Publications by authors named "Krogstad D"

Production of biofuels from biological feedstocks, such as soybean oil, is an important piece of the transition to renewable energy sources. Processes have been developed to co-refine these feedstocks with traditional feedstocks, however, the high concentration of polar functional groups in biofeedstocks can cause a wide range of intermediate chemical reactions and interactions. An improved understanding of the interactions of biofeedstocks and their degradation products is needed to continue to expand the usage of biofeedstocks in fuel production.

View Article and Find Full Text PDF

Background: Over the past decade, three strategies have reduced severe malaria cases and deaths in endemic regions of Africa, Asia and the Americas, specifically: (1) artemisinin-based combination therapy (ACT); (2) insecticide-treated bed nets (ITNs); and, (3) intermittent preventive treatment with sulfadoxine-pyrimethamine in pregnancy (IPTp). The rationale for this study was to examine communities in Dangassa, Mali where, in 2015, two additional control strategies were implemented: ITN universal coverage and seasonal malaria chemoprevention (SMC) among children under 5 years old.

Methods: This was a prospective study based on a rolling longitudinal cohort of 1401 subjects participating in bi-annual smear surveys for the prevalence of asymptomatic Plasmodium falciparum infection and continuous surveillance for the incidence of human disease (uncomplicated malaria), performed in the years from 2012 to 2020.

View Article and Find Full Text PDF

Background: The current first-line treatments for uncomplicated malaria recommended by the National Malaria Control Programme in Mali are artemether-lumefantrine (AL) and artesunate-amodiaquine (ASAQ). From 2015 to 2016, an in vivo study was carried out to assess the clinical and parasitological responses to AL and ASAQ in Sélingué, Mali.

Methods: Children between 6 and 59 months of age with uncomplicated Plasmodium falciparum infection and 2000-200,000 asexual parasites/μL of blood were enrolled, randomly assigned to either AL or ASAQ, and followed up for 42 days.

View Article and Find Full Text PDF

Background: Implementation and upscale of effective malaria vector control strategies necessitates understanding the multi-factorial aspects of transmission patterns. The primary aims of this study are to determine the vector composition, biting rates, trophic preference, and the overall importance of distinguishing outdoor versus indoor malaria transmission through a study at two communities in rural Mali.

Methods: Mosquito collection was carried out between July 2012 and June 2016 at two rural Mali communities (Dangassa and Koïla Bamanan) using pyrethrum spray-catch and human landing catch approaches at both indoor and outdoor locations.

View Article and Find Full Text PDF

There are high hopes that a development towards smarter urban environments, backed up by various big data sources, can help solve many of the challenges facing today's large cities related to providing security, mitigating environmental damages, improving services and upscaling innovative and entrepreneurial activities. This study explores the acceptance of use of (MPD) in different areas, and how it is related to different types of trust. Based on a representative survey of citizens in the two smart cities, Oslo and Tallinn, four similar trust cultures are located.

View Article and Find Full Text PDF

Mali aims to reach the pre-elimination stage of malaria by the next decade. This study used functional regression models to predict the incidence of malaria as a function of past meteorological patterns to better prevent and to act proactively against impending malaria outbreaks. All data were collected over a five-year period (2012-2017) from 1400 persons who sought treatment at Dangassa's community health center.

View Article and Find Full Text PDF

Background: The identification of asymptomatic individuals with Plasmodium falciparum infection is difficult because they do not seek medical treatment and often have too few asexual parasites detectable using microscopy or rapid diagnostic tests (≤ 200 parasites per μl). Quantitative PCR (qPCR) may provide greater sensitivity and permits estimation of the initial template DNA concentration. This study examined the hypothesis that qPCR assays using templates with higher copy numbers may be more sensitive for P.

View Article and Find Full Text PDF

Background: Because clustering of Plasmodium falciparum infection had been noted previously, the clustering of infection was examined at four field sites in West Africa: Dangassa and Dioro in Mali, Gambissara in The Gambia and Madina Fall in Senegal.

Methods: Clustering of infection was defined by the percent of persons with positive slides for asexual P. falciparum sleeping in a house which had been geopositioned.

View Article and Find Full Text PDF

Bioinformatics and data science research have boundless potential across Africa due to its high levels of genetic diversity and disproportionate burden of infectious diseases, including malaria, tuberculosis, HIV and AIDS, Ebola virus disease, and Lassa fever. This work lays out an incremental approach for reaching underserved countries in bioinformatics and data science research through a progression of capacity building, training, and research efforts. Two global health informatics training programs sponsored by the Fogarty International Center (FIC) were carried out at the University of Sciences, Techniques and Technologies of Bamako, Mali (USTTB) between 1999 and 2011.

View Article and Find Full Text PDF

Background: Developing and sustaining a data collection and management system (DCMS) is difficult in malaria-endemic countries because of limitations in internet bandwidth, computer resources and numbers of trained personnel. The premise of this paper is that development of a DCMS in West Africa was a critically important outcome of the West African International Centers of Excellence for Malaria Research. The purposes of this paper are to make that information available to other investigators and to encourage the linkage of DCMSs to international research and Ministry of Health data systems and repositories.

View Article and Find Full Text PDF

Background: Chloroquine was used for malaria treatment until resistant Plasmodium falciparum was identified. Because 4-aminoquinolines with modified side chains, such as AQ-13, are active against resistant parasites, we compared AQ-13 against artemether plus lumefantrine for treatment of uncomplicated P falciparum malaria.

Methods: We did a randomised, non-inferiority trial.

View Article and Find Full Text PDF

Polyelectrolytes are known to greatly affect calcium phosphate (CaP) mineralization. The reaction kinetics as well as the CaP phase, morphology and aggregation state depend on the relative concentrations of the polyelectrolyte and the inorganic ions in a complex, nonlinear manner. This study examines the structural evolution and kinetics of polyaspartic acid (pAsp) directed CaP mineralization at high concentrations of polyelectrolytes, calcium, and total phosphate (19-30 mg/mL pAsp, 50-100 mM Ca, Ca/P = 2).

View Article and Find Full Text PDF

Background: The monitoring of Plasmodium falciparum sensitivity to anti-malarial drugs is a necessity for effective case management of malaria. This species is characterized by a strong resistance to anti-malarial drugs. In Senegal, the first cases of chloroquine resistance were reported in the Dakar region in 1988 with nearly 7% population prevalence, reaching 47% by 1990.

View Article and Find Full Text PDF
Article Synopsis
  • The study addresses the urgent need for effective tools to detect drug resistance in malaria, focusing on two regions with different malaria prevalence: Tanzania (high endemicity) and Sénégal (low endemicity).
  • Researchers collected blood samples from malaria patients in both countries, employing two molecular techniques—high-resolution melting (HRM) and PCR-RFLP—to analyze drug resistance markers (DHFR and DHPS).
  • Findings revealed a high prevalence of mutant DHFR alleles in both populations, with HRM outperforming PCR-RFLP in detecting mixed infections, particularly in Senegal, where certain mutations were more common than in Tanzania.
View Article and Find Full Text PDF
Article Synopsis
  • Rapid diagnostic tests (RDTs) for malaria, specifically HRP2-based tests, can produce false negatives due to the deletion of the hrp2 gene in Plasmodium falciparum, which raises concerns about their reliability as malaria transmission decreases.
  • An observational study in Rwanda compared the sensitivity of HRP2 and pLDH-based RDTs against microscopy, finding that when malaria transmission intensity dropped, the sensitivity of HRP2 tests also significantly reduced from 88% to 67%.
  • Among the samples that produced false-negative results with the HRP2 RDT, about 38% were confirmed as P. falciparum through PCR, with over half of the isolates missing the hrp2
View Article and Find Full Text PDF

In 2006, artemether-lumefantrine (AL) became the first-line treatment of uncomplicated malaria in Senegal, Mali, and the Gambia. To monitor its efficacy, between August 2011 and November 2014, children with uncomplicated Plasmodium falciparum malaria were treated with AL and followed up for 42 days. A total of 463 subjects were enrolled in three sites (246 in Senegal, 97 in Mali, and 120 in Gambia).

View Article and Find Full Text PDF

Background: The use of artemisinin as a monotherapy resulted in the emergence of artemisinin resistance in 2005 in Southeast Asia. Monitoring of artemisinin combination therapy (ACT) is critical in order to detect and prevent the spread of resistance in endemic areas. Ex vivo studies and genotyping of molecular markers of resistance can be used as part of this routine monitoring strategy.

View Article and Find Full Text PDF

The health-care needs and resources of disease-endemic regions such as west Africa have been a major focus during the recent Ebola outbreak. On the basis of that experience, we call attention to two priorities that have unfortunately been ignored thus far: 1) the development of clinical research facilities and 2) the training of host country investigators to ensure that the facilities and expertise necessary to evaluate candidate interventions are available on-site in endemic regions when and where they are needed. In their absence, as illustrated by the recent uncertainty about the use of antivirals and other interventions for Ebola virus disease, the only treatment available may be supportive care, case fatality rates may be unacceptably high and there may be long delays between the time potential interventions become available and it becomes clear whether those interventions are safe or effective.

View Article and Find Full Text PDF

Background: Although the epidemiology of malaria has been based primarily on microscopy and rapid diagnostic tests, molecular methods are necessary to understand the complexity of natural infection in regions where transmission is intense and simultaneous infection with multiple parasite genotypes is common such as sub-Saharan Africa.

Methods: To compare microscopic and molecular estimates of the incidence and clearance of Plasmodium falciparum infection, we followed 80 children monthly for 1 year in the village of Bancoumana in Mali.

Results And Discussion: Similar seasonal patterns were observed with both methods (rainy season peak, dry season nadir), although molecular methods detected more infections than microscopy (571 vs 331 in 906 specimens), more new infections (311 vs 104 during 829 person-months) and spontaneous clearance events (317 vs 116) and found higher incidence (0.

View Article and Find Full Text PDF
Article Synopsis
  • - In a study on uncomplicated P. falciparum malaria, researchers analyzed gene expression in 10 subjects at three stages: acute illness, treatment, and recovery, using recovery samples as baselines.
  • - During acute illness, there was increased expression of immune response and inflammation-related genes, especially in individuals with high parasitemia and elevated body temperatures.
  • - Conversely, genes that regulate immune responses and inhibit apoptosis were initially downregulated but normalized as patients recovered, highlighting distinct gene expression patterns during various stages of malaria.
View Article and Find Full Text PDF

Understanding the epidemiological features and metrics of malaria in endemic populations is a key component to monitoring and quantifying the impact of current and past control efforts to inform future ones. The International Centers of Excellence for Malaria Research (ICEMR) has the opportunity to evaluate the impact of malaria control interventions across endemic regions that differ in the dominant Plasmodium species, mosquito vector species, resistance to antimalarial drugs and human genetic variants thought to confer protection from infection and clinical manifestations of plasmodia infection. ICEMR programs are conducting field studies at multiple sites with the aim of generating standardized surveillance data to improve the understanding of malaria transmission and to monitor and evaluate the impact of interventions to inform malaria control and elimination programs.

View Article and Find Full Text PDF

Molecular epidemiology leverages genetic information to study the risk factors that affect the frequency and distribution of malaria cases. This article describes molecular epidemiologic investigations currently being carried out by the International Centers of Excellence for Malaria Research (ICEMR) network in a variety of malaria-endemic settings. First, we discuss various novel approaches to understand malaria incidence and gametocytemia, focusing on Plasmodium falciparum and Plasmodium vivax.

View Article and Find Full Text PDF

A major public health question is whether urbanization will transform malaria from a rural to an urban disease. However, differences about definitions of urban settings, urban malaria, and whether malaria control should differ between rural and urban areas complicate both the analysis of available data and the development of intervention strategies. This report examines the approach of the International Centers of Excellence for Malaria Research (ICEMR) to urban malaria in Brazil, Colombia, India (Chennai and Goa), Malawi, Senegal, and Uganda.

View Article and Find Full Text PDF

Bone is an important material to study due to its exceptional mechanical properties and relevance with respect to hard tissue regeneration and repair. A significant effort has been directed toward understanding the bone formation process and the production of synthetic bone mimicking materials. Here, the formation and structural evolution of calcium phosphate (CaP) was investigated in the presence of relatively high concentrations of calcium, phosphate, and polyaspartic acid (pAsp) using dynamic light scattering (DLS) and cryo-transmission electron microscopy (cryo-TEM).

View Article and Find Full Text PDF