A survey of bacterial infections in sturgeon farming in Italy

Sturgeon aquaculture production has increased worldwide, particularly in Italy, yet there is little information about diseases that affect sturgeons. With this study we describe the results of screening for bacterial infections during monitoring campaigns carried out from 2014 to 2017. A total of 402 sturgeons from six sturgeon farms with one or more reared sturgeon species among five species and two hybrids were analysed. Bacteriological exam was positive in 93 individuals (23%) and negative in the remaining 309 (77%). Generally, no external or internal macroscopic lesions were present, though some specimens showed skin lesions, liver anaemia or splenomegaly, which are non‐pathognomonic signs of bacterial infection. The majority of the isolated bacteria were opportunistic. This knowledge base is important to help create a bacterial profile of sturgeons reared in Italy.     

Toll‐like receptors in prostate infection and cancer between bench and bedside

Toll‐Like receptors (TLRs) are a family of evolutionary conserved transmembrane proteins that recognize highly conserved molecules in pathogens. TLR‐expressing cells represent the first line of defence sensing pathogen invasion, triggering innate immune responses and subsequently priming antigen‐specific adaptive immunity. In vitro and in vivo studies on experimental cancer models have shown both anti‐ and pro‐tumoural activity of different TLRs in prostate cancer, indicating these receptors as potential targets for cancer therapy. In this review, we highlight the intriguing duplicity of TLR stimulation by pathogens: their protective role in cases of acute infections, and conversely their negative role in favouring hyperplasia and/or cancer onset, in cases of chronic infections. This review focuses on the role of TLRs in the pathophysiology of prostate infection and cancer by exploring the biological bases of the strict relation between TLRs and prostate cancer. In particular, we highlight the debated question of how reliable mutations or deregulated expression of TLRs are as novel diagnostic or prognostic tools for prostate cancer. So far, the anticancer activity of numerous TLR ligands has been evaluated in clinical trials only in organs other than the prostate. Here we review recent clinical trials based on the most promising TLR agonists in oncology, envisaging a potential application also in prostate cancer therapy.     

Essential Oils as Biocides for the Control of Fungal Infections and Devastating Pest (Tuta absoluta) of Tomato (Lycopersicon esculentum Mill.)

Thymus capitatus and Tetraclinis articulata essential oils as well their major components (carvacrol and α‐pinene) were evaluated for their antifungal and insecticidal activities. Both oils showed good in vitro antifungal activity against Fusarium oxysporum, Aspergillus niger, Penicillium sp., Alternaria alternata, and Botrytis cinerea, the fungi causing tomato rot. In vivo results indicate the efficacies of both essential oils and carvacrol of reduce postharvest fungal pathogens, such as B. cinerea and Al. alternata that are responsible of black and gray rot of tomato fruit. Disease incidence of Al. alternata and B. cinerea decreased on average from 55% to 80% with essential oil of Th. capitatus and pure carcvacrol, while Te. articulata essential oil exhibited inhibition of fungal growth of 55% and 25% against Al. alternata and B. cinerea, respectively, with concentration of 0.4 μl/l air. The insecticidal activity of Th. capitatus and Te. articulata essential oils exhibited also a good insecticidal activity. At the concentration of 0.2 μl/ml air, the oils caused mortality over 80% for all larval stages of Tuta absoluta and 100% mortality for the first‐instar after 1.5 h only of exposure. α‐Pinene presented lower insecticidal and antifungal activities compared to essential oils of Th. capitatus, Te. articulata and pure carvacrol. Thus, these essential oils can be used as a potential source to develop control agents to manage some of the main pests and fungal diseases of tomato crops.     

Distribution and population structure of the anther smut Microbotryum silenes‐acaulis parasitizing an arctic–alpine plant

Cold‐adapted organisms with current arctic–alpine distributions have persisted during the last glaciation in multiple ice‐free refugia, leaving footprints in their population structure that contrast with temperate plants and animals. However, pathogens that live within hosts having arctic–alpine distributions have been little studied. Here, we therefore investigated the geographical range and population structure of a fungus parasitizing an arctic–alpine plant. A total of 1437 herbarium specimens of the plant Silene acaulis were examined, and the anther smut pathogen Microbotryum silenes‐acaulis was present throughout the host's geographical range. There was significantly greater incidence of anther smut disease in more northern latitudes and where the host locations were less dense, indicating a major influence of environmental factors and/or host demographic structure on the pathogen distribution. Genetic analyses with seven microsatellite markers on recent collections of 195 M. silenes‐acaulis individuals revealed three main genetic clusters, in North America, northern Europe and southern Europe, likely corresponding to differentiation in distinct refugia during the last glaciation. The lower genetic diversity in northern Europe indicates postglacial recolonization northwards from southern refugia. This study combining herbarium surveys and population genetics thus uniquely reveals the effects of climate and environmental factors on a plant pathogen species with an arctic–alpine distribution.     

Shoe soles as a potential vector for pathogen transmission: a systematic review

Shoe soles are possible vectors for infectious diseases. Although studies have been performed to assess the prevalence of infectious pathogens on shoe soles and decontamination techniques, no systematic review has ever occurred. The aim of this study was to perform a systematic review of the literature to determine the prevalence of infectious agents on shoe bottoms and possible decontamination strategies. Three electronic bibliographic databases were searched using a predefined search strategy evaluating prevalence of infectious pathogens on shoe bottoms and decontamination strategies. Quality assessment was performed independently by two reviews with disagreements resolved by consensus. Thirteen studies were identified that supported the hypothesis that shoe soles are a vector for infectious pathogens. Methicillin‐resistant Staphylococcus aureus, Clostridium difficile and multidrug‐resistant Gram‐negative species among other pathogens were documented on shoe bottoms in the health care setting, in the community and among food workers. Fifteen studies were identified that investigated decontamination strategies for shoe soles. A number of decontamination strategies have been studied of which none have been shown to be consistently successful at disinfecting shoe soles. In conclusion, a high prevalence of microbiological pathogens was identified from shoe soles studied in the health care, community and animal worker setting. An effective decontamination strategy for shoe soles was not identified. Studies are needed to assess the potential for contaminated shoes to contribute to the transmission of infectious pathogens.     

Detection of latent infections caused by Colletotrichum sp. in olive fruit

Aims

To set up a practical method to detect latent infections of Colletotrichum sp., the causal agent of olive anthracnose, on olives before the onset of disease symptoms.

Methods and Results

Freezing, sodium hydroxide (NaOH), ethanol and ethylene treatments were evaluated to detect latent infections on inoculated and naturally infected olive fruit by Colletotrichum sp. as non‐hazardous alternatives to paraquat. Treatments were conducted using fruit of cultivars Arbequina and Hojiblanca. The disease incidence and T₅₀ were calculated. Dipping in NaOH 0·05% solution and the paraquat method were the most effective treatments on both inoculated and naturally infected fruit, although the value of T₅₀ was lower for the NaOH method than for the paraquat method in one of the experiments. Subsequently, the dipping time in NaOH 0·05% was evaluated. Longer dipping times in NaOH 0·05% were better than shorter ones in cultivar Arbequina, with 72 h being the most effective in cultivar Hojiblanca.

Conclusions

NaOH solution is a practical method to detect latent infections of Colletotrichum sp. on immature olive fruit.

Significance and Impact of the Study

This study is relevant because we set up a viable, non‐hazardous alternative to paraquat to detect latent infections of Colletotrichum sp. using NaOH. The use of NaOH is a simple and eco‐friendly tool that allows the determination of the level of latent infections by Colletotrichum in olives. Therefore, our method will be useful in decision‐making processes for disease management before the appearance of the first visible symptoms.     

Genetic structure and host–parasite co‐divergence: evidence for trait‐specific local adaptation

Host–parasite co‐evolution can lead to genetic differentiation among isolated host–parasite populations and local adaptation between parasites and their hosts. However, tests of local adaptation rarely consider multiple fitness‐related traits although focus on a single component of fitness can be misleading. Here, we concomitantly examined genetic structure and co‐divergence patterns of the trematode Coitocaecum parvum and its crustacean host Paracalliope fluviatilis among isolated populations using the mitochondrial cytochrome oxidase I gene (COI). We then performed experimental cross‐infections between two genetically divergent host–parasite populations. Both hosts and parasites displayed genetic differentiation among populations, although genetic structure was less pronounced in the parasite. Data also supported a co‐divergence scenario between C. parvum and P. fluviatilis potentially related to local co‐adaptation. Results from cross‐infections indicated that some parasite lineages seemed to be locally adapted to their sympatric (home) hosts in which they achieved higher infection and survival rates than in allopatric (away) amphipods. However, local, intrinsic host and parasite characteristics (host behavioural or immunological resistance to infections, parasite infectivity or growth rate) also influenced patterns of host–parasite interactions. For example, overall host vulnerability to C. parvum varied between populations, regardless of parasite origin (local vs. foreign), potentially swamping apparent local co‐adaptation effects. Furthermore, local adaptation effects seemed trait specific; different components of parasite fitness (infection and survival rates, growth) responded differently to cross‐infections. Overall, data show that genetic differentiation is not inevitably coupled with local adaptation, and that the latter must be interpreted with caution in a multi‐trait context.     

Addressing the conflict between partner notification and patient confidentiality in serodiscordant relationships: How can Ubuntu help?

This study evaluates the conflict between patient confidentiality and partner notification in sero‐discordant relationships, and argues the thesis that based on a theoretical formulation of Ubuntu, a health provider is obliged to facilitate friendly relationships in which individuals are true subjects and/or objects of communal friendship. In serodiscordant relationships, the health professional can fulfil this obligation by notifying “others” (particularly a partner with whom an HIV positive patient has a “present” and “actual relationship”) of their spouse's HIV seroconversion, since without such relevant information a partner (subject) of an HIV positive patient cannot “appropriately” care for the patient's condition (object). There is a need to move away from the medical traditional emphasis that has for so long put primacy on doctor‐patient confidentiality as is the case with the Health Professions Council of South Africa Guidelines (Booklet 12) which favours patient confidentiality over partner notification. Given empirical evidence to support effectiveness of partner notification amongst sero‐discordant couples, there is thus, a need to focus emphasis on latter. This shift is necessary for achieving the United Nations’ Sustainable Development of Goal of ending HIV/AIDS epidemic by 2030. I proposed in this study that African ethics, specifically Ubuntu, will do a better job than current ethical frameworks at ensuring that partner notification receives more emphasis in the care of serodiscordant couples. If this framework is integrated into ethical guidelines and codes, it would significantly enhance the care of serodiscordant couples, as well as further boost global effort at ending HIV/AIDS epidemic by 2030.     

Malaria infection increases bird attractiveness to uninfected mosquitoes

The epidemiology of vector‐borne pathogens is largely determined by the host‐choice behaviour of their vectors. Here, we investigate whether a Plasmodium infection renders the host more attractive to host‐seeking mosquitoes. For this purpose, we work on a novel experimental system: the avian malaria parasite Plasmodium relictum, and its natural vector, the mosquito Culex pipiens. We provide uninfected mosquitoes with a choice between an uninfected bird and a bird undergoing either an acute or a chronic Plasmodium infection. Mosquito choice is assessed by microsatellite typing of the ingested blood. We show that chronically infected birds attract significantly more vectors than either uninfected or acutely infected birds. Our results suggest that malaria parasites manipulate the behaviour of uninfected vectors to increase their transmission. We discuss the underlying mechanisms driving this behavioural manipulation, as well as the broader implications of these effects for the epidemiology of malaria.     

The virulence–transmission relationship in an obligate killer holds under diverse epidemiological and ecological conditions,but where is the tradeoff?

Parasite virulence is a leading theme in evolutionary biology. Modeling the course of virulence evolution holds the promise of providing practical insights into the management of infectious diseases and the implementation of vaccination strategies. A key element of virulence modeling is a tradeoff between parasite transmission rate and host lifespan. This assumption is crucial for predicting the level of optimal virulence. Here, I test this assumption using the water flea Daphnia magna and its castrating and obligate‐killing bacterium Pasteuria ramosa. I found that the virulence–transmission relationship holds under diverse epidemiological and ecological conditions. In particular, parasite genotype, absolute and relative parasite dose, and within‐host competition in multiple infections did not significantly affect the observed trend. Interestingly, the relationship between virulence and parasite transmission in this system is best explained by a model that includes a cubic term. Under this relationship, parasite transmission initially peaks and saturates at an intermediate level of virulence, but then it further increases as virulence decreases, surpassing the previous peak. My findings also highlight the problem of using parasite‐induced host mortality as a “one‐size‐fits‐all” measure of virulence for horizontally transmitted parasites, without considering the onset and duration of parasite transmission as well as other equally virulent effects of parasites (e.g., host castration). Therefore, mathematical models may be required to predict whether these particular characteristics of horizontally transmitted parasites can direct virulence evolution into directions not envisaged by existing models.     

Ichnodiversity and ichnodisparity: significance and caveats

Ichnodiversity has been used as a proxy for environmental stress and stability in facies interpretations and to reconstruct evolutionary radiations and colonization histories in evolutionary palaeoecology. The three components of global diversity are exported from ecology and adapted for ichnology. Alpha ichnodiversity is used for palaeoenvironmental characterization, being assessed for individual facies. Beta ichnodiversity is commonly overlooked, although it may provide information about degree of similarity between ichnofaunas formed along environmental gradients. Gamma ichnodiversity may provide clues to detect ichnofossil provincialism. The concept of disparity may also prove to be significant in ichnological studies. Whereas ichnodiversity refers to ichnotaxonomic richness, ichnodisparity provides a measure of the variability of morphological plans in biogenic structures. Changes in global ichnodiversity do not necessarily parallel changes in ichnodisparity. For example, while the Cambrian explosion involved a dramatic increase in both, the Ordovician radiation essentially reflects an increase only in the former. Ichnodiversity and ichnodisparity should be used with caution because they are both affected by taphonomic processes. High diversity of superficial to shallow‐tier trace fossils may result from enhanced preservation due a poorly developed mixed layer, rather than a true reflection of ecosystem performance, as shown by underexploited infaunal ecospace after biotic crises (e.g. end‐Permian mass extinction).     

Emerging and re-emerging bacterial diseases in India

There has been a remarkable progress in the prevention, control and even eradication of infectious diseases with improved hygiene and development of antimicrobials and vaccines. However, infectious diseases still remain a leading cause of global disease burden with high morbidity and mortality especially in the developing world. Furthermore, there have been threats of new diseases during the past three decades due to the evolution and adaptation of microbes and the re-emergence of old diseases due to the development of antimicrobial resistance and the capacity to spread to new geographic areas. The impact of the emerging and re-emerging diseases in India has been tremendous at socioeconomic and public health levels. Their control requires continuing surveillance, research and training, better diagnostic facilities and improved public health system. Emerging and reemerging zoonotic diseases, foodborne and waterborne diseases and diseases caused by multiresistant organisms constitute the major threats in India. This review of bacterial emerging and re-emerging diseases should be of critical importance to microbiologists, clinicians, public health personnel and policy makers in India.     

Gut physiology mediates a trade‐off between adaptation to malnutrition and susceptibility to food‐borne pathogens

The animal gut plays a central role in tackling two common ecological challenges, nutrient shortage and food‐borne parasites, the former by efficient digestion and nutrient absorption, the latter by acting as an immune organ and a barrier. It remains unknown whether these functions can be independently optimised by evolution, or whether they interfere with each other. We report that Drosophila melanogaster populations adapted during 160 generations of experimental evolution to chronic larval malnutrition became more susceptible to intestinal infection with the opportunistic bacterial pathogen Pseudomonas entomophila. However, they do not show suppressed immune response or higher bacterial loads. Rather, their increased susceptibility to P. entomophila is largely mediated by an elevated predisposition to loss of intestinal barrier integrity upon infection. These results may reflect a trade‐off between the efficiency of nutrient extraction from poor food and the protective function of the gut, in particular its tolerance to pathogen‐induced damage.     

The Mitochondrial Genome and a 60‐kb Nuclear DNA Segment from Naegleria fowleri,the Causative Agent of Primary Amoebic Meningoencephalitis

Naegleria fowleri is a unicellular eukaryote causing primary amoebic meningoencephalitis, a neuropathic disease killing 99% of those infected, usually within 7–14 days. Naegleria fowleri is found globally in regions including the US and Australia. The genome of the related nonpathogenic species Naegleria gruberi has been sequenced, but the genetic basis for N. fowleri pathogenicity is unclear. To generate such insight, we sequenced and assembled the mitochondrial genome and a 60‐kb segment of nuclear genome from N. fowleri. The mitochondrial genome is highly similar to its counterpart in N. gruberi in gene complement and organization, while distinct lack of synteny is observed for the nuclear segments. Even in this short (60‐kb) segment, we identified examples of potential factors for pathogenesis, including ten novel N. fowleri‐specific genes. We also identified a homolog of cathepsin B; proteases proposed to be involved in the pathogenesis of diverse eukaryotic pathogens, including N. fowleri. Finally, we demonstrate a likely case of horizontal gene transfer between N. fowleri and two unrelated amoebae, one of which causes granulomatous amoebic encephalitis. This initial look into the N. fowleri nuclear genome has revealed several examples of potential pathogenesis factors, improving our understanding of a neglected pathogen of increasing global importance.     

VIP and CRF reduce ADAMTS expression and function in osteoarthritis synovial fibroblasts

ADAMTS (a disintegrin and metalloproteinase with thrombospondin motifs) family is known to play an important role in the pathogenesis of osteoarthritis (OA), working on aggrecan degradation or altering the integrity of extracellular matrix (ECM). Thus, the main purpose of our study was to define the role of vasoactive intestinal peptide (VIP) and corticotrophin‐releasing factor (CRF), as immunoregulatory neuropeptides, on ADAMTS production in synovial fibroblasts (SF) from OA patients and healthy donors (HD). OA‐ and HD‐SF were stimulated with pro‐inflammatory mediators and treated with VIP or CRF. Both neuropeptides decreased ADAMTS‐4, ‐5, ‐7 and ‐12 expressions, aggrecanase activity, glycosaminoglycans (GAG), and cartilage oligomeric matrix protein (COMP) degradation after stimulation with fibronectin fragments (Fn‐fs) in OA‐SF. After stimulation with interleukin‐1β, VIP reduced ADAMTS‐4 and ‐5, and both neuropeptides decreased ADAMTS‐7 production and COMP degradation. Moreover, VIP and CRF reduced Runx2 and β‐catenin activation in OA‐SF. Our data suggest that the role of VIP and CRF on ADAMTS expression and cartilage degradation could be related to the OA pathology since scarce effects were produced in HD‐SF. In addition, their effects might be greater when a degradation loop has been established, given that they were higher after stimulation with Fn‐fs. Our results point to novel OA therapies based on the use of neuropeptides, since VIP and CRF are able to stop the first critical step, the loss of cartilage aggrecan and the ECM destabilization during joint degradation.