Prevalence and risk distribution of schistosomiasis among adults in Madagascar: a cross-sectional study

Abstract

Background The goal to eliminate the parasitic disease of poverty schistosomiasis as a public health problem is aligned with the 2030 United Nations agenda for sustainable development goals, including universal health coverage (UHC). Current control strategies focus on school-aged children, systematically neglecting adults. We aimed at providing evidence for the need of shifting the paradigm of schistosomiasis control programs from targeted to generalized approaches as key element for both the elimination of schistosomiasis as a public health problem and the promotion of UHC. Methods In a cross-sectional study performed between March 2020 and January 2021 at three primary health care centers in Andina, Tsiroanomandidy and Ankazomborona in Madagascar, we determined prevalence and risk factors for schistosomiasis by a semi-quantitative PCR assay from specimens collected from 1482 adult participants. Univariable and multivariable logistic regression were performed to evaluate odd ratios. Results The highest prevalence of S. mansoni, S. haematobium and co-infection of both species was 59.5%, 61.3% and 3.3%, in Andina and Ankazomborona respectively. Higher prevalence was observed among males (52.4%) and main contributors to the family income (68.1%). Not working as a farmer and higher age were found to be protective factors for infection. Conclusions Our findings provide evidence that adults are a high-risk group for schistosomiasis. Our data suggests that, for ensuring basic health as a human right, current public health strategies for schistosomiasis prevention and control need to be re-addressed towards more context specific, holistic and integrated approaches.

Comparative evaluation of plasma biomarkers ofSchistosoma haematobiuminfection in endemic populations from Burkina Faso

“…Discordant CAA negative/cfDNA positive results could be attributed to differences in the stage specificity of the two markers, with cfDNA detecting all stages including larval ones while CAA detecting adults [37], and/or by recently cleared infections with cfDNA persisting in circulation longer than CAA [38]. On the other hand, discordant CAA positive/cfDNA negative results could be attributed to a suboptimal cfDNA sensitivity at low CAA concentrations because of an insufficient plasma volume used for nucleic acid extraction in this study (1000µl of plasma was used in a previous work [22] compared to the 100µl used in the present study), an hypothesis supported by the observation that the proportion of “false negative” cfDNA results decreases significantly with increasing CAA levels. Despite some discordant results, there was a substantial agreement between CAA and cfDNA testing, along with a comparable agreement with the results of CRS and LCA.…”

“…Cell free circulating DNA (cfDNA) was extracted from 100 µL plasma samples using the QIA amp Min Elute cfDNA Mini Kit according to the manufacturer’s protocol. Real Time PCR was performed at the Bernard Nocht Institute for Tropical Medicine, Germany, to amplify and detect S. heamatobium ( Dra1 ) and S. mansoni ( Sm1-7 ) target sequences (Sh-Forward Primer: 5’-GATCTCACCTATCAGACG AAAC-3’, Sh-Reverse Primer: 5’-TCACAACGATACGACCAAC-3’, Sh-Probe: 5’-Joe-TGTTGGAAGZGCCTGTTTCGCAA-BHQ1-3’; Sm-Forward Primer: 5’-CAACCGTTCTATGAA AATCGTTGT-3’, Sm-Reverse Primer: 5’-CCA CGCTCTCGCAAATAATCT-3’, Sm-Probe: 5‘-Fam-TCCGAAACCACTGGACGGATTTTTATGAT-BHQ1-3’) as previously described [21–22]. Primers and probe were included for the detection of Phocid herpesvirus (PhHV) DNA as internal PCR control (PhHV—Forward Primer: 5′ GGG CGA ATC ACA GAT TGA ATC 3′, PhHV—Reverse Primer: 5′ GCG GTT CCA AAC GTA CCA A 3′, PhHV—Probe: 5′ Cy5.5-TTT TTA TGT GTC CGC CAC CA-BBQ 3′).…”

Geography and health: role of human translocation and access to care

“…Two articles address the spatial distribution of risk factors, in the context of surveillance Xue et al [ 20 ] developed satellite-based models for recognition and monitoring livestock bovine as reservoir source of Schistosoma japonicum infection, demonstrating that high-resolution satellite images capturing the spatial distribution of bovine can be effective for surveillance, control and elimination of schistosomiasis in the People’s Republic of China. By means of a cross-sectional study in three specific regions of Madagascar, Gruninger et al [ 21 ] focussed on the prevalence and risk distribution of schistosomiasis for adults living in endemic areas. Based on the general high level of infection, and the specific high risk for farmers, the results indicate the need to re-address control activities towards more context-specific, holistic and integrated approaches.…”

Awareness and knowledge of female genital schistosomiasis in a population with high endemicity: a cross-sectional study in Madagascar

“…Progress on control has been made through vertical programs based on mass drug administration (MDA) with praziquantel, used as preventive chemoprophylaxis in school aged children. These strategies systematically neglected adults, favouring the conditions for the development of chronic forms of the disease especially in highly endemic contexts ( Kura et al, 2020 ; Gruninger et al, 2023 ). Chronic intestinal schistosomiasis caused by S. mansoni can lead to hepato-splenomegaly and portal hypertension while chronic urogenital schistosomiasis caused by S. haematobium increases the risk of developing squamous bladder cancer and can lead to male and female genital schistosomiasis.…”