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Background: Schistosomiasis is one of the neglected tropical diseases (NTDs) selected for worldwide elimination in the near future. Egypt has made strong progress against its two endemic species of Schistosoma mansoni and S. haematobium. The former is prevalent in the Nile Delta with the latter dominating in the Nile south of Cairo. Innovative efforts are needed to reach the goal as further reduction of the prevalence has stalled due to ongoing transmission. In this study we aimed to explore the difference between low and high prevalence villages with regard to knowledge attitude and practice about schistosomiasis, utilization of health services, infection and transmission indices. Methods: A hybrid cross-sectional longitudinal study was conducted with three annual follow-ups conducted during 1994–1996. We used a representative systematic random sampling technique investigating 993 individuals from the high prevalence village and 614 from the low prevalence village. Data were analyzed using SPSS, comparing proportions with the Chi square test and means with the Student t test, and ANOVA. Results: Compliance of faecal sampling and chemotherapy was above 70% in both villages over the whole study period. Selective praziquantel treatment resulted in a significant reduction of prevalence and intensity of infection in both villages, dropping from 35.8% prevalence to 20.6%, in the low-prevalence village, and from 69.5 to 45.9% in the high-prevalence one. Intensity of infection at the base line was 30 eggs per gram (EPG) of stool in the low-prevalence village versus 105 EPG in the high-prevalence village. However, after the second round, reinfection rebounded by 22% in the high-prevalence village, while a slight improvement of the infection indices was demonstrated in the low-prevalence one. The level of knowledge was modest in both villages: people knew about self-protection and treatment, but not much about the role of human excreta for schistosomiasis transmission. While all participants maintained that using the water from the canals was inevitable, inhabitants in the high-prevalence village showed significantly lower scores reflecting higher water contact compared to the low-prevalence one. Many of them (67%) did not utilize the health centre at all compared to 26% of the people in the low-prevalence village. Interestingly, private clinics were seen as the primary source of health care by both villages, but more frequently so in the high-prevalence village (used by 87.2% of the inhabitants) compared to the low-prevalence one (59.8%). Conclusions: Even if chemotherapy works well as reflected by the observed downregulation of intensity of infection in both villages, reinfection continued due to difficulties to avoid water contact. Efforts must be made to make people understand the role of human excreta for transmission. There is also a need to make people better trust the medical services available. [ABSTRACT FROM AUTHOR]

A double-blind, randomized controlled trial was conducted in an endemic focus for Schistosoma mansoni in Kafr El-Sheikh Governorate, Northern Nile Delta, Egypt, to evaluate the prophylactic effect of artemether (ART) given in conjunction with praziquantel (PZQ). The study encompassed 913 primary school children randomly assigned to two treatment groups PZQ/ART and PZQ/ART-placebo. At baseline, both groups received 40 mg/kg body weight of PZQ twice four weeks apart, after which one group received 6 mg/kg body weight of ART every 3 weeks in 5 cycles during the transmission season and the other group received ART-placebo. At the end of the study, prevalence of infection among the PZQ/ART was approximately half that of the PZQ/ART-placebo group, i.e. 6.7% versus 11.6%, and incidence of new infections for the PZQ/ART was 2.7% versus 6.5% for the PZQ/ART-placebo. In conclusion, PZQ/ART combined therapy might be considered as an adjunct measure against human schistosomiasis, by specifically reducing transmission and therefore contribute to disease elimination. [ABSTRACT FROM AUTHOR]

Background: Control of human schistosomiasis remains a longstanding issue on the agenda of the Egyptian Ministry of Health and Population (MOHP). Substantial impact on morbidity and prevalence of S. mansoni was widely reported after the National Schistosomiasis Control Program (NSCP) extended selective treatment with praziquantel (PZQ) to the Nile Delta in 1992 and upgrading this approach to mass drug administration (MDA) in 1997. Disease elimination, however, eludes NSCP as the micro-level includes many high-risk foci that sustain transmission, which has not been subjected to investigation., Methods: The study included five high-risk Nile Delta villages situated in the Kafr El-Sheikh Governorate. The total sample size amounted to 2382 individuals of both sexes and all ages. Diagnosis was based on four Kato-Katz slides from two consecutive stool samples. Data were investigated using SPSS, comparing proportions with the Chi square test and means with the Student t test, while strength of the associations were subjected to Odds Ratio (OR) analysis., Results: The overall prevalence of schistosomiasis in the study area was found to be 29%, while the mean geometric mean egg count (GMEC) was low (66.78 ± 4.4) indicating low intensity of infection. The mean village prevalence rates ranged from 16.5% to 49.5% and the GMECs from 35.2 to 86.2 eggs per gram (EPG) of stool. The difference of prevalence between villages was statistically significant at P < 0.05, and the prevalence was significantly higher among males than among females, P < 0.05, OR =1.4 and 95% CI (1.16-1.60). Infection peaked in the next youngest age group (5- ≤ 10 years of age) at an average prevalence of 50.8% with the GMEC reaching 209 EPG of stool in the village with the highest prevalence. The average prevalence and GMEC among children <5 years were 20.6% and 92.7 EPG, respectively., Conclusion: Transmission of S mansoni in high-risk areas in the Nile Delta remains uninterrupted calling for improved, more comprehensive control strategies. Further investigations are needed to find out whether these results are due to inefficacy of PZQ, surviving immature worms or drug resistance.

Few studies comparing schistosomiasis vaccine candidate antigens between laboratories have been carried out and published. Generally, only the investigators who discovered the molecules have evaluated them in either experimental animal models or in human correlate studies. In an attempt to identify responses against specific antigens and investigate their association with resistance versus susceptibility to re-infection, we studied the serological reactions and the cytokine responses stimulated by a panel of 10 candidate vaccine molecules in 225 long-term residents of an area endemic for Schistosoma mansoni in Egypt. The panel consisted of four recombinant antigens (Sm62-Irv5, Sm37-G3PDH, Sm28-GST and Sm14-FABP), one full-length native protein (Sm97-paramyosin), two synthetic peptides (MAP3 and MAP4) and three unpublished antigens (PR52-filamin, PL45-phosphoglycerate kinase, PN18-cyclophilin). Two different study designs, one based on retrospective and the other on prospective parasitological data were applied in the evaluation of the immune responses. Using historical data collected over the previous 5 years, correlations between frequency of re-infection and antigen-specific immune responses were investigated. In the prospective arm of the study, the subjects were followed over time after treatment with praziquantel with periodic immunological tests and stool examinations. Thus, highly specific humoral and cellular immune reactions in response to the 10 antigens described above could be correlated, both prospectively and retrospectively, with detailed epidemiological data covering a 66-month period. The immune response profiles produced were unique to each antigen but no clear "winner" or "winners" were identified. However, markers for both resistance and susceptibility to re-infection were identified for each molecule indicating which types of responses to aim for in vaccination and which ones to avoid. The insights gained from this approach should be useful for antigen selection and ultimately for vaccine formulation prior to Phase I/II trials in humans.