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PLoS Neglected Tropical Diseases Jun 2024Plague, a zoonotic disease caused by Yersinia pestis, was responsible for 3 historical human pandemics that killed millions of people. It remains endemic in rodent... (Review)
Review
BACKGROUND
Plague, a zoonotic disease caused by Yersinia pestis, was responsible for 3 historical human pandemics that killed millions of people. It remains endemic in rodent populations in Africa, Asia, North America, and South America but human plague is rare in most of these locations. However, human plague is still highly prevalent in Madagascar, which typically records a significant part of all annual global cases. This has afforded an opportunity to study contemporary human plague in detail using various typing methods for Y. pestis.
AIM
This review aims to summarize the methods that have been used to type Y. pestis in Madagascar along with the major discoveries that have been made using these approaches.
METHODS
Pubmed and Google Scholar were used to search for the keywords: "typing Yersinia pestis Madagascar," "evolution Yersinia pestis Madagascar," and "diversity Yersinia pestis Madagascar." Eleven publications were relevant to our topic and further information was retrieved from references cited in those publications.
RESULTS
The history of Y. pestis typing in Madagascar can be divided in 2 periods: the pre-genomics and genomics eras. During the pre-genomics era, ribotyping, direct observation of plasmid content and plasmid restriction fragment length polymorphisms (RFLP) were employed but only revealed a limited amount of diversity among Malagasy Y. pestis strains. Extensive diversity only started to be revealed in the genomics era with the use of clustered regularly interspaced palindromic repeats (CRISPR), multiple-locus variable number tandem repeats (VNTR) analysis (MLVA), and single-nucleotide polymorphisms (SNPs) discovered from whole genome sequences. These higher-resolution genotyping methods have made it possible to highlight the distribution and persistence of genotypes in the different plague foci of Madagascar (Mahajanga and the Central and Northern Highlands) by genotyping strains from the same locations across years, to detect transfers between foci, to date the emergence of genotypes, and even to document the transmission of antimicrobial resistant (AMR) strains during a pneumonic plague outbreak. Despite these discoveries, there still remain topics that deserve to be explored, such as the contribution of horizontal gene transfer to the evolution of Malagasy Y. pestis strains and the evolutionary history of Y. pestis in Madagascar.
CONCLUSIONS
Genotyping of Y. pestis has yielded important insights on plague in Madagascar, particularly since the advent of whole-genome sequencing (WGS). These include a better understanding of plague persistence in the environment, antimicrobial AMR and multi-drug resistance in Y. pestis, and the person-to-person spread of pneumonic plague. Considering that human plague is still a significant public health threat in Madagascar, these insights can be useful for controlling and preventing human plague in Madagascar and elsewhere, and also are relevant for understanding the historical pandemics and the possible use of Y. pestis as a biological weapon.
Topics: Yersinia pestis; Madagascar; Plague; Humans; Animals; Genotype; Genotyping Techniques
PubMed: 38935608
DOI: 10.1371/journal.pntd.0012252 -
Molecules (Basel, Switzerland) May 2024There is a myriad of diseases that plague the world ranging from infectious, cancer and other chronic diseases with varying interventions. However, the dynamism of... (Review)
Review
There is a myriad of diseases that plague the world ranging from infectious, cancer and other chronic diseases with varying interventions. However, the dynamism of causative agents of infectious diseases and incessant mutations accompanying other forms of chronic diseases like cancer, have worsened the treatment outcomes. These factors often lead to treatment failure via different drug resistance mechanisms. More so, the cost of developing newer drugs is huge. This underscores the need for a paradigm shift in the drug delivery approach in order to achieve desired treatment outcomes. There is intensified research in nanomedicine, which has shown promises in improving the therapeutic outcome of drugs at preclinical stages with increased efficacy and reduced toxicity. Regardless of the huge benefits of nanotechnology in drug delivery, challenges such as regulatory approval, scalability, cost implication and potential toxicity must be addressed via streamlining of regulatory hurdles and increased research funding. In conclusion, the idea of nanotechnology in drug delivery holds immense promise for optimizing therapeutic outcomes. This work presents opportunities to revolutionize treatment strategies, providing expert opinions on translating the huge amount of research in nanomedicine into clinical benefits for patients with resistant infections and cancer.
Topics: Humans; Drug Delivery Systems; Nanostructures; Nanomedicine; Neoplasms; Animals; Nanotechnology
PubMed: 38893460
DOI: 10.3390/molecules29112584 -
Animals : An Open Access Journal From... May 2024Fleas (Siphonaptera) are ectoparasitic hematophagous insects responsible for causing bites and itchy skin conditions in both humans and animals. Furthermore, they can...
Fleas (Siphonaptera) are ectoparasitic hematophagous insects responsible for causing bites and itchy skin conditions in both humans and animals. Furthermore, they can act as vectors of different pathogens of a wide variety of diseases worldwide, including bartonellosis, rickettsiosis, and bubonic plague. Accurate identification of fleas is necessary for the study of their epidemiology, prevention, and control. In addition to traditional morphological classification approaches and molecular biology techniques, geometric morphometrics is increasingly proving to be a useful complementary tool for discriminating between Siphonaptera taxa. With the objective of determining the capacity of this technique to identify and differentiate synanthropic fleas, a principal component analysis was carried out on populations of , , and collected in distinct regions of Andalusia (Spain). The analysis carried out on 81 male and female specimens revealed factorial maps that allowed the differentiation of the populations under study, with only partial overlaps that did not prevent their correct identification. Global size differences were also detected, with a slightly larger size in males and a bigger size in females. Therefore, the present study emphasizes the role of geometric morphometrics as a useful complementary technique in taxonomic studies of arthropods, especially in the case of flea specimens lacking representative morphological features.
PubMed: 38891629
DOI: 10.3390/ani14111582 -
Journal of Invertebrate Pathology Jun 2024Introduced into Europe from North America 150 years ago alongside its native crayfish hosts, the invasive pathogen Aphanomyces astaci is considered one of the main...
Introduced into Europe from North America 150 years ago alongside its native crayfish hosts, the invasive pathogen Aphanomyces astaci is considered one of the main causes of European crayfish population decline. For the past two centuries, this oomycete pathogen has been extensively studied, with the more recent efforts focused on containing and monitoring its spread across the continent. However, after the recent introduction of new strains, the newly-discovered diversity of A. astaci in North America and several years of coevolution with its European host, a new assessment of the traits linked to the pathogen's virulence is much needed. To fill this gap, we investigated the presence of phenotypic patterns (i.e., in vitro growth and sporulation rates) possibly associated with the pathogen's virulence (i.e., induced mortality in crayfish) in a collection of 14 A. astaci strains isolated both in North America and in Europe. The results highlighted a high variability in virulence, growth rate and motile spore production among the different strains, while the total-sporulation rate was more similar across strains. Surprisingly, growth and sporulation rates were not significantly correlated with virulence. Furthermore, none of the analysed parameters, including virulence, was significantly different among the major A. astaci haplogroups. These results indicate that each strain is defined by a characteristic combination of pathogenic features, specifically assembled for the environment and host faced by each strain. Thus, canonical mitochondrial markers, often used to infer the pathogen's virulence, are not accurate tools to deduce the phenotype of A. astaci strains. As the diversity of A. astaci strains in Europe is bound to increase due to translocations of new carrier crayfish species from North America, there is an urgent need to deepen our understanding of A. astaci's virulence variability and its ability to adapt to new hosts and environments.
PubMed: 38866297
DOI: 10.1016/j.jip.2024.108153 -
Frontiers in Immunology 2024is the etiological agent of plague, which can manifest as bubonic, septicemic, and/or pneumonic disease. Plague is a severe and rapidly progressing illness that can...
BACKGROUND
is the etiological agent of plague, which can manifest as bubonic, septicemic, and/or pneumonic disease. Plague is a severe and rapidly progressing illness that can only be successfully treated with antibiotics initiated early after infection. There are no FDA-approved vaccines for plague, and some vaccine candidates may be less effective against pneumonic plague than bubonic plague. is not known to impact males and females differently in mechanisms of pathogenesis or severity of infection. However, one previous study reported sex-biased vaccine effectiveness after intranasal challenge. As part of developing a safe and effective vaccine, it is essential that potential sex differences are characterized.
METHODS
In this study we evaluated novel vaccines in male and female BALB/c mice using a heterologous prime-boost approach and monitored survival, bacterial load in organs, and immunological correlates. Our vaccine strategy consisted of two subcutaneous immunizations, followed by challenge with aerosolized virulent nonencapsulated . Mice were immunized with a combination of live pPstΔ, live pPstΔ/Δ, or recombinant F1-V (rF1-V) combined with adjuvants.
RESULTS
The most effective vaccine regimen was initial priming with rF1-V, followed by boost with either of the live attenuated strains. However, this and other strategies were more protective in female mice. Males had higher bacterial burden and differing patterns of cytokine expression and serum antibody titers. Male mice did not demonstrate synergy between vaccination and antibiotic treatment as repeatedly observed in female mice.
CONCLUSIONS
This study provides new knowledge about heterologous vaccine strategies, sex differences in plague-vaccine efficacy, and the immunological factors that differ between male and female mice.
Topics: Animals; Female; Plague; Male; Yersinia pestis; Plague Vaccine; Mice; Mice, Inbred BALB C; Antibodies, Bacterial; Sex Characteristics; Sex Factors; Disease Models, Animal; Vaccine Efficacy
PubMed: 38835755
DOI: 10.3389/fimmu.2024.1397579 -
Le Infezioni in Medicina 2024Plague raged in Europe for over 1400 years and was responsible for three major pandemics. Today, plague still poses a serious threat to global public health and...
Plague raged in Europe for over 1400 years and was responsible for three major pandemics. Today, plague still poses a serious threat to global public health and surveillance is imperative. Plague is still present in natural reservoirs on several continents, including Africa, Asia and the Americas, and sometimes causes local cases and epidemics. The Third Plague Pandemic caused millions of deaths worldwide, including in Europe. Plague arrived in Europe in the autumn of 1896 mostly through maritime trade routes, where it spread with several epidemic events until 1945, when, in the port city of Taranto, the last known outbreak was recorded. In this paper, we present an overview of the natural history and pathogenicity of , the bacterium responsible for plague, its spread from Asia to Europe during the Third Pandemic, and the therapies used to treat and prevent the disease in Europe, with particular focus on the case of Taranto. In Taranto, the Pasteur Institute's antiserum antimicrobial therapy, and vaccination were used to treat and stop the advance of the bacterium, with mixed results.
PubMed: 38827832
DOI: 10.53854/liim-3202-14 -
Heliyon May 2024No licensed vaccine exists for the lethal plague and yersiniosis. Therefore, a combination of recombinant YopE and LcrV antigens of was evaluated for its vaccine...
No licensed vaccine exists for the lethal plague and yersiniosis. Therefore, a combination of recombinant YopE and LcrV antigens of was evaluated for its vaccine potential in a mouse model. YopE and LcrV in formulation with alum imparted a robust humoral immune response, with isotyping profiles leaning towards the IgG1 and IgG2b subclasses. It was also observed that a significantly enhanced expression of IFN-γ, TNF-α, IL-6, IL-2, and IL-1β from the splenic cells of vaccinated mice, as well as YopE and LcrV-explicit IFN-γ eliciting T-cells. The cocktail of YopE + LcrV formulation conferred complete protection against 100 LD infection, while individually, LcrV and YopE provided 80 % and 60 % protection, respectively. Similarly, the YopE + LcrV vaccinated animal group had significantly lower colony forming unit (CFU) counts in the spleen and blood compared to the groups administered with YopE or LcrV alone when challenged with and . Histopathologic evidence reinforces these results, indicating the YopE + LcrV formulation provided superior protection against acute lung injury as early as day 3 post-challenge. In conclusion, the alum-adjuvanted YopE + LcrV is a promising vaccine formulation, eliciting a robust antibody response including a milieu of pro-inflammatory cytokines and T-cell effector functions that contribute to the protective immunity against infections. YopE and LcrV, conserved across all three human-pathogenic Yersinia species, provide cross-protection. Therefore, our current vaccine (YopE + LcrV) targets all three pathogens: , , and . However, the efficacy should be tested in other higher mammalian models.
PubMed: 38826713
DOI: 10.1016/j.heliyon.2024.e31446 -
BioRxiv : the Preprint Server For... May 2024In allosteric proteins, identifying the pathways that signals take from allosteric ligand-binding sites to enzyme active sites or binding pockets and interfaces remains...
In allosteric proteins, identifying the pathways that signals take from allosteric ligand-binding sites to enzyme active sites or binding pockets and interfaces remains challenging. This avenue of research is motivated by the goals of understanding particular macromolecular systems of interest and creating general methods for their study. An especially important protein that is the subject of many investigations in allostery is the SARS-CoV-2 main protease (Mpro), which is necessary for coronaviral replication. It is both an attractive drug target and, due to intense interest in it for the development of pharmaceutical compounds, a gauge of the state-of-the-art approaches in studying protein inhibition. Here we develop a computational method for characterizing protein allostery and use it to study Mpro. We propose a role of the protein's C-terminal tail in allosteric modulation and warn of unintuitive traps that can plague studies of the role of protein dihedrals angles in transmitting allosteric signals.
PubMed: 38826232
DOI: 10.1101/2024.05.22.595309 -
PLoS Neglected Tropical Diseases May 2024Plague continues to be a major public health concern in African countries. Several social practices and environmental conditions have been associated with the...
INTRODUCTION
Plague continues to be a major public health concern in African countries. Several social practices and environmental conditions have been associated with the reoccurrence of bubonic plague, especially in places where the disease is prevalent. Therefore, it remains important to understand people knowledge, behavior and practices related to disease risks in order to identify factors that may hinder prevention and control strategies in the foci.
METHODS AND RESULTS
A study survey of 100 households was conducted in Mbulu district to assess plague knowledge, factors that influence flea bite and measures used for rodent and flea control. Majority of participants (86%) were familiar with the plague disease and about (50%) mentioned swelling lymph nodes as a common symptom. Most of the participants (62%) claimed to observe human plague cases during the long rain season. The majority of participants (97%) reported to experience flea bite in their domestic settings, with most stating that they experienced more flea bites during the dry season. Houses with livestock had a greater likelihood of flea bite (OR = 2.7; 95% CI: 0.36-18.80, p = 0.267) compared to houses with no livestock. Furthermore, residents reported using both local and chemical methods to control rodents and flea inside houses. Most respondents preferred using local methods in flea control. Respondents stated that the efficacy of flea control methods being applied ranged from few days to several months. There was limited knowledge of the residual effects of the agricultural chemicals being used to control fleas among the surveyed community.
CONCLUSION
Our study highlights the importance of raising awareness and adopting effective control methods for controlling fleas and lower the risk of plague transmission and other flea borne diseases in the local communities. Sensitization of the local community on the use of appropriate chemicals for flea control is urgent to avoid any potential long-term impacts of the residual effects on the health of the local communities.
Topics: Plague; Tanzania; Humans; Animals; Health Knowledge, Attitudes, Practice; Female; Adult; Male; Siphonaptera; Middle Aged; Young Adult; Surveys and Questionnaires; Rodentia; Adolescent; Insect Bites and Stings; Endemic Diseases
PubMed: 38814990
DOI: 10.1371/journal.pntd.0012202