Menoufia Medical Journal

ORIGINAL ARTICLE
Year
: 2014  |  Volume : 27  |  Issue : 2  |  Page : 239--243

Study of schistosomiasis among school children in Berket El Sab district, Menoufia Governorate


Mohammed Hamed Bahbah1, Wael Abd El Hamied El Shikhsalem2,  
1 Department of Pediatrics, Faculty of Medicine, Menoufia University, Egypt
2 Berket El Sab Hospital, Ministry of Health and Population, Egypt

Correspondence Address:
Wael Abd El Hamied El Shikhsalem
MBBCh, Menoufia Governorate, Berket El Sab District, Ganzour Village
Egypt

Abstract

Objectives This study aimed to estimate the rate of schistosomiasis among school children in Berket El Sab district and also to determine factors affecting its prevalence among school children. Background The study area was in Menoufia Governorate, the southern part of the Nile Delta 100-150 km north of Cairo. Berket El Sab district is a model for rural Egypt that depends on the water of the Nile for almost all of its agricultural output. Participants and methods In this study, a multistage random sample of 1000 children of school age (6-15 years) was selected randomly from three primary and three preparatory schools in the study rural area of Berket El Sab district. Data were collected through a predesigned questionnaire including data on name, age, sex, parent education, housing sanitation, and some special habits such as swimming at river. Urine and stool samples were collected for laboratory investigation for schistosomiasis by microscopic examination. Results The rate of schistosomiasis among children in Berket El Sab district was 0.8%. All positive cases were of Schistosoma mansoni, but no Schistosoma haematobium was detected. A highly significant positive correlation was found between male sex and increasing prevalence of schistosomiasis (P<0.05) as 87.5% of positive cases were among males and 12.5% among females. Conclusion The rate of schistosomiasis among children in Berket El Sab district is high, raising an alarm that schistosomiasis remains a major public health problem among children in rural Egypt. There was a predominance of S. mansoni in the study area. The majority of positive cases were among males than females.



How to cite this article:
Bahbah MH, El Shikhsalem WA. Study of schistosomiasis among school children in Berket El Sab district, Menoufia Governorate.Menoufia Med J 2014;27:239-243


How to cite this URL:
Bahbah MH, El Shikhsalem WA. Study of schistosomiasis among school children in Berket El Sab district, Menoufia Governorate. Menoufia Med J [serial online] 2014 [cited 2020 Mar 28 ];27:239-243
Available from: http://www.mmj.eg.net/text.asp?2014/27/2/239/141664


Full Text

 Introduction



Schistosomiasis is the second most common parasitic infection of humans after malaria. Approximately 200 million individuals are infected worldwide in 76 countries and about 600 million are exposed to infection in tropical and subtropical regions of Africa, Asia, South America, and the Caribbean [1].

In 1937, Scott reported on the prevalence of schistosomiasis in 100 Egyptian villages. At that time, Schistosoma haematobium infection was common, whereas Schistosoma mansoni infection was rare in the Nile Delta [2].

Since 1977, this pattern of schistosomiasis in Egypt has changed as the prevalence of S. mansoni infection increased and that of S. haematobium decreased. This change has important public health implications because the hepatosplenic schistosomiasis caused by S. mansoni is more difficult to detect early and is associated with greater morbidity and mortality than the urinary schistosomiasis caused by S. haematobium [3].

In parts of Egypt, especially in the Nile Delta, the prevalence of S. mansoni remains quite high. Furthermore, S. mansoni is replacing S. haematobium in the Delta and has become well established in the past decade in Middle Egypt [4].

The causative agent is a blood fluke of the genus Schistosoma. There are five species: S. haematobium, S. mansoni, Schistosoma japonicum, Schistosoma mekongi, and Schistosoma intercalatum, with the former three being the most widespread [5],[1]. Schistosomiasis is strongly connected to the construction and operation of irrigation systems, multipurpose small dams, and large hydroelectric dams for power production and irrigation-fed agriculture [6],[7].

An individual can become infected by prolonged contact with fresh water containing free-swimming cercariae, the infective stage of the parasite, which then enters the subcutaneous tissues, the blood stream, migrates to the lungs, then to the liver, and finally to the mesenteric and perivesical venous plexuses. The parasite is excreted from the body through urine and feces into fresh water and the miracidia eventually infects its intermediate hosts, the fresh water snails, where they develop into cercariae and the vicious cycle starts again [8].

Schistosomiasis is asymptomatic in up to 80% of those infected, with tiredness being the most common symptom [9].

Disease syndromes associated with schistosomiasis include cercarial dermatitis, larval pneumonitis, acute schistosomiasis (Katayama fever), chronic schistosomiasis, and ectopic schistosomiasis [10]. Schistosomiasis is a disease caused predominantly by the host's immune response to schistosome eggs (ova) and the granulomatous reaction they induce [5].

The disease has an especially detrimental effect on the growth and development of school-age children, causing anemia, malnutrition, stunted growth, reduced physical activity, and impaired cognitive function [11],[12].

In 90% of infected individuals, the egg-associated inflammation recedes, resulting in intestinal schistosomiasis. In contrast, 10% of infected individuals present with severe hepatic and periportal fibrosis, and portal hypertension [13].

Bleeding from gastroesophageal varices is the most serious, commonly fatal, complication of fibrotic hepatic schistosomiasis [5].

The most serious complication of urinary schistosomiasis is an increase in squamous cell carcinoma of the urinary bladder [14].

The diagnosis of schistosomiasis is usually made on the basis of the microscopic detection of eggs in stool and urine samples. These methods have high specificity and low sensitivity especially in minor infections with the presence of daily variation phenomenon [15].

Immunodiagnosis of schistosomiasis has been proposed to overcome some of the limitations with parasitological methods, that is, day-to-day and intraspecimen variations in schistosome egg output, the risk of missing low-intensity infections, relatively time-consuming methodologies, and the need for well-trained laboratory technicians [16],[17].

There have been considerable advances in chemotherapy of schistosomiasis in the past two decades. Compared with antimonials, which were the only available chemotherapeutic agents for schistosomiasis from the 1920s to the 1960s, new drugs are more consistently effective, less toxic, and allow oral rather than parenteral administration, thereby making field trials of mass chemotherapy feasible. The major antischistosomal drugs that have been or are still in use against infection with schistosomes are metrifonate, oxamniquine, and praziquantel, and all three are included in the WHO list of essential drugs [18].

The complexity of the schistosome and the life cycle of this parasite may, at least partly, contribute toward the difficulties associated with vaccine development [19],[20].

 Participants and methods



In this study, a multistage random sample of 1000 child of school age (6-15 years) was selected randomly from three primary and three preparatory schools in a rural area (Berket El Sab district). Data were collected through a predesigned questionnaire including data on name, age, sex, parents' education, housing sanitation, and some special habits such as swimming at river. Urine and stool samples were collected for laboratory investigation for schistosomiasis by microscopic examination.

Laboratory diagnosis by microscopic examination

Both urine and stool samples were taken to the laboratory, processed, and examined immediately for schistosoma eggs.

Urinary examination of schistosomiasis

The specimens were collected when the chance of finding eggs was the highest (between 10 a.m. and 2 p.m.). We used two main methods for the detection of S. haematobium eggs.

Sedimentation: We allowed the fresh urine sample to sediment for 1 h, then centrifugation for not more than 2 min at 2000g. was performed, and then the sediment was examined for the presence of ova.Filtration: We placed a polycarbonate or a nylon fiber filter (12-20 mm pore size) in a filter holder, agitated the urine, and filled a syringe (10-20 ml). The filter holder was attached and the urine was expelled. The filter was removed with forceps on a microscopic slide. The entire filter was examined for eggs after staining with Lugol's iodine.

We used the Kato Katz technique for the detection of S. mansoni eggs in stool.

Materials

Kato set (template with hole, screen, plastic spatula).Microscopic slides.Cellophane as a cover strip, soaked in a glycerol-malachite green solution.Fresh stool.Gloves.

Methods

The template with a hole was placed in the center of a microscopic slide.The screen was pressed on top so that some of the feces filtered through and scraped with the flat spatula across the upper surface to collect the filtered feces.The template was removed carefully.The fecal material was covered with the presoaked cellophane strip.The microscope slide was inverted and the fecal sample was firmly pressed against the cellophane strip on a smooth hard surface such as a tile and the material was spread evenly.The smear was examined in a systematic manner and the eggs were reported.

 Results



Among the studied group, 451 children were males (45.1%) and 549 were females (54.9%) [Table 1].{Table 1}

The results showed that eight children were infected (0.8%); all of them were infected with S. mansoni and no S. haematobium was detected among the studied group [Table 2].{Table 2}

Seven males (87.5%) and one female (12.5%) were infected, and the difference was statistically significant at a P-value of 0.01 (<0.05) [Table 3].{Table 3}

The results showed that 59.2% of children were 6-10 years old and 40.8% of children were 11-15 years old [Table 1].

The results showed that there was a nonsignificant difference relation between age group and schistosoma infection in the studied group (P > 0.05) [Table 3].

There was a significant difference between fathers' occupation as farmers and nonfarmers in terms of schistosoma infection among the studied group (P < 0.05) as the results showed that seven of all infected children had fathers who were farmers, whereas only one child had a father who was not a farmer [Table 3].

There was a nonsignificant difference between those with pure water supply and those with nonpure water supply in terms of schistosoma infection among the studied group (P > 0.05) [Table 3].

There was a significant difference between those with sanitary sewage disposable and those with nonsanitary sewage disposable in terms of schistosoma infection among the studied group (P < 0.05) as the results showed that the homes of seven of all infected children had sanitary sewage disposable, whereas the home of only one child had nonsanitary sewage disposable [Table 3].

There was a nonsignificant difference between anemia and schistosoma infection among the studied group (P > 0.05) [Table 3]; [Figure 1] and [Figure 2].{Figure 1}{Figure 2}

 Discussion



This study is a cross-sectional study that aimed to study the prevalence of schistosomiasis in rural Egypt during the years 2011-2012 in Menoufia Governorate, Berket El Sab district, as a model to show the magnitude of this health problem in Egyptian children between 6 and 15 years of age so that we can plan a strategy to deal with it as the main technical difficulty lies in the identification of remaining cases [Table 4].{Table 4}

In this study, the prevalence of schistosomiasis in the studied group was 0.8%, which is higher than that reported by MOHP in 2009, which was 0.5% in Menoufia and 0.6% in Egypt.

This study alarmingly indicates that schistosomiasis remains a major public health problem among children in rural Egypt as reported by El Shafie and Bahbah (2011), who showed that the rate of schistosomiasis among school children in Menoufia Governorate, Quesna district, is 2%, which is very high [21].

The prevalence of S. mansoni infection was estimated to have decreased from ~15% in 1993 to 3% in 2002, decreasing to 1.5% in 2006, and the prevalence of S. haematobium infection decreased from 7% in 1993 to 2% in 2002 and then to 1% in 2006 [22].

Studies from 2006 indicated approximately seven million cases of schistosomiasis in Egypt [23].

In this study, the diagnosis of S. mansoni was made on the basis of the microscopic detection of eggs in urine and stool samples, respectively, as it remains the gold standard for the diagnosis of schistosomiasis, in agreement with Feldmeier and Poggensee [24].

In this study, S. mansoni was more predominant than S. haematobium as all positive cases included S. mansoni.

Over the last 5 years, however, these numbers have decreased, with S. haematobium infection almost eliminated and S. mansoni infections remaining only in what are described as 'hot spots' in the Nile Delta-irrigated area in the northern part of the country. The major interventions responsible for this situation include the building of the Aswan High Dam in 1960, which changed irrigation patterns in the Nile Delta, leading to an improved habitat for Biomphalaria spp. snails as opposed to Bulinus spp. snails, and therefore a reduction in the prevalence of S. haematobium, as well as implementation of mass treatments initially with tartar emetic and subsequently with praziquantel [23].

In this study, a significant positive association was found between male sex and increasing prevalence of schistosomiasis (P < 0.05) as 87.5% of positive cases were among males and 12.5% among females; this is in agreement with Jemal et al., who reported that the predominance of male sex is because of socioeconomic and cultural factors [25].

 Acknowledgements



Conflicts of interest

None declared.[26]

References

1Davis A. In: Cook GC, Zumla AI, editors. Schistosomiasis. Manson′s tropical diseases. 22nd ed. Saunders/Elsevier; 2009. 1425-1460.
2Scott JA. The incidence and distribution of human schistosomiasis in Egypt. Am J Epidemiol 1973; 25 :566-614.
3Abdel-Wahab MF, Strickland GT, El-Sahly A, Ahmed L, Zakaria S, El Kady N, et al. Schistosomiasis mansoni in an Egyptian village in the Nile Delta. Am J Trop Med Hyg 1980; 29 :868-874.
4Lotfy WM, Dejong RJ, Abdel-Kader A, Loker ES. A molecular survey of biomphalaria in Egypt: is B. glabrata present? Am J Trop Med.Hyg 2005; 73 :131-139.
5WHO. The control of schistosomiasis. First report of a WHO expert committee. Geneva: World Health Organization; 1985. 1-113.
6Gryseels B, Polman K, Clerinx J, Kestens L. Human schistosomiasis. Lancet 2006; 368 :1106-1118.
7Amerasinghe FP. Irrigation and mosquito-borne diseases. J Parasitol 2003; 89 :S14-S22.
8Steinmann P, Keiser J, Bos R, Tanner M, Utzinger J. Schistosomiasis and water resources development: systematic review, meta-analysis, and estimates of people at risk. Lancet Infect Dis 2006; 6 :411-425.
9Paul J, Verma S, Berry K. Urinary schistosomiasis. Emerg Med J 2002; 19:483-484.
10Bierman WF, Wetsteyn JC, van Gool T. Presentation and diagnosis of imported schistosomiasis: relevance of eosinophilia, microscopy for ova, and serology. J Travel Med 2005; 12 :9-13.
11Bica I, Hamer DH, Stadecker MJ. Hepatic schistosomiasis. Infect Dis Clin North Am 2000; 14 :583-604.
12WHO: WHO Expert Committee. Prevention and control of schistosomiasis and soil transmitted helminthiasis. Technical report series. Geneva: WHO; 2002.
13King CH, Dickman K, Tisch DJ. Reassessment of the cost of chronic helminthic infection: a meta-analysis of disability-related outcomes in endemic schistosomiasis. Lancet 2005; 365 :1561-1569.
14Henderson GS, Nix NA, Montesano MA, Gold D, Freeman GLJ, McCurley TL, et al. Two distinct pathological syndromes in male CBA/J inbred mice with chronic Schistosoma mansoni infections. Am J Pathol 1993; 142 :703-714.
15Behrman AJ. Schistosomiasis of the bladder. Med Instant Access 2002; 2 :133-148.
16De Vlas SJ, Gryseels B. Underestimation of Schistosoma mansoni prevalences. Parasitol Today 1992; 8 :274-277.
17Van Lieshout L, Polderman AM, Deelder AM. Immunodiagnosis of schistosomiasis by determination of the circulating antigens CAA and CCA, in particular in individuals with recent or light infections. Acta Trop 2000; 77 :69-80.
18Doenhoff MJ, Chiodini PL, Hamilton JV. Specific and sensitive diagnosis of schistosome infection: can it be done with antibodies? Trends Parasitol 2004; 20 :35-39.
19Cioli D, Pica-Mattoccia L, Archer S. Drug resistance in schistosomes. Parasitol Today 1993; 9 :162-166.
20Bergquist NR. Schistosomiasis vaccine development: approaches and prospects. Mem Inst Oswaldo Cruz 1995; 90 :221-227.
21Capron A, Riveau GJ, Bartley PB, McManus DP. Prospects for a schistosome vaccine. Curr Drug Targets Immune Endocr Metabol Disord 2002; 2 :281-290.
22El Shafie AM, Bahbah MH. Study of schistosomiasis among basic school children in Menoufia governorate, Quesna district (2011)
23Salem S, Mitchell RE, El-Alim El-Dorey A, Smith JA, Barocas DA. Successful control of schistosomiasis and the changing epidemiology of bladder cancer in Egypt. BJU Int 2011; 107 :206-211.
24Hotez PJ, Savioli L, Fenwick A. Neglected tropical diseases of the Middle East and North Africa: review of their prevalence, distribution and opportunities for control. PLoS Negl Trop Dis 2012; 6 :e1475.
25Feldmeier H, Poggensee G. Diagnostic techniques in schistosomiasis control. A review. Acta Trop 1993; 52: 205-220.
26Jemal T, Murray E, Ward A, Samuels R, Tiwari AC, Ghafoor E, et al. Cancer statistics. CA Cancer J Clin 2005; 5:10-30.