Publications by authors named "Daniel Bridges"

The emergence of antimalarial drug resistance is a major threat to malaria control and elimination. Using whole genome sequencing of 282 samples collected during the 2018 Zambia National Malaria Indicator Survey, we determined the prevalence and spatial distribution of known and candidate antimalarial drug resistance mutations. High levels of genotypic resistance were found across Zambia to pyrimethamine, with over 94% (n=266) of samples having the triple mutant (N51, C59, and S108), and sulfadoxine, with over 84% (n=238) having the double mutant (A437 and K540).

View Article and Find Full Text PDF

Background: A highly effective vaccine for malaria remains an elusive target, at least in part due to the under-appreciated natural parasite variation. This study aimed to investigate genetic and structural variation, and immune selection of leading malaria vaccine candidates across the Plasmodium falciparum's life cycle.

Methods: We analysed 325 P.

View Article and Find Full Text PDF

Background: A highly effective vaccine for malaria remains an elusive target, at least in part due to the under-appreciated natural parasite variation. This study aimed to investigate genetic and structural variation, and immune selection of leading malaria vaccine candidates across the 's life cycle.

Methods: We analyzed 325 whole genome sequences from Zambia, in addition to 791 genomes from five other African countries available in the MalariaGEN Pf3k Rdatabase.

View Article and Find Full Text PDF

Background: Genomic surveillance is crucial for monitoring malaria transmission and understanding parasite adaptation to interventions. Zambia lacks prior nationwide efforts in malaria genomic surveillance among African countries.

Methods: We conducted genomic surveillance of Plasmodium falciparum parasites from the 2018 Malaria Indicator Survey in Zambia, a nationally representative household survey of children under five years of age.

View Article and Find Full Text PDF

Genomic surveillance plays a critical role in monitoring malaria transmission and understanding how the parasite adapts in response to interventions. We conducted genomic surveillance of malaria by sequencing 241 genomes from regions with varying levels of malaria transmission across Zambia. We found genomic evidence of high levels of within-host polygenomic infections, regardless of epidemiological characteristics, underscoring the extensive and ongoing endemic malaria transmission in the country.

View Article and Find Full Text PDF

Genomic surveillance of Plasmodium falciparum malaria can provide policy-relevant information about antimalarial drug resistance, diagnostic test failure, and the evolution of vaccine targets. Yet the large and low complexity genome of P. falciparum complicates the development of genomic methods, while resource constraints in malaria endemic regions can limit their deployment.

View Article and Find Full Text PDF

Nanopore-based sequencing platforms offer the potential for affordable malaria molecular surveillance (MMS) in resource-limited settings to track and ultimately counteract emerging threats, such as drug resistance and diagnostic escape. Here, we discuss opportunities and challenges to implementing MMS using nanopore sequencing, highlighting priority areas for technical development and innovation.

View Article and Find Full Text PDF

Efforts to eliminate malaria transmission need evidence-based strategies. However, accurately assessing end-game malaria elimination strategies is challenging due to the low level of transmission and the rarity of infections. We hypothesised that presumptively treating individuals during reactive case detection (RCD) would reduce transmission and that serology would more sensitively detect this change over standard approaches.

View Article and Find Full Text PDF

Objectives: To determine the prevalence of COVID-19 postmortem setting in Lusaka, Zambia.

Design: A systematic, postmortem prevalence study.

Setting: A busy, inner-city morgue in Lusaka.

View Article and Find Full Text PDF
Article Synopsis
  • A lot of money has been spent on studying the COVID-19 virus in Africa, leading to over 100,000 virus samples being analyzed to understand the spread of the disease.
  • *More countries in Africa are now able to do these studies themselves, which helps them get results faster and keep a close watch on the virus.
  • *To keep fighting COVID and other diseases, more funding and support for testing and research in Africa is really important for the future.
View Article and Find Full Text PDF

Background: A new more highly sensitive rapid diagnostic test (HS-RDT) for Plasmodium falciparum malaria (Alere™/Abbott Malaria Ag P.f RDT [05FK140], now called NxTek™ Eliminate Malaria Ag Pf) was launched in 2017. The test has already been used in many research studies in a wide range of geographies and use cases.

View Article and Find Full Text PDF
Article Synopsis
  • The SARS-CoV-2 pandemic in Africa has varied significantly across countries, and its overall impact remains unclear.
  • An analysis of 8,746 genomes from 33 African countries indicated that most outbreaks originated from Europe before international travel restrictions took effect.
  • As the pandemic continued, increased movement and local transmission led to the emergence of several variants within Africa, emphasizing the need for a strong pandemic response on the continent to prevent becoming a source of new variants.
View Article and Find Full Text PDF

Background: Zambia continues to advance on the path to elimination with significant reductions in malaria morbidity and mortality. Crucial components that have contributed to progress thus far and are necessary for achieving the national malaria elimination goals include properly identifying and treating all malaria cases through accurate diagnosis. This study sought to compare and assess the diagnostic performance of Rapid Diagnostic Tests (RDT) and Light Microscopy (LM) with photo-induced electron transfer polymerase chain reaction (PET-PCR) as the gold standard using 2018 Malaria Indicator Survey (MIS) data across Zambia to better understand diagnostic accuracy metrics and how these vary across a transmission gradient.

View Article and Find Full Text PDF
Article Synopsis
  • COVID-19 cases in Zambia began in March 2020, with a significant rise starting in mid-December, particularly after the identification of the B.1.351 variant strain from South Africa.
  • The B.1.351 variant, linked to increased transmissibility, spread quickly from South Africa to other countries, including Zambia, causing a dramatic surge in cases.
  • By January 10, 2021, Zambia experienced a 16-fold increase in daily COVID-19 cases, from 44 to 700, coinciding with the presence of the B.1.351 variant in the region.
View Article and Find Full Text PDF

This article describes data on selected resistance markers for antimalarial drugs used in Zambia. Antimalarial drug resistance has hindered the progress in the control and elimination of malaria. Blood samples were collected during a cross-sectional household survey, conducted during the peak malaria transmission, April to May of 2017.

View Article and Find Full Text PDF

Purpose: For stereotactic radiosurgery (SRS), accurate evaluation of dose-volume metrics for small structures is necessary. The purpose of this study was to compare the DVH metric capabilities of five commercially available SRS DVH analysis tools (Eclipse, Elements, Raystation, MIM, and Velocity).

Methods: DICOM RTdose and RTstructure set files created using MATLAB were imported and evaluated in each of the tools.

View Article and Find Full Text PDF

Antimalarial resistance is an inevitable feature of control efforts and a key threat to achieving malaria elimination. Plasmodium falciparum, the deadliest of several species causing human malaria, has developed resistance to essentially all antimalarials. This study sought to investigate the prevalence of molecular markers associated with resistance to sulfadoxine-pyrimethamine (SP) and artemether-lumefantrine (AL) in Southern and Western provinces in Zambia.

View Article and Find Full Text PDF

A mass drug administration trial was carried out in Southern Province, Zambia, between 2014 and 2016, in conjunction with a standard of care package that included improved surveillance, increased access to malaria case management, and sustained high levels of vector control coverage. This was preceded by mass test and treatment in the same area from 2011 to 2013. Concordant decreases in malaria prevalence in Southern Province and deaths attributed to malaria in Zambia over this time suggest that these strategies successfully reduced the malaria burden.

View Article and Find Full Text PDF

Malaria burden in Zambia has significantly declined over the last decade because of improved coverage of several key malaria interventions (e.g., vector control, case management, bed net distributions, and enhanced surveillance/responses).

View Article and Find Full Text PDF

Rigorous evidence of effectiveness is needed to determine where and when to apply mass drug administration (MDA) or focal MDA (fMDA) as part of a malaria elimination strategy. The Zambia National Malaria Elimination Centre recently completed a community-randomized controlled trial in Southern Province to evaluate MDA and fMDA for transmission reduction. To assess the role of MDA and fMDA on infection incidence, we enrolled a longitudinal cohort for an 18-month period of data collection including monthly malaria parasite infection detection based on polymerase chain reaction and compared time to first infection and cumulative infection incidence outcomes across study arms using Cox proportional hazards and negative binomial models.

View Article and Find Full Text PDF
Article Synopsis
  • Passively collected malaria data is crucial for public health decisions, especially in low-transmission areas where symptoms may not prompt individuals to seek help for infections.
  • This study estimated the detection rate of malaria infections, P(Detect), using data from surveys and health facilities, finding that only about 12.5% of Plasmodium falciparum and 10.1% of Plasmodium vivax infections were detected on average.
  • Factors such as smaller populations, high transmission seasons, and better health-seeking behavior were linked to higher detection rates, indicating that as transmission intensity decreases, the health system's ability to detect infections improves.
View Article and Find Full Text PDF

Background: Zambia has set itself the ambitious target of eliminating malaria by 2021. To continue tracking transmission to zero, new interventions, tools and approaches are required.

Methods: Urban reactive case detection (RCD) was performed in Lusaka city from 2011 to 2015 to better understand the location and drivers of malaria transmission.

View Article and Find Full Text PDF

Background: Anti-malarial resistance is, and continues to be a significant challenge in the fight against malaria and a threat to achieving malaria elimination. In Zambia, chloroquine (CQ), a safe, affordable and well-tolerated drug, was removed from use in 2003 due to high levels of resistance evidenced with treatment failure. This study sought to investigate the prevalence of chloroquine resistance markers in Southern and Western Provinces of Zambia 14 years after the withdrawal of CQ.

View Article and Find Full Text PDF

Purpose: Our purposes are to compare the accuracy of RaySearch's analytical pencil beam (APB) and Monte Carlo (MC) algorithms for clinical proton therapy and to present clinical validation data using a novel animal tissue lung phantom.

Methods: We constructed a realistic lung phantom composed of a rack of lamb resting on a stack of rectangular natural cork slabs simulating lung tissue. The tumor was simulated using 70% lean ground lamb meat inserted in a spherical hole with diameter 40 ± 5 mm carved into the cork slabs.

View Article and Find Full Text PDF