of Schistosoma mansoni infection in rural Ismailia was 42.9% and the geometric mean egg count (GMEC) was 93.3 eggs/gram of stool, with considerable variability between communities. Prevalence and intensity peaked in the 20-30-year-old age group and was higher in males than in females. Prevalence and intensity of S. haematobium was very low: 1.8% and 3.5 ova/10 ml of urine GMEC, respectively. Canal water exposure risk factors for S. mansoni infection were males bathing (odds ratio [OR] = 2.2), females washing clothes (OR = 1.9), and children playing or swimming (OR = 2.3). Presence of in-house piped water supply and latrine lowered infection rates (P < 0.001 and P = 0.002, respectively). Histories of S. mansoni infection (OR = 1.6) or treatment (OR = 1.5) and blood in feces (OR = 3.5) were associated with infection. Hepatomegaly (16.0%) was more frequently detected than splenomegaly (3.6%) by physical examination, with both being more frequent in older age groups. Splenomegaly, but not hepatomegaly, was associated with presence of S. mansoni ova in stools (OR = 1.4) and the community burden of infection (P = 0.02). Ultrasonographically detected hepatomegaly, splenomegaly, and periportal fibrosis (PPF) were detected in 43.0%, 17.4%, and 39.7% of the subjects, respectively. The higher grades of PPF were rare. Ultrasonographically detected splenomegaly, not hepatomegaly, was associated with S. mansoni infection, community burden of infection, and PPF. Risk factors for PPF were the same as for S. mansoni infection. There was a marginal association of PPF with infection and none (P = 0.33) with the intensity of infection in individuals or in the community. We conclude that in rural Ismailia, S. haematobium infection is rare but the prevalence and intensity of infection with S. mansoni is high. The risk of infection is associated with environmentally detected factors and behaviors. Hepatosplenic morbidity attributable to S. mansoni infection is low, presumably because of the favorable effect of wide application of praziquantel therapy.