Progress in understanding the evolution of infectious diseases has inspired proposals to manage the evolution of pathogen (including parasite) virulence. A common view is that social interventions that lower pathogen transmission will indirectly select lower virulence because of a trade-off between transmission and virulence. Here, we argue that there is little theoretical justification and no ...

Malaria parasites vary in virulence, but the effects of mosquito transmission on virulence phenotypes have not been systematically analysed. Using six lines of malaria parasite that varied widely in virulence, three of which had been serially blood-stage passaged many times, we found that mosquito transmission led to a general reduction in malaria virulence. Despite that, the between-line varia...

Human health is threatened by various infectious bacterial pathogens but is also supported by many commensal bacteria particularly in the intestinal tract. However, many of the bacterial pathogens and commensal bacteria are taxonomically indistinguishable, with pathogenic and commensal bacteria existing in the same genus and even species. A typical example is Escherichia coli, which is commonly...

The virulence index of three Meloidogyne incognita field isolates to the resistance gene Rk in cowpea was 0%, 75%, and 120%, with the index measured as reproduction on resistant plants as a percentage of the reproduction on susceptible plants. Continuous culture of the 75% virulent isolate on susceptible tomato for more than 5 years (about 25 generations) resulted in virulence decline to about ...

Magnesium oxalate agar was found to select against virulent types of Yersinia enterocolitica. Small colonies isolated from magnesium oxalate agar which were presumably virulent generally contained no detectable virulence-specific plasmids, did not agglutinate with virulence-specific antiserum, and exhibited various degrees of virulence in mice. Results indicate that the virulence potential of a...

Abstract As a conserved epigenetic mark, DNA cytosine methylation, at the 5’ position (5-mC), plays important roles in multiple biological processes, including plant immunity. However, involvement of methylation determinants virulence phytopathogenic fungi remains elusive. In this study, we profiled patterns fungus Verticillium dahliae , one major causal pathogens wilt disease that causes great...

Listeria monocytogenes has evolved an extensive array of mechanisms for coping with stress and adapting to changing environmental conditions, ensuring its virulence phenotype expression. For this reason, L. been identified as a significant food safety public health concern. Among these adaptation systems are cold shock proteins (Csps), which facilitate rapid response exposure. three highly cons...

Multidrug-resistant bacteria such as Staphylococcus aureus constitute a global health problem. Gram-positive S. secretes various toxins associated with its pathogenesis, and biofilm formation plays an important role in antibiotic tolerance virulence. Hence, we investigated if the metabolites of vitamin A 1 might diminish toxin production. Of three retinoic acids examined, 13- cis -retinoic acid...

A small percentage of natural Escherichia coli isolates (both commensal and pathogenic) have a mutator phenotype related to defects in methyl-directed mismatch repair (MR) genes. We investigated whether there was a direct link between the mutator phenotype and virulence by (i) studying the relationships between mutation rate and virulence in a mouse model of extraintestinal virulence for 88 com...

The trade-off hypothesis proposes that the evolution of pathogens' virulence is shaped by a link between virulence and contagiousness. This link is often assumed to come from the fact that pathogens are contagious only if they can reach high parasitic load in the infected host. In this paper we present an experimental test of the hypothesis that selection on fast replication can affect virulenc...