Malaria epidemiology in Kobeni department,southeastern Mauritania from 2015 to 2017

Background:Plasmodium falciparum malaria is endemic in the southern sahelian zone of Mauritania where intense internal and trans-border human and livestock movement occurs.The risk of importation and spread of drugresistant parasites need to be regularly assessed in this region.The objective of the study was to assess the recent malaria situation near the Mauritania-Mali border.Methods:Between February 2015 and December 2017,patients with fever or history of fever during the previous 48 h,presenting at the health centre of Kobeni city,were screened for malaria using a rapid diagnostic test(RDT)and microscopic examination of blood smears.The diagnosis was later confirmed by PCR.Cohen’s kappa statistics was used to estimate the degree of agreement between diagnostic methods.Fisher’s exact test was used to compare proportions.The odds ratio was calculated to measure the association between the use of bed nets and malaria infection.Results:A total of 2326 febrile patients(mean age,20.2 years)were screened for malaria.The presence of malaria parasites was detected by RDT and microscopy in 53.0%and 49.3%of febrile patients,respectively,and was confirmed by PCR in 59.7%(45 missing data).Of 1361 PCR-positive samples,1205(88.5%)were P.falciparum,47(3.5%)P.vivax,and 99(7.3%)P.falciparum-P.vivax mixed infection.Malaria transmission occurred mostly during and shortly after the rainy season.The annual rainfall was relatively low in 2016(267 mm)and 2017(274 mm),compared to 2015(448 mm),and coincided with a decline in malaria prevalence in 2016–2017.Although 71.8%of febrile patients reported to possess at least one bed net in the household in our questionnaire,its reported use was not protective against malaria infection(odds ratio:1.1,95%CI:0.91–1.32).Conclusions:Our study confirmed that P.falciparum is the dominant species in the sahelian zone and that malaria transmission is seasonal and associated with rainfall in this zone.The application of the current national policy based on rapid and reliable malaria diagnosis,case management with artemisinin-based combination therapy,intermittent preventive treatment for pregnant women,distribution and use of long-lasting insecticide impregnated bed nets,and the planned introduction of seasonal malaria chemoprevention for all children under 6 years old is expected to sustainably reduce malaria transmission in this zone.

Assessment of CareStart G6PD rapid diagnostic test and CareStart G6PD biosensor in Mauritania

Background::The elimination of Plasmodium vivax malaria requires 8-aminoquinolines,which are contraindicated in patients with glucose-6-phosphate dehydrogenase(G6PD)deficiency due to the risk of acute haemolytic anaemia.Several point-of-care devices have been developed to detect G6PD deficiency.The objective of the present study was to evaluate the performance of two of these devices against G6PD genotypes in Mauritania.Methods::Outpatients were screened for G6PD deficiency using CareStart?rapid diagnostic test(RDT)and CareStart?G6PD biosensor in Nouakchott,Mauritania,in 2019-2020.African-type and Mediterranean-type G6PD genotypes commonly observed in Africa were determined by polymerase chain reaction-restriction fragment length polymorphism and sequencing.Qualitative variables were compared using Fisher’s exact test.Results::Of 323 patients(74 males and 249 females),5 males and 2 homozygous females had the African-type A-genotype:A-(202)in 3 males and 2 females and G6PD A-(968)in 2 males.Among heterozygous females,13 carried G6PD A-(202),12 G6PD A-(968),and 3 G6PD A-(542)variants.None had the Mediterranean-type G6PD genotype.Eight had a positive G6PD RDT result,including all 7 hemizygous males and homozygous females with A-or A-A-(0.12 to 2.34 IU/g haemoglobin,according to G6PD biosensor),but RDT performed poorly(sensitivity,11.1%at the cutoff level of<30%)and yielded many false negative tests.Thirty-seven(50.0%)males and 141(56.6%)females were anaemic.The adjusted median values of G6PD activity were 5.72 and 5.34 IU/g haemoglobin in non-anaemic males(n=35)and non-anaemic males and females(n=130)with normal G6PD genotypes using G6PD biosensor,respectively.Based on the adjusted median of 5.34 IU/g haemoglobin,the performance of G6PD biosensor against genotyping was as follows:at 30%cut-off,the sensitivity and specificity were 85.7%and 91.7%,respectively,and at 80%cut-off,the sensitivity was 100%while the specificity was 64.9%.Conclusions::Although this pilot study supports the utility of biosensor to screen for G6PD deficiency in patients,further investigation in parallel with spectrophotometry is required to promote and validate a more extensive use of this point-of-care device in areas where P.vivax is highly prevalent in Mauritania.