Molecular identification of Plasmodium species responsible for malaria reveals Plasmodium vivax isolates in Duffy negative individuals from southwestern Nigeria.

BACKGROUND: Malaria in Nigeria is principally due to Plasmodium falciparum and, to a lesser extent to Plasmodium malariae and Plasmodium ovale. Plasmodium vivax is thought to be absent in Nigeria in particular and sub-Saharan Africa in general, due to the near fixation of the Duffy negative gene in this population. Nevertheless, there are frequent reports of P. vivax infection in Duffy negative individuals in the sub-region, including reports from two countries sharing border with Nigeria to the west (Republic of Benin) and east (Cameroon). Additionally, there were two cases of microscopic vivax-like malaria from Nigerian indigenous population. Hence molecular surveillance of the circulating Plasmodium species in two states (Lagos and Edo) of southwestern Nigeria was carried out. METHODS: A cross-sectional survey between September 2016 and March 2017 was conducted. 436 febrile patients were included for the present work. Venous blood of these patients was subjected to RDT as well as microscopy. Further, parasite DNA was isolated from positive samples and PCR diagnostic was employed followed by direct sequencing of the 18S rRNA of Plasmodium species as well as sequencing of a portion of the promoter region of the Duffy antigen receptor for chemokines. Samples positive for P. vivax were re-amplified several times and finally using the High Fidelity Taq to rule out any bias introduced. RESULTS: Of the 256 (58.7%) amplifiable malaria parasite DNA, P. falciparum was, as expected, the major cause of infection, either alone 85.5% (219/256; 97 from Edo and 122 from Lagos), or mixed with P. malariae 6.3% (16/256) or with P. vivax 1.6% (4/256). Only one of the five P. vivax isolates was found to be a single infection. DNA sequencing and subsequent alignment of the 18S rRNA of P. vivax with the reference strains displayed very high similarities (100%). Remarkably, the T-33C was identified in all P. vivax samples, thus confirming that all vivax-infected patients in the current study are Duffy negative. CONCLUSION: The present study gave the first molecular evidence of P. vivax in Nigeria in Duffy negative individuals. Though restricted to two states; Edo in South-South and Lagos in South-west Nigeria, the real burden of this species in Nigeria and sub-Saharan Africa might have been underestimated, hence there is need to put in place a country-wide, as well as a sub-Saharan Africa-wide surveillance and appropriate control measures.

Private sector malaria RDT initiative in Nigeria: lessons from an end-of-project stakeholder engagement meeting.

The malaria rapid diagnosis testing (RDT) landscape is rapidly evolving in health care delivery in Nigeria with many stakeholders playing or having potential for critical roles. A recent UNITAID grant supported a pilot project on the deployment of quality-assured RDTs among formal and informal private service outlets in three states in Nigeria. This paper describes findings from a series of stakeholder engagement meetings held at the conclusion of the project. The agreed meeting structure was a combination of plenary presentations, structured facilitated discussions, and nominal group techniques to achieve consensus. Rapporteurs recorded the meeting proceeding and summaries of the major areas of discussion and consensus points through a retrospective thematic analysis of the submitted meeting reports. Key findings indicate that private providers were confident in the use of RDTs for malaria diagnosis and believed it has improved the quality of their services. However, concerns were raised about continued access to quality-assured RDT kits. Going forward, stakeholders recommended increasing client-driven demand, and continuous training and supervision of providers through integration with existing monitoring and supervision mechanisms.

Provider and patient perceptions of malaria rapid diagnostic test use in Nigeria: a cross-sectional evaluation.

BACKGROUND: Nigeria commenced a phased programmatic deployment of rapid diagnostic tests (RDT) at the primary health care (PHC) facility levels since 2011. Despite various efforts, the national testing rate for malaria is still very low. The uptake of RDT has been variable. This study was undertaken to determine the provider and patient perceptions to RDT use at the PHC level in Nigeria with their implications for improving uptake and compliance. METHODS: A cross-sectional survey was conducted in 120 randomly selected PHCs across six states, across the six-geopolitical zones of Nigeria in January 2013. Health facility staff interviews were conducted to assess health workers (HW) perception, prescription practices and determinants of RDT use. Patient exit interviews were conducted to assess patient perception of RDT from ten patients/caregivers who met the eligibility criterion and were consecutively selected in each PHC, and to determine HW's compliance with RDT test results indirectly. Community members, each selected by their ward development committees in each Local Government Area were recruited for focus group discussion on their perceptions to RDT use. RESULTS: Health workers would use RDT results because of confidence in RDT results (95.4%) and its reduction in irrational use of artemisinin-based combination therapy (ACT) (87.2%). However, in Enugu state, RDT was not used by health workers because of the pervasive notion RDT that results were inaccurate. Among the 1207 exit interviews conducted, 549 (45.5%) had received RDT test. Compliance rate (administering ACT to positive patients and withholding ACT from negative patients) from patient exit interviews was 90.2%. Among caregivers/patients who had RDT done, over 95% knew that RDT tested for malaria, felt it was necessary and liked the test. Age of patients less than 5 years (p = 0.04) and "high" educational status (p = 0.0006) were factors influencing HW's prescription of ACT to RDT negative patients. CONCLUSION: The study demonstrated positive perception to RDT use by HW and among community members with good compliance rate among health workers at the PHC level. This positive perception should be explored in improving the current low level of malaria testing in Nigeria while addressing the influence of age on HW administration of ACT to RDT negative cases.

Multicenter Pivotal Clinical Trial of Urine Malaria Test for Rapid Diagnosis of Plasmodium falciparum Malaria.

The need to expand malaria diagnosis capabilities alongside policy requirements for mandatory testing before treatment motivates exploration of noninvasive rapid diagnostic tests (RDTs). We report the outcome of the first cross-sectional, single-blind clinical performance evaluation of a urine malaria test (UMT) for diagnosis of Plasmodium falciparum malaria in febrile patients. Matched urine and finger-prick blood samples from participants ≥2 years of age with fever (axillary temperature of ≥37.5°C) or with a history of fever in the preceding 48 h were tested with UMT and microscopy (as the gold standard). BinaxNOW (Pf and Pan versions) blood RDTs were done to assess relative performance. Urinalysis and rheumatoid factor (RF) tests were conducted to evaluate possible interference. Diagnostic performance characteristics were computed at 95% confidence intervals (CIs). Of 1,800 participants screened, 1,691 were enrolled; of these 566 (34%) were febrile, and 1,125 (66%) were afebrile. Among enrolled participants, 341 (20%) tested positive by microscopy, 419 (25%) were positive by UMT, 676 (40%) were positive by BinaxNOW Pf, and 368 (22%) were positive by BinaxNow Pan. UMT sensitivity among febrile patients (for whom the test was indicated) was 85%, and specificity was 84%. Among febrile children ≤5 years of age, UMT sensitivity was 93%, and specificity was 83%. The area under the receiver-operator characteristic curve (AUC) of UMT (0.84) was not significantly different from that of BinaxNOW Pf (0.86) or of BinaxNOW Pan (0.87), indicating that the tests do not differ in overall performance. Gender, seasons, and RF did not impact UMT performance. Leukocytes, hematuria, and urobilinogen concentrations in urine were associated with lower UMT specificities. UMT performance was comparable to that of the BinaxNOW Pf/Pan tests, making UMT a promising tool to expand malaria testing in public and private health care settings where there are challenges to blood-based malaria diagnosis testing.

When it just won't go away: oral artemisinin monotherapy in Nigeria, threatening lives, threatening progress.

BACKGROUND: Oral artemisinin monotherapy (AMT), an important contributor to multi-drug resistant malaria, has been banned in Nigeria. While oral AMT has scarcely been found for several years now in other malaria-endemic countries, availability has persisted in Nigeria's private sector. In 2015, the ACTwatch project conducted a nationally representative outlet survey. Results from the outlet survey show the extent to which oral AMT prevails in Nigeria's anti-malarial market, and provide key product information to guide strategies for removal. RESULTS: Between August 10th and October 3rd, 2015 a total of 13,480 outlets were screened for availability of anti-malarials and/or malaria blood testing services. Among the 3624 anti-malarial outlets, 33,539 anti-malarial products were audited, of which 1740 were oral AMT products, primarily artesunate (n = 1731). Oral AMT was imported from three different countries (Vietnam, China and India), representing six different manufacturers and 11 different brands. Availability of oral AMT was highest among pharmacies (84.0%) and Patent Propriety Medicine Vendors (drug stores, PPMVs) (38.7%), and rarely found in the public sector (2.0%). Oral AMT consisted of 2.5% of the national anti-malarial market share. Of all oral AMT sold or distributed, 52.3% of the market share comprised of a Vietnamese product, Artesunat®, manufactured by Mekophar Chemical Pharmaceutical Joint Stock Company. A further 35.1% of the market share were products from China, produced by three different manufacturers and 12.5% were from India by one manufacturer, Medrel Pharmaceuticals. Most of the oral AMT was distributed by PPMVs accounting for 82.2% of the oral AMT market share. The median price for a package of artesunate ($1.78) was slightly more expensive than the price of quality-assured (QA) artemether lumefantrine (AL) for an adult ($1.52). The median price for a package of artesunate suspension ($2.54) was three times more expensive than the price of a package of QA AL for a child ($0.76). CONCLUSION: Oral AMT is commonly available in Nigeria's private sector. Cessation of oral AMT registration and enforcement of the oral AMT ban for removal from the private sector are needed in Nigeria. Strategies to effectively halt production and export are needed in Vietnam, China and India.

Early rising asexual parasitaemia in Nigerian children following a first dose of artemisinin-based combination treatments of falciparum malaria.

BACKGROUND: Early rising asexual parasitaemia (ERAP), initially defined as 'an increase in the parasite count over the baseline pre-treatment level during the first 24 h of treatment' of falciparum malaria with artemisinin derivatives is well documented, but there is no characterization of its risk factors, kinetics, molecular features or relationship to late-appearing anaemia (LAA) in acute falciparum malaria in African children following oral artemisinin-based combination therapies (ACTs). METHODS: ERAP was defined as ≥5% increase in pre-treatment parasitaemia within 8 h of initiating treatment. Parasitaemia was quantified pre-treatment and 1-2 hourly for 8 h, and less frequently thereafter for 6 weeks following randomized treatment of acutely malarious children with artesunate-amodiaquine, artemether-lumefantrine or dihydroartemisinin-piperaquine. Risk factors were determined by stepwise multiple logistic regression model. Kinetics of release into and of elimination of asexual parasites and DNA clones from peripheral blood were evaluated by method of residuals and non-compartment model, respectively. Parasite population changes were evaluated morphologically and by molecular genotyping. RESULTS: ERAP occurred in 205 of 416 children. A parasitaemia <100,000/µL and parasitaemia 1 day post-treatment initiation were independent predictors of ERAP. In children with ERAP: mean and peak time of increase in parasitaemia were 105.6% (95% CI 81-130.1) and 2.5 h (95% CI 2.2-2.7), respectively. Mean lag time, half-time and rate constant of release were 0.2 h (95% CI 0.2-0.3), 1 h (95% CI 0.9-1.1), and 0.9 h-1 (95% CI 0.8-1), respectively. Schizonts and young gametocytes were seen only in peripheral blood of few children with ERAP. In age-, gender-, baseline parasitaemia- and treatment-matched children with and without ERAP, parasite DNA clearance time and area under curve of number of DNA clones versus time were significantly higher in children with ERAP indicating peripheral retention of released parasites followed by elimination. DNA clone elimination was monoexponential. CONCLUSION: ERAP is common, occurs rapidly as first order process and may be due to mobilization of parasites from deep tissue following a first dose of ACTs of acute childhood falciparum malaria. TRIALS REGISTRATION: Pan African Clinical Trial Registry PACTR201508001188143 , 3 July 2015; PACTR201510001189370, 3 July 2015; PACTR201508001191898, 7 July 2015 and PACTR201508001193368, 8 July 2015.

Factors contributing to anaemia after uncomplicated falciparum malaria in under five year-old Nigerian children ten years following adoption of artemisinin-based combination therapies as first-line antimalarials.

BACKGROUND: Artemisinin-based combination therapies (ACTs) have remained efficacious treatments of acute falciparum malaria in many endemic areas but there is little evaluation of factors contributing to the anaemia of acute falciparum malaria following long term adoption of ACTs as first-line antimalarials in African children. METHODS: Malarious <5 year-olds randomized to artemether-lumefantrine, artesunate-amodiaquine or dihydroartemisinin-piperaquine treatments were followed up clinically for 6 weeks. Anaemia was defined as haematocrit <30%; Malaria-attributable fall in haematocrit (MAFH) as the difference between haematocrit 28-42 days post- and pre-treatment; Total MAFH (TMAFH) as the difference between days 28-42 haematocrit and the lowest haematocrit recorded in the first week post-treatment initiation; Drug-attributable fall in haematocrit (DAFH) as the difference between MAFH and TMAFH; Early appearing anaemia (EAA) as haematocrit <30% occurring within 1 week in children with normal haematocrit pre-treatment. Predictors of anaemia pre-treatment, EAA, MAFH or DAFH >4% were evaluated by stepwise multiple logistic regression models. Survival analysis and kinetics of DAFH were evaluated by Kaplan-Meier estimator and non-compartment model, respectively. RESULTS: Pre-treatment, 355 of 959 children were anaemic. Duration of illness >2 days and parasitaemia ≤10,000 µL-1 were independent predictors of anaemia pre-treatment. EAA occurred in 301 of 604 children. Predictors of EAA were age ≤ 15 months, history of fever pre-treatment and enrolment haematocrit ≤35%. The probabilities of progression from normal haematocrit to EAA were similar for all treatments. MAFH >4% occurred in 446 of 694 children; its predictors were anaemia pre-treatment, enrolment parasitaemia ≤50,000 µL-1, parasitaemia one day post-treatment initiation and gametocytaemia. DAFH >4% occurred in 334 of 719 children; its predictors were history of fever pre-and fever 1 day post-treatment initiation, haematocrit ≥37%, and parasitaemia >100,000 µL-1. In 432 children, declines in DAFH deficits were monoexponential with overall estimated half-time of 2.2d (95% CI 1.9-2.6). Area under curve of deficits in DAFH versus time and estimated half-time were significantly higher in non-anaemic children indicating greater loss of haematocrit in these children. CONCLUSION: After ten years of adoption of ACTs, anaemia is common pre-and early post-treatment, falls in haematocrit attributable to a single infection is high, and DAFH >4% is common and significantly lower in anaemic compared to non-anaemic Nigerian children. TRIAL REGISTRATION: Pan African Clinical Trial Registry (PACTR) [ PACTR201709002064150, 1 March 2017 ].

Anaemia following Artemisinin-Based Combination Treatments of Uncomplicated Plasmodium falciparum Malaria in Children: Temporal Patterns of Haematocrit and the Use of Uncomplicated Hyperparasitaemia as a Model for Evaluating Late-Appearing Anaemia.

BACKGROUND: In severe malaria, intravenous artesunate may cause delayed haemolytic anaemia but there has been little evaluation of the propensity of oral artemisinin-based combination treatments (ACTs) to cause late-appearing anaemia. METHODS: The frequency of anaemia (haematocrit <30%), and temporal changes in haematocrit were evaluated in 1,191 malarious children following ACTs. "Haematocrit conservation" was evaluated by using the fall in haematocrit/1,000 asexual parasites cleared from the peripheral blood (FIH/1,000 asexual parasites cpb), and the ratio of the average haematocrit (on the first 3 days of starting treatment):total parasitaemia cleared. RESULTS: The frequency of anaemia decreased significantly following treatment. FIH/1,000 asexual parasites cpb, average haematocrit:total parasitaemia cleared, and mean haematocrit 5 weeks after treatment began were significantly lower in hyperparasitaemic children than in children without hyperparasitaemia, suggesting haematocrit conservation during treatment followed later by a loss of haematocrit. Asymptomatic late-appearing anaemia occurred in 6% of the children. CONCLUSION: Artesunate-amodiaquine and artemether-lumefantrine contribute to haematocrit conservation at high parasitaemias but may cause late-appearing anaemia.

Status of the use and compliance with malaria rapid diagnostic tests in formal private health facilities in Nigeria.

BACKGROUND: Nigeria has the largest number of malaria-related deaths, accounting for a third of global malaria deaths. It is important that the country attains universal coverage of key malaria interventions, one of which is the policy of universal testing before treatment, which the country has recently adopted. However, there is a dearth of data on its implementation in formal private health facilities, where close to a third of the population seek health care. This study identified the level of use of malaria rapid diagnostic testing (RDT), compliance with test results and associated challenges in the formal private health facilities in Nigeria. METHODS: A cross-sectional study that involved a multi-stage, random sampling of 240 formal private health facilities from the country's six geo-political zones was conducted from July to August 2014. Data were collected using health facility records, healthcare workers' interviews and an exit survey of febrile patients seen at the facilities, in order to determine fever prevalence, level of testing of febrile patience, compliance with test results, and health workers' perceptions to RDT use. RESULTS: Data from the 201 health facilities analysed indicated a fever prevalence of 38.5% (112,521/292,430). Of the 2077 exit interviews for febrile patients, malaria testing was ordered in 73.8% (95% CI 71.7-75.7%). Among the 1270 tested, 61.8% (719/1270) were tested with microscopy and 38.2% (445/1270) with RDT. Compliance to malaria test result [administering arteminisin-based combination therapy (ACT) to positive patients and withholding ACT from negative patients] was 80.9% (95% CI 78.7-83%). Compliance was not influenced by the age of patients or type of malaria test. The health facilities have various cadres of the health workers knowledgeable on RDT with 70% knowing the meaning, while 84.5% knew what it assesses. However, there was clearly a preference for microscopy as only 20% reported performing only RDT. CONCLUSION: In formal private health facilities in Nigeria there is a high rate of malaria testing for febrile patients, high level of compliance with test results but relatively low level of RDT utilization. This calls for improved engagement of the formal private health sector with a view to achieving universal coverage targets on malaria testing.

Clinical illness and outcomes in Nigerian children with late-appearing anaemia after artemisinin-based combination treatments of uncomplicated falciparum malaria.

BACKGROUND: Late-appearing anaemia (LAA) following treatment with artemisinins for severe malaria has been reported and well described, but there are limited clinical and parasitological data on LAA in African children with uncomplicated falciparum malaria following oral artemisinin-based combination therapies (ACTs). METHODS: This was an open label study with the main objectives of evaluating the clinical features, the risk factors for, the temporal changes in haematocrit and the outcomes of a LAA in malarious children treated with artesunate-amodiaquine (AA), artemether-lumefantrine (AL) or dihydroartemisinin-piperaquine (DHP). The diagnosis of LAA was made using the criteria: clearance of parasitaemia, fever and other symptoms within 1 week of commencing treatment; adequate clinical and parasitological response at 4-6 weeks after treatment began; haematocrit ≥30 % 1 and/or 2 weeks after treatment began; and haematocrit <30 %, parasite negativity by microscopy and polymerase chain reaction and absence of concomitant illness 3-6 weeks after treatment began. RESULTS: LAA occurred in 84 of 609 children, was mild, moderate or severe in 77, 6 or 1 child, respectively and was relatively asymptomatic. Mean time elapsing from commencement of treatment to LAA was 27.1 days (95 % CI 25.3-28.9). In a multivariate analysis, an age <3 years (adjusted odd ratio [AOR] = 2.6, 95 % CI 1.3-5.2, P = 0.005), fever 1 day after treatment began (AOR = 3.8, 95 % CI 1.8-8.2, P < 0.0001), haematocrit <25 % at presentation (AOR = 2.2, 95 % CI 1.3-3.7, P = 0.003), haematocrit <30 % 1 day after treatment began (AOR = 2.1, 95 % CI 1.0-4.3, P = 0.04), parasite reduction ratio >10(4) 2 days after treatment began (AOR = 2.1, 95 % CI 1.1-3.9, P = 0.03) and spleen enlargement at presentation (AOR = 2.0, 95 % CI 1.1-3.9, P < 0.0001) were independent predictors of LAA. During 6 weeks of follow-up, uneventful recovery from anaemia occurred in 56 children [mean recovery time of 11.8 days (95 % CI 10.3-13.3)]. The only independent predictor of failure of recovery was LAA occurring 4 weeks after starting treatment (AOR = 7.5, 95 % CI 2.5-22.9, P < 0.0001). CONCLUSION: A relatively asymptomatic LAA with uneventful recovery can occur in young malarious children following ACTs. Its occurrence may have implications for case and community management of anaemia and for anaemia control efforts in sub-Saharan Africa where ACTs have become first-line antimalarials. TRIALS REGISTRATION: Pan African Clinical Trial Registry PACTR201508001188143, 3 July 2015; PACTR201510001189370, 3 July 2015; PACTR201508001191898, 7 July 2015 and PACTR201508001193368, 8 July 2015 http://www.pactr.org .

Temporal changes in haematocrit following artemisinin-based combination treatments of uncomplicated falciparum malaria in children.

BACKGROUND: Artemisinin-based combination treatments (ACTs) or intravenous artesunate are used in over 100 countries for uncomplicated or severe falciparum malaria. Although intravenous artesunate may cause delayed haemolytic anaemia, there is little evaluation of the temporal changes in haematocrit following ACTs. METHODS: Clinical and parasitological parameters were measured before and following treatment of uncomplicated falciparum malaria in children with artesunate-amodiaquine (AA) or artemether-lumefantrine (AL) over 6-weeks. Changes in haematocrit were characterized in individual patients based on a haematocrit <30 % or ≥30 % before and following treatment. Kinetics of the deficit in haematocrit from <30 % until attainment of ≥30 % were estimated by a non-compartment model. RESULTS: In 248 of 1180 children eligible for evaluation, common temporal patterns were: no change or increase in haematocrit from ≥ 30 % [50 % of patients], haematocrit >30 % at presentation declining to <30 % within 2 weeks (early monophasic fall) [19 % of patients], and haematocrit <30 % at presentation increasing to ≥ 30 % [23 % of patients]. Haematocrit >30 % at presentation declining to <30 %, 3-5 weeks later (late monophasic fall) occurred in 7 children (3 %). Fall in haematocrit ≥5 units following treatment occurred in 57 children [23 %] between 14 and 28 days after treatment began. Baseline parasitaemia and proportion with > 100,000µL(-1) asexual forms were significantly higher in children with ≥5 units compared to <5 units fall in haematocrit 21 or 28 days after treatment began. Irrespective of pattern, declines in haematocrit deficit from <30 % were mono-exponential, with similar half-times for AA- and AL-treated children (1.32 d versus 1.14 d). Anaemia half-time correlated significantly positively with anaemia recovery time in the same patients (r = 0.55, P < 0.0001). Bland-Altman analysis of 9 or 10 multiples of anaemia half-time and anaemia recovery times showed narrow limit of agreement with insignificant biases (P = 0.19 or 0.63, respectively). CONCLUSIONS: In uncomplicated falciparum malaria, increases or falls in haematocrit are common following ACTs. Falls in haematocrit ≥ 5 units are common and may or may not result in early or late anaemia. In children who recovered from acute falciparum malaria-associated anaemia following ACTs, decline in haematocrit deficit is mono-exponential. TRIALS REGISTRATION: Pan African Clinical Trial Registry PACTR201508001188143 , 3 July 2015; PACTR201508001191898 , 7 July 2015 http://www.pactr.org .

Correction: Neonatal blood lead concentration predicts medium term lead-related outcomes in children ≤5 years old with congenital lead poisoning: A retrospective cohort study in Northern Nigeria.

[This corrects the article DOI: 10.1371/journal.pgph.0001644.].

Neonatal blood lead concentration predicts medium term lead-related outcomes in children ≤5 years old with congenital lead poisoning: A retrospective cohort study in Northern Nigeria.

Mother-to-child-transmission of lead via the placenta is known to result in congenital lead toxicity. Between 2010 and 2021, Médecins Sans Frontières and other stakeholders responded to a severe lead poisoning outbreak related to artisanal gold mining in Northern Nigeria. Extensive environmental remediation occurred following outbreak identification; source control efforts are ongoing within the community. We aimed to describe the prevalence of congenital lead poisoning in this cohort and analyse the association between neonatal blood lead concentration (BLC) and medium-term lead-related outcomes during the study period. Children enrolled in the lead poisoning programme between July 2010 and 25 January 2018 who had a screening BLC at ≤4 weeks of age were included. For time-to-event analysis, medium-term outcomes were classified as lead-related (death from lead encephalopathy, and/or met chelation threshold) and non-lead-related (non-lead-related death, on programme no chelation, exit from programme without chelation). Cox regression analysis and ROC analysis were performed. 1468 children were included. All-cause mortality 2.3%; geometric mean neonatal BLC 13.7 µg/dL; 'lead-related death or treatment' 19.3%. For every doubling in neonatal BLC, there was an almost 8-fold increase in adjusted hazard ratio (HR) for the composite lead-related outcome (p<0.001). A neonatal BLC ≥ 15.0 µg/dL had 95% sensitivity for identifying children who went on to have the composite outcome (with specificity 67%; positive likelihood ratio 2.86). Congenital lead poisoning predicts ongoing exposure in this population, even after environmental remediation. This suggests a complex, early, multidisciplinary approach to source control and exposure management is required when elevated neonatal BLC is observed in lead poisoning clusters in low-and-middle-income contexts.

Malaria parasite density and detailed qualitative microscopy enhances large-scale profiling of infection endemicity in Nigeria.

With global progress towards malaria reduction stalling, further analysis of epidemiology is required, particularly in countries with the highest burden. National surveys have mostly analysed infection prevalence, while large-scale data on parasite density and different developmental forms rarely available. In Nigeria, the country with the largest burden globally, blood slide microscopy of children up to 5 years of age was conducted in the 2018 National Demographic and Health Survey, and parasite prevalence previously reported. In the current study, malaria parasite density measurements are reported and analysed for 7783 of the children sampled across the 36 states within the six geopolitical zones of the country. Asexual and sexual stages, and infections with different malaria parasite species are analysed. Across all states of Nigeria, there was a positive correlation between mean asexual parasite density within infected individuals and prevalence of infection in the community (Spearman's rho = 0.39, P = 0.02). Asexual parasite densities were highest in the northern geopolitical zones (geometric means > 2000 µL-1), extending the evidence of exceptionally high infection burden in many areas. Sexual parasite prevalence in each state was highly correlated with asexual parasite prevalence (Spearman's rho = 0.70, P < 0.001), although sexual parasite densities were low (geometric means < 100 µL-1 in all zones). Infants had lower parasite densities than children above 1 year of age, but there were no differences between male and female children. Most infections were of P. falciparum, which had higher asexual densities but lower sexual parasite densities than P. malariae or P. ovale mono-infections. However, mixed species infections had the highest asexual parasite densities. It is recommended that future large surveys in high burden countries measure parasite densities as well as developmental stages and species, to improve the quality of malaria epidemiology and tracking of future changes.

Geographical and temporal variation in reduction of malaria infection among children under 5 years of age throughout Nigeria.

INTRODUCTION: Global progress in reducing malaria has stalled since 2015. Analysis of the situation is particularly needed in Nigeria, the country with by far the largest share of the burden, where approximately a quarter of all cases in the world are estimated to occur. METHODS: We analysed data from three nationwide surveys (Malaria Indicator Surveys in 2010 and 2015 and a National Demographic and Health Survey in 2018), with malaria parasite prevalence in children under 5 years of age determined by sampling from all 36 states of Nigeria, and blood slide microscopy performed in the same accredited laboratory for all samples. Changes over time were evaluated by calculating prevalence ratio (PR) values with 95% CIs for each state, together with Mantel-Haenszel-adjusted PRs (PRadj) for each of the six major geopolitical zones of the country. RESULTS: Between 2010 and 2018, there were significant reductions in parasite prevalence in 25 states, but not in the remaining 11 states. Prevalence decreased most in southern zones of the country (South West PRadj=0.53; South East PRadj=0.59; South South PRadj=0.51) and the North Central zone (PRadj=0.36). Changes in the north were less marked, but were significant and indicated overall reductions by more than 20% (North-West PRadj=0.74; North East PRadj=0.70). Changes in the south occurred mostly between 2010 and 2015, whereas those in the north were more gradual and most continued after 2015. Recent changes were not correlated with survey-reported variation in use of preventive measures. CONCLUSION: Reductions in malaria infection in children under 5 have occurred in most individual states in Nigeria since 2010, but substantial geographical variation in the timing and extent indicate challenges to be overcome to enable global malaria reduction.

Clinical illness and outcomes in Nigerian children with persistent early-appearing anaemia following initiation of artemisinin-based combination treatments of uncomplicated falciparum malaria.

In non-anaemic children with malaria, early-appearing anaemia (EAA) is common following artemisinin-based combination treatments (ACTs) and it may become persistent (PEAA). The factors contributing to and kinetics of resolution of the deficit in haematocrit from baseline (DIHFB) characteristic of ACTs-related PEAA were evaluated in 540 consecutive children with malaria treated with artemether-lumefantrine, artesunate-amodiaquine or dihydroartemisinin-piperaquine. Asymptomatic PEAA occurred in 62 children. In a multiple logistic regression model, a duration of illness ≤3 days before presentation, haematocrit <35% before and <25% one day after treatment initiation, drug attributable fall in haematocrit ≥6%, and treatment with dihydroartemisinin-piperaquine independently predicted PEAA. Overall, mean DIHFB was 5.7% (95% CI 4.8-6.6) 7 days after treatment initiation and was similar for all treatments. Time to 90% reduction in DIHFB was significantly longer in artemether-lumefantrine-treated children compared with other treatments. In a one compartment model, declines in DIHFB were monoexponential with overall mean estimated half-time of 3.9 days (95% CI 2.6-5.1), Cmax of 7.6% (95% CI 6.7-8.4), and Vd of 0.17 L/kg (95% CI 0.04-0.95). In Bland-Altman analyses, overall mean anaemia recovery time (AnRT) of 17.4 days (95% CI 15.5-19.4) showed insignificant bias with 4, 5 or 6 multiples of half-time of DIHFB. Ten children after recovery from PEAA progressed to late-appearing anaemia (LAA). Progression was associated with female gender and artesunate-amodiaquine treatment. Asymptomatic PEAA is common following ACTs. PEAA or its progression to LAA may have implications for case and community management of anaemia and for anaemia control efforts in sub-Saharan Africa where ACTs have become first-line antimalarials. Trial registration: Pan Africa Clinical Trial Registration PACTR201709002064150, 1 March 2017 http://www.pactr.org.

Declining responsiveness of childhood Plasmodium falciparum infections to artemisinin-based combination treatments ten years following deployment as first-line antimalarials in Nigeria.

BACKGROUND: The development and spread of artemisinin-resistant Plasmodium falciparum malaria in Greater Mekong Subregion has created impetus for continuing global monitoring of efficacy of artemisinin-based combination therapies (ACTs). This post analyses is aimed to evaluate changes in early treatment response markers 10 years after the adoption of ACTs as first-line treatments of uncomplicated falciparum malaria in Nigeria. METHODS: At 14 sentinel sites in six geographical areas of Nigeria, we evaluated treatment responses in 1341 children under 5 years and in additional 360 children under 16 years with uncomplicated malaria enrolled in randomized trials of artemether-lumefantrine versus artesunate-amodiaquine at 5-year interval in 2009-2010 and 2014-2015 and at 2-year interval in 2009-2010 and 2012-2015, respectively after deployment in 2005. RESULTS: Asexual parasite positivity 1 day after treatment initiation (APPD1) rose from 54 to 62% and 2 days after treatment initiation from 5 to 26% in 2009-2010 to 2014-2015 (P = 0.002 and P <  0.0001, respectively). Parasite clearance time increased significantly from 1.6 days (95% confidence interval [CI]: 1.55-1.64) to 1.9 days (95% CI, 1.9-2.0) and geometric mean parasite reduction ratio 2 days after treatment initiation decreased significantly from 11 000 to 4700 within the same time period (P <  0.0001 for each). Enrolment parasitaemia > 75 000 µl- 1, haematocrit > 27% 1 day post-treatment initiation, treatment with artemether-lumefantrine and enrolment in 2014-2015 independently predicted APPD1. In parallel, Kaplan-Meier estimated risk of recurrent infections by day 28 rose from 8 to 14% (P = 0.005) and from 9 to 15% (P = 0.02) with artemether-lumefantrine and artesunate-amodiaquine, respectively. Mean asexual parasitaemia half-life increased significantly from 1.1 h to 1.3 h within 2 years (P <  0.0001). CONCLUSIONS: These data indicate declining parasitological responses through time to the two ACTs may be due to emergence of parasites with reduced susceptibility or decrease in immunity to the infections in these children. TRIAL REGISTRATION: Pan African Clinical Trial Registration PACTR201508001188143 , 3 July 2015; PACTR201508001191898 , 7 July 2015 and PACTR201508001193368 , 8 July 2015 PACTR201510001189370 , 3 July 2015; PACTR201709002064150 , 1 March 2017; https://www.pactr.samrca.ac.za.

Parasite reduction ratio one day after initiation of artemisinin-based combination therapies and its relationship with parasite clearance time in acutely malarious children.

BACKGROUND: In acute falciparum malaria, asexual parasite reduction ratio two days post-treatment initiation (PRRD2) ≥ 10 000 per cycle has been used as a measure of the rapid clearance of parasitaemia and efficacy of artemisinin derivatives. However, there is little evaluation of alternative measures; for example, parasite reduction ratio one day after treatment initiation (PRRD1) and its relationship with parasite clearance time (PCT) or PRRD2. This study evaluated the use of PRRD1 as a measure of responsiveness to antimalarial drugs. METHODS: In acutely malarious children treated with artesunate-amodiaquine (AA), artemether-lumefantrine (AL) or dihydroartemisinin-piperaquine (DHP), the relationships between PRRD1 or PRRD2 and PCT, and between PRRD1 and PRRD2 were evaluated using linear regression. Agreement between estimates of PCT using PRRD1 and PRRD2 linear regression equations was evaluated using the Bland-Altman analysis. Predictors of PRRD1 > 5000 per half cycle and PRRD2 ≥ 10 000 per cycle were evaluated using stepwise multiple logistic regression models. Using the linear regression equation of the relationship between PRRD1 and PCT previously generated in half of the DHP-treated children during the early study phase, PCT estimates were compared in a prospective blinded manner with PCTs determined by microscopy during the later study phase in the remaining half. RESULTS: In 919 malarious children, PRRD1 was significantly higher in DHP- and AA-treated compared with AL-treated children (P <  0.0001). PRRD1 or PRRD2 values correlated significantly negatively with PCT values (P <  0.0001 for each) and significantly positively with each other (P <  0.0001). PCT estimates from linear regression equations for PRRD1 and PRRD2 showed insignificant bias on the Bland-Altman plot (P = 0.7) indicating the estimates can be used interchangeably. At presentation, age > 15 months, parasitaemia > 10 000/µl and DHP treatment independently predicted PRRD1 > 5000 per half cycle, while age > 30 months, haematocrit ≥31%, body temperature > 37.4 °C, parasitaemia > 100 000/µl, PRRD1 value > 1000 and no gametocytaemia independently predicted PRRD2 ≥ 10 000 per cycle. Using the linear regression equation generated during the early phase in 166 DHP-treated children, PCT estimates and PCTs determined by microscopy in the 155 children in the later phase were similar in the same patients. CONCLUSIONS: PRRD1 and estimates of PCT using PRRD1 linear regression equation of PRRD1 and PCT can be used in therapeutic efficacy studies. TRIAL REGISTRATION: Pan African Clinical Trial Registration PACTR201709002064150, 1 March 2017, http://www.pactr.org.

Efficacy of Artemisinin-Based Combination Treatments of Uncomplicated Falciparum Malaria in Under-Five-Year-Old Nigerian Children Ten Years Following Adoption as First-Line Antimalarials.

The efficacies of 3-day regimens of artemether-lumefantrine (AL), artesunate-amodiaquine (AA), and dihydroartemisinin-piperaquine (DHP) were evaluated in 910 children < 5 years old with uncomplicated malaria from six geographical areas of Nigeria. Parasite positivity 1 day and Kaplan-Meier estimated risk of persistent parasitemia 3 days after therapy initiation were both significantly higher, and geometric mean parasite reduction ratio 1 day after treatment initiation (PRRD1) was significantly lower in AL-treated children than in AA- and DHP-treated children. No history of fever, temperature > 38°C, enrollment parasitemia > 75,000 µL-1, and PRRD1 < 5,000 independently predicted persistent parasitemia 1 day after treatment initiation. Parasite clearance was significantly faster and risk of reappearance of asexual parasitemia after initial clearance was significantly lower in DHP-treated children. Overall, day 42 polymerase chain reaction-corrected efficacy was 98.3% (95% confidence interval [CI]: 96.1-100) and was similar for all treatments. In a non-compartment model, declines of parasitemias were monoexponential with mean terminal elimination half-life of 1.3 hours and unimodal frequency distribution of half-lives. All treatments were well tolerated. In summary, all three treatments evaluated remain efficacious treatments of uncomplicated malaria in young Nigerian children, but DHP appears more efficacious than AL or AA.

Impact of comorbidity on adverse drug reaction profile in a cohort of patients treated with Artemisinin combination therapies for uncomplicated malaria in Nigeria.

Artemisinin-based combination antimalarial therapy (ACTs), is still highly effective in uncomplicated falciparum malaria, however, there remain some concerns in relation to its safety and tolerability. Comorbid disease conditions may influence susceptibility to adverse drug reactions (ADRs) as the presence of multiple disease conditions may predisposes patients to ADRs due to the use of many medicines. There is therefore need to assess the impact of comorbidities on the ADR profile of malaria patients treated with ACTs. The study was carried out in health care facilities spread across Nigeria. From the database of over 10,000 patients recruited into an initial cohort, data for 1000 patients with comorbidities was extracted and matched with a control group of 1000 randomly selected patients with no comorbidity. There were 1105 adverse drug reactions in all, of which 66.2% were recorded in patients with comorbidity, and 34% are patients without comorbidity. The mean age of patients with comorbidities was 38.3 ± 17.5 years and 23.8 ± 17.2 for those without comorbidity. Out of the 979 patients with comorbidity, 36% were hypertensive, 2.2% hypertensive-diabetes, 16.4% peptic ulcer disease, 10.4% HIV/AIDS, 4.4% diabetes and 4.3% were asthmatic. Patients with comorbidity were three times more likely to have adverse drug reaction than those without comorbidity (Odds ration = 2.96; 95% CI = 2.23-3.93). HIV/AIDS and osteoarthritis were significantly associated with development of adverse drug reactions. Probability was <0.0001. Age, weight, and height of patients were also found to be risk factor for development of adverse drug reactions.