Asian schistosomiasis is a parasitic disease caused by two species of blood flukes (trematode worms), Schistosoma japonicum and Schistosoma mekongi. These can cause serious morbidity such as liver dysfunction and cerebral symptoms, and sometimes death from complications. In the Western Pacific Region, S. mekongi is endemic in Cambodia and the Lao Peoples Democratic Republic, and S. japonicum is currently endemic in China and the Philippines.
The Western Pacific Region has a long history of the fight against Asian schistosomiasis. Significant progress has been made in recent decades in reducing the prevalence of schistosomiasis in many endemic areas in the Western Pacific Region by means of preventive chemotherapy. However, poor sanitation and animal reservoirs have contributed to rapid resurgence of infection and continuing transmission of schistosomiasis, and preventive chemotherapy alone has not sufficed to interrupt transmission of Asian schistosomiasis.
An Expert Consultation to Accelerate Elimination of Asian Schistosomiasis was held in Shanghai, China on 22-23 May 2017 to review the experience of various control interventions and the current status of schistosomiasis in the Western Pacific Region. Participants recommended that community empowerment through a One Health approach, composed of health promotion, improving water, sanitation and hygiene (WASH), preventive chemotherapy, treatment and management of domestic animals and livestock (buffalo and cattle, dogs, sheep, pigs, goats) and focal snail control (for S. japonicum), supported by high-level political advocacy, should be the core strategy to accelerate and sustain elimination of Asian schistosomiasis.
The Consultation participants also agreed on the provisional criteria, goals and indicators for the elimination of transmission (referred to as interruption of transmission) of Asian schistosomiasis in the Western Pacific Region, taking into consideration the zoonotic nature of the disease. All countries endemic for schistosomiasis in the Western Pacific Region will aim to achieve the aforementioned criteria by 2025 and be validated for elimination of transmission of schistosomiasis by 2030.
As prevalence goes down and countries accelerate their efforts to eliminate the disease, surveillance systems need to be improved by intensifying active surveillance, establishing passive surveillance and improving diagnostic techniques to be able to detect infected individuals in low-prevalence settings. WHO, with the support of WHO collaborating centres and other academic and research institutions, should support endemic countries to build capacity for effective active and passive surveillance systems.