Using whole-cell phenotypic assays, the GlaxoSmithKline high-throughput screening (HTS) diversity set of 1.8 million compounds was screened against the three kinetoplastids most relevant to human disease, i.e. Leishmania donovani, Trypanosoma cruzi and Trypanosoma brucei. Secondary confirmatory and orthogonal intracellular anti-parasiticidal assays were conducted and the potential for non-specific cytotoxicity determined. Hit compounds were chemically clustered and triaged for desirable physicochemical properties. The hypothetical biological target space covered by these diversity sets was investigated through bioinformatics methodologies. Consequently, three anti-kinetoplastid chemical boxes of ~200 compounds each were assembled. Functional analyses of these compounds suggest a wide array of potential modes of action against kinetoplastid kinases, proteases and cytochromes as well as potential host–pathogen targets. This is the first published parallel high throughput screening of a pharma compound collection against kinetoplastids. The compound sets are provided as an open resource for future lead discovery programs and to address important research questions.
13 February 2019 in Expert Review of Anti-infective Therapy
Chagas disease, caused by infection with the parasite Trypanosoma cruzi, represents a huge public health problem in the Americas, where millions of people are affected. Despite the availability of two drugs against the infection (benznidazole and nifurtimox), multiple factors impede their effective usage: (1) gaps in patient and healthcare provider awareness; (2) lack of access to diagnosis; (3) drug toxicity and absence of treatment algorithms to address adverse effects; (4) failures in drug supply and distribution; and (5) inconsistent drug efficacy against the symptomatic chronic stage. Areas covered: We review new approaches and technologies to enhance access to diagnosis and treatment to reduce the disease burden. We also provide an updated picture of recently published and ongoing anti-T. cruzi drug clinical trials. Although there has been progress improving the research and development (R&D) landscape, it is unclear whether any new treatments will emerge soon. Literature search methodologies included multiple queries to public databases and the use of own-built libraries. Expert opinion: Besides R&D, there is a major need to continue awareness and advocacy efforts by patient associations, local and national governments, and international agencies. Overall, health systems strengthening is essential to ensure vector control commitments, as well as patient access to diagnosis and treatment.
Recombinant vectors based on human adenovirus serotype 5 (HAdV-5) have been extensively studied in preclinical models and clinical trials over the past two decades. However, the thorough understanding of the HAdV-5 interaction with human subjects has uncovered major concerns about its product applicability. High vector-associated toxicity and widespread preexisting immunity have been shown to significantly impede the effectiveness of HAdV-5–mediated gene transfer. It is therefore that the in-depth knowledge attained working on HAdV-5 is currently being used to develop alternative vectors. Here, we provide a comprehensive overview of data obtained in recent years disqualifying the HAdV-5 vector for systemic gene delivery as well as novel strategies being pursued to overcome the limitations observed with particular emphasis on the ongoing vectorization efforts to obtain vectors based on alternative serotypes.
20 June 2024 in The Lancet Regional Health - Americas
Chagas disease, caused by Trypanosoma cruzi, affects millions worldwide. The 2030 WHO roadmap aims to eliminate it as a public health concern, emphasising the need for timely diagnosis to enhance treatment access. Current diagnostic algorithms, which rely on multiple tests, have prolonged turnaround times. This proves particularly problematic in resource-limited settings. Addressing this issue necessitates the validation and adoption of innovative tools. We explore recent developments in Chagas disease diagnosis, reviewing historical context and advancements. Despite progress, challenges persist. This article contributes to the understanding of current and future directions in this neglected healthcare area. Parasitological methods are simple but exhibit low sensitivity and require supplementary tests. Molecular methods, with automation potential, allow quantification and higher throughput. Serological tools show good performance but struggle with parasite antigenic diversity. Prioritising point-of-care tests is crucial for widespread accessibility and could offer a strategy to control disease impact. Ultimately, balancing achievements and ongoing obstacles is essential for comprehensive progress.
Chagas disease is caused by the parasite Trypanosoma cruzi. It affects several million people, mainly in Latin America, and severe cardiac and/or digestive complications occur in ~30% of the chronically infected patients. Disease acute stage is mostly asymptomatic and infection goes undiagnosed. In the chronic phase direct parasite detection is hampered due to its concealed presence and diagnosis is achieved by serological methods, like ELISA or indirect hemagglutination assays. Agreement in at least two tests must be obtained due to parasite wide antigenic variability. These techniques require equipped labs and trained personnel and are not available in distant regions. As a result, many infected people often remain undiagnosed until it is too late, as the two available chemotherapies show diminished efficacy in the advanced chronic stage. Easy-to-use rapid diagnostic tests have been developed to be implemented in remote areas as an alternative to conventional tests. They do not need electricity, nor cold chain, they can return results within an hour and some even work with whole blood as sample, like Chagas Stat-Pak (ChemBio Inc.) and Chagas Detect Plus (InBIOS Inc.). Nonetheless, in order to qualify a rapidly diagnosed positive patient for treatment, conventional serological confirmation is obligatory, which might risk its start. In this study two rapid tests based on distinct antigen sets were used in parallel as a way to obtain a fast and conclusive Chagas disease diagnosis using whole blood samples. Chagas Stat-Pak and Chagas Detect Plus were validated by comparison with three conventional tests yielding 100% sensitivity and 99.3% specificity over 342 patients seeking Chagas disease diagnosis in a reference centre in Sucre (Bolivia). Combined used of RDTs in distant regions could substitute laborious conventional serology, allowing immediate treatment and favouring better adhesion to it. Chagas disease is a neglected tropical disease caused by the parasite Trypanosoma cruzi. It affects 6–7 million people, mainly in Latin America. An initial asymptomatic phase make the infection go undiagnosed and untreated, silently progressing into its chronic stage. About 30% of the chronically infected patients end up developing life-threatening disruption of the heart and/or gut tissues. Two drugs are available but their efficacy diminishes the longer a person has been infected. Therefore, it is of paramount importance to achieve an early diagnosis to start treatment before symptoms advance. In the chronic stage parasite presence is intermittent and diagnosis is made by serological assays that detect parasite-specific immunoglobulins. Problem is that conventional serological techniques are laborious and require equipment and trained personnel unavailable in remote regions with high disease prevalence. To circumvent those inconveniences easy-to-use rapid diagnostic tests were developed. They return results within an hour and some work with whole blood as sample allowing diagnosis out of digital puncture. We propose that conventional assays could be substituted by whole blood-friendly rapid tests in order to achieve a conclusive Chagas disease diagnosis in remote regions. This would ease access to treatment increasing adherence rates to it.
1 September 2011 in Vector-Borne and Zoonotic Diseases
West Nile virus (WNV), the most widely distributed flavivirus worldwide, has lately reemerged in Europe, causing worrisome outbreaks in humans and horses. Serological analysis by enzyme-linked immunoassay and plaque reduction neutralization test showed for the first time in Serbia that 12% of 349 horses presented specific neutralizing WNV antibodies, which in one case also cross-neutralized Usutu virus (USUV). This is the first time that anti-USUV high neutralizing antibody titers are reported in horses. All these data indicate that WNV and USUV are circulating in the region and advise on the convenience of implementing surveillance programs.