Publications by authors named "ASHTON P"

Article Synopsis
  • Researchers have identified the first two enterotoxigenic E. coli (ETEC) genomes from Malawi, isolated in 2014.
  • These genomes were taken from the feces of children who were infected but did not show symptoms.
  • The genomes contain a version of the heat-labile toxin found in pigs, but lack any recognized ETEC colonization factors.
View Article and Find Full Text PDF

Background: A predominantly endoscopic approach for acute admissions with choledocholithiasis with a gallbladder in situ (CGIS) resulted in prolonged hospital length of stay due to delays at investigation and treatment junctures. We initiated a quality improvement program of trans-cystic biliary stenting to facilitate efficient patient progress to acute cholecystectomy and outpatient ERCP if required.

Methods: We utilized implementation frameworks with regular re-assessment for this quality improvement project.

View Article and Find Full Text PDF

Indonesia has the third highest number of tuberculosis (TB) patients infected with Mycobacterium tuberculosis (MTB) Lineage 1 (L1). Most of these MTB L1 cases can be found in Indonesia's remote easternmost province of Papua, one of Indonesia's most underdeveloped provinces with a particularly high burden for TB. In this study, we sequenced and described 42 MTB L1 isolates from a well-characterized cohort of patients.

View Article and Find Full Text PDF
Article Synopsis
  • Enteric fever, caused by Salmonella enterica serovars Typhi and Paratyphi A, poses a significant public health issue due to rising antimicrobial resistance, complicating treatment options and worsening health outcomes.
  • *The study sequenced bacteria samples from blood cultures of febrile patients in urban sites of Dhaka (Bangladesh), Kathmandu (Nepal), and Blantyre (Malawi) to analyze their genetic characteristics and resistance mechanisms.
  • *Findings revealed that different genotypes of S. Typhi were present across the sites, with high rates of multidrug resistance in Blantyre and Dhaka but not in Kathmandu, highlighting diverse transmission dynamics and resistance patterns.
View Article and Find Full Text PDF

Invasive non-typhoidal (iNTS) disease is a serious bloodstream infection that targets immune-compromised individuals, and causes significant mortality in sub-Saharan Africa. serovar Typhimurium ST313 causes the majority of iNTS in Malawi. We performed an intensive comparative genomic analysis of 608 .

View Article and Find Full Text PDF

Background: Ciprofloxacin is the first-line drug for treating typhoid fever in many countries in Africa with a high disease burden, but the emergence of non-susceptibility poses a challenge to public health programmes. Through enhanced surveillance as part of vaccine evaluation, we investigated the occurrence and potential determinants of ciprofloxacin non-susceptibility in Blantyre, Malawi.

Methods: We conducted systematic surveillance of typhoid fever cases and antibiotic prescription in two health centres in Blantyre, Malawi, between Oct 1, 2016, and Oct 31, 2019, as part of the STRATAA and TyVAC studies.

View Article and Find Full Text PDF

We present the requirements, design, and evaluation of the cryogenic continuously rotating half-wave plate (CHWP) for the Simons Observatory (SO). SO is a cosmic microwave background polarization experiment at Parque Astronómico de Atacama in northern Chile that covers a wide range of angular scales using both small (⌀0.42 m) and large (⌀6 m) aperture telescopes.

View Article and Find Full Text PDF

Trees structure the Earth's most biodiverse ecosystem, tropical forests. The vast number of tree species presents a formidable challenge to understanding these forests, including their response to environmental change, as very little is known about most tropical tree species. A focus on the common species may circumvent this challenge.

View Article and Find Full Text PDF

The COVID-19 pandemic has profoundly impacted health systems globally and robust surveillance has been critical for pandemic control, however not all countries can currently sustain community pathogen surveillance programs. Wastewater surveillance has proven valuable in high-income settings, but less is known about the utility of water surveillance of pathogens in low-income countries. Here we show how wastewater surveillance of SAR-CoV-2 can be used to identify temporal changes and help determine circulating variants quickly.

View Article and Find Full Text PDF

Background: The Global Typhoid Genomics Consortium was established to bring together the typhoid research community to aggregate and analyse serovar Typhi (Typhi) genomic data to inform public health action. This analysis, which marks 22 years since the publication of the first Typhi genome, represents the largest Typhi genome sequence collection to date (n=13,000).

Methods: This is a meta-analysis of global genotype and antimicrobial resistance (AMR) determinants extracted from previously sequenced genome data and analysed using consistent methods implemented in open analysis platforms GenoTyphi and Pathogenwatch.

View Article and Find Full Text PDF

Talaromycosis, a severe and invasive fungal infection caused by Talaromyces marneffei, is difficult to treat and impacts those living in endemic regions of Southeast Asia, India, and China. While 30% of infections result in mortality, our understanding of the genetic basis of pathogenesis for this fungus is limited. To address this, we apply population genomics and genome-wide association study approaches to a cohort of 336 T.

View Article and Find Full Text PDF

The COVID-19 pandemic continues to impact health systems globally and robust surveillance is critical for pandemic control, however not all countries can sustain community surveillance programs. Wastewater surveillance has proven valuable in high-income settings, but little is known about how river and informal sewage in low-income countries can be used for environmental surveillance of SARS-CoV-2. In Malawi, a country with limited community-based COVID-19 testing capacity, we explored the utility of rivers and wastewater for SARS-CoV-2 surveillance.

View Article and Find Full Text PDF
Article Synopsis
  • * Researchers analyzed 336 fungal isolates from a clinical trial in Vietnam, discovering distinct genetic clades linked to disease severity and instances of relapse due to multi-strain infections.
  • * The study highlights specific genetic variants associated with patient outcomes, showing how pathogen genetics affects disease progression and identifying rapid evolutionary responses to external pressures.
View Article and Find Full Text PDF

Offering patients with tuberculosis (TB) an optimal and timely treatment regimen depends on the rapid detection of Mycobacterium tuberculosis (Mtb) drug resistance from clinical samples. Finding Low Abundance Sequences by Hybridization (FLASH) is a technique that harnesses the efficiency, specificity, and flexibility of the Cas9 enzyme to enrich targeted sequences. Here, we used FLASH to amplify 52 candidate genes probably associated with resistance to first- and second-line drugs in the Mtb reference strain (H37Rv), then detect drug resistance mutations in cultured Mtb isolates, and in sputum samples.

View Article and Find Full Text PDF

The SARS-CoV-2 Omicron variant has resulted in a high number of cases, but a relatively low incidence of severe disease and deaths, compared to the pre-Omicron variants. Therefore, we assessed the differences in symptom prevalence between Omicron and pre-Omicron infections in a sub-Saharan African population. We collected data from outpatients presenting at two primary healthcare facilities in Blantyre, Malawi, from November 2020 to March 2022.

View Article and Find Full Text PDF

Invasive nontyphoidal (iNTS) disease is a clinical condition distinct from gastroenteritis. With an overall case-fatality rate of 14.5%, iNTS remains a major cause of morbidity and mortality, particularly in sub-Saharan Africa.

View Article and Find Full Text PDF

Background: Compared to the abundance of clinical and genomic information available on patients hospitalised with COVID-19 disease from high-income countries, there is a paucity of data from low-income countries. Our aim was to explore the relationship between viral lineage and patient outcome.

Methods: We enrolled a prospective observational cohort of adult patients hospitalised with PCR-confirmed COVID-19 disease between July 2020 and March 2022 from Blantyre, Malawi, covering four waves of SARS-CoV-2 infections.

View Article and Find Full Text PDF

Molecular and genomic studies have revealed that Lineage 4 (L4, Euro-American lineage) emerged in Europe before becoming distributed around the globe by trade routes, colonial migration and other historical connections. Although L4 accounts for tens or hundreds of thousands of tuberculosis (TB) cases in multiple Southeast Asian countries, phylogeographical studies have either focused on a single country or just included Southeast Asia as part of a global analysis. Therefore, we interrogated public genomic data to investigate the historical patterns underlying the distribution of L4 in Southeast Asia and surrounding countries.

View Article and Find Full Text PDF
Article Synopsis
  • Invasive Salmonella infections are a major health issue in Sub-Saharan Africa, but the specifics of how the disease spreads are not fully understood.
  • A study conducted in Blantyre, Malawi involved recruiting 60 patients with invasive Salmonella infections and comparing them with matched control households to sample bacteria from various sources.
  • Results showed that while some Salmonella strains from patients matched those found in household members, there was no connection to strains found in animals or the environment, suggesting that iNTS infections may spread directly between humans.
View Article and Find Full Text PDF
Article Synopsis
  • The study investigates COVID-19 patient outcomes and viral lineages in Malawi, highlighting a lack of data from low-income countries.
  • Conducted from July 2020 to March 2022, researchers analyzed 314 hospitalized patients, discovering distinct variants during each wave—B.1, Beta, Delta, and Omicron.
  • Results indicated that patients during the Delta wave had higher mortality rates compared to earlier waves, while those infected with Omicron showed fewer chronic conditions and required less intensive treatment.
View Article and Find Full Text PDF

The evolution and diversification of ancient megathermal angiosperm lineages with Africa-India origins in Asian tropical forests is poorly understood because of the lack of reliable fossils. Our palaeobiogeographical analysis of pollen fossils from Africa and India combined with molecular data and fossil amber records suggest a tropical-African origin of Dipterocarpaceae during the mid-Cretaceous and its dispersal to India during the Late Maastrichtian and Paleocene, leading to range expansion of aseasonal dipterocarps on the Indian Plate. The India-Asia collision further facilitated the dispersal of dipterocarps from India to similar climatic zones in Southeast Asia, which supports their out-of-India migration.

View Article and Find Full Text PDF

In the southern mountain ranges of Yunnan province, China, deep valleys of several large rivers create rain shadows with hot dry summers, and are locally designated tropical; towards the north, notably in the Lancang (Upper Mekong) valley, these regions may experience frost during winter. The woody forest canopy of these valleys is predominantly deciduous, with evergreen elements in the north, where the canopy is open and the forest savanna-like. However, we here present tall forest with a closed deciduous canopy and semi-evergreen subcanopy observed in hot dry valleys of these rivers and their tributaries in the tropical south.

View Article and Find Full Text PDF