Parasitoses urinaires

Towards elimination of schistosomiasis after 5000 years of endemicity in Egypt

Schistosomiasis is a snail-transmitted infectious disease caused by a long lasting infection with a blood fluke of the genus Schistosoma. S. haematobium and S. mansoni are the species endemic in Egypt. The country has been plagued and seriously suffered from schistosomiasis over the past 5000 years. Great strides had been done in controlling the disease since 1922. The history, epidemiology and the different control approaches were reviewed. Currently, Egypt is preparing towards schistosomiasis elimination by 2020. The new strategy depends on four main axes; large scale treatment in all areas of residual transmission by targeting entire populations with PZQ, intensified snail control, heath education and behavioral changes and expansion of the complementary public health interventions. While on the road towards elimination, we addressed here the important challenges, lessons and the key issues from the different control strategies to help the achievement of our goal. Notably, frangibility of the drug based control, emergence of resistance against PZQ, persistence of some hot spots areas, the need of further control efforts to the high risk individuals and community involvement in the control programs, reconsideration of diagnostic tests used in surveillance, and continous monitoring of the field to detect changes in the snail intermediate host. Importantly, the adaptation between the parasite and its intermediate snail host throughout water bodies in Egypt merits attention as Schistosoma infection can be introduced to the new reclaimed areas. This review may help supplying information for the policy makers to tailor control measures suitable to the local context that could help in the transfer from control to elimination.

Schistosomiasis in Egypt: A never-ending story?

Schistosomiasis has plagued the Egyptian population since the antiquity. The disease is still a public health problem in Egypt, despite the tendency of being overlooked. In the first part of this review, the past and current trends of schistosomiasis in Egypt are reviewed, including history, epidemiology, morbidity, therapy, and control of the disease. Most of these aspects are more or less relevant to other schistosome-endemic regions all over the world. As only one drug is currently available for individual treatment and preventive mass chemotherapy, the quest for complementary measures is urgently warranted. Indeed, one promising approach is the discovery of a vaccine. Herein, we point out the efforts of the Egyptian scientists to develop an efficacious and affordable vaccine against schistosomiasis - a step forward in the battle of elimination of Schistosoma infection. Based on the candidate vaccine antigens, four types of vaccine formulations are discussed: purified antigen vaccines, DNA constructs, attenuated cercariae, and excretory-secretory antigen vaccines. Finally, this review provides insights into this ancient seemingly long-lasting parasitic disease.