Factors Affecting the Prevalence of Human Schistosomiasis in Aseer Region, Saudi Arabia

Some epidemiological and serological studies on schistosomiasis in Najran area, Saudi Arabia

Schistosomiasis is a major cause of morbidity and mortality and has been estimated to infect over 200 million people. Diagnosis of schistosomiasis by detection of specific antibodies is likely to be more sensitive than the traditional method of diagnosis by detection of eggs in stool or urine. Therefore the present study was the first attempt to highlight the seroepidemiology of schistosomiasis among the general population of Najran City, southern of Saudi Arabia, as well as to achieve the performance of the diagnostic tests used. A total of 180 participants attending King Khaled hospital in Najran Province, Saudi Arabia, over a one year period, from September 2013 to September 2014 were screened for the presence of Schistosoma antibody in their blood serum using an indirect hemagglutination assay (IHA). Specific immunoglobulin (Ig) G antibody was evaluated using an enzyme-linked immunosorbent assay (ELISA). Out of the 180 samples of sera tested using IHA, 32 (20 %) were found to be positive with a titer ranging from 1:160 to 1:1280, while 42(23.2 %) revealed Schistosoma IgG. A positive relationship was found between the seroprevalence of schistosomiasis and age of tested participants, especially in the age group of 20-40 years old. Additionally, prevalence of infection was more in males (36 %) than females (7.5 %), and showed statistical significance (P < 0.001). Similarly, there was significant association between the presence of Schistosoma antibodies and the nationality of residence, and education of participants (P < 0.05). The current investigation reveals an alarmingly high prevalence of schistosomiasis among participants in Najran, southern region of Saudi Arabia and this supports an urgent need to re-evaluate the current control measures and implement an integrated, targeted and effective schistosomiasis control measures.

Time to set the agenda for schistosomiasis elimination

It is time to raise global awareness to the possibility of schistosomiasis elimination and to support endemic countries in their quest to determine the most appropriate approaches to eliminate this persistent and debilitating disease. The main interventions for schistosomiasis control are reviewed, including preventive chemotherapy using praziquantel, snail control, sanitation, safe water supplies, and behaviour change strategies supported by information, education and communication (IEC) materials. Differences in the biology and transmission of the three main Schistosoma species (i.e. Schistosoma haematobium, S. mansoni and S. japonicum), which impact on control interventions, are considered. Sensitive diagnostic procedures to ensure adequate surveillance in areas attaining low endemicity are required. The importance of capacity building is highlighted. To achieve elimination, an intersectoral approach is necessary, with advocacy and action from local communities and the health community to foster cooperative ventures with engineers, the private sector, governments and non-governmental organizations specialized in water supply and sanitation. Examples of successful schistosomiasis control programmes are reviewed to highlight what has been learnt in terms of strategy for control and elimination. These include St. Lucia and other Caribbean islands, Brazil and Venezuela for S. mansoni; Saudi Arabia and Egypt for both S. mansoni and S. haematobium; Morocco, Tunisia, Algeria, Mauritius and the Islamic Republic of Iran for S. haematobium; Japan and the People's Republic of China for S. japonicum. Additional targets for elimination or even eradication could be the two minor human schistosome species S. guineenisis and S. intercalatum, which have a restricted distribution in West and Central Africa. The examples show that elimination of schistosomiasis is an achievable and desirable goal requiring full integration of preventive chemotherapy with the tools of transmission control. An agenda for the elimination of schistosomiasis would aim to identify the gaps in knowledge, and define the tools, strategies and guidelines that will help national control programmes move towards elimination, including an internationally accepted mechanism that allows verification/confirmation of elimination.