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Due to resistance to chloroquine and sulfadoxine/pyrimethamine, treatment for uncomplicated Plasmodium falciparum malaria switched to artemisinin-based combination therapy (ACT) in 2006 in Senegal. Several mutations in the gene encoding the kelch13 helix (pfk13-propeller) have been identified as associated with in vitro and in vivo artemisinin resistance in Southeast Asia. Additionally, three mutations in the pfcoronin gene (G50E, R100K and E107V) have been identified in two culture-adapted Senegalese field isolates that became resistant in vitro to artemisinin after 4 years of intermittent selection with dihydroartemisinin. The aims of this study were to assess the prevalence of pfcoronin and pfk13 mutations in Senegalese field isolates from Dakar and to investigate their association with artemisinin derivative clinical failures. A total of 348 samples of P. falciparum from 327 patients, collected from 2015-2019 in Dakar, were successfully analysed. All sequences had wild-type pfk13 allele. The three mutations (G50E, R100K and E107V), previously identified in parasites with reduced susceptibility to artemisinin, were not found in this study, but a new mutation (P76S) was detected (mean prevalence 16.2%). The P76S mutation was identified in 5 (31.3%) of 16 isolates collected from patients still parasitaemic on Day 3 after ACT treatment and in 31 samples (15.3%) among 203 patients considered successfully cured. There was no significant association between in vivo reduced efficacy to artemisinin derivatives and the P76S mutation (P = 0.151, Fisher's exact test). These data suggest that polymorphisms in pfk13 and pfcoronin are not the best predictive markers for artemisinin resistance in Senegal., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

In 2006, the Senegalese National Malaria Control Programme recommended artemisinin-based combination therapy as first-line treatment for uncomplicated malaria. In addition, intravenous (i.v.) injection of artesunate and artemether has gradually replaced quinine for the treatment of severe malaria. Mutations in the propeller domain of the Kelch 13 gene (K13-propeller, PF3D71343700), such as Y493H, R539T, I543T and C580Y, were recently associated with in vivo and in vitro resistance to artemisinin in Southeast Asia. However, these mutations were not identified in Africa. In total, 181 isolates of Plasmodium falciparum from 161 patients from Dakar, Senegal, were collected between August 2015 and January 2016. The K13-propeller gene of the isolates was sequenced. A search for non-synonymous mutations in the propeller region of K13 was performed in the 181 isolates collected from Dakar from 2015 to 2016. Three synonymous mutations were detected (D464D, C469C and R471R). Of 119 patients treated with i.v. artesunate or intramuscular artemether followed by artemether/lumefantrine, 9 patients were still parasitaemic on Day 3. Parasites from these nine patients were wild-type for K13-propeller. None of the polymorphisms known to be involved in artemisinin resistance in Asia were detected. These results suggest that K13 is not the best predictive marker for artemisinin resistance in Africa. More isolates from clinical failure cases or patients with delayed parasite clearance after treatment with artemisinin derivatives are necessary to identify new molecular markers., (Copyright © 2017 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.)

Background: To determine the impact of the introduction of artemisinin-based combination therapy (ACT) on parasite susceptibility, a molecular surveillance for antimalarial drug resistance was conducted on local isolates from the Hôpital Principal de Dakar between November 2013 and January 2014 and between August 2014 and December 2014., Methods: The prevalence of genetic polymorphisms in antimalarial resistance genes (pfcrt, pfmdr1, pfdhfr and pfdhps) was evaluated in 103 isolates., Results: The chloroquine-resistant haplotypes CVIET and CVMET were identified in 31.4 and 3.9 % of the isolates, respectively. The frequency of the pfcrt K76T mutation was increased from 29.3 % in 2013-2014 to 43.2 % in 2014. The pfmdr1 N86Y and Y184F mutations were identified in 6.1 and 53.5 % of the isolates, respectively. The pfdhfr triple mutant (S108N, N51I and C59R) was detected in the majority of the isolates (82.3 %). The prevalence of quadruple mutants (pfdhfr S108N, N51I, C59R and pfdhps A437G) was 40.4 %. One isolate (1.1 %) harboured the pfdhps mutations A437G and K540E and the pfdhfr mutations S108N, N51I and C59R., Conclusions: Despite a decline in the prevalence of chloroquine resistance due to the official withdrawal of the drug and to the introduction of ACT, the spread of resistance to chloroquine has continued. Furthermore, susceptibility to amodiaquine may be decreased as a result of cross-resistance. The frequency of the pfmdr1 mutation N86Y declined while the Y184F mutation increased in prevalence, suggesting that selective pressure is acting on pfmdr1, leading to a high prevalence of mutations in these isolates and the lack of specific mutations. The 50.5 % prevalence of the pfmdr1 polymorphisms N86Y and Y184F suggests a decrease in lumefantrine susceptibility. Based on these results, intensive surveillance of ACT partner drugs must be conducted regularly in Senegal.

The kelch 13 (K13) propeller gene is associated with artemisinin resistance. In a previous work, there were no mutations found in 138 Plasmodium falciparum isolates collected in 2012 and 2013 from patients residing in Dakar, Senegal (M. Torrentino-Madamet et al., Malar J 13:472, 2014, http://dx.doi.org/10.1186/1475-2875-13-472). However, the N554H, Q613H, and V637I mutations were identified in the propeller region of K13 in 92 (5.5%) isolates in 2013 and 2014. There were five polymorphisms identified in the Plasmodium/Apicomplexa-specific domain (K123R, N137S, N142NN/NNN, T149S, and K189T/N)., (Copyright © 2015, American Society for Microbiology. All Rights Reserved.)

The involvement of Pfmdr1 (Plasmodium falciparum multidrug resistance 1) polymorphisms in antimalarial drug resistance is still debated. Here, we evaluate the association between polymorphisms in Pfmdr1 (N86Y, Y184F, S1034C, N1042D, and D1246Y) and Pfcrt (K76T) and in vitro responses to chloroquine (CQ), mefloquine (MQ), lumefantrine (LMF), quinine (QN), monodesethylamodiaquine (MDAQ), and dihydroartemisinin (DHA) in 174 Plasmodium falciparum isolates from Dakar, Senegal. The Pfmdr1 86Y mutation was identified in 14.9% of the samples, and the 184F mutation was identified in 71.8% of the isolates. No 1034C, 1042N, or 1246Y mutations were detected. The Pfmdr1 86Y mutation was significantly associated with increased susceptibility to MDAQ (P = 0.0023), LMF (P = 0.0001), DHA (P = 0.0387), and MQ (P = 0.00002). The N86Y mutation was not associated with CQ (P = 0.214) or QN (P = 0.287) responses. The Pfmdr1 184F mutation was not associated with various susceptibility responses to the 6 antimalarial drugs (P = 0.168 for CQ, 0.778 for MDAQ, 0.324 for LMF, 0.961 for DHA, 0.084 for QN, and 0.298 for MQ). The Pfmdr1 86Y-Y184 haplotype was significantly associated with increased susceptibility to MDAQ (P = 0.0136), LMF (P = 0.0019), and MQ (P = 0.0001). The additional Pfmdr1 86Y mutation increased significantly the in vitro susceptibility to MDAQ (P < 0.0001), LMF (P < 0.0001), MQ (P < 0.0001), and QN (P = 0.0026) in wild-type Pfcrt K76 parasites. The additional Pfmdr1 86Y mutation significantly increased the in vitro susceptibility to CQ (P = 0.0179) in Pfcrt 76T CQ-resistant parasites., (Copyright © 2014, American Society for Microbiology. All Rights Reserved.)

Background: Although the World Health Organization recommends replacing quinine (QN) by artesunate due to its increased efficacy and the higher tolerance to the drug in both adults and children, QN remains a first-line treatment for severe malaria, especially in Africa. Investigations of microsatellite Pfnhe-1 ms4760 polymorphisms in culture-adapted isolates from around the world have revealed that an increase in the number of DNNND amino acid motifs was associated with decreased QN susceptibility, whereas an increase in the number of DDNHNDNHNND motifs was associated with increased QN susceptibility., Methods: In this context, to further analyse associations between Pfnhe-1 ms4760 polymorphisms and QN susceptibility, 393 isolates freshly collected between October 2009 and January 2010 and July 2010 and February 2011, respectively, at the Hôpital Principal de Dakar, Senegal were assessed ex vivo for QN susceptibility, and their genes were amplified and sequenced., Results: Of the 393 Plasmodium falciparum clinical isolates collected, 145 were successfully cultured. The 145 QN IC50s ranged from 2.1 to 1291 nM, and 17 isolates (11.7%) exceed the QN reduced susceptibility threshold of 611 nM. Among the 393 P. falciparum clinical isolates, 47 different alleles were observed. The three most prevalent profiles were ms4760-1 (no = 72; 18.3%), ms4760-3 (no = 65; 16.5%) and ms4760-7 (no = 40; 10.2%). There were no significant associations observed between QN IC50 values and i) the number of repeats of DNNND in block II (p = 0.0955, Kruskal-Wallis test); ii) the number of repeats of DDNHNDNHNND in block V (p = 0.1455, Kruskal-Wallis test); or iii) ms4760 profiles (p = 0.1809, Kruskal-Wallis test)., Conclusions: Pfnhe-1 ms4760 was highly diverse in parasite isolates from Dakar (47 different profiles). Three profiles (ms4760-1, ms4760-3 and ms4760-7) were predominant. The number of repeats for block II (DNNND) or block V (DDNHNDNHNND) was not significantly associated with QN susceptibility. New studies, and especially in vivo studies, are necessary to confirm the role of Pfnhe-1 ms4760 as a marker of QN resistance.

This prospective survey, conducted at the Dakar airport from August 18, 2011, to May 8, 2012, asked a sample of travelers living in France and returning there after a stay in Senegal to complete a questionnaire. The aim of the study was to assess the determinants of vaccination coverage against yellow fever. The study included 10 298 travelers, with a median age of 48 years (interquartile range: 27-58); 52% were tourists, and 22% were traveling for business purposes. The measured level of anti-yellow fever vaccination coverage was 39.3%. Vaccination coverage was influenced by the travelers' level of knowledge and their perception of the risk.

Background: An accurate diagnosis is essential for the rapid and appropriate treatment of malaria. The accuracy of the histidine-rich protein 2 (PfHRP2)-based rapid diagnostic test (RDT) Palutop+4® was assessed here. One possible factor contributing to the failure to detect malaria by this test is the diversity of the parasite PfHRP2 antigens., Methods: PfHRP2 detection with the Palutop+4® RDT was carried out. The pfhrp2 and pfhrp3 genes were amplified and sequenced from 136 isolates of Plasmodium falciparum that were collected in Dakar, Senegal from 2009 to 2011. The DNA sequences were determined and statistical analyses of the variation observed between these two genes were conducted. The potential impact of PfHRP2 and PfHRP3 sequence variation on malaria diagnosis was examined., Results: Seven P. falciparum isolates (5.9% of the total isolates, regardless of the parasitaemia; 10.7% of the isolates with parasitaemia ≤0.005% or ≤250 parasites/μl) were undetected by the PfHRP2 Palutop+4® RDT. Low parasite density is not sufficient to explain the PfHRP2 detection failure. Three of these seven samples showed pfhrp2 deletion (2.4%). The pfhrp3 gene was deleted in 12.8%. Of the 122 PfHRP2 sequences, 120 unique sequences were identified. Of the 109 PfHRP3 sequences, 64 unique sequences were identified. Using the Baker's regression model, at least 7.4% of the P. falciparum isolates in Dakar were likely to be undetected by PfHRP2 at a parasite density of ≤250 parasites/μl (slightly lower than the evaluated prevalence of 10.7%). This predictive prevalence increased significantly between 2009 and 2011 (P = 0.0046)., Conclusion: In the present work, 10.7% of the isolates with a parasitaemia ≤0.005% (≤250 parasites/μl) were undetected by the PfHRP2 Palutop+4® RDT (7.4% by the predictive Baker'model). In addition, all of the parasites with pfhrp2 deletion (2.4% of the total samples) and 2.1% of the parasites with parasitaemia >0.005% and presence of pfhrp2 were not detected by PfHRP2 RDT. PfHRP2 is highly polymorphic in Senegal. Efforts should be made to more accurately determine the prevalence of non-sensitive parasites to pfHRP2.

The objective of this study was to validate the use of pftetQ and pfmdt genes as molecular markers of decreased in vitro susceptibility to doxycycline in 113 Plasmodium falciparum isolates from Dakar, Senegal. The results show that copy numbers of pftetQ and pfmdt, estimated by TaqMan real-time PCR, are not significantly associated with reduced susceptibility to doxycycline in vitro; however, the number of samples with a high doxycycline IC(50) was likely to be too low to derive statistically significant results. Thus, no definitive conclusions could be drawn. The markers should be further tested by analysing more isolates., (© 2012 The Authors. Clinical Microbiology and Infection © 2012 European Society of Clinical Microbiology and Infectious Diseases.)

Background: As a result of the widespread resistance to chloroquine and sulphadoxine-pyrimethamine, artemisinin-based combination therapy (ACT) (including artemether-lumefantrine and artesunate-amodiaquine) has been recommended as a first-line anti-malarial regimen in Senegal since 2006. Intermittent preventive treatments with anti-malarial drugs based on sulphadoxine-pyrimethamine are also given to children or pregnant women once per month during the transmission season. Since 2006, there have been very few reports on the susceptibility of Plasmodium falciparum to anti-malarial drugs. To estimate the prevalence of resistance to several anti-malarial drugs since the introduction of the widespread use of ACT, the presence of molecular markers associated with resistance to chloroquine and sulphadoxine-pyrimethamine was assessed in local isolates at the military hospital of Dakar., Methods: The prevalence of genetic polymorphisms in genes associated with anti-malarial drug resistance, i.e., Pfcrt, Pfdhfr, Pfdhps and Pfmdr1, and the copy number of Pfmdr1 were evaluated for a panel of 174 isolates collected from patients recruited at the military hospital of Dakar from 14 October 2009 to 19 January 2010., Results: The Pfcrt 76T mutation was identified in 37.2% of the samples. The Pfmdr1 86Y and 184F mutations were found in 16.6% and 67.6% of the tested samples, respectively. Twenty-eight of the 29 isolates with the 86Y mutation were also mutated at codon 184. Only one isolate (0.6%) had two copies of Pfmdr1. The Pfdhfr 108N/T, 51I and 59R mutations were identified in 82.4%, 83.5% and 74.1% of the samples, respectively. The double mutant (108N and 51I) was detected in 83.5% of the isolates, and the triple mutant (108N, 51I and 59R) was detected in 75.3%. The Pfdhps 437G, 436F/A and 613S mutations were found in 40.2%, 35.1% and 1.8% of the samples, respectively. There was no double mutant (437G and 540E) or no quintuple mutant (Pfdhfr 108N, 51I and 59R and Pfdhps 437G and 540E). The prevalence of the quadruple mutant (Pfdhfr 108N, 51I and 59R and Pfdhps 437G) was 36.5%., Conclusions: Since 2004, the prevalence of chloroquine resistance had decreased. The prevalence of isolates with high-level pyrimethamine resistance is 83.5%. The prevalence of isolates resistant to sulphadoxine is 40.2%. However, no quintuple mutant (Pfdhfr 108N, 51I and 59R and Pfdhps 437G and 540E), which is associated with a high level of sulphadoxine-pyrimethamine resistance, has been identified to date. The resistance to amodiaquine remains moderate.

Background: As a result of widespread chloroquine and sulphadoxine-pyrimethamine resistance, artemisinin-based combination therapy (ACT) (which includes artemether-lumefantrine and artesunate-amodiaquine) has been recommended as a first-line anti-malarial regimen in Senegal since 2006. Since then, there have been very few reports on the ex vivo susceptibility of Plasmodium falciparum to anti-malarial drugs. To examine whether parasite susceptibility has been affected by the widespread use of ACT, the ex vivo susceptibility of local isolates was assessed at the military hospital of Dakar., Methods: The ex vivo susceptibility of 93 P. falciparum isolates from Dakar was successfully determined using the Plasmodium lactate dehydrogenase (pLDH) ELISA for the following drugs: chloroquine (CQ), quinine (QN), mefloquine (MQ), monodesethylamodiaquine (MDAQ), lumefantrine (LMF), dihydroartemisinin (DHA) and doxycycline (DOX)., Results: After transformation of the isolate IC50 in ratio of IC50 according to the susceptibility of the 3D7 reference strain (isolate IC50/3D7 IC50), the prevalence of the in vitro resistant isolates with reduced susceptibility was 50% for MQ, 22% for CQ, 12% for DOX, 6% for both QN and MDAQ and 1% for the drugs LMF and DHA. The highest significant positive correlations were shown between responses to CQ and MDAQ (r = 0.569; P < 0.0001), LMF and QN (r = 0.511; P < 0.0001), LMF and DHA (r = 0.428; P = 0.0001), LMF and MQ (r = 0.413; P = 0.0002), QN and DHA (r = 0.402; P = 0.0003) and QN and MQ (r = 0.421; P = 0.0001)., Conclusions: The introduction of ACT in 2002 has not induced a decrease in P. falciparum susceptibility to the drugs DHA, MDAQ and LMF, which are common ACT components. However, the prevalence of P. falciparum isolates with reduced susceptibility has increased for both MQ and DOX. Taken together, these data suggest that intensive surveillance of the P. falciparum in vitro susceptibility to anti-malarial drugs in Senegal is required.

We report a highly probable case of moderately severe blackwater fever. A French woman, living in Guinea Bissau, was used to taking self-medication halofantrine for malaria. On this occasion, she felt unusual chills and pyrexia after a non documented bout of malaria, followed by nausea, then jaundice with dark-red urines despite another treatment with halofantrine. A sepsis was eliminated by two negatives thick peripheral blood drop examinations. Hemolysis was noted with 8.1 g/dl of hemoglobin, Coombs positive, and LDH at 1,452 IU/l, associated to renal failure with 34 ml per minute of clearance. The outcome was favourable with rehydration. Blackwater fever has been described with the three aminoalcohols, but mainly in severe presentations. Clinicians are not familiar with this disease, even though it has major therapeutic implications: quinine, halofantrine, and mefloquine become strictly contra-indicated. Moderate forms may be unknown, and this observation should be taken into account to prevent mistreatment in future patients.