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.

Detection of Fasciola-specific excretory/ secretory (E/S) protein fraction band (49.5 kDa) and its utilization in diagnosis of early fascioliasis using different diagnostic techniques.

The objective of the present work is to evaluate Fasciola E/S antigens for diagnosis of early fascioliasis utilizing different diagnostic techniques. Using enzyme-linked immunoelectro-transfer blot (EITB), Fasciola-specific E/ S protein fraction band (49.5 kDa) was determined and electroeluted. The mono-specific antibodies against this specific fraction band were prepared by immunizing pathogen-free rabbit. Assessment of the prepared mono-specific antibodies in diagnosis of human fascioliasis was performed through the detection of E/S copro-antigens by enzyme-linked immunosorbent assay (ELISA) in stool eluates obtained from patients with confirmed fascioliasis, other parasites as well as from other healthy individuals. Serum samples were collected and tested to detect serum antibodies against Fasciola E/S antigen using EITB and counter immunoelectrophoresis (CIEP). Analysis of Fasciola adult worm E/S products by SDS/PAGE revealed a number of bands, the molecular weight (MW) of which ranged from 14-200 kDa; with three major bands (27.5, 32.5 and 55 kDa). Fasciola EIS 49.5 kDa protein fraction proved to be specific to F. gigantica. Cross reaction with S. mansoni was observed at higher MW (110-120 kDa). The sensitivity, specificity and diagnostic accuracy of EITB were 45.2%, 100% and 70.7%, respectively, while those of CIEP were 38.7%, 100% and 67.2%, respectively. ELISA technique using mono-specific anti-49.5 kDa to detect copro-antigens proved to be practical and reliable. It showed higher sensitivity (91.4%) and higher diagnostic accuracy (91.8%), while the specificity was 92.3%. In addition, ELISA had higher negative predictive value (88.9%) and fair positive predictive value (94.1%).

Rate of reinfection with S. mansoni following treatment in two newly reclaimed areas of Egypt.

This paper reports an on-going study in two newly reclaimed areas in Ismailia Governorate, El-Manayef, 10 km south-west of the city of Ismailia (area 1) and the other in Siani Peninsula, just east of the Bitter Lakes (area 2). In he baseline survey, the prevalence of infection of 49.9% and 40.1% and high intensity infection of 21.8% and 15.7% were found for S. mansoni in areas 1 and 2 respectively. Geometric mean egg counts for those found positive were 101.2 and 75.9. In a subsequent survey, a year after treatment of positives, the overall prevalence was 30.2% and 30.5% and the prevalence of high intensity infection was 8.6% and 10.5% in the two areas. The prevalence among those found positive and then treated during the first round (reinfection rate) was 31.7% and 19.2%. Geometric mean egg counts had declined from 141.3 to 63.1 and from 133.6 to 59 among those who were reinfected. The occurrence of reinfection was strongly associated with younger age in both areas. Rates of reinfection showed a strong but not significant association with male sex in area 2 (p = 0.087), but no association in area 1. These high rates of reinfection demonstrate the importance of promotion of hygiene behaviors as well as ensuring access to chemotherapy.

Factors affecting knowledge of the symptoms of schistosomiasis in two rural areas near Ismailia, Egypt.

The primary method of control of schistosomiasis in Egypt is through passive chemotherapy, in which people who suspect they have the disease are encouraged to go to their local health unit to be tested and treated. If people are unable to recognize the symptoms of schistosomiasis, this strategy may fail. This paper presents data on local knowledge of the symptoms of schistosomiasis from two areas recently reclaimed from the desert near Ismailia. Using data from free-listing and triadic comparisons, it is shown that schistosomiasis is primarily seen as a urinary disease. Factor analysis performed on a series of 12 questions on the symptoms of schistosomiasis included in a survey demonstrated that responses group into three patterns, the first stressing constitutional symptoms such as weakness, the second stressing abdominal symptoms and the third blood in the urine, burning on urination and blood in the stool. The paper discusses the implications of these findings for efforts to promote regular treatment with praziquantel of people living in or near the Nile Delta who are at risk for intestinal schistosomiasis.

The prevalence of hepatitis B and C infections among immigrants to a newly reclaimed area endemic for Schistosoma mansoni in Sinai, Egypt.

Serology for hepatitis B and C markers was performed on a community-based random sample of 506 residents of an area recently reclaimed from the desert and endemic for Schistosoma mansoni. The mean age of the study subjects was (20 +/- 14), and 52% were males. The overall seroprevalence of hepatitis B (Anti-HBc and/or HBsAg) was 19.6%, hepatitis C (Anti-HCV) was 10.3%, while 5% were positive for both hepatitis B and C. A strong association was present with increasing age for both hepatitis B and C markers. However, there was no association with either sex, S. mansoni infection or schistosomal periportal fibrosis. Also HBV seropositivity was not associated with increased risk of HCV seropositivity. Anti-HCV seropositivity was significantly associated with previous parenteral treatment for schistosomiasis (OR = 7.9), and with history of previous surgery (OR = 3). Hepatitis B and C are major public health problems in this population. It is recommended to consolidate the Egyptian programme of infant hepatitis B vaccination, and to extend it to older children and high risk adult groups. There is also an urgent need to study more closely the epidemiology, natural history, risk factors and modes of transmission of hepatitis C.

PIP: In Egypt, infection with hepatitis B (HBV) and C (HCV), together with schistosomiasis are major causes of chronic liver disease. Findings are presented from a study conducted in January 1994 to determine the prevalence of HBV and HCV infections in a Schistosoma mansoni-endemic area east of the Bitter Lakes recently reclaimed from the desert for agriculture. Serology for hepatitis B and C markers was performed on a community-based random sample of 506 area residents of mean age 20 years, and 52% male. The seroprevalences of hepatitis infection were 19.6% for HBV, 10.3% for HCV, and 5% both HBV and HCV. The prevalence of HBV and HCV markers generally increased with age. No association, however, was found with either sex, S. mansoni infection, or schistosomal periportal fibrosis. HBV seropositivity was not associated with increased risk of HCV seropositivity. Anti-HCV seropositivity was significantly associated with previous parenteral treatment for schistosomiasis and history of previous surgery. HBV and HCV infection is a major problem in this population. The Egyptian program of infant hepatitis B vaccination should be consolidated and extended to older children and high-risk adult groups. There is also an urgent need to study more closely the epidemiology, natural history, risk factors, and modes of hepatitis C transmission.

Intestinal opportunistic parasites among different groups of immunocompromised hosts.

The present study was designed to find out the prevalence of different intestinal opportunistic parasites in different groups of immunocompromised hosts; patients suffering from malignancy with or without immuno-suppressive drugs, or with chronic renal failure, or diabetes mellitus, or subjects under cortisone therapy. Examination of stool samples collected from 427 immunocompromised hosts revealed the detection of intestinal opportunistic parasites in 98 samples, with a prevalence of 23%. Infection with opportunistic parasites was higher in males than in females (32.6% versus 12.9%). There was statistically significant association of infection with G. lamblia and Cryptosoporidium in the mixed infection detected. The highest group affected with the opportunistic parasites was the group of patients under corticosteroid therapy (31.7%), followed by patients suffering from renal failure (28.8%) and malignancy (25.7%), while the least group affected were the diabetic patients (8%). The highest prevalence rate was 10.3% for G. lamblia, being followed by E. histolytica (7%), C. parvum (6.3%), Microsporidia (2.3%) and the least one was for Strongyloides (0.7%). No cases of Isospora belli infection was detected. Relation between presence of opportunistic parasites and risk factors was discussed and evaluated.

The use and limitations of ultrasonography in the diagnosis of liver morbidity attributable to Schistosoma mansoni infection in community-based surveys

The objective of this population-based study was to estimate the liver morbidity attributable to Schistosoma mansoni infection by ultrasonography adopting the proposed standard protocols of the Cairo Meeting on Ultrasonography, 1991. We examined 2384 individuals representing 20 of the households of the rural population of the Ismailia Governorate, East of Delta, Egypt. Prevalence of S. mansoni and S. haematobium infections were 40.3 and 1.7 respectively. Portal tract thickening (PTT) grade 1, 2 and 3 considered diagnostic of schistosomal liver morbidity was detected in 35.1, 1.3 and 0.2 individuals respectively. Generally, ultrasonographically-detected pathological changes increased with age, but correlated with intensity of infection only in age group 20-59 years. Comparing individuals with and without S. mansoni infections in an endemic and a non-endemic community indicated no significant difference between the former and the latter in either case. IN CONCLUSION: ultrasonography had a limited value in estimating schistosomal liver morbidity in our population-based study where early grades of liver morbidly were prevalent. The criteria of diagnosing grade I portal fibrosis need to be revised as well as the staging system proposed by the Cairo Meeting on ultrasonography in schistosomiasis.

The use and limitations of ultrasonography in the diagnosis of liver morbidity attributable to Schistosoma mansoni infection in community-based surveys.

UNLABELLED: The objective of this population-based study was to estimate the liver morbidity attributable to Schistosoma mansoni infection by ultrasonography adopting the proposed standard protocols of the Cairo Meeting on Ultrasonography, 1991. We examined 2384 individuals representing 20% of the households of the rural population of the Ismailia Governorate, East of Delta, Egypt. Prevalence of S. mansoni and S. haematobium infections were 40.3% and 1.7% respectively. Portal tract thickening (PTT) grade 1, 2 and 3 considered diagnostic of schistosomal liver morbidity was detected in 35.1%, 1.3 and 0.2 individuals respectively. Generally, ultrasonographically-detected pathological changes increased with age, but correlated with intensity of infection only in age group 20-59 years. Comparing individuals with and without S. mansoni infections in an endemic and a non-endemic community indicated no significant difference between the former and the latter in either case. IN CONCLUSION: ultrasonography had a limited value in estimating schistosomal liver morbidity in our population-based study where early grades of liver morbidly were prevalent. The criteria of diagnosing grade I portal fibrosis need to be revised as well as the staging system proposed by the Cairo Meeting on ultrasonography in schistosomiasis.

Prevalence and epidemiology of Schistosoma mansoni and S. haematobium infection in two areas of Egypt recently reclaimed from the desert.

Projects are being carried out in many regions of Egypt to reclaim land from the desert for agriculture. This paper presents findings from a baseline epidemiologic study conducted in 1992 in two newly reclaimed areas near Ismailia, Egypt. In the first area, just east of the Suez Canal, 40.0% of the residents tested positive for Schistosoma mansoni and 1.7% tested positive for S. haematobium, while in the second area, 15 km southwest of Ismailia, 49.3% tested positive for S. mansoni and 3.3% tested positive for S. haematobium. The intensities of S. mansoni infection were moderately high, with a geometric mean egg count of 76 eggs/gram of feces among positive individuals in the first area, and 100 eggs/gram of feces in the second area. When compared with a previous study conducted in 1985, the prevalence of S. mansoni infection in the first area has increased from 21.7% to 42.1% among settlers in the last seven years, while that of S. haematobium has decreased from 7.8% to 1.7%. These trends may result from changes in irrigation practices or other alterations in the local environment. There is a risk of schistosomiasis becoming a major public health problem in reclaimed areas if adequate control measures are not taken.

Isoenzyme profiles of four strains of Giardia lamblia and their infectivity to jirds.

The infectivity to jirds (Meriones unguiculatus) and the cyst excretion pattern of a recently isolated strain of Giardia lamblia from Egypt, Strain CDC:1088:1 (EGY), were compared to those of three well-established strains. All five jirds inoculated orally with strain UNO:0487:1 (UNO) became infected and began excreting cysts 3-6 days post-infection (dpi); no cysts were detected between 8-12 dpi after which time cysts were produced through day 19. Four of the five jirds infected with Strain ATCC:30957 (WB) and three of the five jirds infected with strain CDC:0284:1 (VA) excreted cysts from 6-20 dpi and 6-22 dpi, respectively. One of five jirds inoculated with EGY excreted cysts on 8 dpi only. At necropsy, trophozoites were recovered from only three UNO-infected jirds but from all WB- and VA-infected jirds that excreted cysts. The one jird which excreted cysts of EGY was negative at necropsy, but EGY trophozoites were found in one non-patient jird. Isoelectric focusing indicated that these four strains of G. lamblia represented three zymodemes. WB and VA were assigned to one zymodeme, EGY to a second, and UNO, which shared common bands with both other zymodemes, to the third. Although the similarities and differences in infectivity and cyst excretion patterns appear to coincide with the zymodemes to which the strains can be assigned, further study is needed to examine the parasitologic behavior of these strains in relation to isoenzyme patterns.