Soil-Transmitted Helminths in Pre-School-Aged and School-Aged Children in an Urban Slum: A Cross-Sectional Study of Prevalence,Distribution, and Associated Exposures

Soil-transmitted helminths (STHs) are controlled by regular mass drug administration. Current practice targets school-age children (SAC) preferentially over pre-school age children (PSAC) and treats large areas as having uniform prevalence. We assessed infection prevalence in SAC and PSAC and spatial infection heterogeneity, using a cross-sectional study in two slum villages in Kibera, Nairobi. Nairobi has low reported STH prevalence. The SAC and PSAC were randomly selected from the International Emerging Infections Program''s surveillance platform. Data included residence location and three stools tested by Kato-Katz for STHs. Prevalences among 692 analyzable children were any STH: PSAC 40.5%, SAC 40.7%; Ascaris: PSAC 24.1%, SAC 22.7%; Trichuris: PSAC 24.0%, SAC 28.8%; hookworm < 0.1%. The STH infection prevalence ranged from 22% to 71% between sub-village sectors. The PSAC have similar STH prevalences to SAC and should receive deworming. Small areas can contain heterogeneous prevalences; determinants of STH infection should be characterized and slums should be assessed separately in STH mapping.     

Limitations of the intradermal test for schistosomiasis mansoni: experience from epidemiologic studies in a Puerto Rican community

The intradermal reaction with Schistosoma mansoni adult-worm antigen (35-40 microgram/ml nitrogen) was evaluated as an edpidemiologic tool in an endemic Puerto Rican community where the prevalence of S. mansoni infection was 36% and the geometric-mean egg count was 17.6 eggs/g. Subcutaneous injections of antigen were made in forearms, and stool specimens were examined for S. mansoni eggs by a formol-ether concentration method. Of 296 persons tested, 43% had positive intradermal reactions (greater than or equal to 1.0 cm 2 at least twice the area of the control wheal), compared to 48% positive stool examinations. However, sensitivity was low at 36% for children 14 yr old or less, and only 73% to 79% for adults. The test results were very specific for children (96%), but 32% of stool negative adults were positive. Mean wheal area was not directly related to intensity of infection as determined by egg counts in either children or adults, but did increase directly with age. Mean wheal areas were greater for males than females (both children and adults) at all intensities of infection. Because of unsatisfactory sensitivity and specificity the intradermal test may overestimate the prevalence of infection when rates are low, and underestimate prevalence of infection when rates are high. For its proper interpretation, complementary parasitologic data from stool surveys are required.     

Prevalence of intestinal parasites among children referred to Children's Medical Center during 18 years (1991-2008), Tehran, Iran

Epidemiological studies show that parasitic inections are among the most common infections and one of the biggest health problems of the society worldwide. Children at school age have the highest morbidity compared with other ages. Therefore, by treating these children, the disease burden in the total population is reduced. In this study, prevalence of parasitic infection in children referred to Children's Medical Center was compared in different years. In this retrospective cross-sectional study, the subjects were children under 13 years who were referred to Children's Medical Center Laboratory during 18 years (1991-2008) and underwent stool exam by any reason. The specimens were evaluated by different common methods of stool parasitology. In suspected cases, parasites was cultured in specific medium and stained as needed. Required data were obtained from the laboratory files and analysed according to study's purpose. Subjects were 124 366 children. Among them, 0.78% of cases had parasitic infections and 60.54% cases were male. Parasitic infections were related to protozoa in 95.33% cases and intestinal worms in 4.87%. Of them, 50.352% were pathogenic protozoa. The most parasitic infection was Giardia lamblia. Among intestinal worms, the highest prevalence was related to Hymenolepis nana (40.7%). A comparison between the first 10 years and the next 8 years of the study showed that the prevalence of intestinal parasites were 8% and 1% (P < 0.001) and the rate for protozoal infection were 14.9% and 4.3%, respectively (P < 0.001). The prevalence of intestinal parasites was reduced during recent years; however, more attempts should be performed to make it lower.     

广西人体重要寄生虫病现状调查

目的了解广西人体重要寄生虫病的流行现状和流行因素。方法按照全国人体重要寄生虫病现状调查的抽样方法进行抽样;粪便虫卵检查采用改良加藤厚涂片法、蛲虫卵检查采用透明胶纸拭肛法,血清学检查采用ELISA方法,并进行绦/囊虫病问卷调查。结果土源性线虫（钩、蛔、鞭、蛲）、华支睾吸虫总感染率为44.23%,检出7种虫种;其中,钩虫、蛔虫、鞭虫、蛲虫、华支睾吸虫感染率分别为18.52%、23.25%、11.37%、19.85%和3.71%。桂东、桂南地区总感染率较高（59.72%、47.98%）;学生总感染率（45.69%）较其他职业人群高;瑶族人群总感染率（76.77%）较其他民族高。≤15岁组人群蛔虫感染率较高,钩虫感染率随年龄的增加而增加,鞭虫感染者主要为5～15岁儿童。绦虫病主要集中在桂北和桂中的少数民族地区,以融水县绦虫感染率最高（8.46%）。结论广西人群土源性线虫感染率与12年前比较有较大幅度下降,但仍然处于较高水平,桂东、桂南地区感染率较高;食源性寄生虫感染呈上升趋势。     

Intestinal schistosomiasis among preschool children along the shores of Lake Victoria in Uganda

Schistosomiasis, a disease caused by Schistosoma trematode parasites, affects hundreds of millions of people and accounts for more than 40% of the global health burden due to neglected tropical diseases. In Uganda, intestinal schistosomiasis is endemic in 73 out of 112 districts and about 55% of the population of 36 million individuals are at risk. There is scanty information on the status and burden of schistosomiasis in preschool children less than six years of age in Uganda. This study aimed to assess the status of Schistosoma mansoni infections in children aged 1–5 years in Uganda. S. mansoni prevalence and intensity of infection were examined in 3058 children from 5 districts along Lake Victoria shoreline, eastern Uganda. For each child one stool sample was collected on three consecutive days. The Kato–Katz technique was used to prepare stool smears on slides for microscopic examination. Short interviews with a standardized pre-tested questionnaire prepared in the local language (Lusoga) were administered to each caregiver to identify risk factors associated with S. mansoni infection. An overall S. mansoni prevalence of 39.3% (95% CI: 38.0–41.1%) was estimated out of the 3058 stool samples examined. The geometric mean intensity of S. mansoni among the infected children was 273 (95% CI: 241–305) eggs per gram of faeces. Both prevalence and intensity of infection increased linearly with age (P < 0.0001) and were highest in the age group 49–60 months. Majority (61%) of the children, especially in the age group 12–24 months (84.2%; 95% CI: 75.6–90.1%), were lightly infected. Short interviews with caregivers revealed that preschool children, 1–5 years old, get exposed to S. mansoni infested waters through bathing, playing or swimming. It is important that the Uganda national control programme for schistosomiasis takes preschool children into consideration and that health education on transmission of schistosomiasis is delivered to the endemic communities regularly.     

A prospective study of visceral leishmaniasis in an endemic area of Brazil

The epidemiology, clinical patterns, and risk factors for visceral leishmaniasis were prospectively studied in an endemic area of Brazil. The prevalence of disease was 3.1% for children less than 15 years of age, and the annual incidence was 4.3 cases per 1,000 children. The number of children with disease fluctuated yearly and seasonally, and distribution of the disease varied within the endemic area. Risk factors included young age (median, three years) and malnutrition before the onset of disease. Intestinal parasitism, recent migration into the area, and house location within the area did not influence the progression of infection to disease. Serological testing indicated that 7.5% of children were infected with Leishmania each year and that the ratio of disease to infection was 1:18.5 for the whole area and 1:6.5 for the section with the highest prevalence of disease. Early diagnosis and therapy altered clinical patterns of the disease.     

The intensity and effects of infection with Schistosoma mansoni in a rural community in northeast Brazil.

The intensity of infection with Schistosoma mansoni and its effects were investigated in a defined population living on three contiguous fazendas (subcounties) in a nonmalarious area of northeast Brazil near Salvador, Bahia. Quantitative stool egg counts (Bell technique) were performed on 363 of 417 individuals (90%) of all ages; physical examinations were done on 294 of 357 individuals (82%) 5 years of age and older. The maximum increase in prevalence was observed between the 1- to 4- and 5- to 9-year age groups, while the maximum increase in fecal egg count occurred between 5- to 9- and 10- to 14-year age groups. Highest egg counts were observed in the 10- to 14-year age group (geometric mean of 301 eggs per ml of stool) while the maximum prevalence (100%) was in the 20- to 24-year age group. In the fazenda with the lowest quantitative egg counts the age specific prevalence rates increased more slowly than in the fazendas with higher egg counts. In the study group nearly 50% of the total fecal egg output was accounted for by 22 individuals (6%) who had a mean age of 12.6 years. Egg counts for this selected group were all over 800 eggs per ml of stool with a mean of 1,514 eggs per ml of stool. In children under 15 years of age, the frequency of hepatomegaly and splenomegaly varied directly with the egg count; further, the degree of hepatomegaly was directly correlated with increasing egg counts. No splenic enlargement was noted in children not excreting eggs. In adults, on the other hand, neither splenomegaly nor hepatomegaly could be directly related to schistosomal infection per se. In children, neither the presence of infection with S. mansoni nor its intensity was reflected by altered anthropometric measurements. In the one fazenda tested the frequency of stools positive for occult blood correlated with increasing S. mansoni egg counts.     

The effect of the number of stool samples on the observed prevalence and the infection intensity with Schistosoma mansoni among a population in an area of low transmission

Examination of faecal material by Kato Katz (KK) technique is a widely used approach for the diagnosis of intestinal schistosomiasis, particularly in epidemiological surveys. However, this technique lacks diagnostic sensitivity in individuals with low infection intensity or in low endemic areas. In the total population (TP) of 1265 individuals prevalence and infection intensity were established by examining two KK slides. A representative subset of 305 individuals, denominated experimental group (EG), was defined to assess the comparative advantage of an increased sampling effort using the KK technique. In addition stools of the participants of the EG were examined by the formol ether centrifugation technique. The proportion of all positive stool examinations detected by both methods among the experimental group served as reference value for prevalence (diagnostic 'gold' standard). Prevalence of schistosomiasis among TP based on two KK slides was 12.5%. Prevalence among the EG varied from 13.8%, based on one KK slide, over 27.2 based on 10 KK slides of three stool samples to 35.4% as value for the diagnostic 'gold' standard. The comparison of values for prevalence, stratified by age, revealed significant elevated numbers for all age groups, and interestingly, an extension of the highest prevalence levels until an age of 50 years. The overall infection intensity in eggs per gram (epg), calculated as geometric mean, was 83 epg for the TP based on one KK slide, 78 epg for the GE based on one KK slide and 28 epg based on 10 KK slides of three stool samples. In summary our data demonstrate that control programmes based on the examination of a single KK slide, as it is the case in Brazil, tend to underestimate significantly the prevalence and overestimate infection intensity. This applies especially for low endemic areas, where the efficacy and cost-effectiveness of such programmes become questionable. Our data also indicate that the possible solution of this problem lies in targeted mass treatment including age groups with the highest proportions of those infected. This will give high sensitivity together with sustainability and suitability under field conditions.     

Highlights on the World Bank Loan Schistosomiasis Control Program in China (1991-1998): a special focus on Hunan Province

A region-wide sampling survey was conducted in 1995 in order to evaluate the current epidemiological status of schistosomiasis japonica in Hunan Province, China. A total of 45,590 humans and 3,726 domestic animals, from 52 villages, were examined parasitologically and/or serologically for current Schistosoma japonicum infections. In uncontrolled endemic areas (43 villages) the overall human prevalence of S. japonicum was 7.81% across the different geographical subtypes. The geometric mean intensity of infection was 17.71 eggs per gram (epg) among infected individuals and only 1.25 epg in the general population. The bovine prevalence, as determined by the hatching test, was 9.63% in the uncontrolled endemic villages. Only one sero-positive (by indirect hemagglutination assay) child was found among 1,072 children tested aged 10-14 years in the 9 endemic villages under effective control. No infection was confirmed by the Kato-Katz thick smear stool examination. When the results of this survey were compared to those seen at baseline (1989) an overall reduction of 45.65% was seen in the human prevalence but no significant change was apparent in the lake-beach ecotype. Additionally, there was more than a 60% reduction in the prevalence among bovines over the same sampling period. The results demonstrate that the World Bank Loan Schistosomiasis Program was successful in achieving its most basic objectives for this province - to reduce human and bovine infections by 40%.     

A Five-Country Evaluation of a Point-of-Care Circulating Cathodic Antigen Urine Assay for the Prevalence of Schistosoma mansoni

We evaluated a commercial point-of-care circulating cathodic antigen (POC-CCA) test for assessing Schistosoma mansoni infection prevalence in areas at risk. Overall, 4,405 school-age children in Cameroon, Côte d''Ivoire, Ethiopia, Kenya, and Uganda provided urine for POC-CCA testing and stool for Kato-Katz assays. By latent class analysis, one POC-CCA test was more sensitive (86% versus 62%) but less specific (72% versus ∼100%) than multiple Kato-Katz smears from one stool. However, only 1% of POC-CCA tests in a non-endemic area were false positives, suggesting the latent class analysis underestimated the POC-CCA specificity. Multivariable modeling estimated POC-CCA as significantly more sensitive than Kato-Katz at low infection intensities (< 100 eggs/gram stool). By linear regression, 72% prevalence among 9–12 year olds by POC-CCA corresponded to 50% prevalence by Kato-Katz, whereas 46% POC-CCA prevalence corresponded to 10% Kato-Katz prevalence. We conclude that one urine POC-CCA test can replace Kato-Katz testing for community-level S. mansoni prevalence mapping.     

Longitudinal cohort study of the epidemiology of malaria infections in an area of intense malaria transmission II. Descriptive epidemiology of malaria infection and disease among children.

A large-scale longitudinal cohort project was initiated in western Kenya in June 1992. Between June 1992 and July 1994, 1,848 children less than 15 years of age were monitored prospectively for a mean of 236 days. During this period, 12,035 blood smears were examined for malaria and only 34% were found to be negative. Parasite prevalence (all species) decreased with age (from a high of 83% among children 1-4 years old to 60% among children 10-14 years old). Even more dramatic decreases were noted in the prevalence of high density falciparum infection (from 37% among children 12-23 months old to < 1% among 10-14-year-old children) and in clinical malaria (20% to 0.3% in the same age groups). Children < 1 year of age accounted for 55% of all cases of anemia detected. Anemia was consistently associated with high density infection in children < 10 years of age (20% to 210% increased risk relative to aparasitemic children). These results demonstrate the relationship between high-density malaria infection and two clinical manifestations of malarial illness.     

Seroepidemiology of schistosomiasis japonica by ELISA in the Philippines. III. Selective mass chemotherapy with praziquantel in a control program

After a pre-control (pre-treatment) prevalence rate of schistosomiasis japonica was established by stool examination and by ELISA in about 400 school children in school year 1979, annual prevalence rates were measured in the following 3 assessment years. From 54-80% of children found infected primarily by stool examination were treated with praziquantel 3-9 months before the assessment examinations. Both stool examination and ELISA showed statistically significant reductions of prevalence from the 1st to the 3rd assessment years (average reduction of 50% measured by stool examination and average reduction of 19% measured by ELISA). These reductions were expected as a result of the biologic activity of the effective schistosomicide; they are therefore not acceptable evidence of reduced transmission levels. By decreasing human sources of snail infection, an effective schistosomicide may have the epidemiologic impact of reducing transmission; assessment prevalence rates can be relevant indices of transmission levels only if the biologic effect of the schistosomicide is dissociated from its epidemiologic impact in a control program in which selective mass chemotherapy plays a dominant role. This dissociation was accomplished in this study by measurements in an essentially untreated group of "new" pupils, i.e., those who entered the school at the beginning of each assessment year. Overall prevalence rates among the "new" pupils did not show a significant reduction until the 3rd assessment year as measured by stool examination (reduction by 36% of pre-control level); as measured by ELISA, a significant reduction (by 15-17%) was detected in the 2nd and 3rd assessment years. The youngest children, and girls more than boys, were the most sensitive indicators of change.(ABSTRACT TRUNCATED AT 250 WORDS)     

Toxocara seroprevalence in children from a subtropical city in Argentina

Most studies from Argentina have focused on toxocariasis as an environmental problem of big cities, and there are no available data about children infection from small or middle-sized cities. In order to assess the prevalence of anti-Toxocara antibodies in infantile population, 206 children from Resistencia, of both sexes, aged 1-14 years old were studied by Elisa testing with E/S T. canis L2 antigens. Hematological parameters and immunoglobulin levels were determined; five days' stool samples were studied and epidemiological data were obtained by means of a questionnaire to parents. Results showed that 73% of the children had one or more dogs living at home, 57% reported geophagia and 37.9% were positive for Toxocara serology, but there was no significant difference in prevalence neither for boys and girls, nor concerning age. An increased risk of infection was observed in age groups 5-6 and 7-8 for boys, and in age groups 3-4 and 5-6 for girls.     

Onchocerciasis in pre-primary school children in Nigeria: lessons for onchocerciasis country control programme.

There is limited data on the prevalence of onchocerciasis in young children in Nigeria, partly because treatment with the effective drug Ivermectin has been contra-indicated in children less than 5. As the risk of complications of onchocerciasis is related to duration and intensity of infection, it would be beneficial to know the prevalence in young children for design of control programmes. A study was therefore undertaken to determine the prevalence of onchocerciasis in 642 children 0-4 years old in a rain forest endemic community in South East Nigeria. The overall onchocerciasis prevalence (positive skin snips) for children 0-4 years old in three Local Government Areas in Enugu State, Eastern Nigeria was 15.7% with no significant difference in infection rates between male and female children. There was no detectable infection in children less than 1 year old. Characteristic onchocercal rash was identified in 11.1% of the children and presence of typical onchocercal subcutaneous palpable nodules in 4.6%. Total prevalence for adults in the same population was found to be 26.9%. This indicates that in onchocerciasis endemic communities, everybody may be at risk of infection irrespective of age.     

Cryptosporidium infection in young children with diarrhea in Rawalpindi, Pakistan.

Fecal excretion of Cryptosporidium parvum oocysts was determined in 625 children less than five years old who presented at the pediatric clinic of a teaching hospital in Rawalpindi, Pakistan. Single stool specimens were collected from 475 children with acute diarrhea and from 150 children without diarrhea. The Cryptosporidium infection rate was significantly higher in children with diarrhea than in children without diarrhea (10.3% versus 3.3%). The C. parvum infection rate was highest in children 19-24 months of age (21.8%). There was no significant difference in the Cryptosporidium infection rate among male and female children of any age group studied. Sociodemographic information, drinking water supply, and contact with domestic animals had no significant role in the acquisition of C. parvum infection in our study population. The data suggest that C. parvum is relatively endemic in young children in the Rawalpindi area and that C. parvum may be an important pathogen associated with diarrhea.     

Annual risk of tuberculous infection in rural areas of Uttar Pradesh, India.

SETTING: Rural areas in Uttar Pradesh, the most populous state in India. OBJECTIVES: 1) To estimate the average annual risk of tuberculous infection (ARI), 2) to study ARI trends with age, and 3) to compare tuberculin reactions among children with and without BCG scar. STUDY DESIGN: A cross-sectional tuberculin survey was conducted among children aged 1-9 years residing in Rae Bareli, Hardoi and Jaunpur districts, Uttar Pradesh. Tuberculin testing was performed using 1TU of PPD RT23 with Tween 80, and indurations were measured 72 hours later. Prevalence of infection was estimated in children without BCG scar based on the cut-off point identified on the frequency distribution of reaction sizes. The ARI was computed from the estimated prevalence. RESULTS: The proportion of children with BCG scar varied from 25% to 31% in the study districts. Using a cut-off of 14 mm among children without BCG scar, the ARI was estimated at 2.3% in Rae Bareli, 1.9% in Hardoi and 1.5% in Jaunpur, and was observed to increase with age. Tuberculin test results among children with BCG scar suggest that they may be included in tuberculin surveys to estimate ARI. CONCLUSION: High rates of transmission of tuberculous infection suggest that tuberculosis control measures need to be intensified.     

Annual risk of tuberculous infection in the western zone of India.

SETTING: Rural and urban areas of six selected districts in the western zone of India. OBJECTIVES: To estimate the annual risk of tuberculous infection (ARI). DESIGN: A community-based, cross-sectional tuberculin survey was conducted among children aged 1-9 years residing in a sample of rural and urban areas of six districts in the western zone of India. Stratified two-stage cluster sampling was adopted for selection of rural and urban clusters. A total of 48473 children in 600 clusters underwent tuberculin testing with 1TU PPD RT23 with Tween 80; the induration was measured about 72 h after the test. RESULTS: The BCG scar was observed in 52% of the test-read children. Estimation of the prevalence of infection was based on the frequency distribution of tuberculin reaction size among 22259 children without BCG scar. Reactions > or = 15 mm were considered attributable to infection with tubercle bacilli. The prevalence of infection was estimated to be 9.3%, and the ARI computed from the estimated prevalence was 1.8%. The proportion of infected children was found to be significantly higher in urban than in rural areas. CONCLUSION: The high rate of ARI in the western zone of India calls for further intensification of tuberculosis control efforts.     

Factors associated with Schistosoma mansoni infection 5 years after selective treatment in a low endemic area in Brazil.

Five years after a single dose treatment, prevalence, intensity and morbidity of schistosomiasis mansoni were evaluated in Agua Branca, a low endemic community in the South East Brazil (cure rate 94%). At community level, prevalence showed a decrease from 38.9 to 24.5% and the intensity of infection dropped from 119.5 to 38.9 eggs per g of faeces (epg). However, after the exclusion of immigrants, newborn children and individuals that had left the area after the first evaluation, the prevalence among the treated and followed population was not significantly affected. Multivariate analysis showed that the 10-29 age group and water contact for agricultural purposes were independently associated with the presence of infection on post treatment evaluation [OR 3.9 and 5.09, respectively]. A previous treatment among subjects older than 15 years was inversely associated [OR 0.58]. The authors wish to draw attention to the fact that mobility may lead to a serious bias in evaluating the impact of the control programme.     

Iodine status and goiter prevalence in Turkey before mandatory iodization

Endemic goiter is an important public health problem in Turkey. Legislation for mandatory iodization of household salt was passed in July 1999. Current study is aimed at ascertaining the goiter prevalence and iodine nutrition in school-age children (SAC) living in known endemic areas of Turkey. Sonographic thyroid volumes (STV) and urinary iodine concentrations (UIC) of 5,948 SAC from 20 cities were measured between 1997-1999. STV of 31.8% of the SAC examined stayed above the upper-normal limits for the same age and gender recommended by the World Health Organization (WHO). Goiter prevalence ranged between 5 to 56% and median UIC ranged between 14 to 78 microg/l, indicating severe to moderate iodine deficiency (ID) in 14 and mild ID in 6 of the cities surveyed. Neither of the cities was found to have sufficient median UIC levels. The current study shows that endemic goiter is an important public health problem and iodine nutrition is inadequate nationwide. It also provides reliable scientific evidence and shows the need for a controlled and effective iodine supplementation program nationwide. Mandatory iodization of household salt seems to be the essential measure taken for the moment, additional measures may be needed in the near future.     

Seroepidemiology of schistosomiasis japonica by ELISA in the Philippines. I. Underestimation by stool examination of the prevalence of infection in school children

In a longitudinal seroepidemiological study in the Schistosoma japonicum endemic area of Leyte, the ELISA technique to determine prevalence and incidence rates in elementary school children was compared with similar determinations made by a modified quantitative stool examination (MIFC). In the area of this study, Barrio Salvador, Tanauan, Leyte, the ongoing schistosomiasis japonica control program in the Philippines is dependent on stool examination by MIFC and/or the quantitative thick smear (Kato-Katz) for measurement of prevalence and incidence. Over a 3-year period with multiple periodic examinations, infection rates were measured and the serologic technique was compared to stool examination in 598 untreated children (mostly 7-10 years of age) of Salvador Elementary School. A group of 150 school children from a non-endemic area, Milagros, Masbate, provided sera as a reference negative control. ELISA results are expressed as ELISA activity (EAc) in reference to a positive control serum pooled from parasitologically confirmed cases, dilutions of which were always included in each assay. A convenient positive-negative discrimination level was chosen based on the EAc values obtained from 170 stool-positive Salvador pupils and the 150 pupils of the non-endemic area. Using the chosen discrimination level, ELISA in this study had a sensitivity of 98% and a specificity of 96%. ELISA was significantly more sensitive than stool examination in detecting infections; only 28% of the children were stool positive on a single examination in contrast with 56% positive by ELISA. A single stool examination underestimated serologic positives by 50% while two stool examinations 4 months apart reduced the underestimate to 29%. The underestimation varied by age and sex, and showed no consistent pattern in this regard. Stool-positive children had a wide variation of egg counts with a geometric mean of 6.4 eggs/g of stool, with 52% of the stool positives excreting only 1-5 eggs/g. A high percentage of infected children have a misdiagnosis of infection by stool examination. This has, in the past, resulted in many being misclassified as noninfected. This erroneous classification has serious consequences on the measurement of prevalence and incidence, on studies of clinical manifestations of the disease, and on the evaluation of serologic techniques for diagnosis. Stool examination does not give an accurate measurement of prevalence, and therefore it cannot be relied upon for the evaluation of the current control program. It is recommended that the capability to undertake serodiagnostic tests for schistosomiasis japonica be encouraged and adopted in the Philippines for field