Search Results (19)

Neglected tropical diseases (NTDs) constitute a group of infectious diseases that severely affect the health of impoverished populations, and the health, economies, and health systems of affected countries. Leishmaniasis and human African trypanosomiasis (HAT) are particularly notable, and malaria, despite not being neglected, is part of the “big three” (HIV, tuberculosis, and malaria) with high incidence, increasing the probability of infection by NTDs. Therefore, efforts are ongoing in the search for new drugs targeting the enzyme N-myristoyltransferase (NMT), a potential drug target that has been explored. Thus, we provide a review here that highlights the epidemiological data for these diseases and the importance of discovering new drugs against these agents. Here, the importance of NMT and its inhibitors is clear, with this study highlighting thiochromene, pyrazole, thienopyridine, oxadiazole, benzothiophene, and quinoline scaffolds, identified by computational methods followed by biological assays to validate the findings; for example, this study shows the action of the aminoacylpyrrolidine derivative 13 against Leishmania donovani NMT (IC₅₀ of 1.6 nM) and the pyrazole analog 23 against Plasmodium vivax NMT (IC₅₀ of 9.48 nM), providing several insights that can be used in drug design in further work. Furthermore, the selectivity and improvement in activity are related to interactions with the residues Val⁸¹, Phe⁹⁰, Tyr²¹⁷, Tyr³²⁶, Tyr³⁴⁵, and Met⁴²⁰ for leishmaniasis (LmNMT); Tyr²¹¹, Leu⁴¹⁰, and Ser³¹⁹ for malaria (PvNMT); and Lys²⁵ and Lys³⁸⁹ for HAT (TbNMT). We hope our work provides valuable insights that research groups worldwide can use to search for innovative drugs to combat these diseases. Full article

Bacterial natural ecological niches are characterized by variations in the availability of nutrients, resulting in a complex metabolism. Their impressive ability to adapt to changeable nutrient conditions is possible through the utilization of large amounts of substrates. Recent discoveries in bacterial metabolism have suggested the importance of polyamine metabolism in bacteria, particularly in those of the order Actinomycetales, in enabling them to survive in their natural habitats. This makes such enzymes promising targets to inhibit their growth. Since the polyamine metabolisms of soil bacteria of the genus Streptomyces and the human pathogenic Mycobacteria are surprisingly similar, target-based drug development in Streptomyces and Mycobacterium spp. is an alternative approach to the classical search for antibiotics. The recent development of drugs to treat epidemic diseases like tuberculosis (TB) has gained attention due to the occurrence of multidrug-resistant strains. In addition, drug repurposing plays a crucial role in the treatment of various complex diseases, such as malaria. With that notion, the treatment of TB could also benefit from this approach. For example, molecular chaperones, proteins that help other proteins to fold properly, are found in almost all living organisms, including the causative agents of TB. Therefore, targeting these molecules could help in the treatment of TB. We aim to summarize our knowledge of the nitrogen and carbon metabolism of the two closely related actinobacterial genera, Streptomyces and Mycobacterium, and of the identification of new potential drug targets. Full article

Background: Drug-resistant tuberculosis (DR-TB) remains a major public health challenge in China, with varying treatment outcomes across different regions. Understanding the spatial distribution of DR-TB treatment outcomes is crucial for targeted interventions to improve treatment success in high-burden areas such as Hunan Province. This study aimed to map the spatial distribution of DR-TB treatment outcomes at a local level and identify sociodemographic and environmental factors associated with poor treatment outcomes in Hunan Province, China. Methods: A spatial analysis was conducted using DR-TB data from the Tuberculosis Control Institute of Hunan Province, covering the years 2013 to 2018. The outcome variable, the proportion of poor treatment outcomes, was defined as a composite measure of treatment failure, death, and loss to follow-up. Sociodemographic, economic, healthcare, and environmental variables were obtained from various sources, including the WorldClim database, the Malaria Atlas Project, and the Hunan Bureau of Statistics. These covariates were linked to a map of Hunan Province and DR-TB notification data using R software version 4.4.0. The spatial clustering of poor treatment outcomes was analyzed using the local Moran’s I and Getis–Ord statistics. A Bayesian logistic regression model was fitted, with the posterior parameters estimated using integrated nested Laplace approximation (INLA). Results: In total, 1381 DR-TB patients were included in the analysis. An overall upward trend in poor DR-TB treatment outcomes was observed, peaking at 14.75% in 2018. Deaths and treatment failures fluctuated over the years, with a notable increase in deaths from 2016 to 2018, while the proportion of patients lost to follow-up significantly declined from 2014 to 2018. The overall proportion of poor treatment outcomes was 9.99% (95% credible interval (CI): 8.46% to 11.70%), with substantial spatial clustering, particularly in Anxiang (50%), Anren (50%), and Chaling (42.86%) counties. The proportion of city-level indicators was significantly associated with higher proportions of poor treatment outcomes (odds ratio (OR): 1.011; 95% CRI: 1.20 December 2024 001–1.035). Conclusions: This study found a concerning increase in poor DR-TB treatment outcomes in Hunan Province, particularly in certain high-risk areas. Targeted public health interventions, including enhanced surveillance, focused healthcare initiatives, and treatment programs, are essential to improve treatment success. Full article

Background/Objectives: We developed a multistage Plasmodium falciparum vaccine using a heterologous prime-boost immunization strategy. This involved priming with a highly attenuated, replication-competent vaccinia virus strain LC16m8Δ (m8Δ) and boosting with adeno-associated virus type 1 (AAV1). This approach demonstrated 100% efficacy in both protection and transmission-blocking in a murine model. In this study, we compared our LC16m8∆/AAV1 vaccine, which harbors a gene encoding Pfs25-PfCSP fusion protein, to RTS,S/AS01 (RTS,S) in terms of immune responses, protective efficacy, and transmission-blocking activity (TBA) in murine models. Methods: Mice were immunized following prime-boost vaccine regimens m8∆/AAV1 or RTS,S and challenged with transgenic Plasmodium berghei parasites. Immune responses were assessed via ELISA, and TB efficacy was evaluated using direct feeding assays. Results: m8∆/AAV1 provided complete protection (100%) in BALB/c mice and moderate (40%) protection in C57BL/6 mice, similar to RTS,S. Unlike RTS,S’s narrow focus (repeat region), m8∆/AAV1 triggered antibodies for all PfCSP regions (N-terminus, repeat, and C-terminus) with balanced Th1/Th2 ratios. Regarding transmission blockade, serum from m8∆/AAV1-vaccinated BALB/c mice achieved substantial transmission-reducing activity (TRA = 83.02%) and TB activity (TBA = 38.98%)—attributes not observed with RTS,S. Furthermore, m8∆/AAV1 demonstrated durable TB efficacy (94.31% TRA and 63.79% TBA) 100 days post-immunization. Conclusions: These results highlight m8∆/AAV1′s dual action in preventing sporozoite invasion and onward transmission, a significant advantage over RTS,S. Consequently, m8∆/AAV1 represents an alternative and a promising vaccine candidate that can enhance malaria control and elimination strategies. Full article

The coronavirus disease 2019 (COVID-19) has left a devasting effect on various regions globally. Africa has exceptionally high rates of other infectious diseases, such as tuberculosis (TB), human immunodeficiency virus (HIV), and malaria, and was not impacted by COVID-19 to the extent of other continents Globally, COVID-19 has caused approximately 7 million deaths and 700 million infections thus far. COVID-19 disease severity and susceptibility vary among individuals and populations, which could be attributed to various factors, including the viral strain, host genetics, environment, lifespan, and co-existing conditions. Host genetics play a substantial part in COVID-19 disease severity among individuals. Human leukocyte antigen (HLA) was previously been shown to be very important across host immune responses against viruses. HLA has been a widely studied gene region for various disease associations that have been identified. HLA proteins present peptides to the cytotoxic lymphocytes, which causes an immune response to kill infected cells. The HLA molecule serves as the central region for infectious disease association; therefore, we expect HLA disease association with COVID-19. Therefore, in this narrative review, we look at the HLA gene region, particularly, HLA class I, to understand its role in COVID-19 disease. Full article

Tuberculosis (TB) is among the top 10 leading causes of death in low-income countries. Statistically, TB kills more than 30,000 people each week and leads to more deaths than any other infectious disease, such as acquired immunodeficiency syndrome (AIDS) and malaria. TB treatment is largely dependent on BCG vaccination and impacted by the inefficacy of drugs, absence of advanced vaccines, misdiagnosis improper treatment, and social stigma. The BCG vaccine provides partial effectiveness in demographically distinct populations and the prevalence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) TB incidences demands the design of novel TB vaccines. Various strategies have been employed to design vaccines against TB, such as: (a) The protein subunit vaccine; (b) The viral vector vaccine; (c) The inactivation of whole-cell vaccine, using related mycobacteria, (d) Recombinant BCG (rBCG) expressing Mycobacterium tuberculosis (M.tb) protein or some non-essential gene deleted BCG. There are, approximately, 19 vaccine candidates in different phases of clinical trials. In this article, we review the development of TB vaccines, their status and potential in the treatment of TB. Heterologous immune responses generated by advanced vaccines will contribute to long-lasting immunity and might protect us from both drug-sensitive and drug-resistant TB. Therefore, advanced vaccine candidates need to be identified and developed to boost the human immune system against TB. Full article

The manner in which high-impact, life-saving health interventions reach populations in need is a critical dimension of health system performance. Intervention coverage has been a standard metric for such performance. To better understand and address the decay of intervention effectiveness in real-world health systems, the more complex measure of “effective coverage” is required, which includes the health gain the health system could potentially deliver. We have carried out a narrative review to trace the origins, timeline, and evolution of the concept of effective coverage metrics to illuminate potential improvements in coherence, terminology, application, and visualizations, based on which a combination of approaches appears to have the most influence on policy and practice. We found that the World Health Organization first proposed the concept over 45 years ago. It became increasingly popular with the further development of theoretical underpinnings, and after the introduction of quantification and visualization tools. The approach has been applied in low- and middle-income countries, mainly for HIV/AIDS, TB, malaria, child health interventions, and more recently for non-communicable diseases, particularly diabetes and hypertension. Nevertheless, despite decades of application of effective coverage concepts, there is considerable variability in the terminology used and the choices of effectiveness decay steps included in the measures. Results frequently illustrate a profound loss of service effectiveness due to health system factors. However, policy and practice rarely address these factors, and instead favour narrowly targeted technical interventions. Full article

This study aimed to evaluate the accuracy of the thick blood smear (TBS) versus quantitative polymerase chain reaction (qPCR) for the diagnosis of malaria associated with pregnancy (MAP) caused by P. falciparum or P. vivax in Colombia in its gestational malaria (GM), placental malaria (PM), and congenital malaria (CM) forms as well as to compare its accuracy in different subgroups of pregnant women according to the presence of fever, anemia and a history of malaria. This was a diagnostic evaluation of 829 pregnant women, 579 placentas, 381 umbilical cord samples, and 221 neonatal peripheral blood samples. Accuracy was evaluated based on the parameters of sensitivity, specificity, predictive values, likelihood ratios, and validity index, with their 95% confidence intervals. The frequency of GM was 36% (n = 297/829), PM 27% (n = 159/579), and CM 16.5% (n = 63/381) in umbilical cord samples and 2% (n = 5/221) in neonatal peripheral blood samples. For GM, the sensitivity was 55%, with higher rates in those infected with P. vivax (68%), with a history of malaria (69%), and with fever (96%). These three subgroups presented the best results in terms of the negative likelihood ratio and validity index. For PM, sensitivity was 8%; in subgroup analyses in terms of species, symptomatology (anemia and fever), and history of malaria, it was 1–18%, and the negative likelihood ratio was >0.80 in all subgroups. No false positives were recorded in any of the subgroups. The TBS did not detect any cases of CM. This study found the TBS yielded satisfactory results in terms of diagnosing GM for P. vivax, pregnant women with previous malaria and febrile. It also showed that the TBS is not useful for diagnosing PM and CM. It is necessary to conduct surveillance of MAP with molecular methods in in groups where TBS is deficient (asymptomatic GM, P. falciparum, and pregnant women without history of malaria) to optimize the timely treatment of PM and CM, avoid the deleterious effects of MAP and achieve the malaria elimination goals in Colombia. Full article

Healthcare waste (HCW) is generated in different healthcare facilities (HCFs), such as hospitals, laboratories, veterinary clinics, research centres and nursing homes. It has been assessed that the majority of medical waste does not pose a risk to humans. It is estimated that 15% of the total amount of produced HCW is hazardous and can be infectious, toxic or radioactive. Hazardous waste is a special type of waste which, if not properly treated, can pose a risk to human health and to the environment. HCW contains potentially harmful microorganisms that can be spread among healthcare personnel, hospital patients and the general public, causing serious illnesses. Healthcare personnel are the specialists especially exposed to this risk. The most common medical procedure, which pose the highest risk, is injection (i.e, intramuscular, subcutaneous, intravenous, taking blood samples). The World Health Organization (WHO) estimates that around 16 billion injections are administered worldwide each year. However, if safety precautions are not followed, and needles and syringes are not properly disposed of, the risk of sharps injuries increases among medical staff, waste handlers and waste collectors. What is more, sharps injuries increase the risk of human immunodeficiency virus (HIV), hepatitis B and C viruses (HBV/HCV), tuberculosis (TB), diphtheria, malaria, syphilis, brucellosis and other transmissions. Disposing of medical waste in a landfill without segregation and processing will result in the entry of harmful microorganisms, chemicals or pharmaceuticals into soil and groundwater, causing their contamination. Open burning or incinerator malfunctioning will result in the emission of toxic substances, such as dioxins and furans, into the air. In order to reduce the negative impact of medical waste, waste management principles should be formulated. To minimize health risks, it is also important to build awareness among health professionals and the general public through various communication and educational methods. The aim of this paper is to present a general overwiev of medical waste, its categories, the principles of its management and the risks to human health and the environment resulting from inappropriate waste management. Full article

The interaction of malaria parasites with their human host is extensively studied, yet only few studies reported how P. falciparum infection affects urinary metabolite profiles and how this is associated with immunity. We present a longitudinal study of the urinary metabolic profiles of twenty healthy Africans with lifelong exposure to malaria and five malaria-naïve Europeans, who were all challenged with direct venous inoculation of live P. falciparum sporozoïtes (PfSPZ) and followed up until they developed symptoms or became thick blood smear positive (TBS). Urine samples were collected before and at 2, 5, 9 and 11 days post challenge and were analysed. Upon infection, all Europeans became TBS positive, while Africans showed either a delay in time to parasitaemia or controlled infection. Our metabolic data showed that Europeans and Africans had distinct alterations in metabolite patterns, with changes mostly seen on days 5 and 9 post PfSPZ infection, and more prominently in Europeans. Within the African group, the levels of formate, urea, trimethylamine, threonine, choline, myo-inositol and acetate were significantly higher in TBS positive whereas the levels of pyruvate, 3-methylhistidine and dimethylglycine were significantly lower in individuals who remained TBS negative. Notably, before inoculation with PfSPZ, a group of metabolites including phenylacetylglutamine can potentially be used to predict parasitaemia control among Africans. Taken together, this study highlights the difference in urinary metabolic changes in response to malaria infection as a consequence of lifelong exposure to malaria and that change detectable before challenge might predict the control of parasitaemia in malaria-endemic areas. Full article

From the early stage of the millennium development goals campaign, HIV/AIDS, tuberculosis and malaria have received huge aid funds. With the datasets published by the Institute for Health Metrics and Evaluation, Organization for Economic Cooperation and Developments, and World Health Organization from 2005 to 2017, we analyzed the association between the total DAH or DAH per capita and the disease burden. We measured the total DAH or DAH per capita as the dependent variable, with six independent variables of disease burden for Disability Adjusted Life Year (DALY), number of infected people, number of deaths, prevalence, incidence, and mortality rate. For the trend in ODA targeting, the likelihood ratio test of the fixed effects models was used to assess any existence of slope changes in linear regression across the years. The total amount of DAH and DAH per capita was found positively related with every aspect of disease burden, with the regression coefficients increasing during 2005–2017. For instance, the slope of association between the DAH per capita and the disease burden of malaria became steeper over time (likelihood ratio, χ² = 26.14, p < 0.001). Although the selection criteria for the recipient country have been controversial, ODA targeting has been performed based on disease burden in this research. Full article

The onset of an adaptive immune response provides the signals required for differentiation of antigen-specific lymphocytes into effector cells and imprinting of these cells for re-circulation to the most appropriate anatomical site (i.e., homing). Lymphocyte homing is governed by the expression of tissue-specific lymphocyte homing receptors that bind to unique tissue-specific ligands on endothelial cells. In this study, a whole-parasite malaria vaccine (radiation-attenuated sporozoites (RAS)) was used as a model system to establish homing receptor signatures induced by the parasite delivered through mosquito bite to provide a benchmark of desirable homing receptors for malaria vaccine developers. This immunization regimen resulted in the priming of antigen-specific B cells and CD8⁺ T cells for homing primarily to the skin and T/B cell compartments of secondary lymphoid organs. Infection with live sporozoites, however, triggers the upregulation of homing receptor for the liver and the skin, demonstrating that there is a difference in the signal provided by attenuated vs. live sporozoites. This is the first report on imprinting of homing routes by Plasmodium sporozoites and, surprisingly, it also points to additional, yet to be identified, signals provided by live parasites that prime lymphocytes for homing to the liver. The data also demonstrate the utility of this method for assessing the potential of vaccine formulations to direct antigen-specific lymphocytes to the most relevant anatomical site, thus potentially impacting vaccine efficacy. Full article

Chagas disease caused by the protozoan Trypanosoma cruzi is endemic to 21 countries in the Americas, effects approximately 6 million people and on average results in 12,000 deaths annually. Human African Trypanosomiasis (HAT) is caused by the Trypanosoma brucei sub-species, endemic to 36 countries within sub-Saharan Africa. Treatment regimens for these parasitic diseases are complicated and not effective against all disease stages; thus, there is a need to find improved treatments. To identify new molecules for the drug discovery pipelines for these diseases, we have utilised in vitro assays to identify compounds with selective activity against both T. cruzi and T.b. brucei from the Medicines for Malaria Venture (MMV) Pathogen Box compound collection. To prioritise these molecules for further investigation, temporal and wash off assays were utilised to identify the speed of action and cidality of compounds. For translational relevance, compounds were tested against clinically relevant T.b. brucei subspecies. Compounds with activity against T. cruzi cytochrome P450 (TcCYP51) have not previously been successful in clinical trials for chronic Chagas disease; thus, to deprioritise compounds with this activity, they were tested against recombinant TcCYP51. Compounds with biological profiles warranting progression offer important tools for drug and target development against kinetoplastids. Full article

The stable isomers of the higher fullerenes C₇₆-D₂ and C₈₄-D₂:22, as well as fullerenes C₆₀ and C₇₀ were isolated from carbon soot by the new and improved extraction and chromatographic methods and processes. Characterizations of the C₈₄-D₂:22 isomer in this study were performed by infrared and electronic absorption spectroscopy. All of the experimentally observed IR and UV/VIS bands were in excellent agreement with the semi-empirical, DFT and TB potential theoretical calculations for this molecule. The molar extinction coefficients and the integrated molar extinction coefficients of the observed larger number of completely separated infrared absorption maxima and shoulders of fullerene C₈₄-D₂:22, as well as of its main convoluted maxima, in different and new relevant entire integration ranges, including neighboring, and all surrounding absorption shoulders were determined and their relative intensities compared. In addition, the molar absorptivity of the electronic absorption bands of this carbon cluster was found. The new IR and UV/VIS spectroscopic parameters that are significant for the quantitative determination, identification and numerous possible applications of C₈₄-D₂:22 are obtained and their changes compared to C₇₆-D₂ observed. Isolated and characterized C₈₄-D₂:22, as well as other fullerenes from this research can be used in electronic, optical, chemical and biomedical devices, superconductors, semiconductors, batteries, catalysts, polymers, sensors, solar cells, nanophotonic lenses with better optical transmission, refraction and wettability, diagnostic and therapeutic pharmaceutical substances, such as those against diabetes, cancer, neurodegenerative disorders, free radical scavenging, radio nuclear, antibacterial and antiviral agents that can inhibit HIV 1, HSV, COVID-19, influenza, malaria and so forth. Full article

Galectin-9 (Gal-9) is a β-galactoside-binding lectin capable of promoting or suppressing the progression of infectious diseases. This protein is susceptible to cleavage of its linker-peptides by several proteases, and the resulting cleaved forms, N-terminal carbohydrate recognition domain (CRD) and C-terminal CRD, bind to various glycans. It has been suggested that full-length (FL)-Gal-9 and the truncated (Tr)-Gal-9s could exert different functions from one another via their different glycan-binding activities. We propose that FL-Gal-9 regulates the pathogenesis of infectious diseases, including human immunodeficiency virus (HIV) infection, HIV co-infected with opportunistic infection (HIV/OI), dengue, malaria, leptospirosis, and tuberculosis (TB). We also suggest that the blood levels of FL-Gal-9 reflect the severity of dengue, malaria, and HIV/OI, and those of Tr-Gal-9 markedly reflect the severity of HIV/OI. Recently, matrix metallopeptidase-9 (MMP-9) was suggested to be an indicator of respiratory failure from coronavirus disease 2019 (COVID-19) as well as useful for differentiating pulmonary from extrapulmonary TB. The protease cleavage of FL-Gal-9 may lead to uncontrolled hyper-immune activation, including a cytokine storm. In summary, Gal-9 has potential to reflect the disease severity for the acute and chronic infectious diseases. Full article