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Gender, Behavior, and HealthSchistosomiasis Transmission and Control in Rural Egypt$

Samiha El Katsha and Susan Watts

Print publication date: 2004

Print ISBN-13: 9789774247286

Published to Cairo Scholarship Online: September 2011

DOI: 10.5743/cairo/9789774247286.001.0001

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Schistosomiasis in Egypt: 1988–96

Schistosomiasis in Egypt: 1988–96

Chapter:
(p.53) 5 Schistosomiasis in Egypt: 1988–96
Source:
Gender, Behavior, and Health
Author(s):

Samiha El Katsha

Publisher:
American University in Cairo Press
DOI:10.5743/cairo/9789774247286.003.0005

Abstract and Keywords

Egypt, with its long history of research and schistosomiasis control activities, was in 1988 the first country in the world to adopt the new drug praziquantel as the mainstay of its national treatment and control program. Public health officials in Egypt realized that the long courses of injections required by tartar emetic and its derivatives could not solve the problem. The Ministry of Health, which already provided screening and treatment for school children, set about identifying the most appropriate way to incorporate the new drug into their program. An initial prevalence survey assessed the situation before praziquantel was administered; the second survey followed one year later and the third assessed the situation the following year and no praziquantel having been administered between these two surveys.

Keywords:   praziquantel, treatment, derivatives, prevalence, surveys

Praziquantel: a new tool for schistosomiasis control in Egypt

Egypt, with its long history of research and schistosomiasis control activities, was in 1988 the first country in the world to adopt the new drug praziquantel as the mainstay of its national treatment and control program. At the same time, the Ministry of Health launched a collaborative Schistosomiasis Research Project (SRP) to provide information to support the program. Projects supported by the SRP led to an explosion of (mainly epidemiological) information about the status of the disease in the early 1990s. In this chapter we present those research findings which provide a national context for our own local level research work. Our study, initiated in 1991, also funded by the Schistosomiasis Research Project, used a rather different approach from other SRP projects. Before describing it, however, we need to explore some of the events leading up to the introduction of praziquantel in 1988.

From the late 1960s onward, as the number of people afflicted with schistosomiasis continued to grow, public health officials in Egypt realized that the long courses of injections required by tartar emetic and its derivaatives could not solve the problem. They turned to new drugs, such as oxamniquine and metrifonate, and, later, praziquantel, which promised higher cure rates and fewer side effects. WHO, UNICEF, the World Bank, and pharmaceutical companies supported an international program to assess the effectiveness of these various drugs.

By 1980, based on studies in Egypt, South Africa, and Kenya, researchers had identified the single dose drug praziquantel as the most suitable antischistsomal (p.54) drug. They found that it was safe and effective, and could be used for both S. mansoni and S. haematobium. As a result of these studies, in 1984 the WHO Expert Committee on the Control of Schistosomiasis endorsed the use of praziquantel to control morbidity due to schistosomiasis, as part of an integrated strategy of treatment and prevention (WHO 1993: 1).

The cure rate for praziquantel is now estimated to be over 80% for S. haematobium, and between 60% and 80% for S. mansoni. Treatment for S. haematobium has been found to reduce proteinuria (protein in the urine), hematuria, urinary iron loss, and leukocyturia (abnormal levels of leukocytes, cells, in the blood). Half of all S. mansoni patients who were treated experienced a reduction in liver and spleen size (El Khoby et al. 2001: 12, 14). These results were achieved after patients had taken a single dose of praziquantel orally. The recommended dose was 40 mg. for every kilogram of body weight, which for an adult meant three or four 600 mg. tablets. Praziquantel was particularly valuable in Egypt because it could be used against both S. mansoni and S. haematobium.

Children, in Egypt as elsewhere, had been shown to have high infection rates and high worm burdens. The Ministry of Health, which already provided screening and treatment for school children, set about identifying the most appropriate way to incorporate the new drug into their program. In 1983 a pilot program was established in two highly endemic districts of Beheira governorate, south of Alexandria. The purpose of the project was to assess the impact of a single treatment on a population of school-age children. An initial prevalence survey assessed the situation before praziquantel was administered; the second survey followed one year later, and the third assessed the situation the next year (no praziquantel having been administered between these two surveys). S. mansoni infection rates fell from 60.3% before treatment to 24.8% one year later, increasing to 41% the following year. The corresponding figures for S. haematobium were 37.6% before treatment, 5.5% one year later, and 9.9% two years later (Spencer et al1990 ). These findings reflected both the greater effectiveness of praziquantel against S. haematobium, and the fact that many children were being reinfected. Although the decline in infection rates immediately after the administration of praziquantel was dramatic, it was clear that repeated treatments would be needed to make a real impact on overall infection rates.

The Beheira governorate researchers estimated that they had only been able to screen about 70% of all school-age boys, and an even smaller proportion, about 30%, of school-age girls (El Malatawy et al. 1992 ). But they apparently did not see this discrepancy in coverage rates between boys and girls as a potential problem for a school-based program. As we will see in (p.55) chapter 11, for a number of reasons programs in operation in the early 1990s did not reach girls as effectively as boys.

The National Schistosomiasis Control Program: Objectives

During the thirty year period when laboratory scientists were working on a new generation of antischistosomal drugs, and epidemiologists were field testing them, the government of Egypt had not been standing still. In 1977 (eleven years before the official adoption of praziquantel) the National Schistosomiasis Control Program (NSCP) was launched. Its main objective was to “reduce schistosomiasis to a level at which it is no longer a public health problem” (El Khoby et al. 2001: 9–10). The Program eventually covered all the rural areas of the Nile delta, the valley south of Cairo, Fayoum, and the newly settled agricultural areas.

In 1988, at the same time that the Ministry of Health officially incorporated praziquantel into the National Control Program, it modified other aspects of its overall program. Among other things, it modernized its approach to the control of snail vectors. It also gave new emphasis to preventing the spread of schistosomiasis in newly settled areas (such as the eastern and western fringes of the Delta and around the Suez Canal). Also emphasized after 1988 was the prevention of the spread of S. mansoni in Upper Egypt, where an increasing number of cases were being found. The revitalized Program also strengthened its earlier strategy to target vulnerable groups, especially school children. The scope of the Program, as of 1988, is indicated in table 5.1.

Table 5.1: The scope of the Egyptian National Schistosomiasis Control Program, 1988

1.

Free diagnosis and treatment for:

all school children, with periodic screening at rural health facilities; all adults attending rural health facilities all adults who, in village sample surveys of around 10% of residents a month, were found positive;

2.

Snail control through the application of niclosamide to canals in villages with over 20% prevalence, and in canals where infected snails were found;

3.

Health education through the Health Education Department of the MOH and through the mass media;

4.

Liaising with other authorities to improve water, drainage and irrigation conditions.

(p.56) The main activity of the Program after 1988, as had been the case since 1977, was free diagnosis and treatment administered through the national primary health care system. These services were delivered chiefly at the 2,400 rural health units in the Nile valley and the Delta. The Program targeted Egypt's 15 million school children between the ages of 6 and 14, the years of compulsory, free schooling. In addition, all adults attending the health centers were required to undergo testing for both types of schistosomiasis, regardless of the symptoms they presented. The MOH estimated that in 1995, 3,500 technicians at MOH units tested 22 million stool and urine samples (El Khoby 1995 ). Inchapter 11, we will discuss the stool testing facilities we found in operation in the early 1990s in our study communities.

After 1988, as in the years after 1977, canals continued to be treated to destroy snail vectors. However, two important changes were introduced. Blanket mollusciciding was replaced by focal treatment restricted to canals in highly endemic villages, and at sites where infected snails were found. Copper sulfate was gradually phased out and replaced by niclosamide, an agent that was seen as less toxic to the aquatic environment. Focal treatment was also advantageous as it required the use of far smaller quantities of molluscide, at a time when the cost of niclosamide, a petroleum derived chemical, was rising sharply.

In 1988 the health education program was expanded, and focused on the mass media, mostly in the form of TV messages. The MOH pledged to continue to work with other government agencies to improve water, drainage, and irrigation conditions (seeEl Khoby et al.2001 ).

The organization of the Program

In this section we will describe the National Schistosomiasis Control Program as found in operation during our research in Munufiya governorate, beginning in 1991. As the Program undertook a number of activities designed to control the disease, both curative and preventive, it could claim to be an integrated program, following the recommendations of WHO.

Overall responsibility for the NSCP rested with the Ministry of Health in Cairo. The Ministry was a highly centralized organization, although, at the time of our study, it was developing a strategy for decentralization. For the sake of clarity it is best to regard the Program as a conglomerate that contained more than one chain of command; depending on circumstances, one chain sometimes overlapped with others. For some activities the chain of command was clearly vertical (top-down) from the central Ministry of Health to regional (governorate), to the district (markaz) and to the local village level. But for other activities at the intermediate level, the top-down linkage (p.57) was supplemented by a horizontal linkage. In these cases, the Schistosomiasis Control Program in the governorate was obliged to cooperate with other Units at the same level, such as health education, in order to provide certain schistosomiasis services, as shown in figure 5.1.

Schistosomiasis in Egypt: 1988–96

Figure 5.1: The organization of the National Schistosomiasis Control Program

Within the Ministry of Health in Cairo, the Endemic Diseases Department had specific responsibility for the NSCP. Other Departments in the center that collaborated with the work of the NSCP included, for example, the Health Education Department and the Training Department. Each Department in the Ministry prepared the work plans for the corresponding like-named Units at the governorate level.

At the governorate level (as in Munufiya governorate), the Schistosomiasis Control Program was situated in the Endemic Diseases Unit. When the governorate Program required support activities such as health education or training, staff had to request the support from their sister Units in the governorate, such as the Health Education Unit or the Training Unit.

The Schistosomiasis Control Program at governorate level was responsible for collecting all reports from health personnel at the markaz (district) level and sending them to the NSCP office in the Endemic Diseases Department (p.58) in Cairo. An exception to that rule was the Snail Control Section, which sent all findings directly to the Ministry of Health in Cairo.

Still at the governorate level, a coordinating body—the High Committee for Schistosomiasis—had a mandate to meet monthly under the chairmanship of the Governor, and to report to the governorate Health Directorate. Members of the schistosomiasis committee included representatives from the Ministries of Education, Public Works and Water Resources, Housing, and Information, and religious leaders.

Moving down the hierarchy, all the Units in the Governorate Health Directorate communicated directly with the markaz (district level) Department of Health; this was a single department, with no subsections. The markaz Department of Health sent reports to the relevant Units in the Governorate, such as the SCP in the Endemic Diseases Unit. The markaz Department of Health was responsible for providing primary health services at the local level.

At the local level, MOH facilities could link up with other departments that had an interest in schistosomiasis control through the Executive Village Council and elected representatives from various villages and sub-villages served by the Council. Diagnosis and treatment was provided free for the local population, as well as for school children.

In 1992, overall responsibility for the school screening program was given to another governmental organization, the Health Insurance Organization (HIO). It was intended that the HIO should operate independently, without collaborating with the rural health units. However, as of 1996, the HIO was not yet operational in the study area. Other changes in the organization of the National Program have also been introduced, such as mass treatment (without prior diagnostic testing) in highly endemic areas. However, this too had not yet come into effect in the Munufiya study villages during the time of our research there. The impact of these changes will be considered in a final chapter, as part of an assessment of the relevance of our study to the situation as it exists in Egypt at the beginning of the new millennium.

The Schistosomiasis Research Project

In 1988, in the same year that the Ministry of Health began to use praziquantel in its national control program, it launched the Schistosomiasis Research Project (SRP). This multi-million dollar project was undertaken in collaboration with USAID and Egyptian universities. The stated objective was to provide information and guidelines for the newly revised praziquantel - based control Program. A major component of the Schistosomiasis Research Project was a survey of the disease in nine Delta and Nile valley (p.59) governorates. In addition, the SRP also asked research teams at Egyptian universities to submit proposals on topics relevant to the MOH control program.

The nine-governorate survey was called EPI 1, 2, 3, because of its three major goals. The first was to provide an overview of the distribution and intensity of infection. The second was to identify and attempt to explain the differences in levels of schistosomiasis infection between villages. The third goal was to measure the severity of the clinical pathology due to the disease (morbidity).

In an attempt to get a balanced picture of infection levels in each governorate, EPI 1, 2, 3 used a specially designed multi-stage sampling frame. On the basis of this sample, researchers felt confident to make generalizations about the whole population of these governorates.

The initial survey, conducted in each governorate in 1992, provided information on infection rates at that time (“prevalence” in epidemiological terminology) and intensity of infection (measured by the number of schistosome eggs in urine or stool specimens) for both S. haematobium and S. mansoni. Subsequent annual surveys identified infections that had occurred since the previous round of tests (“incidence”).

The 1992 survey initially covered 17,172 households in 251 rural communities. It surveyed slightly more females than males, 45,874 compared to 45,176, a total of more than 90,000 people. In the light of this achievement, the survey was said to be the largest community-based epidemiological study to have been conducted anywhere in the world (El Khoby et al2000 A; Hussein et al.2000 ).

Main Findings of the 1992 survey: distribution and intensity of disease

The 1992 survey provided baseline data on the prevalence and intensity of infection for both types of schistosomiasis in nine governorates, five in the Delta and four in the Nile valley south of Cairo (see page xxii for a map of governorates). It confirmed that S. haematobium was the main form of the disease in Upper Egypt, and that S. mansoni now predominated in the Delta. These findings, showing the predominant form of schistosomiasis at the governorate level, are summarized in table 5.2.

In addition to indicating the regional distribution of each type of schistosomiasis, the findings also showed that the prevalence of S. haematobium in Upper Egypt was lower than that of S. mansoni in the Delta. The prevalence rates of S. mansoni in the Delta were actually higher than those found by earlier surveys and by MOH records. (p.60)

Table 5.2: Summary findings for nine governorates, 1992

Total

Male

Female

Odds ratio

Community prevalence

Lower Egypt (the Nile Delta): S. mansoni

Kafr al-Sheikh

39.3%

55.3%

36%

1.44

24.5—68.9%

Gharbia

37.7%

46.9%

37.9%

1.45

17.9—79.5%

Munufiya

28.5%

34%

21.1%

1.93

0.3—72.9%

Ismailia

42.9%

50.5%

36.1%

1.81

12.3—71.3%

Qalyubia

17.5%

25.3%

16.9%

1.67

2—45%

Upper Egypt: S. haematobium

Fayoum

13.7%

16%

11.5%

1.46

0—27%

Minya

8.9%

12.1%

5.9%

2.19

1.9—32.7%

Asyut

5.2%

8.2%

4.3%

1.96

1.5—20.9%

Qena

4.8%

7.1%

3.8%

1.94

0—20.6%

Source: Summarized from papers in the American Journal of Tropical Medicine and Hygiene, 2000, 62 (2) Supplement.

However, a few people with S. mansoni were found in all the Upper Egyptian governorates surveyed. The overall level of S. mansoni was higher in Fayoum governorate, just south of Cairo, than in the other Upper Egyptian governorates. In Fayoum, the fact that three of the four hamlets recording high S. mansoni rates (between 25 and 35%) also recorded low S. haematobium infection rates (〈7%) suggested that S. mansoni might actually be replacing S. haematobium as the major type of schistosomiasis in those communities (Abdel-Wahab et al. 2000 A and 1993).

In the other three Upper Egyptian governorates surveyed, the S. mansoni cases were concentrated in a small number of villages. This finding was alarming as it suggested that active transmission of S. mansoni was now taking place there. In earlier surveys, S. mansoni had only been found among migrants or visitors from S. mansoni endemic areas to the north (El Khoby et al.2000 B; King et al. 1982 ).

Overall, the 1992 survey found a significantly higher rate of infection among males than among females. For S. haematobium in Upper Egypt, the infection level was 5.6% for females and 10.1% for males, with an odds ratio of 1.91 (the odds ratio measures the strength of the correlation between two variables, in this case infection and a demographic variable; the higher the odds ratio the stronger the correlation). In the Delta, gender differences in (p.61) infection with S. mansoni were somewhat less marked, 31.4% for females and 41.5% for males, an odds ratio of 1.56.

The 1992 survey confirmed earlier findings that young people under the age of twenty had the highest infection rates. For example, in some villages in Fayoum the odds for infection with S. haematobium among children and young people were double or triple those for adults. Here, almost 80% of those infected with S. mansoni were aged 20 or younger (Abdel-Wahab et al.2000 A ).

Overall, the survey recorded that the peak infection rates occurred at a younger age for S. haematobium than for S. mansoni. In Kafr al-Sheikh governorate, in the northern Delta, fairly high rates of infection for S. mansoni continued into middle age ( Barakat et al.2000 ). In Ismailia, on either side of the Suez Canal, S. mansoni infection levels peaked among those aged 20 to 30, but were higher than elsewhere until age 55; this pattern was thought to be the result of the relatively recent introduction of the disease into this newly settled area (Nooman et al.2000 ).

In all governorates, the differences in prevalence rates from village to village confirmed that the infection was highly localized. For example, in the delta governorate of Munufiya, with an overall prevalence of 28.5%, the prevalence of S. mansoni in 27 rural settlements ranged from 0.03% to 79.5%. However, no SRP researcher made a serious attempt to identify local conditions that might have accounted for village-to-village contrasts, beyond noting that hamlets usually had higher infection rates than the larger villages.

Technicians in SRP projects used the modified Kato-Katz thick smear technique for fecal specimens and Nucleopore filtration for urine to count eggs in fecal or urine specimens, rather than simply noting the presence or absence of eggs (Cline et al. 2000 ). Thus, the 1992 survey provided information on the intensity of infection; intensity is an indicator based on the number of eggs expelled by an infected individual per gram of stool or 10 ml. of urine. A composite measure of intensity for the whole infected population or a subgroup of that population is provided by the Geometric Mean Egg Count (GMEC). Intensity provides epidemiologists with an approximate indication of morbidity, and of the potential for disease transmission.

The EPI 1, 2, 3 survey found that, for both forms of schistosomiasis, and in all age groups, intensity was higher for males than females. For children between 5 and 14 years of age with S. haematobium, the intensity of infection was higher than for any other age group, with a GMEC of just over 10 eggs per 10 ml. of urine. Adults over 25 in different age and gender groupings recorded GMECs around half those recorded for children. For S. mansoni, the (p.62) intensity of infection was highest among young people, specifically for children between the ages of 10 and 14 (El Khoby et al. B 2000 ).

In some governorates, such as Kafr al-Sheikh and Munufiya, the survey researchers considered that the overall low level of intensity recorded in 1992 was the result of effective diagnosis and treatment at rural health units (Abdel-Wahab et al. 2000 B; Barakat et al. 2000;El Sayed et al. 1997). It is known that most patients who become reinfected after treatment have lower egg counts than in previous infections.

The low overall egg counts revealed in the EPI 1, 2, 3 surveys may have resulted in an underestimate of the overall infection rates for the nine governorates. This underestimate occurred because all surveys relied on a single fecal or urine sample for diagnosis. As egg output is variable over time, both within a 24 hour period and from day to day, some low intensity cases (with a smaller number of eggs excreted) were likely to have been missed. Thus, in Kafr al-Sheikh governorate, the principal investigator estimated that the actual prevalence in the 1992 survey was probably at least 50%, although the overall corrected prevalence in the sample survey (based on a single Kato - Katz test) was 39.3% (Barakat et al. 2000 ). However, as all parasitological testing for EPI 1, 2, 3 and all other SRP sponsored projects was standardized, the overall comparison of rates in different areas of Egypt would not have been affected.

Identifying those at risk of infection

Following standard epidemiological practice, in the 1992 survey the infection rates of different categories of people were calculated in order to identify “risk factors” for infection. Thesea “risk factors” were based on a statistically significant correlation between a certain “factor” and infection. The “risk factors” identified in the 1992 survey were similar for both kinds of schistosomiasis. Overall, males had a significantly higher infection rate than females, as did young people aged 5 to 20 (except in Ismailia governorate). Thus, being male was identified as a “risk factor,” as was being under the age of twenty.

The EPI 1, 2, 3 interviewers asked individuals if they had come into contact with canal water. Three different groups who reported specific kinds of canal contacts were identified as “at risk”: males who had entered the canal to bathe, children under 15 years of age who reported that they had played in the canal, and women who had reported “washing” in the canal—the kind of washing was not specified. The survey also categorized as “at risk” people who had reported that they had been previously infected or treated for schistosomiasis, or who had had symptoms of the disease at some time.

(p.63) The survey also identified people living in hamlets (‘izab) as “at risk” because they had significantly higher rates of infection than those living in villages. The researchers suggested that, compared to inhabitants of larger settlements, these people lacked safe water and sanitation and were more likely to come into contact with canal water; they also lacked easy access to facilities for diagnosis and treatment. However, they did not follow up these suggestions.

EPI 1, 2, 3 researchers also were unable to identify any link between an individual's educational status and infection. However, they made no comment about the possible reason for their finding. They probably had originally hypothesized that people who had little or no education would be more likely to use the canals on the grounds that they may not know of the disease danger, or that they were poor and more likely to live in houses without safe water or sanitation.

The interviewers asked individuals over fifteen years old about their main occupation. This data on the primary occupation, when correlated with infection status, apparently did not indicate any of these occupations as a risk factor (El Khoby 2000B). Thus, in spite of the emphasis in earlier epidemiological studies on farming and irrigation as associated with infection, the EPI 1, 2, 3 survey could not specifically identify farmers as being at risk. It is likely that they failed to do so because they did not attempt to identify the many part-time farmers, women and children as well as men, who worked in the fields after their regular working day and on Fridays. Inchapter 9, we will explore this issue as it relates to our two Munufiya study villages.

Morbidity due to schistosomiasis

Doctors practicing in Egypt often assumed a connection between certain of their patients' conditions and chronic schistosomiasis infection. For example, by the 1970s physicians in the Nile delta were reporting long-term morbidity such as high blood pressure, portal hypertension, and death from hematemesis (internal bleeding), which they considered were related to the increasing rates of S. mansoni in the Delta ( El Khoby et al.1998 ). However, it is difficult to assess the precise extent and severity of these conditions and their relationship to schistosomiasis infection from such reports. Large scale studies that could identify various kinds of morbidity and relate these to current or previous infection with schistosomiasis were clearly needed.

Aware of this problem, the EPI 1, 2, 3 1992 survey pioneered the use of a new technique to identify morbidity in the community, using a new type of ultrasound machine that was portable. Brought into the village, this machine could identify morbidity among local people at an early stage of the disease.

(p.64) The heavy ultrasound equipment used previously could not be easily moved about. Suitable only for use in a hospital, its main function was to identify more serious morbidity and disease conditions that were already well advanced.

The results of these EPI 1, 2, 3 community-based ultrasound examinations were compared to results for the same individual obtained from physicians’ clinical examinations and the individual's disease history (Abdel - Wahab et al.2000 C). The findings in some cases seemed to establish a clear cause and effect relationship between the presence of schistosomiasis and certain conditions, while in other cases the results were more ambivalent.

In Munufiya governorate, clinical and ultrasound examinations identified a clear association between peri-portal fibrosis and infection with S. mansoni in adults (but not in children). Here, ultrasound was found to be more effective than routine clinical examinations in identifying enlargement of the liver and spleen due to S. mansoni (Abdel-Wahab et al.2000 C; El Khoby et al.2000 B ). Later, a large-scale study in Fayoum governorate compared ultrasound data collected in 1997 to that of the 1992 survey collected five years earlier. The 1997 data indicated a significant decrease in the prevalence of both hepatosplenic (liver and spleen) and urinary tract morbidity over the five year period. El Khoby 2001 suggested that these findings were related to the decrease in cases of both types of schistosomiasis in the governorate during that time.

Many researchers have noted the relationship between bladder cancer and chronic, heavy, and repeated infection with S. haematobium. Detailed information about the different kinds of cancer in Egypt is now available from cancer registries in the two largest cities, Cairo and Alexandria, and from the records of cases treated in the National Cancer Institute in Cairo. These data show that the pattern of cancers in Egypt is very different from that in most high income countries, where lung, colonorectal, and breast cancers are the three most frequent malignancies. In Egypt, as of the early 1990s, bladder cancer was the most frequently recorded type of cancer, responsible for around one quarter of all malignant tumors, thus reinforcing earlier conclusions about the relationship between bladder cancer and S. haematobium infection.

Similarly, statistics collected after the introduction of universally available praziquantel treatment in 1988, suggest that the number of new cases of squamous cell carcinoma, the type of bladder cancer associated with S. haematobium, was in decline, compared with the number of new cases reported earlier in the decade (El Khoby 2001 ). Further confirmation of these findings might be possible if the cancer records could be analyzed (p.65) according to the patients' rural or urban residence, as almost all schistosomiasis is transmitted in rural areas.

Another legacy of the pre-praziquantel era (before 1988) has been pinpointed in a recent study that shows that standard injections with tartar emetic were likely to have been responsible for the current high rate of infection with the blood borne hepatitis C virus (HCV). In Egypt the level of HCV is 10–15%, one of the highest in the world. At the time when tartar emetic injections were being used for schistosomiasis, public health specialists were not aware that the standard sterilization procedures for the injection equipment could not protect patients from viral infections. These could be transmitted during mass treatment that required a series of tartar emetic injections over several weeks. The authors of the study suggested that the greater number of men and adolescent boys receiving injections for schistosomiasis could explain why the majority of cases of HCV in Egypt in the 1990s were men over 40, who had received injections 20 or more years ago (Frank et al. 2000 ).

What we need to know about gender differences in infection

Beginning in the 1930s, epidemiological reports of infection in rural communities found more males than females infected with schistosomiasis. In the 1960s, in villages in Beheira governorate, just south of Alexandria, Farooq and his colleagues found that infection rates for both types of schistosomiasis were higher among males than among females for all age groups except for those under five years of age. At a time when farming was still a full-time occupation (rather than a part-time activity as it has become now), Farooq identified farmers and farm laborers as the occupational group with the highest infection rates for both S. mansoni and S. haematobium; 43% for the 2,842 female farmers and 52.8% for the 2,900 males. Farooq's survey indicated an approximately equal proportion of men and women were farmers, just under half of the women and half of the men surveyed (Farooq et al. 1966A ).

In the 1970s and 1980s, a number of researchers noted a bigger gap between the infection rate of females and males in Upper Egyptian communities than in the Delta (Mansour et al. 1981; Miller et al.1981; Hammam et al.1975; King et al. 1982 ). In 1982 C.L. King and his colleagues suggested a reason for this gender gap. They wrote that: “It is frequently said that the females of Upper Egypt have had less exposure to contaminated water than their northern counterparts due to different working patterns and more conservative behavior.” (King et al.1982: 326)

(p.66) The 1992 nine-governorate survey found that more males than females were infected in all governorates. They also found that, overall, the difference between male and female infection rates in the four Upper Egypt governorates (an odds ratio of 1.91) was greater than in the five Lower Egyptian governorates (an odds ratio of 1.56). On the governorate level, differences between male and female prevalence rates were highest in Minya (12.15% for males and 5.9% for females, an odds ratio of 2.19), a governorate endemic for S. haematobium. They were lowest in the Delta governorate of Kafr al-Sheikh (55% for males and 36% for females, an odds ratio of 1.44), where overall prevalence rates were highest and only S. mansoni was found.

In Minya, the association between infection and the three kinds of canal exposure identified by EPI 1, 2, 3 were relatively low: an odds ratio of 1.67 for males bathing, 2.10 for children playing and 1.48 for females washing. The comparable figures for Kafr al-Sheikh were 3.45, 3.74 and 3.09 (Barakat et al. 2000; Gabr et al. 2000 ). This suggests that in Minya (with an overall prevalence rate of 8.9% compared to 39.3% in Kafr al-Sheikh) many water contact activities took place at sites where there were few or no vector snails or schistosomes. In contrast, in Kafr al-Sheikh, where vector snails and schistosomes were much more widely distributed, the correlation between water contact activities and infection was much higher for all three “at risk” groups.

These kinds of comparisons suggest the need to look more closely at the relative risk of different kinds of exposure activities for women, men and children, in various parts of Egypt. While the 1992 survey provided information on the number of males and females infected, and on certain behaviors that could be interpreted as “risk factors,” it did not explore these questions in greater depth. There is clearly also a need to find out how people actually behave, in contrast to the way they say they behave when confronted by an interviewer.

Overall, the various constituent parts of the Schistosomiasis Research Project, including the EPI 1, 2, 3 study, prompted many questions about gender differences in infection (and indeed about other aspects of gender and schistosomiasis). The absence of any discussion about gender in EPI 1, 2, 3 and most other SRP studies is probably the result of the near absence of anthropologists or other social scientists working in health related topics in collaboration with biomedical and public health colleagues. When SRP made a special request for proposals on socio-economic topics, few local social scientists responded.

Only two of the projects accepted by SRP had social scientists as principal investigators—both were carried out under the auspices of the Social Research Center at the American University in Cairo. Only ten of the 103 (p.67) completed SRP projects were on socio-economic topics. The only studies that used the rich database provided by EPI 1, 2, 3 focused on the coverage of screening for school-age children. One study found that children (especially girls) who did not attend school were more frequently infected than boys and girls who went to school (Husein et al. 1996 ). Concerned by these findings, the researchers then designed and tested a strategy to reach children who were not in school (Talaat et al. 1999A ). This study, which shares our concern for gender equity, will be discussed in chapter 11.

The epidemiological studies presented in this chapter, particularly EPI 1, 2, 3, give a broad picture of the distribution of the two forms of schistosomiasis in Egypt in the early 1990s, of the characteristics (such as age and sex) of those infected, and of “risk factors” for infection. As such, these studies reflect a biomedical and epidemiological view of disease and disease agents. They were not designed to study gender and human behavior in detail, or their relationship to schistosomiasis infection. They do, however, pose questions about gender and real-world risk behaviors. To these topics we now turn.