Discovery of a Hidden Schistosomiasis Endemic in the Salamat Region of Chad, Africa

Visclosky, Timothy; Hashikawa, Andrew; Kroner, Eric

doi:10.9745/ghsp-d-20-00703

Cited by 1 publication

(4 citation statements)

References 17 publications

(28 reference statements)

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“…Every year, hundreds of articles are published on schistosomiasis. Table 2 summarizes the recently reported prevalence of UGS in SSA that was indexed in PubMed [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 ,…”

Section: Recent Status Of Ugs In Sub-saharan Africamentioning

confidence: 99%

“…As shown in Table 2 , most surveys screened SAC following WHO recommendations, which is a cost-effective approach and well reflects endemicity in the surveyed locality [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 ,…”

Section: Recent Status Of Ugs In Sub-saharan Africamentioning

confidence: 99%

“…Field surveys in endemic areas have continuously reported the persistent transmission of UGS in all of SSA ( Table 2 ). Several articles have reported a high prevalence of over 50% positivity in recent local surveys, including 100% and 39.2% in Chad [ 14 , 15 ], 60.4% in Mozambique [ 40 ], 67.4% and 65.3% in Nigeria [ 45 , 54 ], and 59.7% and 66.7% in Senegal [ 55 , 56 ]. Most of these reports were from hotspots with high re-infection rates, but some were unrecognized hyperendemic foci.…”

Section: Recent Status Of Ugs In Sub-saharan Africamentioning

confidence: 99%

“…Most of these reports were from hotspots with high re-infection rates, but some were unrecognized hyperendemic foci. Additionally, all surveys conducted in Cameroon [ 10 , 11 , 12 , 13 ], Chad [ 14 , 15 ], Gabon [ 23 , 24 , 25 ], and Senegal [ 55 , 56 ] reported over 30% egg-positive rates. In endemic areas of these countries, UGS is still highly transmitted locally, although many previously known areas have become less endemic by repeated MDAs.…”

Section: Recent Status Of Ugs In Sub-saharan Africamentioning

confidence: 99%

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Review of Recent Prevalence of Urogenital Schistosomiasis in Sub-Saharan Africa and Diagnostic Challenges in the Field Setting

Hong

2023

Life

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Human schistosomiasis is one of neglected tropical diseases that remain highly prevalent in sub-Saharan Africa (SSA). Human schistosomiasis is mainly caused by two species, Schistosoma haematobium and S. mansoni, leading to urogenital and intestinal schistosomiasis, respectively. The World Health Organization (WHO) recommends mass drug administration (MDA) with praziquantel as the primary method of global intervention. Currently, MDA with praziquantel covers over half of the target population in endemic SSA countries. However, an accurate diagnosis is crucial for monitoring and evaluating the effectiveness of MDA. The standard diagnosis of both urogenital and intestinal schistosomiasis relies on the microscopic identification of eggs. However, the diagnostic sensitivity of this approach is low, especially for light or ultra-light infections. This is because Schistosoma eggs are laid inside of the venous plexus of the urinary bladder or mesenteric vein, where the adult flukes live. Approximately half of the eggs circulate in the blood vessels or are packed in neighboring tissues, while the remaining half are expelled into the lumen of the urinary bladder or intestine intermittently when the blood vessels are ruptured. In the field setting, the accuracy of any diagnostic method is critical for proper management of the intervention. The present article reviews the recent prevalence of urogenital schistosomiasis in SSA and highlights the practical limitations of diagnostic methods such as urine microscopy, urine reagent strips, molecular diagnosis, and ultrasound scanning in the field setting. Despite continuous global efforts to eliminate schistosomiasis over the past 20 years, many areas still remain endemic in SSA. No single diagnostic approach achieves acceptable sensitivity and specificity in the field setting. Therefore, any field survey should employ a combination of these methods based on the purpose of the study to accurately monitor and evaluate urogenital schistosomiasis. Based on diagnostic values and a cost–benefit analysis, a urine reagent strip test can replace urine microscopy in the field setting. The WHO criteria by ultrasound diagnosis should be updated including the echogenic snow sign and contour distortion.

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