Schistosomiasis in Saudi Arabia
1988; King Faisal Specialist Hospital and Research Centre; Volume: 8; Issue: 3 Linguagem: Italiano
10.5144/0256-4947.1988.169
ISSN0975-4466
Autores Tópico(s)Climate Change and Health Impacts
ResumoOriginal ArticlesSchistosomiasis in Saudi Arabia Zohair A. SebaiMB, BS, MPH, DrPH Zohair A. Sebai Address reprint requests and correspondence to Dr. Sebai: Department of Family and Community Medicine, College of Medicine and Medical Sciences, King Faisal University, P.O. Box 40024, Al-Khobar 31952, Saudi Arabia. From the Department of Family Health and Community Medicine, College of Medicine and Medical Sciences, King Faisal University, Al-Khobar Search for more papers by this author Published Online:24 Apr 2019https://doi.org/10.5144/0256-4947.1988.169SectionsPDF ToolsAdd to favoritesDownload citationTrack citations ShareShare onFacebookTwitterLinked InRedditEmail AboutABSTRACTABSTRACTThe article discusses the prevalence of schistosomiasis in Saudi Arabia and the problems facing its control. Saudi Arabia is located between two of the major endemic schistosomiasis areas in the world, the Nile River and the Tigris and Euphrates valleys. Four species of snail vectors exist in the country. The main natural habitat of the vector snails appears to be in the Sarawat mountains where there are various natural water sources. About 6.5% of the population suffer from schistosomiasis. The disease in general is predominant among the lower age group and affects males more than females. The infection rate is heavy along the permanent and main streams and moderate to low in remote areas. If control measures are carried out appropriately, schistosomiasis need not be a problem in Saudi Arabia by the year 2000.IntroductionSchistosomiasis, or bilharziasis, is a helminthic infection of the mesenteric, portal, and pelvic venous systems. The infection has been demonstrated in the mummies of ancient Egypt, and the etiology was known in 1851 by Bilharz, who discovered the adult worm in the mesenteric veins of an Egyptian. The life cycle involves the human as definitive host and an aquatic snail as intermediate host. The main pathologic effects are the progressive damage to various organs resulting from immunologic reactions to the eggs and the parasite deposited in the tissue. Hepatic fibrosis and portal hypertension occur in the intestinal form, while obstruction and superimposed infection occur in the urinary form.Schistosoma mansoni occurs mainly in Africa, the Arabian Peninsula, South America, and the Caribbean Islands, while S. haematobium occurs mainly in Africa and the Middle East. Schistosoma japonicum occurs in the Orient, and S. mekongi in Laos, Cambodia, and Thailand. About 200 million people in 74 countries are affected, half of them in Africa alone.1 Despite the extensive knowledge of the life cycle, pathogenesis, and methods of prevention, the disease, globally, is not yet under control. The reasons are inefficient management and lack of political commitments and social awareness.HISTORYAs a medical student in Egypt, I was questioning a patient admitted to the hospital with severe chest pains. After taking down the relevant history, I asked him if he had any other complaints. This he denied. I then asked him the classic question for an Egyptian patient, "Do you have blood in your urine?" The answer was "Of course I have blood in my urine." This chronic and insidious feature of the disease and the deceptively peaceful coexistence between humankind and the parasite (at least in the early stages) probably leads to apathy toward the disease in both patients and the public.Historians have taken little interest in schistosomiasis in the Arabian Peninsula compared to other fatal, disfiguring, or painful diseases such as smallpox, cholera, leprosy, plague, or malaria. One of the earliest observations of the disease was made by Hatch, an Indian physician in 1887, who noticed Bilharzia haematobia infection among pilgrims returning from Makkah.2 In 1903 Clemow3 reported that "there are some reasons to believe that it [schistosomiasis] is common in Arabia." This statement was based on reports from Turkish sanitary officers stationed in Arabia. Later on in 1940, ARAMCO (Arabian American Oil Company) health officers observed an increasing number of schistosomiasis cases among laborers working in the Eastern Province.In 1956 Abdul Azim and Gismann,4 WHO consultants, reported that S. haematobium and S. mansoni were endemic in the fertile areas of Saudi Arabia. They identified the vector snails and envisioned that the extension of irrigation and the oil industry, with the inevitable concentration of population, would intensify the disease. Tarizzo,5 in 1952, scrutinized the records of more than 70,000 ARAMCO employees and indicated the presumptive place of origin of 893 cases of S. mansoni and 51 cases of S. haematobium. He identified over 25 localities all over the country with the exception of the Eastern Province where no autochthonous infection was found. In 1956, Tarizzo carried out the first field trial of treatment.6Farooq7 surveyed selected areas of the country in 1960. He reported a high prevalence of the disease in Al-Kharj, Dariya, Taif, Wadi Fatma, Tabuk, and Tayma. His conclusion was that bilharziasis in Saudi Arabia is easy to control since the foci of infection are well defined and therefore lend themselves to focal control and even eradication within a relatively short period.Alio,8 in 1965, carried out an extensive survey on schistosomiasis in Saudi Arabia. His survey allowed a delineation of the endemic areas by finding the vector snails and diagnosing the autochthonous cases.Sources of infection in Saudi Arabia were classified as natural and man-made foci. The natural foci were further subclassified into permanent foci mainly in the perennial mountain streams and springs, temporary foci usually in the intermittent streams, and transitory foci in the ephemeral flood waters.Alio8 estimated the prevalence of the disease among the settled population as up to 90% in Al-Jouf and Sakakah, Ghamid and Zahran Highlands, Bisha oasis, Asir Highland, Tihamat Asir, and Najran; 10% in Southern Najd; 5% in Northern Hijaz and Northern Najd; and none in the Eastern Province. The total number of individuals presumed to be infected was estimated at 1,024,200, or 17% of the total population. He also believed that this was still a conservative estimate. Alio concluded that the problem of schistosomiasis was quite serious in comparison to many other health problems in Saudi Arabia. For the control of disease he suggested upgrading environmental sanitation, training of personnel, planned use of molluscicides, and treatment of patients.In the early 1970s several small-scale studies of the disease were conducted. Arfaa9 and Davis10 referred to Jizan and Madinah as highly endemic areas of S. haematobium, and Riyadh, Madinah, Makkah, and Al-Jouf as endemic foci of S. mansoni. The estimated overall prevalence in the two studies ranged from 2% in Zulfi to 91% in Khoba. They both described the distribution as patchy with rare mixed infection and thought that eradication was feasible in many parts of the Kingdom.Subsequent studies11–17 have been of a clinical nature. They shed light on some features of the pathology, diagnosis, and epidemiology of the disease.Wallace13 and Cutajar15 came to some common conclusions: a low prevalence of the disease among females (4% to 5%), no correlation between urinary schistosomiasis and carcinoma of the uroepithelium, and the relative ease with which the disease can be controlled. On the contrary, Hanash et al17 reported 30 patients with bilharzial bladder cancer. Cutajar15 found that schistosomiasis does not appear to be a significant etiologic factor in urolithiasis, which has a high incidence in Saudi Arabia.Magzoub and Kasim12 observed that water bodies do not show any apparent overlap between the different snail vectors of schistosomiasis whereas Arfaa found up to three species of snail (intermediate hosts) together in some areas (personal communication). Gremillon et al14 emphasized the value of quantitative examination of stool specimens for schistosomiasis eggs.In the 1980s most of the epidemiologic data were compiled by Arfaa18,19 and Githaiga.20THE PRESENT SITUATIONSnail VectorsFour species of snail vectors exist in the country. Biomphalaria arabica, the intermediate host of S. mansoni, is a related species to B. alexandria, which prevails in Egypt and has its main habitat in central Arabia and the northern and southwestern regions.The other three species which transmit S. haematobium are Bulinus truncatus found mainly in the western region, Bul. wrighti found mainly in the central region, and Bul. beccarri found mainly in the central and southwestern regions. The disease distribution follows the snail vector distribution.Theory of Disease DisseminationThe Arabian Peninsula desert is covered by shifting sands on a high, barren, and dry plateau. The rainfall is less than 12.7 cm per year, consisting of one monsoon in the winter in the interior of the peninsula and two monsoons in the winter and summer over the southern part of the Sarawat mountains.Water resources consist of streams, small canals, springs, water holes, dug wells, pools, and ponds.The country could be divided into the following geographic regions: the Red Sea coastal plains, the Sarawat mountains, the central Arabian plateau, the great sand areas (the great Nafud in the north, Rub'al Khali in the south, and Dahana desert belt in between), and the Gulf basin.Saudi Arabia is located between two of the major endemic schistosomiasis areas in the world, the Nile River valley and the Tigris and Euphrates valleys. Evidence indicates that the endemicity of the disease goes back more than 3,000 years in Egypt and over 6,000 years in Iraq, and the type of natural habitats and characteristics of snails suggest the presence of the snails in Saudi Arabia for the same length of time as in the Nile, Tigris, and Euphrates valleys.There are also foci of schistosomiasis in surrounding countries, namely Iraq, Lebanon, Syria, Occupied Palestine, Yemen, Ethiopia, Somalia, and Sudan. Over time, the disease has crossed the borders of the Arabian peninsula by means of population movements, pilgrimage, and trade.The main natural habitat of the vector snails appears to be in the Sarawat mountains where there are various natural water sources such as permanent streams, ponds, and springs. The snails disseminate along the major flood routes from the natural water sources in the Sarawat mountains and fill the wadi beds in the plains. Water often overflows into man-made wells and cisterns and introduces snails to man-made habitats.At least three important wadis (flood water courses) run through the peninsula toward the east until they are interrupted by the sand belt: Wadi Al-Rummah, Wadi Hanifa, and Wadi Al-Dawasir. They carry the snails to oases and villages scattered along their courses. Snails are disseminated to other oases and villages through a gradual progression from one suitable water source to another or by means of periodic seasonal floods. The Eastern Province of Saudi Arabia is free from all the snail vectors and the disease, possibly protected by the sand belt separating it from the rest of the country and the high salinity of the soil.Interestingly, the sand belt in Saudi Arabia delineates the disease distribution. To the west (the African continent and western and central Arabia) schistosomiasis is endemic. To the east of the sand belt, which includes the Eastern Province of Saudi Arabia and the vast majority of the Asian continent, the disease is scarcely found except in Iraq and small foci in Iran. In the Far East another species of the parasites and its vector snail appear.PREVALENCEIn developing countries, data on morbidity and mortality are not always complete. Lack of standardization and inadequate training and supervision of personnel are inherent problems of epidemiological surveys in developing countries.Statistics on schistosomiasis in Saudi Arabia are not exceptions to the rule. There are 12 schistosomiasis stations located at Riyadh, Al-Jouf, Makkah, Madinah, Taif, Hayil, Mahael, Bisha, Abha, Al-Baha, Jizan, and Najran. The health personnel in these stations conduct epidemiologic surveys, but it must be noted that they vary in competence, training, motivation, and degree of supervision they receive.The methods of survey vary from passive case detection (examining patients attending hospitals and health centers) to surveying a whole community or a school. Samples are not always representative, and laboratory tests are not necessarily standardized.20 Nevertheless, the available data still indicate the magnitude of the problem. Table 1 and Figure 1 show the prevalence of schistosomiasis in various regions in Saudi Arabia as reported by stations in 1983-1984.19Table 1. Prevalence of schistosomiasis as reported by the stations.*Table 1. Prevalence of schistosomiasis as reported by the stations.*Figure 1. The overall prevalence of intestinal and urinary schistosomiasis in various parts of Saudi Arabia in 1984. (Modified from Arfaa.19)Download FigureOf 230,802 people examined by all stations, 15,106 were positive for either S. mansoni or S. haematobium (an overall prevalence of 6.5%). There are about 2,000,000 people at risk (mostly living in rural areas), and the estimated number of infected people is within the range of 150,000 to 200,000. The disease has a patchy distribution (the prevalence rate within a region ranges from 0 to 80%). The determining factors are the suitability of the habitats for the vector, the abundance of vector snails, and the lifestyle of the people.The disease in general is predominant among the lower age group and affects males more than females. There is a possible seasonal fluctuation of incidence which follows rainfalls. The infection rate is heavy along the permanent and main streams and moderate to low in remote areas.PROBLEMSAs a result of socioeconomic development and the schistosomiasis control program, a general reduction of the vector snails and the morbidity rate has been noticed, especially in the last five years (Table 2). An exacerbation of the disease in an area is recorded from time to time as a result of an influx of foreign laborers or a change in the ecosystem. In Taif, where the prevalence rate is 3.8%, the examination of 2,277 new expatriates (Egyptians, Sudanese, and Yemenis) revealed that 37% were positive.18Table 2. Changes in schistosomiasis infection in selected areas in Saudi Arabia: 1974-1984.Table 2. Changes in schistosomiasis infection in selected areas in Saudi Arabia: 1974-1984.An outstanding example of the possible effect of ecological changes is found in Al-Baha area. Three years after Al-Sadr Dam was completed in 1981, high infestation with both B. arabica and Bul. truncatus was observed both in the lake behind the dam and downstream in the wadi. Eight of the 14 dams completed by 1985 in Al-Baha area became infested with the snail intermediate host (ZA Sebai, personal observation).Twenty-two projects of dam construction, irrigation schemes, and land reclamation are currently proceeding in Saudi Arabia. Unless the impact of the ecological changes is well studied, an expansion of the disease is highly predictable. In the Eastern Province (a schistosomiasis-free area at present), the possibility of introducing the intermediate host exists. This could happen because of the expansion of the irrigation system and the free and fast movements of bedouins who might carry the vector, for example, in their water bags.The change in the disease pattern following changes in the environment is well documented. A village in the Nile delta was surveyed in 1935 and 1979 for schistosomiasis. During the 44-year period, S. mansoni infection increased from 3.2% to 73% and S. hematobium infection decreased from 74% to 2.2%. The change has been attributed to a change in the ecosystem after the construction of the Aswan High Dam.21In some communities, adults employed in farming have a high risk of infection. Females in bedouin communities who carry water to their homes and herd animals in infested wadis are more exposed to the infection than men in the same community.WHICH WAY FORWARD?Progress in controlling the disease has already been achieved in the last 20 years. It is, however, the opinion of many researchers7–10 that the problem could be completely controlled or even eradicated since the habitats of the vector snails are generally localized. The three bases for further and substantial success are better management, training of personnel, and a multifaceted control approach with emphasis on the environmental modification. The collection of reliable data is extremely important in order to improve planning and monitoring.Research programs are needed in the areas of operational methodology, understanding the lifestyle of the population, developing a vaccine, and even the manipulation of the genetic makeup of the vector snail.Primary health care centers should be upgraded to give maintenance and continuity to schistosomiasis control programs. They should promote health education, active case finding, sanitary engineering, and community participation. By the year 2000 schistosomiasis need not be a problem in Saudi Arabia.This study was supported by King Abdul Aziz City for Science and Technology under grant number AT-S-26.ARTICLE REFERENCES:1. Mott KE. "Schistosomiasis—new goals" . WHO Magazine. 1984; Dec: 3–4. Google Scholar2. Hatch WK. "Bilharzia haematobia" . Lancet. 1887; 1:875. Google Scholar3. Clemow FG. The geography of disease. London: Cambridge University Press, 1903; 570. Google Scholar4. Abdel Azim M, Gismann A. "Bilharziasis survey in south-western Asia: covering Iraq, Israel, Jordan, Lebanon, Sa'udi Arabia, and Syria: 1950-51" . Bull WHO. 1956; 14:403–56. Google Scholar5. Tarizzo ML. "Schistosomiasis in Saudi Arabia. Vemes. Congres internationaux de Medecine tropical et du Paludisme (excerpt)" ., 1956. Google Scholar6. Tarizzo ML. "Schistosomiasis in Saudi Arabia treatment with lucanthone hydrochloride (Nilodin) and with sodium antimonyl gluconate (Triostam)" . Am J Trop Med Hyg. 1956; 5:145–9. Google Scholar7. Farooq M. "Report on a visit to Saudi Arabia" . WHO Assignment Report, 1961; EM/BIL/19/SA24:21. Google Scholar8. Alio IS. Epidemiology of schistosomiasis in Saudi Arabia with emphasis on geographic distribution patterns. New York, NY: Columbia University, NYC; 1967. Dissertation. Google Scholar9. Arfaa F. "Studies on schistosomiasis in Saudi Arabia" . Am J Trop Med Hyg. 1976; 25(2):295–8. Google Scholar10. Davis A. "Schistosomiasis control in the Kingdom of Saudi Arabia (with special reference to chemotherapy)" . WHO Assignment Report, 1977; EM/SCHIS/66,EM/SAA/MPD/002. Google Scholar11. Habib MA, Morsy TA, El-Nayal NA, Shoura MI. "Study of the clinical pattern of bilharziasis in Saudi Arabia" . J Egypt Soc Parasitol. 1977; 7(2): 163–70. Google Scholar12. Magzoub M, Kasim AA. "Schistosomiasis in Saudi Arabia" . Ann Trop Med Parasitol. 1980; 74(5):511–3. Google Scholar13. Wallace DM. "Urinary schistosomiasis in Saudi Arabia" . Ann R Coll Surg Engl. 1979; 61(4):265–70. Google Scholar14. Gremillon DH, Geckler RW, Kuntz RE, Marraro RV. "Schistosomiasis in Saudi Arabian recruits: a morbidity study based on quantitative egg excretion" . Am J Trop Med Hyg. 1978; 27(5):924–7. Google Scholar15. Cutajar CL. "Urinary schistosomiasis in the Asir district of Saudi Arabia" . Mahjoub ES, ed. Proceedings of the 5th Saudi Medical Meeting. Riyadh: College of Medicine, University of Riyadh, 1981:543–52. Google Scholar16. Ibrahim AM, Sebai ZA. "Analytic study of patients attending the bilharzia clinic in Riyadh, Saudi Arabia" . Saudi Med J. 1978; l(l):14–12. Google Scholar17. Hanash KA, Bissada NK, Abla A, et al.. "Predictive value of excretory urography, ultrasonography, computerized tomography, and liver and bone scan in the staging of bilharzial bladder cancer in Saudi Arabia" . Cancer. 1984; 54(l):172–6. Google Scholar18. Arfaa F. "Schistosomiasis control in the Kingdom of Saudi Arabia" . WHO Assignment Report, 1984; EM/SCHIS/89,SAA/MPD/002. Google Scholar19. Arfaa F. "Schistosomiasis control programme in the Kingdom of Saudi Arabia" . WHO Assignment Report, 1983; EM/SCHIS/86,EM/SAA/MPD/002. Google Scholar20. Githaiga HK. "Fact finding visits to bilharzia centers in the Kingdom of Saudi Arabia" . Report to the Ministry of Health Department of Preventive Medicine, Bilharziasis Section, 1984. Google Scholar21. Abdel-Wahab MF, Strickland GT, El-Sahly A, et al.. "Changing pattern of schistosomiasis in Egypt 1935-79" . Lancet. 1979; 2(8136):242–4. Google Scholar Previous article Next article FiguresReferencesRelatedDetailsCited byAbu-Eshy S, Malik G, Khan A, Khan G and Al-Shehri M (2019) Schistosomal Appendicitis, Annals of Saudi Medicine , 15:4, (347-349), Online publication date: 1-Jul-1995.Kattan S, Yousef A, Onuora V, Patil M, Al-Jasser A and Al-Ariyan R (1994) The Clinicopathological Features of Bladder Carcinoma Among Saudis in Riyadh Central Hospital, Annals of Saudi Medicine , 14:2, (114-116), Online publication date: 1-Mar-1994.Al-Shammari S, Jarallah J, Olubuyide I and Bamgboye E (1994) A Prospective Study of the Morbidity Pattern of Patients Seen at a University Primary Care Clinic, Annals of Saudi Medicine , 14:1, (22-25), Online publication date: 1-Jan-1994.Shetty S, Ibrahim A, Patil K, Morad N, Anandan N and Khurana P (2019) Bilharzial and Nonbilharzial Bladder Cancer in Asir: A Comparative Clinicopathological Study, Annals of Saudi Medicine , 13:2, (151-154), Online publication date: 1-Mar-1993.Ghandour A, Al-Robai A, Doenhoff M and Banaja A (2019) Morbidity from Schistosoma Mansoni in Relation to Intensity of Infection in a Community-Based Study, Annals of Saudi Medicine , 10:4, (420-425), Online publication date: 1-Jul-1990.Al-Moagel M (2019) Schistosomiasis in Saudi Arabia, Annals of Saudi Medicine , 9:1, (90-91), Online publication date: 1-Jan-1989. Volume 8, Issue 3May 1988 Metrics History Accepted21 June 1987Published online24 April 2019 KeywordsSchistosomiasisInformationCopyright © 1988, Annals of Saudi MedicinePDF download
Referência(s)