The Epidemiology of Schistosomiasis in Egypt: Minya Governorate

Am. J. Trop. Med. Hyg., 62(2)S, 2000, pp. 65–72 Copyright ᭧ 2000 by The American Society of Tropical Medicine and Hygiene

THE EPIDEMIOLOGY OF SCHISTOSOMIASIS IN EGYPT: MINYA GOVERNORATE

NABIL S. GABR, TAREK A. HAMMAD, ANWAR ORIEBY, EGLAL SHAWKY, MAHMOUD A. KHATTAB, AND G. THOMAS STRICKLAND Departments of Medical Parasitology and Internal Medicine, Minya University School of Medicine, Minya, Egypt; Department of Epidemiology and Preventive Medicine, School of Medicine, University of Maryland at Baltimore, Maryland

Abstract. 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.

Minya is 1 of the 3 Governorates that constitute Middle household levels but the whole household was included in Egypt. It is about 240 km south of Cairo between Beni-Suef the study sample. and Assiut on the Nile River. It is bounded on the east by The interview technique for collecting vital, environmen- the Nile River and on the west by the western desert. There tal, sociodemographic, and medical data is described in de- are three main carrier canals, in addition to the Nile River tail.1 Quantitative microscopic counting of Schistosoma ova that supply Minya with water. The total area of Minya is was performed in stool (using a modified Kato technique) 2,262 km2 and the population density is 1,292 persons/km2. from 11,688 subjects and in urine (using the Nuclepore The total population according to the 1986 census of the [Pleasanton, CA] filter technique) from 12,134 individuals Central Agency for Population Mobilization and Statistics as described.2 was 3,075,691, of whom 75% lived in rural areas. Physical examination and abdominal ultrasonography A population-based study, the Epidemiology 1, 2, 3 Pro- were performed by trained physicians upon inhabitants of ject, sponsored by the Egyptian Ministry of Health/United every fifth household as described.3 Although the protocol States Agency for International Development (USAID)- called for excluding children less than 5 years old, many sponsored Schistosomiasis Research Project, performed were examined and the data from those evaluated are in- cross-sectional surveys in 9 Governorates in Egypt in 1991 cluded; 2,208 inhabitants from 479 households had clinical and 1992. The objectives were to assess 1) the prevalence and ultrasound investigations, the results of which were re- and intensity of infection with Schistosoma sp., 2) the prev- corded on 2 additional forms. alence and magnitude of morbidity caused by schistosomi- Not all data from the 2,208 subjects having physical and asis, and 3) the changing pattern of schistosomiasis in Egypt. ultrasonographic examinations were available for complete Herein, we report the results of this survey in Minya Gov- analysis for the following reasons: 1) 233 (10.6%) did not ernorate. provide urine specimens for parasitology, hematuria, and proteinuria examinations; 2) 327 (14.8%) did not provide

SUBJECTS AND METHODS stool specimens for parasitology examination; 3) 1,404 (63.6%) did not have height and weight measured and re- The sample size, selected by multistage random sampling, corded; 4) 31 (1.4%) did not respond to the question re- was calculated to detect a prevalence of Schistosoma sp. as garding a history of schistosomiasis; 5) 29 (1.3%) did not low as 5% in each ezba (satellite communities) or mother respond to the question regarding prior treatment for schis- village with a 90% conﬁdence level. The ﬁndings are con- tosomiasis; 6) 136 (6.2%) failed to respond to the question sidered representative of the rural areas of the entire gov- regarding burning micturition; and 7) 115 (5.2%) did not ernorate.1 The total sample population consisted of 16,433 answer the question regarding blood in the urine. individuals from 2,409 households in 8 villages and their The most important among these omissions are 1) the ab- ezbas. Randomization took place at the village/ezba and sence of urine specimens from 10% of the subjects, which 65 66 GABR AND OTHERS

TABLE 1 Odds ratio and 95% conﬁdence limits for risk factors for infection with Schistosoma haematobium in Minya Governorate*

Infected Risk factor Total in group No. (%) Odds ratio Confidence limits Demographics Age groups (years) 0–10 4,015 357 (8.9) 11–20 2,775 493 (17.8) 2.21 1.91–2.56 21–35 2,506 152 (6.1) 0.66 0.54–0.81 36–55 1,891 51 (2.7) 0.28 0.21–0.38 Ͼ55 947 32 (3.4) 0.36 0.25–0.52 Gender Female 6,182 365 (5.9) Male 5,952 720 (12.1) 2.19 1.92–2.50 Domicile Village (Ն500 houses) 4,053 401 (9.9) Ezba (Ͻ500 houses) 8,081 684 (8.5) 0.84 0.74–0.96 Exposure to canal water Bathing (males) No 4,667 510 (10.9) Yes 1,150 196 (17.0) 1.67 1.40–2.00 Washing (females) No 4,633 247 (5.3) Yes 1,536 118 (7.7) 1.48 1.18–1.85 Playing (children Ͻ15 years old) No 4,752 513 (10.8) Yes 479 97 (20.3) 2.10 1.65–2.67 Clinical findings History of schistosomiasis No 8,698 749 (8.6) Yes 1,633 210 (12.9) 1.57 1.33–1.84 Prior treatment of schistosomiasis No 9,759 827 (8.5) Yes 1,637 210 (12.8) 1.59 1.35–1.87 History of burning micturition No 1,298 108 (8.3) Yes (total) 641 66 (10.3) 1.26 0.92–1.75 Ͻ15 years 180 32 (17.8) 1.62 1.02–2.58 Ն15 years 461 34 (7.4) 1.26 0.79–1.99 History of blood in urine No 1,622 125 (7.7) Yes 339 50 (14.7) 2.07 1.46–2.94 Ͻ15 years 127 26 (20.5) 1.94 1.18–3.19 Ն15 years 212 24 (11.3) 2.23 1.35–3.68 Hepatomegaly in MCL (by PE) No 565 49 (8.7) Yes 164 10 (6.1) 0.68 0.34–1.38 Ͻ15 years 71 7 (9.9) 0.88 0.35–2.16 Ն15 years 93 3 (3.2) 0.41 0.12–1.39 Splenomegaly (by PE) No 1,829 167 (9.1) Yes 129 8 (6.2) 0.66 0.32–1.37 Ͻ15 years 19 4 (21.1) 1.76 0.57–5.41 Ն15 years 110 4 (3.6) 0.53 0.19–1.47 Laboratory findings Hematuria No 9,433 426 (4.5) Yes 2,477 648 (26.2) 7.49 6.56–8.55 Ͻ15 years 915 382 (41.7) 12.64 10.48–15.25 Ն15 years 1,562 266 (17.0) 5.17 4.26–6.27 SCHISTOSOMIASIS IN EGYPT 67

TABLE 1 Continued

Infected Risk factor Total in group No. (%) Odds ratio Confidence limits Proteinuria No 11,429 889 (7.8) Yes 478 185 (38.7) 6.49 6.15–9.11 Ͻ15 years 217 133 (61.3) 14.83 11.11–19.80 Ն15 years 261 52 (19.9) 3.66 2.66–5.05 Ultrasonography Hepatomegaly in MCL No 565 48 (8.5) Yes 165 12 (7.3) 0.84 0.44–1.63 Ͻ15 years 73 10 (13.7) 1.41 0.62–3.22 Ն15 years 92 2 (2.2) 0.26 0.06–1.13 Hepatomegaly in MSL No 697 58 (8.3) Yes 32 2 (6.3) 0.73 0.17–3.15 Ͻ15 years 13 1 (7.7) 0.65 0.08–5.21 Ն15 years 19 1 (5.3) 0.77 0.10–5.94 Splenomegaly No 1,675 151 (9.0) Yes 267 17 (6.4) 0.69 0.41–1.15 Ͻ15 years 56 5 (8.9) 0.64 0.25–1.65 Ն15 years 211 12 (5.7) 0.89 0.47–1.68 Periportal fibrosis No 1,689 150 (8.9) Yes (Ն3 mm) 266 24 (9.0) 1.02 0.65–1.60 Ͻ15 years 56 9 (16.1) 1.26 0.60–2.66 Ն15 years 210 15 (7.1) 1.17 0.65–2.10 Grade I (3–Ͻ5 mm) 262 22 (8.4) 0.94 0.59–1.50 Grade II (5–Ͻ7 mm) 2 2 (100.0) Grade III (Ն7 mm) 2 0 (0.0) Bladder wall lesions No 1,969 174 (8.8) Yes 6 1 (16.7) 2.06 0.24–17.76 Ͻ15 years 3 1 (33.3) 3.28 0.29–36.55 Ն15 years 3 0 (0.0) Obstructive uropathy No 1,964 174 (8.9) Yes 54 3 (5.6) 0.61 0.19–1.96 Ͻ15 years 5 0 (0.0) Ն15 years 49 3 (6.1) 0.88 0.27–2.85 * MCL ϭ midclavicular line; PE ϭ physical examination; MSL ϭ midsternal line. excludes them from any analyses based on S. haematobium lence of morbidity variables of interest, e.g., hepatomegaly, infection; and 2) the absence of height measurements in splenomegaly, bladder wall lesions, obstructive uropathy, 64%, which excludes them from any analyses of hepatic en- with the 33 community burdens of schistosomiasis. largement since height was used to adjust hepatic span according to body size. RESULTS All data was transferred from the data collection forms to standard precoded sheets for computer entry using Epi-Info The prevalence of S. haematobium in the 33 surveyed 5.01b (Centers for Disease Control and Prevention, Atlanta, communities ranged from 1.9% to 32.7% and showed a GA) and verified prior to analysis. Survey Data Analysis mean Ϯ SE value of 8.9 Ϯ 0.8% (Figure 1). The average (SUDAAN) software1 was used to calculate Schistosoma intensity of infection (GMEC) in the surveyed villages was prevalence and the geometric mean egg count (GMEC) for 8.5/10 ml of urine and ranged from 1.6 to 30.9. each governorate in its entirety and distributed by commu- Prevalence followed the classical community pattern for nity, gender, and age. Further analysis was performed by S. haematobium, being maximum (18–20%) in those 10–20 using SPSS/PCϩ version 4.01 (SPSS, Inc., Chicago, IL). years of age, decreasing to approximately 12% in those 20– Community burdens of schistosomiasis haematobia were es- 25 years old and lower in those Ͻ10 or Ͼ25 years old (Fig- timated using the log(X ϩ 1) GMEC. Correlation coeffi- ure 2). Intensity of infection followed the same pattern, be- cients were calculated to test the association of the preva- ing higher, i.e., 12.5 ova/10 ml of urine in those 5–15 years 68 GABR AND OTHERS

TABLE 2 Odds ratio and 95% conﬁdence limits for risk factors for urinary tract morbidity (obstructive uropathy and/or bladder wall lesion) with Schistosoma haematobium in Minya Governorate*

Morbidity Risk factor Total in group No. (%) Odds ratio Confidence limits Demographics Age groups (years) 0–10 584 6 (1.0) 11–20 530 5 (0.9) 0.92 0.28–3.02 21–35 517 19 (3.7) 3.67 1.46–9.27 36–55 380 22 (5.8) 5.92 2.38–14.74 Ͼ55 197 10 (5.1) 5.15 1.85–14.36 Gender Female 1,154 19 (1.6) Male 1,054 43 (4.1) 2.54 1.47–4.39 Domicile Village (Ն500 houses) 782 16 (2.0) Ezba (Ͻ500 houses) 1,426 46 (3.2) 1.60 0.90–2.84 Exposure to canal water Bathing (males) No 780 36 (4.6) Yes 246 6 (2.4) 0.52 0.22–1.24 Washing (females) No 811 11 (1.4) Yes 342 8 (2.3) 1.74 0.69–4.37 Playing (children Ͻ15 years old) No 706 8 (1.1) Yes 102 1 (1.0) 0.86 0.11–6.98 Parasitologic findings S. haematobium infection No 1,800 55 (3.1) Yes 175 4 (2.3) 0.74 0.27–2.07 Ͻ20 ova/10 ml of urine 132 4 (3.0) 0.99 0.35–2.78 Ն20 ova/10 ml of urine 43 0 (0.0) Clinical findings History of schistosomiasis No 1,541 46 (3.0) Yes 345 11 (3.2) 1.07 0.55–2.09 Prior treatment of schistosomiasis No 1,752 49 (2.8) Yes 345 11 (3.2) 1.14 0.59–2.22 History of burning micturition No 1,370 27 (2.0) Yes (total) 702 31 (4.4) 2.30 1.36–3.88 Ͻ15 years 189 3 (1.6) 1.80 0.43–7.60 Ն15 years 513 28 (5.5) 2.06 1.17–3.64 History of blood in urine No 1,726 41 (2.4) Yes 367 20 (5.4) 2.37 1.37–4.09 Ͻ15 years 134 2 (1.5) 1.57 0.31–7.88 Ն15 years 233 18 (7.7) 2.54 1.41–4.57 Hepatomegaly in MCL (by PE) No 596 22 (3.7) Yes 176 2 (1.1) 0.30 0.07–1.29 Ͻ15 years 77 1 (1.3) 1.28 0.11–14.28 Ն15 years 99 1 (1.0) 0.19 0.03–1.46 Splenomegaly (by PE) No 1,957 57 (2.9) Yes 140 4 (2.9) 0.98 0.35–2.74 Ͻ15 years 21 0 (0.0) Ն15 years 119 4 (3.4) 0.83 0.29–2.33 SCHISTOSOMIASIS IN EGYPT 69

TABLE 2 Continued

Morbidity Risk factor Total in group No. (%) Odds ratio Confidence limits Laboratory findings Hematuria No 1,544 31 (2.0) Yes 433 27 (6.2) 3.25 1.92–5.50 Ͻ15 years 131 3 (2.3) 2.73 0.64–11.56 Ն15 years 302 24 (7.9) 3.09 1.75–5.47 Proteinuria No 1,888 53 (2.8) Yes 90 5 (5.6) 2.04 0.79–5.27 Ͻ15 years 35 0 (0.0) Ն15 years 55 5 (9.1) 3.09 0.98–6.77 Ultrasonography Hepatomegaly in MCL No 618 23 (3.7) Yes 185 4 (2.2) 0.57 0.20–1.67 Ͻ15 years 86 2 (2.3) 4.67 0.42–52.17 Ն15 years 99 2 (2.0) 0.37 0.09–1.62 Hepatomegaly in MSL No 770 25 (3.2) Yes 32 2 (6.3) 1.99 0.45–8.79 Ͻ15 years 13 0 (0.0) Ն15 years 19 2 (10.5) 2.56 0.56–11.76 Splenomegaly No 1,866 54 (2.9) Yes 296 8 (2.7) 0.93 0.44–1.98 Ͻ15 years 63 1 (1.6) 1.46 0.18–11.89 Ն15 years 233 7 (3.0) 0.73 0.33–1.64 Periportal fibrosis No 1,882 53 (2.8) Yes (Ն3 mm) 296 7 (2.4) 0.84 0.38–1.86 Ͻ15 years 64 0 (0.0) Ն15 years 232 7 (3.0) 0.76 0.34–1.71 Grade I (3–Ͻ5 mm) 292 7 (2.4) 0.85 0.38–1.88 Grade II (5–Ͻ7 mm) 2 0 (0.0) Grade III (Ն7 mm) 2 0 (0.0) * MCL ϭ midclavicular line; PE ϭ physical examination; MSL ϭ midsternal line.

of age and usually lower in those Ͻ5 and Ͼ15 years of age. teinuria were highly associated, particularly in children, with The prevalence and intensity of infection were usually much S. haematobium infection. higher, particularly in children and young adults, in males The presence of hepatomegaly or splenomegaly on phys- than in females. Infection with S. mansoni was present main- ical examination was not associated with S. haematobium ly in 1 village (Atnia); 16.1% of its inhabitants had ova ova in the urine. Neither hepatomegaly, as measured by ul- detected in their stool and the GMEC was 97.7 ova/g of trasonography in the midclavicular line (MCL) or the mid- stool. Atnia also was endemic for schistosomiasis haemato- sternal line (MSL) nor ultrasonography-detected splenomeg- bia with a community prevalence of 10.0% and GMEC of aly were more frequently present in infected than in unin- 12.0 ova/10 ml of urine. fected subjects. A total of 164 (22.5%) of 729 had hepato- Risk factors signiﬁcantly associated with S. haematobium megaly detected by physical examination and 129 of (6.6%) infection were an age from 11 to 20 years, male gender, 1,958 had splenomegaly detected by physical examination. males bathing in canals, females washing clothing or utensils The frequency of ultrasonography-detected hepatomegaly of in canals, children swimming or playing in canals, and a the right lobe of the liver (measured in the MCL) was similar history of, or treatment for, schistosomiasis (Table 1). A pre- (165 of 730, 22.6%) but splenomegaly was detected more sent or past history of burning micturition was associated frequently by ultrasonography (267 of 1942, 13.7%) than by with infection in children, but not in adults, while a history physical examination. Hepatomegaly of the left lobe of the of blood in the urine correlated with S. haematobium ova in liver (measured in the MSL) was detected by ultrasonogra- the urine in both age groups. Those living in ezbas had a phy in only 32 (4.4%) of 729 subjects. Schistosoma ova were lower prevalence of S. haematobium than inhabitants of larg- not detected more frequently in urine from subjects with er communities. Reagent strip-detected hematuria and pro- periportal ﬁbrosis (PPF) compared with urine from subjects 70 GABR AND OTHERS

FIGURE 1. Prevalence (%) (bars) and intensity (asterisks)of Schistosoma mansoni infection in Minya Governorate. Solid hori- FIGURE 3. Age-adjusted prevalence of ultrasound-detected uri- zontal bars show prevalences in villages, hatched horizontal bars nary tract lesions in Minya Governorate. UB ϭ urinary bladder wall. show prevalences in ezbas, the solid vertical line is the mean prevalence for all communities, the broken vertical line is the mean intensity of infection, and the asterisks are the geometric mean egg ing more prevalent in adults than in children (Table 2). It counts/10 ml of urine for each community. also was more common in males than in females, but not in inhabitants of ezbas. There was no relationship between ul- without this finding. There were only 2 subjects each with trasonography-detected urinary tract morbidity and expo- grade II or grade III lesions. The remaining 262 had grade sures to canal water, the presence or intensity of ova in the I changes, giving a PPF prevalence of 13.6%. Bladder wall urine, or a history of, or treatment for, schistosomiasis. It lesions were very rare, being present in only 6 (0.3%) sub- was associated with histories of burning micturition or blood jects. Therefore, there was no correlation between this pa- in urine in adults, but not in children. Laboratory-detected rameter and infection. Obstructive uropathy was detected in hematuria and proteinuria were associated with morbidity, 54 (2.7%) subjects; the majority with these lesions were but only in adults. adults. Urinary tract obstruction was not associated with S. There was no association between hepatomegaly or haematobium ova in the urine. splenomegaly, as detected by physical examination, or ultra- There was no hepatomegaly detected by either physical sonography-detected hepatomegaly (in either the MCL or examination or ultrasonography or PPF in Atnia, the village MSL), splenomegaly, or PPF and urinary tract morbidity. with a 16.1% prevalence of S. mansoni. Splenomegaly was Hepatomegaly as detected by physical examination had detected in 6.9% of those in that community surveyed by no significant relationship with age, while the prevalence of physical examination and 10.1% of those surveyed by ultra- palpable spleens increased with age. There was no associa- ϭϪ sonography. tion between the prevalence of hepatomegaly (r 0.31, P ϭ ϭ ϭ Morbidity defined as ultrasonography-detected bladder 0.09) or splenomegaly (r 0.01, P 0.48) as detected wall lesions or obstructive uropathy was age dependent, be- in the population by physical examination and the community burden of S. haematobium infection. Ultrasonography- detected enlargement of the right lobe of the liver was more prevalent in adults, while there was a slight age-related increase in enlargement of the left lobe of the liver, PPF, and splenomegaly. The prevalence of ultrasasonography-detected hepatomegaly in both the MCL (r ϭϪ0.35, P ϭ 0.06) and MSL (r ϭϪ0.29, P ϭ 0.11), splenomegaly (r ϭϪ0.18, P ϭ 0.16) and PPF (r ϭϪ0.08, P ϭ 0.33) had no relationship to community burden of schistosomiasis haematobia. Ultra- sonography-detected obstructive uropathy increased with age, but there were too few bladder wall lesions to test its association with age (Figure 3). The prevalence of ultrasonography-detected bladder wall lesions had no relationship (r ϭϪ0.20, P ϭ 0.14), while urinary tract obstruction had a marginal negative correlation (r ϭϪ0.38, P ϭ 0.02) with community burden of schistosomiasis haematobia.

DISCUSSION FIGURE 2. Age- and gender-adjusted prevalence and intensity of Schistosoma mansoni infection in Minya Governorate. GMEC ϭ This is the first detailed description of the epidemiology geometric mean egg count. of schistosomiasis on a community level in Minya Gover- SCHISTOSOMIASIS IN EGYPT 71 norate since Scott’s survey 60 years ago.4 In 1935, S. hae- to confirm studies reporting mild degrees of hepatosplenic matobium prevalence in El-Minya Governorate was 45% involvement with S. haematobium in Egypt.16,22 These latter among 3,022 examined individuals.4 During the past 60 reports evaluated specific pediatric populations. Older sub- years, the infection rate has decreased: 39% of 8,597 in jects would have other causes of hepatic pathology, e.g., 19559 to 33.6% in 197710 and to 5% in 1988 following im- those associated with chronic viral hepatitis, which would plementation of the National Bilharzial Control Program.11 reduce the specificity of ultrasonography for evaluating he- Since the current study used a more sensitive diagnostic patosplenic lesions caused by schistosomiasis.23 technique and more comprehensive sampling than the latter In conclusion, this study was unable to correlate any form Ministry of Health report, the overall prevalence of 8.9% of morbidity, except reagent strip-detected hematuria and does not represent an increase in S. haematobium infection proteinuria, with S. haematobium infection in Minya. This rate in Minya Governorate. Nonetheless, the variability in absence of association between infection and morbidity may prevalence of S. haematobium in different communities il- be partially caused by technical difficulties. However, the lustrates the focal nature of schistosomiasis. extensive and frequent use of chemotherapy in the Ministry Gabr recorded the presence of this focus of S. mansoni of Health ongoing control program during the last decade infection in Atnia village together with natural infection of has clearly reduced intensity of infection and, thus, morbid- local Biomphalaria alexandrina snails.12 Our study confirms ity greater than it has reduced prevalence of infection. the spread of this species up the Nile River and its focality in Minya. Continuing surveillance, rapid treatment of in- Acknowledgments: Dr. Mohamed H. Hussein (Kasr El-Aini Faculty fected subjects, and focal attack of snails in transmission of Medicine, Cairo University) supervised Dr. Nabiel N. H. Mikhail sites are required to interrupt the further extension of S. man- (Faculty of Medicine, Assiut University), who performed the data soni into Upper Egypt. analysis. The profile of infection across age groups and gender and Financial support: This research was supported by the Egyptian Min- risk factors for infection is in concordance with many pre- istry of Health/USAID-funded Schistosomiasis Research Project, vious studies of schistosomiasis in Egypt and in other en- 263-0140.2, grants no. 02-04-020 and 10-04-83. demic areas.5–8 Medical histories of canal water exposures, Authors’ addresses: Nabil S. Gabr and Tarek A. Hammad, Depart- prior schistosomiasis, and urinary symptoms all slightly in- ment of Medical Parasitology, Minya University School of Medi- creased the odds of an individual subject having an active cine, Minya, Egypt. Anwar Orieby, Eglal Shawky, and Mahmoud S. haematobium infection. A. Khattab, Department of Internal Medicine, Minya University School of Medicine, Minya, Egypt. G. Thomas Strickland, Interna- Pathology due to S. haematobium occurs primarily in the tional Health Program, Department of Epidemiology and Preventive urinary bladder, the ureters, and the kidneys.13,14 These le- Medicine, School of Medicine, University of Maryland at Baltimore, sions are most commonly visualized by ultrasonography in Baltimore, MD 21201. children in endemic areas.15,16 The fact that we detected blad- Reprint requests: Schistosomiasis Research Project, Medical Servic- der lesions in only 3 of almost 1,000 children examined, es Corporation International, 1716 Wilson Boulevard, Arlington, VA despite an infection rate of 14%, could be explained by a 22209. deficiency in our ultrasonographic examinations. An empha- sis in training was placed on detecting PPF and other hepatic REFERENCES lesions, not on detecting urinary tract lesions. 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