National Serologic Survey of Haematobium Schistosomiasis in Morocco: Evidence for Elimination

Amarir, Fatima; Mansouri, Bouchra El; Fellah, Hajiba; Sebti, Faiza; Lakranbi, Mohammed; Handali, Sukwan; Wilkins, Patricia P.; Idrissi, Abderrahman Laamrani El; Sadak, Abderrahim; Roubal, M.

doi:10.4269/ajtmh.2011.10-0378

Cited by 35 publications

(33 citation statements)

References 14 publications

(14 reference statements)

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“…The total population of the province of Errachidia in 2009 was estimated at 600,000 [31]. Both provinces are under the influence of a semi-arid climate regime and are characterized by relatively cold and humid winters and hot and dry summers [32,33].…”

Section: Methodsmentioning

confidence: 99%

Linking Climate to Incidence of Zoonotic Cutaneous Leishmaniasis (L. major) in Pre-Saharan North Africa

Bounoua

Kahime

Houti³

et al. 2013

IJERPH

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Shifts in surface climate may have changed the dynamic of zoonotic cutaneous leishmaniasis (ZCL) in the pre-Saharan zones of North Africa. Caused by Leishmania major, this form multiplies in the body of rodents serving as reservoirs of the disease. The parasite is then transmitted to human hosts by the bite of a Phlebotomine sand fly (Diptera: Psychodidae) that was previously fed by biting an infected reservoir. We examine the seasonal and interannual dynamics of the incidence of this ZCL as a function of surface climate indicators in two regions covering a large area of the semi-arid Pre-Saharan North Africa. Results suggest that in this area, changes in climate may have initiated a trophic cascade that resulted in an increase in ZCL incidence. We find the correlation between the rainy season precipitation and the same year Normalized Difference Vegetation Index (NDVI) to be strong for both regions while the number of cases of ZCL incidence lags the precipitation and NDVI by 2 years. The zoonotic cutaneous leishmaniasis seasonal dynamic appears to be controlled by minimum temperatures and presents a 2-month lag between the reported infection date and the presumed date when the infection actually occurred. The decadal increase in the number of ZCL occurrence in the region suggests that changes in climate increased minimum temperatures sufficiently and created conditions suitable for endemicity that did not previously exist. We also find that temperatures above a critical range suppress ZCL incidence by limiting the vector’s reproductive activity.

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Section: Methodsmentioning

confidence: 99%

Linking Climate to Incidence of Zoonotic Cutaneous Leishmaniasis (L. major) in Pre-Saharan North Africa

Bounoua

Kahime

Houti³

et al. 2013

IJERPH

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“…In fact antibody specificity may be difficult to confirm and verify when eggs or antigen detection are negative [29]. As an alleged better standard assay (in particular the HAMA-EITB, 100% specificity and sensitivity for S. haematobium detection; determined with confirmed cases [5] was not available it is difficult to conclude which of the two antibody tests applied in this pilot study is most accurate. However, we do believe that it is important to use at least two different serological antibody assays in parallel to achieve sufficient sensitivity in respect to the presence of Schistosoma antibody, demonstrating exposure.…”

Section: Discussionmentioning

confidence: 99%

“…In 2009 validation of interruption of transmission was commenced with the initiation of a national serological survey (using enzyme-linked immunoelectrotransfer blot, EITB) screening for human antibodies against S. haematobium in children, followed by a national molecular malacology survey analyzing the prevalence of infected snails (the intermediate host). The results confirmed interruption of transmission and indicated progress towards elimination as it showed that none of children or the collected snails was infected by S. haematobium [5, 6]. However, given that the exact parasite life spans and the distribution of the post-treatment antibody responses across the whole population are not fully understood [1, 7], prevention of reemerging required a vigilant survey strategy.…”

Section: Introductionmentioning

confidence: 88%

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Selecting accurate post-elimination monitoring tools to prevent reemergence of urogenital schistosomiasis in Morocco: a pilot study

et al. 2017

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BackgroundAfter alleged stop of transmission of schistosomiasis and further down the line in post elimination settings, sensitive tools are required to monitor infection status to prevent potential re-emergence. In Rahala, where transmission cycle of Schistosoma haematobium is interrupted since 2004 but where 30% of snails are still infected by S. bovis, potential human S. bovis infection can’t be excluded. As methods based on egg-counts do not provide the required sensitivity, antibody or antigen assays are envisaged as the most appropriate tools for this type of monitoring.MethodsIn this pilot study, the performances of three assays were compared: two commercially available antibody tests (ELISA and haemagglutination format) indicating exposure, and an antigen test (lateral flow strip format) demonstrating active infection. All 37 recruited study participants resided in Rahala (Akka, province Tata, Morocco). Participants had been diagnosed and cured from schistosomiasis in the period between 1983 and 2003. In 2015 these asymptomatic participants provided fresh clinical samples (blood and urine) for analysis with the aforementioned diagnostics tests.ResultsNo eggs were identified in the urine of the 37 participants. The haemagglutination test indicated 6 antibody positives whereas the ELISA indicated 28 antibody positives, one indecisive and one false positive. ELISA and haemagglutination results matched for 18 individuals, amongst which 5 out of 6 haemagglutination positives. With the antigen test (performed on paired serum and urine samples), serum from two participants (cured 21 and 32 years ago) indicated the presence of low levels of the highly specific Schistosoma circulating anodic antigen (CAA), demonstrating low worm level infections (less than 5 pg/ml corresponding to probably single worm pair). One tested also CAA positive with urine. ELISA indicated the presence of human anti-Schistosoma antibodies in these two CAA positive cases, haemagglutination results were negative.ConclusionsTo prevent reemergence of schistosomiasis in Morocco current monitoring programs require specific protocols that include testing of antibody positives for active infection by the UCP-LF CAA test, the appropriate diagnostic tool to identify Schistosoma low grade infections in travelers, immigrants and assumed cured cases. The test is genus specific will also identify infections related to S. bovis.Electronic supplementary materialThe online version of this article (doi:10.1186/s40249-017-0289-z) contains supplementary material, which is available to authorized users.

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“…Schistosomiasis was endemic to rural areas in southern Morocco for many years, and the first cases were identified in 1914 [10]. The only form of schistosomiasis in Morocco is urinary schistosomiasis due to Schistosoma haematobium [11].…”

Section: Discussionmentioning

confidence: 99%

How Morocco Succeeds in Eliminating Schistosomiasis

Tlamçani

2013

Afro-Egyptian Journal of Infectious and Endemic Diseases

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Schistosomiasis is an endemic parasitic infection very linked to poverty. It is considered a world health problem since it infects people from 76 different countries especially tropical and subtropical regions. For many years, Morocco was endemic for shistosome infection. The unique form is urinary schistosomiasis and the first case was described in 1914. After an alarming prevalence rate (13 416 cases) in 1973, Morocco decided to establish a strategy to control and then to eliminate schistosomiasis through three major phases (control, elimination and consolidation). Since 2004 and until now, it isn't reported any new indigenous case. Morocco achieves the goal and succeeds in decreasing the prevalence of infection to a level of zero so eliminating schistosomiasis in all endemic geographic areas.

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National Serologic Survey of Haematobium Schistosomiasis in Morocco: Evidence for Elimination

Cited by 35 publications

References 14 publications

Linking Climate to Incidence of Zoonotic Cutaneous Leishmaniasis (L. major) in Pre-Saharan North Africa

Linking Climate to Incidence of Zoonotic Cutaneous Leishmaniasis (L. major) in Pre-Saharan North Africa

Selecting accurate post-elimination monitoring tools to prevent reemergence of urogenital schistosomiasis in Morocco: a pilot study

How Morocco Succeeds in Eliminating Schistosomiasis

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