Assessment of Markers of Antimalarial Drug Resistance in Plasmodium falciparum Isolates from Pregnant Women in Lagos, Nigeria.

BACKGROUND: The use of antimalarial drugs for prevention and treatment is a major strategy in the prevention of malaria in pregnancy. Although sulphadoxine-pyrimethamine (SP) is currently recommended for intermittent preventive treatment of malaria during pregnancy in Nigeria, previously used drugs for prophylaxis such as chloroquine (CQ) and pyrimethamine are accessible as they are purchased over the counter. This study describes the markers of absence or presence of resistance to quinoline (Pfcrt and Pfmdr 1) and type 1 antifolate antimalarial medicines (Pfdhfr). METHODS: Plasmodium falciparum-positive dried blood spots from pregnant women attending antenatal clinics for the first time during current pregnancy were investigated for the presence of mutations at codons 72-76 of Plasmodium falciparum chloroquine resistance transporter (Pfcrt) gene by real time polymerase chain reaction (PCR) using haplotype-specific probes. PCR followed by sequence analysis was used to identify mutations at codons 86, 184, 1034, 1042 and 1246 of P. falciparum multi-drug resistance-1 (Pfmdr1) gene; and codons 16, 50, 51, 59, 108, 140 and 164 of Pfdhfr gene. RESULTS: Two haplotypes of Pfcrt (n = 54) were observed: CVMNK 13(24.2%) and CVIET 41 (75.9%) of the samples. The SVMNT haplotype was absent in this population. The Pfmdr1 (n = 28) haplotypes were NYSND 15(53.6%), YYSND 5(17.9%), NFSND 6(21.4%) and YFSND 2(7.1%). The Pfdhfr (n = 15) were ACNCSVI 4(26.7%), and ACICNSVI 1(6.7%) and ACIRNVI 10 (66.7%). The rate of occurrence of Pfcrt 76T, Pfdhfr108N, Pfmdr186Y and 184F were 75.9%, 73.3%, 25% and 28.1% respectively. The Pfmdr1 86Y was associated with low parasitaemia (median = 71 parasites/μl, P = 0.024) while Pfcrt 76T was associated with young maternal age (mean 24.1 ± 4.5 years; P = 0.006). The median parasitaemia were similar (P>0.05) in wild and mutant strains of Pfcrt 76, Pfmdr1 184 and Pfdhfr 108. There was no association between gravidity or gestational age of the women and presence of mutations in the Pfcrt, Pfmdr1 or Pfdhfr genes (P>0.05). CONCLUSION: Markers of resistance to chloroquine and pyrimethamine were high, whereas cycloguanil-resistance marker was not present in the studied population. The low level of mutations in the Pfmdr1gene indicates likely efficacy of amodiaquine against malaria in pregnancy

Assessment of Markers of Antimalarial Drug Resistance in Plasmodium falciparum Isolates from Pregnant Women in Lagos, Nigeria.

BACKGROUND: The use of antimalarial drugs for prevention and treatment is a major strategy in the prevention of malaria in pregnancy. Although sulphadoxine-pyrimethamine (SP) is currently recommended for intermittent preventive treatment of malaria during pregnancy in Nigeria, previously used drugs for prophylaxis such as chloroquine (CQ) and pyrimethamine are accessible as they are purchased over the counter. This study describes the markers of absence or presence of resistance to quinoline (Pfcrt and Pfmdr 1) and type 1 antifolate antimalarial medicines (Pfdhfr). METHODS: Plasmodium falciparum-positive dried blood spots from pregnant women attending antenatal clinics for the first time during current pregnancy were investigated for the presence of mutations at codons 72-76 of Plasmodium falciparum chloroquine resistance transporter (Pfcrt) gene by real time polymerase chain reaction (PCR) using haplotype-specific probes. PCR followed by sequence analysis was used to identify mutations at codons 86, 184, 1034, 1042 and 1246 of P. falciparum multi-drug resistance-1 (Pfmdr1) gene; and codons 16, 50, 51, 59, 108, 140 and 164 of Pfdhfr gene. RESULTS: Two haplotypes of Pfcrt (n = 54) were observed: CVMNK 13(24.2%) and CVIET 41 (75.9%) of the samples. The SVMNT haplotype was absent in this population. The Pfmdr1 (n = 28) haplotypes were NYSND 15(53.6%), YYSND 5(17.9%), NFSND 6(21.4%) and YFSND 2(7.1%). The Pfdhfr (n = 15) were ACNCSVI 4(26.7%), and ACICNSVI 1(6.7%) and ACIRNVI 10 (66.7%). The rate of occurrence of Pfcrt 76T, Pfdhfr108N, Pfmdr186Y and 184F were 75.9%, 73.3%, 25% and 28.1% respectively. The Pfmdr1 86Y was associated with low parasitaemia (median = 71 parasites/μl, P = 0.024) while Pfcrt 76T was associated with young maternal age (mean 24.1 ± 4.5 years; P = 0.006). The median parasitaemia were similar (P>0.05) in wild and mutant strains of Pfcrt 76, Pfmdr1 184 and Pfdhfr 108. There was no association between gravidity or gestational age of the women and presence of mutations in the Pfcrt, Pfmdr1 or Pfdhfr genes (P>0.05). CONCLUSION: Markers of resistance to chloroquine and pyrimethamine were high, whereas cycloguanil-resistance marker was not present in the studied population. The low level of mutations in the Pfmdr1gene indicates likely efficacy of amodiaquine against malaria in pregnancy

Pf7: an open dataset of Plasmodium falciparum genome variation in 20,000 worldwide samples

We describe the MalariaGEN Pf7 data resource, the seventh release of Plasmodium falciparum genome variation data from the MalariaGEN network.  It comprises over 20,000 samples from 82 partner studies in 33 countries, including several malaria endemic regions that were previously underrepresented.  For the first time we include dried blood spot samples that were sequenced after selective whole genome amplification, necessitating new methods to genotype copy number variations.  We identify a large number of newly emerging crt mutations in parts of Southeast Asia, and show examples of heterogeneities in patterns of drug resistance within Africa and within the Indian subcontinent.  We describe the profile of variations in the C-terminal of the csp gene and relate this to the sequence used in the RTS,S and R21 malaria vaccines.  Pf7 provides high-quality data on genotype calls for 6 million SNPs and short indels, analysis of large deletions that cause failure of rapid diagnostic tests, and systematic characterisation of six major drug resistance loci, all of which can be freely downloaded from the MalariaGEN website

Indications for blood transfusion in the study participants.

<p>Indications for blood transfusion in the study participants.</p

Transfusional malaria in the neonatal period in Lagos, South-West Nigeria

<div><p>Background and objectives</p><p>Sick neonates in malaria endemic areas are frequently transfused with donor blood unscreened for malaria parasite. Consequently, they are at risk of transfusional malaria which can lead to increased neonatal mortality. The study aimed to determine the burden of transfusional malaria in neonates to help in policy formulation on prevention of transfusional malaria.</p><p>Materials and methods</p><p>One hundred and sixty four neonates admitted into the neonatal unit of a tertiary hospital over a 10 month period who were scheduled for blood transfusion were screened for malaria parasites pre-transfusion, at three and 14 days post transfusion using Giemsa stained thick and thin films. Donor blood was screened for malaria parasites at the point of transfusion. Neonates who developed malaria parasitaemia post transfusion were followed up for signs of malaria.</p><p>Results</p><p>All recruited neonates tested negative to malaria parasite pre- transfusion. One hundred and twenty (73.2%) were term neonates with 94(57.3%) aged 1-7days. Four (2.4%) neonates developed malaria parasitaemia three days post transfusion and all four developed fever that resolved on treatment for malaria. Three (1.8%) of 164 donor blood samples had malaria parasitaemia and all three (100%) neonates who were transfused with the infected donor blood developed malaria parasitaemia post transfusion. However, one neonate who developed malaria parasitaemia post transfusion was transfused with non-infected donor blood.</p><p>Conclusions</p><p>The prevalence of transfusional malaria in this study is low (2.4%). However, 100% of neonates who received malaria infected donor blood developed transfusional malaria. We therefore recommend routine screening of donor pre-transfusion, testing of neonates who develop fever post transfusion and treatment of those who test positive to malaria.</p></div

Post transfusion malaria parasitaemia in the study participants in relation to demographic factors.

<p>Post transfusion malaria parasitaemia in the study participants in relation to demographic factors.</p

Socio-demographic characteristics of the study participants.

<p>Socio-demographic characteristics of the study participants.</p

Blood products and transfusion types in the study participants.

<p>Blood products and transfusion types in the study participants.</p

haplotypes_dhfr crt mdr1

Plasmodium falciparum resistant markers to Chloroquine and sulphadoxine-pyremethaimn

Binary logistic regression model of the predictors of post transfusion malaria among the study participants.

<p>Binary logistic regression model of the predictors of post transfusion malaria among the study participants.</p