Publications by authors named "Stuart Blacksell"

The global priorities in the field of infectious diseases are constantly changing. While emerging viral infections have regularly dominated public health attention, which has only intensified after the COVID-19 pandemic, numerous bacterial diseases have previously caused, and continue to cause, significant morbidity and mortality-deserving equal attention. Three potentially life-threatening endemic bacterial diseases (leptospirosis, melioidosis, and rickettsioses) are a huge public health concern especially in low- and middle-income countries.

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This Health Policy reviews the preparedness and response of public health laboratories in the WHO South-East Asia Region (SEAR) during the COVID-19 pandemic. Through a scoping review and in-depth interviews with key stakeholders, the study identifies successes, challenges, and lessons learned from available literature and the perspective of senior laboratory leaders. Key themes include human resources, health information systems, diagnostic capacity, public risk communication, biosafety, biosecurity, funding, and laboratory network coordination.

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Background: Hydroxychloroquine (HCQ) has proved ineffective in treating patients hospitalised with Coronavirus Disease 2019 (COVID-19), but uncertainty remains over its safety and efficacy in chemoprevention. Previous chemoprevention randomised controlled trials (RCTs) did not individually show benefit of HCQ against COVID-19 and, although meta-analysis did suggest clinical benefit, guidelines recommend against its use.

Methods And Findings: Healthy adult participants from the healthcare setting, and later from the community, were enrolled in 26 centres in 11 countries to a double-blind, placebo-controlled, randomised trial of COVID-19 chemoprevention.

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Foot-and-mouth disease (FMD) is a highly infectious and endemic disease in Lao PDR. However, surveillance is weak, and outbreaks are not routinely reported. To address this, serum samples were routinely collected from cattle and buffalo from provincial abattoirs between November 2021 and December 2022.

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Scrub typhus, a vector-borne bacterial infection, is an important but neglected disease globally. Accurately characterizing the burden is challenging because of nonspecific symptoms and limited diagnostics. Prior seroepidemiology studies have struggled to find consensus cutoffs that permit comparisons of estimates across contexts and time.

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African Swine Fever (ASF) disease transmission parameters are crucial for making response and control decisions when faced with an outbreak, yet they are poorly quantified for smallholder and village contexts within Southeast Asia. Whilst disease-specific factors - such as latent and infectious periods - should remain reasonably consistent, host, environmental and management factors are likely to affect the rate of disease spread. These differences are investigated using Approximate Bayesian Computation with Sequential Monte-Carlo methods to provide disease parameter estimates in four naïve pig populations in villages of Lao People's Democratic Republic.

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Background: In Laos, colistin is not currently registered for use in humans. This One Health study aimed to estimate the prevalence of meat-producing pigs carrying colistin-resistant and investigate if causing invasive human infections were colistin-resistant.

Methods: Between September 2022 and March 2023, rectal swabs were collected from 895 pigs from abattoirs in 9/17 Lao provinces.

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Article Synopsis
  • Fever is a common symptom in patients in South and Southeast Asia, leading to the need for effective diagnostic methods, particularly for malaria, which often results in unnecessary antibiotic use for malaria-negative cases.
  • The study evaluates a multiplex rapid diagnostic test (DPP Fever Panel II Assay) designed to identify multiple tropical fever agents in one test, aiming to improve cost-effectiveness and diagnostic accuracy compared to conventional methods.
  • Testing involved 300 patients in Laos, comparing whole blood and serum samples using two different DPP readers; results showed no significant difference in diagnostic performance between the two sample types, with whole blood generally yielding better results.
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Anaplasma marginale infection is one of the most common tick-borne diseases, causing a substantial loss in the beef and dairy production industries. Once infected, the pathogen remains in the cattle for life, allowing the parasites to spread to healthy animals. Since clinical manifestations of anaplasmosis occur late in the disease, a sensitive, accurate, and affordable pathogen identification is crucial in preventing and controlling the infection.

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Article Synopsis
  • - The South and Southeast Asia Community-based Trials Network (SEACTN) is conducting a survey to better understand the prevalence of various diseases among rural populations in low to middle-income countries in Southeast Asia, as part of its Rural Febrile Illness project (RFI).
  • - A cross-sectional household survey will be carried out in Bangladesh, Cambodia, and Thailand, using a two-stage cluster-sampling method to enroll about 1,500 participants per country, who will undergo interviews, physical examinations, and laboratory testing.
  • - The study, which has received ethical approval, aims to present disease prevalence data and analyze associations with sociodemographic factors, ultimately contributing to improved healthcare resource allocation in the region.
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Introduction: Emerging infectious diseases pose a threat to public health and the economy, especially in developing countries. Southeast Asian veterinary laboratories handle numerous high-risk pathogens, making pathogen accountability crucial for safe handling and storage.

Methods: Thirteen veterinary laboratories in Cambodia ( = 1), Lao People's Democratic Republic ( = 1), and Thailand ( = 11) participated in a study conducted between 2019 and 2020.

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Introduction: Rickettsia spp. and Orientia spp. are the causes of neglected infections that can lead to severe febrile and systemic illnesses in humans.

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Aims: We investigated the antibacterial efficacy of Umonium and Virkon against Burkholderia pseudomallei, Escherichia coli, Pseudomonas aeruginosa and Methicillin-Resistant Staphylococcus aureus (MRSA) up to 14 days following treatment.

Methods And Results: Umonium was diluted to 0.5%, 1.

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Background: Scrub typhus is an understudied vector-borne bacterial infection.

Methods: We tested archived fever samples for scrub typhus seropositivity to begin charting its geographic distribution in Indonesia. We analysed 1033 serum samples from three sites.

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Laboratory-acquired infections (LAIs) and accidental pathogen escape from laboratory settings (APELS) are major concerns for the community. A risk-based approach for pathogen research management within a standard biosafety management framework is recommended but is challenging due to reasons such as inconsistency in risk tolerance and perception. Here, we performed a scoping review using publicly available, peer-reviewed journal and media reports of LAIs and instances of APELS between 2000 and 2021.

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Introduction: Crimean Congo Hemorrhagic Fever (CCHF) virus and Lassa virus (LASV) are zoonotic agents regarded as high-consequence pathogens due to their high case fatality rates. CCHF virus is a vector-borne disease and is transmitted by tick bites. Lassa virus is spread via aerosolization of dried rat urine, ingesting infected rats, and direct contact with or consuming food and water contaminated with rat excreta.

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Introduction: Foot and mouth disease (FMD) is a highly contagious infection of cloven-hoofed animals. The Biosafety Research Road Map reviewed scientific literature regarding the foot and mouth disease virus (FMDV). This project aims to identify gaps in the data required to conduct evidence-based biorisk assessments, as described by Blacksell et al.

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Background: Scrub typhus is a significant tropical disease, occurring in rural settings and therefore usually afflicting remote agricultural populations who have lower socioeconomic status and limited access to medical care. A large proportion of the hill tribe people in Thailand are financially poor, have limited education, and do not have adequate health care access. This study aimed to estimate the prevalence of and determine factors associated with scrub typhus exposure among the hill tribe population living in high-incidence areas in northern Thailand.

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Diagnosing scrub typhus in travellers is challenging due to symptom similarities with other travel-related illnesses and limited early diagnostic tools. We present a distinctive case of scrub typhus in a child traveller, providing a comprehensive account of the case, the diagnostic challenges encountered, laboratory findings and the dynamics of antibodies.

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Article Synopsis
  • The 2019 African swine fever outbreak in Laos severely impacted the country's naïve pig population, highlighting the challenges for policymakers due to diverse pig management styles.
  • A study focused on Oudomxay province revealed significant pig losses, averaging 3.0-23.3 pigs per household with a mean financial loss of USD 349, which was higher than losses reported in Savannakhet.
  • The investigation identified various ASF risk factors such as swill-feeding, poor biosecurity practices, and inconsistent management, indicating a critical need for enhanced disease control resources at all levels in the affected villages.
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Wild animal trade for human consumption is a global issue, involving complex interactions between economics, culture, food security and conservation. Whilst being a biodiversity issue, it is also a major public health concern, with recent epidemics and pandemics of zoonotic pathogens linked to interactions with wildlife. At three time points, between March 2017 and June 2018, a longitudinal sero-survey of 150 market vendors from three wet markets in Laos (selling vegetables, domestic animal meat and/or wildlife meat) was conducted to determine if vendors had been differentially exposed to three endemic bacterial pathogens - , and spp.

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Background: Scrub typhus is a potentially fatal acute febrile illness caused by bacteria in the genus Orientia. Though cases have been documented, a comprehensive body of evidence has not previously been compiled to give an overview of scrub typhus in Indonesia. This study aimed to address this key knowledge gap by mapping and ranking geographic areas based on existing data on the presence or absence of the pathogen in humans, vectors, and host animals.

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