Browsing by Author "Mbonye, Anthony K."

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    A lab-on-chip for malaria diagnosis and surveillance
    (BioMed Central Ltd., 2014-05-09) Taylor, Brian J.; Howell, Anita; Martin, Kimberly A.; Manage, Dammika P.; Gordy, Walter; Campbell, Stephanie D.; Lam, Samantha; Jin, Albert; Polley, Spncer D.; Samuel, Roshini A.; Atrazhev, Alexey; Stickel, Alex J.; Birungi, Josephine; Mbonye, Anthony K.; Pilarski, Linda M.; Acker, Jason P.; Yanow, Stephanie K.
    Background: Access to timely and accurate diagnostic tests has a significant impact in the management of diseases of global concern such as malaria. While molecular diagnostics satisfy this need effectively in developed countries, barriers in technology, reagent storage, cost and expertise have hampered the introduction of these methods in developing countries. In this study a simple, lab-on-chip PCR diagnostic was created for malaria that overcomes these challenges. Methods: The platform consists of a disposable plastic chip and a low-cost, portable, real-time PCR machine. The chip contains a desiccated hydrogel with reagents needed for Plasmodium specific PCR. Chips can be stored at room temperature and used on demand by rehydrating the gel with unprocessed blood, avoiding the need for sample preparation. These chips were run on a custom-built instrument containing a Peltier element for thermal cycling and a laser/camera setup for amplicon detection. Results: This diagnostic was capable of detecting all Plasmodium species with a limit of detection for Plasmodium falciparum of 2 parasites/μL of blood. This exceeds the sensitivity of microscopy, the current standard for diagnosis in the field, by ten to fifty-fold. In a blind panel of 188 patient samples from a hyper-endemic region of malaria transmission in Uganda, the diagnostic had high sensitivity (97.4%) and specificity (93.8%) versus conventional real-time PCR. The test also distinguished the two most prevalent malaria species in mixed infections, P. falciparum and Plasmodium vivax. A second blind panel of 38 patient samples was tested on a streamlined instrument with LED-based excitation, achieving a sensitivity of 96.7% and a specificity of 100%. Conclusions: These results describe the development of a lab-on-chip PCR diagnostic from initial concept to ready-for-manufacture design. This platform will be useful in front-line malaria diagnosis, elimination programmes, and clinical trials. Furthermore, test chips can be adapted to detect other pathogens for a differential diagnosis in the field. The flexibility, reliability, and robustness of this technology hold much promise for its use as a novel molecular diagnostic platform in developing countries.
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    A new strategy and its effect on adherence to intermittent preventive treatment of malaria in pregnancy in Uganda
    (BMC Pregnancy and Childbirth, 2013-12-18) Mbonye, Anthony K.; Yanow, Stephanie; Birungi, Josephine; Magnussen, Pascal
    Background: Few women in Uganda access intermittent preventive treatment of malaria in pregnancy (IPTp) with sulfadoxine-pyrimethamine (SP). Previous studies have shown that high costs, frequent stock-out of drugs, supplies and poor quality of care are the greatest hindrance for women to access health services. In order to increase adherence to IPTp, we conceptualised an intervention that offset delivery care costs through providing a mama kit, created awareness on health benefits of IPTp and built trust between the provider and the client. Methods: The new strategy was conceived along four constructs namely: 1) creating awareness by training midwives to explain the benefits of SP and the importance of adhering to the two doses of SP as IPTp to all pregnant women who attended ANC and consented to the study. Midwives were trained for two days in customer care and to provide a friendly environment. The pregnant women were also informed of the benefits of attending ANC and delivering at health facilities. 2) Each woman was promised a mama kit during ANC; 3) trust was built by showing the mama kit to each woman and branding it with her name; 4) keeping the promise by providing the mama kit when women came to deliver. The strategy to increase adherence to two doses of SP and encourage women to deliver at health facilities was implemented at two health facilities in Mukono district (Kawolo hospital and Mukono health centre IV). The inclusion criteria were women who: i) consented to the study and ii) were in the second trimester of pregnancy. All pregnant women in the second trimester (4-6 months gestation) who attended ANC and consented to participate in the study were informed of the benefits of SP, the importance of delivering at health facilities, were advised to attend the scheduled visits, promised a mama kit and ensured the kit was available at delivery. The primary outcome was the proportion of pregnant women adhering to a two dose SP regimen. Results: A total of 2,276 women received the first dose of SP and 1,656 (72.8%) came back for the second dose. 1,069 women were involved in the evaluation (384 had participated in the intervention while 685 had not). The main reasons that enabled those who participated in the intervention to adhere to the two doses of IPTp and deliver at the study facilities were: an explanation provided on the benefits of IPTp and delivering at health facilities (25.1%), availability of a mama kit at delivery (24.6%), kind midwives (19.8%) and fearing complications of pregnancy (8.5%). Overall, 78.0% of these women reported that they were influenced to adhere to IPTp by the intervention. In a multivariable regression, nearby facility, P = 0. 007, promising a mama kit, P = 0.002, kind midwives, P = 0.0001 and husbands’ encouragement, P = 0.0001 were the significant factors influencing adherence to IPTp with SP. Conclusion: The new strategy was a good incentive for women to attend scheduled ANC visits, adhere to IPTp and deliver at the study facilities. Policy implications include the urgent need for developing a motivation package based on the Health-Trust Model to increase access and adherence to IPTp.
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    Prescription patterns and drug use among pregnant women with febrile Illnesses in Uganda: a survey in out-patient clinics.
    (2013) Mbonye, Anthony K.; Birungi, Josephine; Yanow, Stephanie; Magnussen, Pascal
    Background: Malaria is a public health problem in Uganda; affecting mainly women and children. Effective treatment has been hampered by over-diagnosis and over-treatment with anti-malarial drugs among patients presenting with fever. In order to understand the effect of drug pressure on sulfadoxine-pyrimethamine (SP) resistance in pregnancy, a sample of pregnant women presenting with fever in out–patient clinics was studied. The main objective was to assess prescription patterns and drug use in pregnancy especially SP; and draw implications on the efficacy of SP for intermittent preventive treatment of malaria in pregnancy (IPTp). Methods: A total of 998 pregnant women with a history of fever were interviewed and blood samples taken for diagnosis of malaria and HIV infections. Data were captured on the drugs prescribed for the current febrile episode and previous use of drugs especially SP, anti-retroviral drugs (ARVs) and cotrimoxazole. Results: Few pregnant women, 128 (12.8%) were parasitaemic for P.falciparum; and of these, 72 (56.3%) received first-line treatment with Artemether-lumefantrine (Coartem®) 14 (10.9%) SP and 33 (25.8%) quinine. Of the parasite negative patients (non-malarial fevers), 186 (21.4%) received Coartem, 423 (48.6%) SP and 19 (2.1%) cotrimoxazole. Overall, malaria was appropriately treated in 35.5% of cases. Almost all febrile pregnant women, 91.1%, were sleeping under a mosquito net. The majority of them, 911 (91.3%), accepted to have an HIV test done and 92 (9.2%) were HIV positive. Of the HIV positive women, 23 (25.0%) were on ARVs, 10 (10.9%) on cotrimoxazole and 30 (32.6%) on SP. A significant proportion of women, 40 (43.5%), were on both SP and cotrimoxazole. Age and occupation were associated with diagnosis and treatment of malaria and HIV infections. Conclusion: There is inappropriate treatment of malaria and non-malarial fevers among pregnant women in these facilities. This is due to non-adherence to the guidelines. Over-prescription and use of anti-malarial drugs, especially SP may have implications on resistance against SP for malaria prevention in pregnancy. The policy implications of these findings are to evaluate SP efficacy as IPTp; and the need to enforce adherence to the current clinical treatment guidelines.
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    Prevalence of Plasmodium falciparum Resistance Markers to Sulfadoxine-Pyrimethamine among Pregnant Women Receiving Intermittent Preventive Treatment for Malaria in Uganda
    (Antimicrobial Agents and Chemotherapy, 2015-09) Mbonye, Anthony K.; Birungi, Josephine; Yanow, Stephanie K.; Shokoples, Sandra; Malamba, Samuel; Alifrangis, Michael; Magnussenf, Pascal
    The aim of this study was to assess the prevalence of mutations in Plasmodium falciparum dihydrofolate reductase (Pfdhfr) and dihydropteroate synthase (Pfdhps) genes among pregnant women using sulfadoxine-pyrimethamine (SP) as an intermittent preventive treatment (IPTp). A molecular epidemiological study of P. falciparum parasite resistance markers to SP was conducted from August 2010 to February 2012 in Mukono district in central Uganda. DNA was extracted from 413 P. falciparum-positive samples. Real-time PCR, followed by melting curve analysis, was used to characterize point mutations in the Pfdhfr and Pfdhps genes that are associated with SP resistance. The prevalence of the single-nucleotide mutations in Pfdhfr at codons 51I, 59R, and 108N and in Pfdhps at codons 437G and 540E was high (>98%), reaching 100% fixation after one dose of SP, while the prevalence of 581G was 3.3% at baseline, reaching 12.5% after one dose of SP. At baseline, the prevalence of Pfdhfr and Pfdhps quintuple mutations was 89%, whereas the sextuple mutations (including 581G) were not prevalent (3.9%), reaching 16.7% after one dose of SP. However, the numbers of infections at follow-up visits were small, and hence there was insufficient statistical power to test whether there was a true rise in the prevalence of this allele. The overall high frequency of Pfdhfr and Pfdhps quintuple mutations throughout pregnancy excluded further analyses of possible associations between certain haplotypes and the risk of lower birth weight and anemia. However, women infected with P. falciparum had 1.3-g/dl-lower hemoglobin levels (P_0.001) and delivered babies with a 400-g-lower birth weight (P_0.001) compared to nonparasitemic women. Despite this, 44 women who were P. falciparum positive at baseline became negative after one or two doses of SP (i.e., 50.5%), implying that SP-IPTp still has some efficacy. P. falciparum resistance markers to SP are high in this population, whereas P. falciparum infection was associated with poor birth outcomes.