The Republic of Sierra Leone is located on the west coast of Africa, bordering Guinea and Liberia, with a population of 7.8 million in 2019 (1). It has a tropical monsoon climate, with high temperatures and plentiful precipitation. As one of the least developed countries in the world (2), Sierra Leone has long struggled with poor health outcomes with a life expectancy at birth of 59 for male and 61 for female, and high maternal and neonatal mortality, threatened by infectious diseases such as malaria, tuberculosis, typhoid fever, cholera, and Lassa fever (3).
Since March 2014, the 3 West African countries of Sierra Leone, Guinea, and Liberia have been hit by the worst outbreak of Ebola virus disease (EVD) in history. A total of 28,610 cases and 11,308 deaths were reported (4). As requested, the Chinese government has rapidly sent 1,200 medical staff to these countries to fight against Ebola (5). In a bid to conduct testing for Ebola and other viral hemorrhagic fevers (VHF), China CDC established the Sierra Leone-China Friendship Fixed Biological Safety Laboratory Level 3 (BSL-3 Laboratory) in Sierra Leone, which was officially put in operation in March 2015. It now serves as the national reference laboratory for VHF in Sierra Leone and the national training center for virus testing and biosafety. Since then, China and Sierra Leone have implemented 2 technical cooperation projects (Phase 1 and Phase 2) based on the BSL-3 Laboratory to provide technical support to Sierra Leone in terms of VHF testing capacity and surveillance capacity of key infectious diseases.
Sierra Leone also suffers from a heavy burden of parasitic diseases, including malaria, schistosomiasis, lymphatic filariasis, onchocerciasis, soil-transmitted helminth diseases, and African trypanosomiasis (6). The Global Burden of Disease Study 2019 showed that the malaria burden in Sierra Leone in 2019 was 824,000 (355,000–1,400,000) disability-adjusted life years (DALYs) per 100,000 individuals, and the onchocerciasis burden was 23,000(9,750–40,000) DALYs per 100,000 individuals (7). According to the World Malaria Report 2020, Sierra Leone reported 2,615,850 malaria cases in 2019 with an average incidence rate of 33.5% (2,615,850/7,813,207), and 6,824 malaria deaths with a case fatality rate of 0.3% (6,824/2,615,850). It is estimated that 2.24 million outpatient visits each year were due to malaria, of which about 1 million were children under 5 years old (8). Parasitic diseases, especially malaria, have posed great threats to health and socioeconomic development in Sierra Leone.
At present, Sierra Leone faces huge challenges in the prevention and control of parasitic diseases. First, many weaknesses exist in its public health system, including laboratory testing capacity, implementation of prevention and control measures, prevention and control personnel, and data quality. Second, prevention and control efforts fall short of strong fundamentals with few national epidemiological data and incomplete vector monitoring data. Third, the parasitic disease control program is unsustainable and needs more investment as it is largely dependent on international aid projects.
To understand the disease spectrum and infection status of parasitic diseases in Sierra Leone, the Sierra Leone-China BSL-3 laboratory for parasitic disease testing and surveillance (parasitic disease laboratory) was jointly established by China CDC and Ministry of Health and Sanitation of the Republic of Sierra Leone. This paper reviews the establishment, development, and impacts of the BSL-3 laboratory.