Abstract:Declining groundwater resources in semi-arid areas are often cited because of anthropization and climate change. This is not the case in Nouakchott (Mauritania) where the water level has risen by 1 to 2 m over the last 40 years in parallel with urban expansion (+1 million inhabitants in 60 years). Using former and new data, primarily water table measurements and chemical indicators (major ions, bromide, 18 O, 2 H), we show that the groundwater level rise is mainly a consequence of the rapid population growth i… Show more
“…A natural salty belt with a width of 1 to 2 km separates the city proper from the Atlantic coast. Since the beginning of the 2010s, a potable water supply system has been developed in the Saharan zone of the country through Aftout Essahli project, with the aim to transport and deliver treated surface water through water pipes from the Senegal River to city residents [ 20 ]. Fig.…”
Background
Plasmodium vivax malaria is one of the major infectious diseases of public health concern in Nouakchott, the capital city of Mauritania and the biggest urban setting in the Sahara. The assessment of the current trends in malaria epidemiology is primordial in understanding the dynamics of its transmission and developing an effective control strategy.
Methods
A 6 year (2015–2020) prospective study was carried out in Nouakchott. Febrile outpatients with a clinical suspicion of malaria presenting spontaneously at Teyarett Health Centre or the paediatric department of Mother and Children Hospital Centre were screened for malaria using a rapid diagnostic test, microscopic examination of Giemsa-stained blood films, and nested polymerase chain reaction. Data were analysed using Microsoft Excel and GraphPad Prism and InStat software.
Results
Of 1760 febrile patients included in this study, 274 (15.5%) were malaria-positive by rapid diagnostic test, 256 (14.5%) were malaria-positive by microscopy, and 291 (16.5%) were malaria-positive by PCR. Plasmodium vivax accounted for 216 of 291 (74.2%) PCR-positive patients; 47 (16.1%) and 28 (9.6%) had P. falciparum monoinfection or P. vivax–P. falciparum mixed infection, respectively. During the study period, the annual prevalence of malaria declined from 29.2% in 2015 to 13.2% in 2019 and 2.1% in 2020 (P < 0.05). Malaria transmission was essentially seasonal, with a peak occurring soon after the rainy season (October–November), and P. vivax infections, but not P. falciparum infections, occurred at low levels during the rest of the year. The most affected subset of patient population was adult male white and black Moors. The decline in malaria prevalence was correlated with decreasing annual rainfall (r = 0.85; P = 0.03) and was also associated with better management of the potable water supply system. A large majority of included patients did not possess or did not use bed nets.
Conclusions
Control interventions based on prevention, diagnosis, and treatment should be reinforced in Nouakchott, and P. vivax-specific control measures, including chloroquine and 8-aminoquinolines (primaquine, tafenoquine) for treatment, should be considered to further improve the efficacy of interventions and aim for malaria elimination.
“…A natural salty belt with a width of 1 to 2 km separates the city proper from the Atlantic coast. Since the beginning of the 2010s, a potable water supply system has been developed in the Saharan zone of the country through Aftout Essahli project, with the aim to transport and deliver treated surface water through water pipes from the Senegal River to city residents [ 20 ]. Fig.…”
Background
Plasmodium vivax malaria is one of the major infectious diseases of public health concern in Nouakchott, the capital city of Mauritania and the biggest urban setting in the Sahara. The assessment of the current trends in malaria epidemiology is primordial in understanding the dynamics of its transmission and developing an effective control strategy.
Methods
A 6 year (2015–2020) prospective study was carried out in Nouakchott. Febrile outpatients with a clinical suspicion of malaria presenting spontaneously at Teyarett Health Centre or the paediatric department of Mother and Children Hospital Centre were screened for malaria using a rapid diagnostic test, microscopic examination of Giemsa-stained blood films, and nested polymerase chain reaction. Data were analysed using Microsoft Excel and GraphPad Prism and InStat software.
Results
Of 1760 febrile patients included in this study, 274 (15.5%) were malaria-positive by rapid diagnostic test, 256 (14.5%) were malaria-positive by microscopy, and 291 (16.5%) were malaria-positive by PCR. Plasmodium vivax accounted for 216 of 291 (74.2%) PCR-positive patients; 47 (16.1%) and 28 (9.6%) had P. falciparum monoinfection or P. vivax–P. falciparum mixed infection, respectively. During the study period, the annual prevalence of malaria declined from 29.2% in 2015 to 13.2% in 2019 and 2.1% in 2020 (P < 0.05). Malaria transmission was essentially seasonal, with a peak occurring soon after the rainy season (October–November), and P. vivax infections, but not P. falciparum infections, occurred at low levels during the rest of the year. The most affected subset of patient population was adult male white and black Moors. The decline in malaria prevalence was correlated with decreasing annual rainfall (r = 0.85; P = 0.03) and was also associated with better management of the potable water supply system. A large majority of included patients did not possess or did not use bed nets.
Conclusions
Control interventions based on prevention, diagnosis, and treatment should be reinforced in Nouakchott, and P. vivax-specific control measures, including chloroquine and 8-aminoquinolines (primaquine, tafenoquine) for treatment, should be considered to further improve the efficacy of interventions and aim for malaria elimination.
“…Since 2011, the water supply provided from the Senegal River has tripled the quantity of water distributed in the capital (about 0.12 hm 3 d −1 presently). Increased leaks from the water distribution network and increased waste water release have increased the aquifer recharge and the water table has risen by up to 0.6 m (Mohamed et al, 2017). Large urban districts are now sub-354 A. S. Mohamed et al: Changes in groundwater recharge in the Trarza aquifer in Mauritania merged and the phenomenon is limited only by a constant pumping in multiple sites of the city (Fig.…”
Abstract. Hydrological processes are rapidly changing in semi-arid areas under the double constraint of climate change and anthropization. Such changes were investigated at different scales of time and space in the Trarza aquifer (SW Mauritania), a flat region of about 40 000 km2 with a low rainfall (100 to 250 mm a−1). All old sources of hydrogeological information were exploited in complement with the more recent surveys. The geochemical information shows the importance of Quaternary eustatic variations in the present groundwater mineralization. In spite of very great variations of rainfall, the piezometric stability over the last 50 years shows that infiltration (about 4 mm a−1) did not vary significantly. Since 1989, the big Diama dam has raised the mean level of the Senegal River, which brings an additional inflow to the alluvium and to the Trarza aquifer (about 34 hm3 a−1). Groundwater recharge from the river and rainfall infiltration over the whole area have the same order of magnitude. In the Nouakchott area, the new supply of water to the capital (45 hm3 a−1) has led to a significant groundwater rise and the submersion of several urban districts.
“…The high groundwater salinity in the capital city of Mauritania, Nouakchott, results from the inter basin water transfer from the Senegal River meant to supply the city. The excess water from the newly diverted water supply resulted in water table rise of the pre-existing saline groundwater body leading to water logging and very high salinity levels in the shallow coastal aquifer (Mohamed et al, 2017). More generally, increases in groundwater salinity can also be the direct result of a range of urban land use pressures, including waste water recharge from various industries as well as domestic waste water and sanitation sources (Lapworth et al, 2017).…”
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