Schistosomiasis in the Democratic Republic of Congo: a literature review

Abstract

Schistosomiasis is a poverty-related parasitic infection, leading to chronic ill-health. For more than a century, schistosomiasis has been known to be endemic in certain provinces of the Democratic Republic of Congo (DRC). However, a clear overview on the status of the disease within the country is currently lacking, which is seriously hampering control. Here, we review the available information on schistosomiasis in DRC of the past 60 years. Findings and data gaps are discussed in the perspective of upcoming control activities.An electronic literature search via PubMed complemented by manual search of non-peer-reviewed articles was conducted up to January 2015. The search concerned all relevant records related to schistosomiasis in the DRC from January 1955 onwards. A total of 155 records were found, of which 30 met the inclusion criteria. Results were summarized by geographical region, mapped, and compared with those reported sixty years ago. The available data reported schistosomiasis in some areas located in 10 of the 11 provinces of DRC. Three species of Schistosoma were found: S. mansoni, S. haematobium and S. intercalatum. The prevalence of schistosomiasis varied greatly between regions and between villages, with high values of up to 95 % observed in some communities. The overall trend over 60 years points to the spread of schistosomiasis to formerly non-endemic areas. The prevalence of schistosomiasis has increased in rural endemic areas and decreased in urban/peri-urban endemic areas of Kinshasa. Hepatosplenomegaly, urinary tract lesions and anaemia were commonly reported in schistosomiasis endemic areas but not always associated with infection status.The present review confirms that schistosomiasis is still endemic in DRC. However, available data are scattered across time and space and studies lack methodological uniformity, hampering a reliable estimation of the current status of schistosomiasis in DRC. There is a clear need for updated prevalence data and well-designed studies on the epidemiology and transmission of schistosomiasis in DRC. This will aid the national control program to adequately design and implement strategies for sustainable and comprehensive control of schistosomiasis throughout the country.

Fig. 1

Flow diagram of the literature search strategy. 1. Additional records consisted of three master theses, one book chapter and one map of schistosomiasis in DRC. 2. Reasons for exclusion were: a) Non relevant association between the keywords (e.g., Congo as name of a reagent, another country “Congo-Brazzaville”, etc.) (20 records); b) Reviews and studies based on mathematical modelling (18 records); c) Case reports and studies on hospitalized patients without any information on their geographic residency (11 records); d) Cases of schistosomiasis among non-Congolese travelers coming from DRC (5 records); e) Malacological studies (11); f) Animal and parasite fundamental research (30 records); g) Test evaluation and others (32 records). 3. Reason for exclusion: duplicates (4 records)

Fig. 2

Distribution map of schistosomiasis in DRC in 1954. Of the total number of 66 survey locations reported, 46 could be mapped; for the other locations geographical coordinates were lacking

Fig. 3

Distribution map of schistosomiasis in DRC based on reports from 1955–2015. Of the total number of 389 survey locations reported, 234 could be mapped; for the other locations geographical coordinates were lacking