Medicine and Health Sciences Commons^™

Molecular Surveillance Of Drug Resistance: Plasmodium Falciparum Artemisinin Resistance Single Nucleotide Polymorphisms In Kelch Protein Propeller (K13) Domain From Southern Pakistan, Najia Karim Ghanchi, Bushra Qurashi, Hadiqa Raees, Mohammad Asim Beg

Department of Pathology and Laboratory Medicine

Background: K13 propeller (k13) polymorphism are useful molecular markers for tracking the emergence and spread of artemisinin resistance in Plasmodium falciparum. Polymorphisms are reported from Cambodia with rapid invasion of the population and almost near fixation in south East Asia. The study describes single nucleotide polymorphisms in Kelch protein propeller domain of P. falciparum associated with artemisinin resistance from Southern Pakistan.
Methods: Two hundred and forty-nine samples were collected from patients with microscopy confirmed P. falciparum malaria attending Aga Khan University Hospital during September 2015-April 2018. DNA was isolated using the whole blood protocol for the QIAmp DNA Blood Kit. …

Implementing Parasite Genotyping Into National Surveillance Frameworks: Feedback From Control Programmes And Researchers In The Asia-Pacific Region, Rintis Noviyanti, Olivo Miotto, Alyssa Barry, Jutta Marfurt, Sasha Siegel, Nguyen Thuy-Nhien, Huynh Hong Quang, Nancy Dian Anggraeni, Ferdinand Laihad, Najia Karim Ghanchi

Department of Pathology and Laboratory Medicine

The Asia-Pacific region faces formidable challenges in achieving malaria elimination by the proposed target in 2030. Molecular surveillance of Plasmodium parasites can provide important information on malaria transmission and adaptation, which can inform national malaria control programmes (NMCPs) in decision-making processes. In November 2019 a parasite genotyping workshop was held in Jakarta, Indonesia, to review molecular approaches for parasite surveillance and explore ways in which these tools can be integrated into public health systems and inform policy. The meeting was attended by 70 participants from 8 malaria-endemic countries and partners of the Asia Pacific Malaria Elimination Network. The participants acknowledged …

Hematological Profile And Gametocyte Carriage In Malaria Patients From Southern Pakistan, Najia Karim Ghanchi, Mohammad Hassaan Khan, Muhammad Abdullah Arain, Mustafa Bin Ali Zubairi, Ahmed Raheem Buksh, Muhammad A. Khan, Mohammad A. Beg

Department of Pathology and Laboratory Medicine

Background: Malarial infection is a major cause of concern, both worldwide and in Pakistan. Gametocytes are the sexual forms of the parasite that are essential for transmission. They fuse inside the mosquito to develop sporozoites. Gametocytes of the plasmodium parasites, which cause the infection, differentiate into male and female gametocytes. These gametocytes constitute the sexual stage of the malaria parasite and are essential in transmission of the disease from human to vector Anopheles. Gametocytes are affected by factors such as host immunity, drug treatment, reticulocytemia, anemia, low levels of asexual parasitemia and stress to the parasite. The aim of this …

High Resolution Melting: A Useful Field-Deployable Method To Measure Dhfr And Dhps Drug Resistance In Both Highly And Lowly Endemic Plasmodium Populations, Yaye Dié Ndiaye, Cyrille K. Diédhiou, Amy K. Bei, Baba Dieye, Aminata Mbaye, Nasserdine Papa Mze, Rachel F. Daniels, Ibrahima M. Ndiaye, Awa B. Déme, Amy Gaye, Mouhamad Sy, Tolla Ndiaye, Aida S. Badiane, Mouhamadou Ndiaye, Zul Premji, Dyann F. Wirth, Souleymane Mboup, Donald Krogstad, Sarah K. Volkman, Ambroise D. Ahouidi, Daouda Ndiaye

Pathology, East Africa

Background: Emergence and spread of drug resistance to every anti-malarial used to date, creates an urgent need for development of sensitive, specifc and feld-deployable molecular tools for detection and surveillance of validated drug resistance markers. Such tools would allow early detection of mutations in resistance loci. The aim of this study was to compare common population signatures and drug resistance marker frequencies between two populations with diferent levels of malaria endemicity and history of anti-malarial drug use: Tanzania and Sénégal. This was accomplished by implementing a high resolution melting assay to study molecular markers of drug resistance as compared to …

Temporal Trends Of Molecular Markers Associated With Artemether- Lumefantrine Tolerance/Resistance In Bagamoyo District, Tanzania, M. Malmberg, B. Ngasala, P.E. Ferreira, E. Larsson, I. Jovel, A. Hjalmarsson, M. Petzold, Zul Premji, J.P. Gil, A. Bjorkman, A. Martensson

Pathology, East Africa

Background: Development and spread of Plasmodium falciparum resistance to artemisinin-based combination therapy (ACT) constitutes a major threat to recent global malaria control achievements. Surveillance of molecular markers could act as an early warning system of ACT-resistance before clinical treatment failures are apparent. The aim of this study was to analyse temporal trends of established genotypes associated with artemether-lumefantrine tolerance/resistance before and after its deployment as first-line treatment for uncomplicated malaria in Tanzania 2006.

Methods: Single nucleotide polymorphisms in the P. falciparum multidrug resistance gene 1 (pfmdr1) N86Y, Y184F, D1246Y and P. falciparum chloroquine transporter gene (pfcrt) K76T were analysed from …

Plasmodium Falciparum Population Dynamics During The Early Phase Of Anti-Malarial Drug Treatment In Tanzanian Children With Acute Uncomplicated Malaria, A.M. Carlsson, B.E. Ngasala, S. Dahlstrom, C. Membi, I.M. Veiga, L. Rombo, S. Abdulla, Zul Premji, J.P. Gil, A. Bjorkman, A. Martensson

Pathology, East Africa

Background: This study aimed to explore Plasmodium falciparum population dynamics during the early phase of anti-malarial drug treatment with artemisinin-based combination therapy in children with clinical malaria in a high transmission area in Africa.

Methods: A total of 50 children aged 1-10 years with acute uncomplicated P. falciparum malaria in Bagamoyo District, Tanzania, were enrolled. Participants were hospitalized and received supervised standard treatment with artemether-lumefantrine according to body weight in six doses over 3 days. Blood samples were collected 11 times, i.e. at time of diagnosis (-2 h) and 0, 2, 4, 8, 16, 24, 36, 48, 60 and 72 …

Population Genetic Analysis Of Large Sequence Polymorphisms In Plasmodium Falciparum Blood-Stage Antigens, A.D. Ahouidi, A.K. Bei, D.E. Neafsey, O. Sarr, S. Volkman, D. Milner, J. Cox-Singh, M.U. Ferreira, O. Ndir, Zul Premji, S. Mboup, M.T. Duraisingh

Pathology, East Africa

Plasmodium falciparum, the causative agent of human malaria, invades host erythrocytes using several proteins on the surface of the invasive merozoite, which have been proposed as potential vaccine candidates. Members of the multi-gene PfRh family are surface antigens that have been shown to play a central role in directing merozoites to alternative erythrocyte receptors for invasion. Recently, we identified a large structural polymorphism, a 0.58 Kb deletion, in the C-terminal region of the PfRh2b gene, present at a high frequency in parasite populations from Senegal. We hypothesize that this region is a target of humoral immunity. Here, by analyzing 371 …

Variant Merozoite Protein Expression Is Associated With Erythrocyte Invasion Phenotypes In Plasmodium Falciparum Isolates From Tanzania, A.K. Bei, C.D. Membi, J.C. Rayner, M. Mubi, B. Ngasala, A.A. Sultan, Zul Premji, M.T. Duraisingh

Pathology, East Africa

[No abstract available]

Plasma Zinc Concentrations Are Depressed During The Acute Phase Response In Children With Falciparum Malaria, C. Duggan, W.B. Macleod, N.F. Krebs, J.L. Westcott, W.W. Fawzi, Zul Premji, V. Mwanakasale, J.L. Simon, K. Yeboah-Antwi, D.H. Hamer

Pathology, East Africa

Plasma concentrations of some micronutrients are altered in the setting of acute infectious or inflammatory stress. Previous studies have provided conflicting evidence concerning the extent and direction of changes in plasma zinc concentrations during the acute phase response. We carried out an observational cohort study in 689 children enrolled in a randomized trial of zinc supplementation during acute falciparum malaria in order to evaluate the relation between plasma zinc concentration and the acute phase response. Plasma zinc was measured by atomic absorption spectrophotometry. On admission, 70% of all subjects had low plasma zinc (<9.2 μmol/L). Multivariate analysis of predictors of admission plasma zinc showed that admission C-reactive protein (CRP), parasite density, and study site were the most important predictors. Predictors of changes in plasma zinc from admission to 72 h included baseline CRP, change in CRP, treatment group, study site, and baseline zinc concentration. In children with acute malaria infection, baseline plasma zinc concentrations were very low and were inversely correlated with CRP (r = -0.24, P < 0.0001) and the degree of parasitemia (r = -0.19, P < 0.0001). Even when CRP and time were taken into account, zinc supplementation increased plasma zinc concentration from admission to 72 h. When available, plasma zinc concentrations should be interpreted with concurrent measures of the acute phase response such as CRP. In children whose age, diet, and/or nutritional status place them at risk of zinc deficiency, those with low plasma zinc levels should be supplemented with oral zinc and followed for clinical and/or biochemical response. © 2005 American Society for Nutritional Sciences.

Higher Il-10 Levels Are Associated With Less Effective Clearance Of Plasmodium Falciparum Parasites, E. Hugosson, S.M. Montgomery, Zul Premji, M. Troye-Blomberg, A. Bjorkman

Pathology, East Africa

The implications of high levels of the immune regulatory cytokine IL-10 in Plasmodium falciparum malaria are unclear. IL-10 may down-regulate pro-inflammatory responses and also exacerbate disease by inhibiting anti-parasitic immune functions. To study possible inhibiting effects on parasite clearance, IL-10 plasma levels were determined in 104 Tanzanian children, 1 to 4 years old, with acute uncomplicated P. falciparum malaria, and analysed for association with parasite densities during 3 days of anti-malarial treatment. Higher baseline IL-10 plasma levels were associated with statistically significantly higher parasite densities after 24, 48 and 72 h of treatment. These associations could not be explained by …

Age, Temperature, And Parasitaemia Predict Chloroquine Treatment Failure And Anaemia In Children With Uncomplicated Plasmodium Falciparum Malaria, D.H. Hamer, W.B. Macleod, E. Addo-Yobo, C.P Duggan, B. Estrella, W.W. Fawzi, J.K. Konde-Lule, V. Mwanakasale, Zul Premji, F. Sempertegui, F.P. Ssengooba, K. Yeboah-Antwi, J.L. Simon

Pathology, East Africa

The prevalence of chloroquine-resistant Plasmodium falciparum malaria has been increasing in sub-Saharan Africa and parts of South America over the last 2 decades, and has been associated with increased anaemia-associated morbidity and higher mortality rates. Prospectively collected clinical and parasitological data from a multicentre study of 788 children aged 6-59 months with uncomplicated P. falciparum malaria were analysed in order to identify risk factors for chloroquine treatment failure and to assess its impact on anaemia after therapy. The proportion of chloroquine treatment failures (combined early and late treatment failures) was higher in the central-eastern African countries (Tanzania, 53%; Uganda, 80%; …

Effect Of Zinc On The Treatment Of Plasmodium Falciparum Malaria In Children: A Randomized Controlled Trial, F. Sempertegui, B. Estrella, F.R. Toapanta, D.S. Torres, D.E. Calahorrano, K. Yeboah-Antwi, E. Addo-Yobo, P. Arthur, S. Newton, Zul Premji, M. Hubert, C.S. Makwaya, F. Ssengooba, J. Konde-Lule, E. Mukisa, D.H. Hamer, W. Macleod, C. Duggan, W. Fawzi, J. Simon, V. Mwanakasale, M. Mulenga, T. Sukwa, J. Tshiula

Pathology, East Africa

Background: Zinc supplementation in young children has been associated with reductions in the incidence and severity of diarrheal diseases, acute respiratory infections, and malaria.

Objective: The objective was to evaluate the potential role of zinc as an adjunct in the treatment of acute, uncomplicated falciparum malaria; a multicenter, double-blind, randomized placebo-controlled clinical trial was undertaken.

Design: Children (n = 1087) aged 6 mo to 5 y were enrolled at sites in Ecuador, Ghana, Tanzania, Uganda, and Zambia. Children with fever and ≥ 2000 asexual forms of Plasmodium falciparum/μL in a thick blood smear received chloroquine and were randomly assigned to …

Acute Haemolysis In Childhood Falciparum Malaria, H. Ekvall, P. Arese, F. Turrini, K. Ayi, F. Mannu, Zul Premji, A. Bjorkman

Pathology, East Africa

Acute haemolysis associated with clinical episodes of high-level Plasmodium falciparum parasitaemia was studied in 20 children from an holoendemic area (coastal Tanzania). The change in blood haemoglobin (Hb) concentration ranged from -46 to +5 g/L during the 72-h observation period and was linearly related to maximum parasitaemia. Balance studies between loss of blood Hb, increase in plasma Hb and appearance of Hb in the urine indicated that extravascular clearance of red cells was the predominant mode of erythrocyte clearance. Most subjects, however, showed minor signs of intravascular haemolysis. The plasma Hb was ≪1% of blood Hb and haemoglobinuria was detected …