Helminti patří stále k významným patogenům člověka, a to především v tropických a subtropických oblastech. Mohou mít jednohostitelské i vícehostitelské životní cykly. Do člověka pronikají zejména perorálně nebo kůží. Po průniku kůží dochází k migraci parazita do cílových tkání. I perorální infekce však mohou být spojeny s migrací helmintů tkáněmi a orgány, a to například jako součást vývoje před usídlením ve střevě nebo jako migrace do cílových orgánů mimo střevo, kde dochází k dospívání a reprodukci. V přehledu jsou uvedena ontogenetická stadia helmintů migrujících v lidském organismu, přičemž člověk může při těchto infekcích vystupovat v různých rolích (např. jako definitivní hostitel, mezihostitel, paratenický hostitel).
Helminths belong to important human pathogens in tropical and subtropical countries. They have simple one-host life cycles or they use several hosts for their development. There are two main entry points for human helminths: the skin and the oral cavity. Skin penetration is followed by tissue migration of helminth stages towards target organs. Also some perorally acquired helminths migrate throughout the human body and then (a) they return to and mature in the intestine or (b) they search for specific final location in other (extraintestinal) tissues/organs. Particular developmental stages having different migration routes, and different roles of human beings as final, intermediate and paratenic hosts are briefly mentioned.
- MeSH
- Ascaris lumbricoides parasitology growth & development MeSH
- Research Support as Topic MeSH
- Helminthiasis metabolism microbiology transmission MeSH
- Trematode Infections parasitology transmission MeSH
- Host-Parasite Interactions MeSH
- Humans MeSH
- Intestinal Diseases, Parasitic epidemiology parasitology transmission MeSH
- Taenia metabolism parasitology growth & development MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Animals MeSH
Parasites alter their host behaviour and vice versa as a result of mutual adaptations in the evolutionary arms race. One of these adaptations involves changes in host thermoregulation, which has the potential to harm the parasite and thereby act as a defence mechanism. We used a model of the brown trout (Salmo trutta) experimentally parasitised with glochidia ectoparasitic larvae from the endangered freshwater pearl mussel (Margaritifera margaritifera) to reveal whether parasitisation alters fish behavioural thermoregulation. A study using radiotelemetry temperature sensors was performed during almost one year of the M. margaritifera parasitic stage. Glochidia-infested S. trutta altered their thermoregulation through active searching for habitats with different thermal regimes. The general preference for temperatures in infested fish varied and was either above or below the temperature preferred by uninfested individuals. Infested fish also preferred different temperatures across localities, whereas uninfested fish maintained their thermal preference no matter which stream they inhabited. Glochidia further induced the expression of a behavioural syndrome among S. trutta personality traits, suggesting that it might increase the probability that the fish host would occur in the glochidia temperature optimum. Our findings present the first evidence that thermoregulation plays a fundamental role in the relationship of affiliated mussels and their fish hosts. Incorporating thermoregulation as a factor in the study of this relationship can help to interpret results from previous behavioural studies, as well as to optimise management measures related to endangered mussels.
- MeSH
- Acclimatization MeSH
- Host-Parasite Interactions MeSH
- Larva growth & development physiology MeSH
- Bivalvia growth & development physiology MeSH
- Fish Diseases parasitology MeSH
- Trout * MeSH
- Body Temperature Regulation * MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Host abundance and landscape structure often interact to shape spatial patterns of many wildlife diseases. Emergence, spread, and persistence of African swine fever (ASF) among wild boar in eastern Europe has raised questions on the factors underlying ASF dynamics in this novel host-pathogen system. This work identifies drivers of ASF occurrence in natural wild boar population. We evaluated factors shaping the probability of ASF-postitive wild boar during the first three years (2014-2016) of the ASF epidemic in Poland. We expected to observe positive effects of wild boar density, proportion of forested area, human activity, and proximity to previous infections on ASF case probability. We tested these predictions using the infection status of 830 wild boar samples and generalized mixed-effects models. The probability of ASF case increased from 3 to 20% as population density rose from 0.4 to 2 ind./km2. The positive effect of population density on ASF case probability was stronger at locations near previous ASF incidents. ASF was more likely to occur in forested areas, with the probability of detecting an ASF positive sample rising from 2 to 11% as forest cover around the sample increased from 0.5 to 100%. This pattern was consistent at both low and high wild boar densities. Indicators of human activity were poor predictors of ASF occurrence. Disease control efforts, such as culling and carcass search, should be focused on high-density populations where chances of detecting and eliminating ASF-positive wild boar are higher. The intensity of control measures should decrease with distance from the infected area to match the observed spatial pattern of ASF case probability. Woodlands represent areas of the highest risk of ASF case occurrence. Distribution and connectivity of suitable habitats over the landscape can be used to prioritize disease-management actions.
- MeSH
- African Swine Fever epidemiology MeSH
- Models, Biological MeSH
- Animals, Wild MeSH
- Epidemics veterinary MeSH
- Host-Pathogen Interactions * MeSH
- Swine MeSH
- Probability MeSH
- Spatial Analysis MeSH
- Sus scrofa MeSH
- African Swine Fever Virus physiology MeSH
- Environment MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Geographicals
- Poland MeSH
INTRODUCTION: In almost half of all sepsis patients, acute kidney injury (AKI) develops. However, the pathobiologic differences between sepsis patients with and without AKI are only poorly understood. We used a unique opportunity to examine dynamic inflammatory, renal hemodynamic, and microvascular changes in two clinically relevant large-animal models of sepsis. Our aim was to assess variability in renal responses to sepsis and to identify both hemodynamic and nonhemodynamic mechanisms discriminating individuals with AKI from those in whom AKI did not develop. METHODS: Thirty-six pigs were anesthetized, mechanically ventilated, and instrumented. After a recovery period, progressive sepsis was induced either by peritonitis (n = 13) or by continuous intravenous infusion of live Pseudomonas aeruginosa (n = 15). Eight sham operated-on animals served as time-matched controls. All animals received standard intensive care unit (ICU) care, including goal-directed hemodynamic management. Before, and at 12, 18, and 22 hours of sepsis, systemic and renal (ultrasound flow probe) hemodynamics, renal cortex microcirculation (laser Doppler), inflammation (interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), oxidative stress (thiobarbituric acid reactive species (TBARS), nitrite/nitrate concentrations (NOx), and renal oxygen kinetics and energy metabolism were measured. RESULTS: In 14 (50%) pigs, AKI developed (62% in peritonitis, 40% in bacteria infusion model). Fecal peritonitis resulted in hyperdynamic circulation, whereas continuous bacteria infusion was associated with normodynamic hemodynamics. Despite insults of equal magnitude, comparable systemic hemodynamic response, and uniform supportive treatment, only those pigs with AKI exhibited a progressive increase in renal vascular resistance. This intrarenal vasoconstriction occurred predominantly in the live-bacteria infusion model. In contrast to AKI-free animals, the development of septic AKI was preceded by early and remarkable inflammatory response (TNF-α, IL-6) and oxidative stress (TBARS). CONCLUSIONS: The observed variability in susceptibility to septic AKI in our models replicates that of human disease. Early abnormal host response accompanied by subsequent uncoupling between systemic and renal vascular resistance appear to be major determinants in the early phase of porcine septic AKI. Nonuniform and model-related renal hemodynamic responses that are unpredictable from systemic changes should be taken into consideration when evaluating hemodynamic therapeutic interventions in septic AKI.
- MeSH
- Acute Kidney Injury blood etiology physiopathology MeSH
- Biomarkers blood MeSH
- Time Factors MeSH
- Hemodynamics physiology MeSH
- Interleukin-6 blood MeSH
- Disease Models, Animal MeSH
- Oxidative Stress physiology MeSH
- Swine MeSH
- Sepsis complications MeSH
- Tumor Necrosis Factor-alpha blood MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
In search of novel targets for influenza inhibitors, a site on PB1 was selected for its high conservation and probable interaction with a host protein, RanBP5, that is key to nuclear import of PB1, where it complexes with PB2, PA, and NP to transcribe viral RNA. Docking with libraries of drug-like compounds led to a selection of five candidates that bound tightly and with a pose likely to inhibit protein binding. These were purchased and tested in vitro, found to be active, and then one was synthetically expanded to explore the structure-activity relationship. The top candidates had a carboxylic acid converted to an ester and electron-withdrawing substituents added to a phenyl group in the original structure. Resistance was slow to develop, but cytotoxicity was moderately high. Nuclear localization of PB1 and in vitro polymerase activity were both strongly inhibited.
- MeSH
- beta Karyopherins metabolism MeSH
- Influenza, Human drug therapy MeSH
- Humans MeSH
- Drug Discovery MeSH
- Computer Simulation MeSH
- Virus Replication drug effects MeSH
- High-Throughput Screening Assays MeSH
- Molecular Docking Simulation MeSH
- Viral Proteins antagonists & inhibitors MeSH
- Influenza A virus drug effects enzymology MeSH
- Structure-Activity Relationship MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
Kayviruses are polyvalent broad host range staphylococcal phages with a potential to combat staphylococcal infections. However, the implementation of rational phage therapy in medicine requires a thorough understanding of the interactions between bacteriophages and pathogens at omics level. To evaluate the effect of a phage used in therapy on its host bacterium, we performed differential transcriptomic analysis by RNA-Seq from bacteriophage K of genus Kayvirus infecting two Staphylococcus aureus strains, prophage-less strain SH1000 and quadruple lysogenic strain Newman. The temporal transcriptional profile of phage K was comparable in both strains except for a few loci encoding hypothetical proteins. Stranded sequencing revealed transcription of phage noncoding RNAs that may play a role in the regulation of phage and host gene expression. The transcriptional response of S. aureus to phage K infection resembles a general stress response with differential expression of genes involved in a DNA damage response. The host transcriptional changes involved upregulation of nucleotide, amino acid and energy synthesis and transporter genes and downregulation of host transcription factors. The interaction of phage K with variable genetic elements of the host showed slight upregulation of gene expression of prophage integrases and antirepressors. The virulence genes involved in adhesion and immune evasion were only marginally affected, making phage K suitable for therapy. IMPORTANCE Bacterium Staphylococcus aureus is a common human and veterinary pathogen that causes mild to life-threatening infections. As strains of S. aureus are becoming increasingly resistant to multiple antibiotics, the need to search for new therapeutics is urgent. A promising alternative to antibiotic treatment of staphylococcal infections is a phage therapy using lytic phages from the genus Kayvirus. Here, we present a comprehensive view on the phage-bacterium interactions on transcriptomic level that improves the knowledge of molecular mechanisms underlying the Kayvirus lytic action. The results will ensure safer usage of the phage therapeutics and may also serve as a basis for the development of new antibacterial strategies.
Schistosomiasis is a snail-borne disease that has a considerable impact on human and animal health, particularly in sub-Saharan Africa. The intermediate hosts of the schistosome parasites are freshwater snails of the genera Biomphalaria Preston, 1910 and Bulinus Müller, 1781. In order to identify existing gaps in the spread of the disease in the Democratic Republic of Congo (DRC), this study compiled the available knowledge of the distribution, population dynamics and ecology of the intermediate hosts of schistosomiasis. A systematic literature search was conducted in PubMed, Embase and Scopus for all malacological studies on schistosoma intermediate hosts in DRC published between 1927 and October 2022. A total of 55 records were found, of which 31 met the inclusion criteria: these were published field and experimental studies conducted in the DRC and focused on snails as intermediate hosts of schistosomes. The analysis of these studies revealed that more up-to-date data on the distribution of snail intermediate hosts in the DRC are needed. Moreover, ecological factors have been less studied for Bulinus species than for Biomphalaria species. These factors play a crucial role in determining suitable snail habitats, and the lack of comprehensive information poses a challenge in snail control. This review makes it clear that there are no current malacological data in the DRC. There is a clear need for molecular and ecological research to update the exact species status and population dynamics of all potential intermediate host species. This will facilitate targeted snail control measures that complement drug treatment in the control of schistosomiasis in the country.
- MeSH
- Biomphalaria * parasitology MeSH
- Bulinus parasitology MeSH
- Snails parasitology MeSH
- Humans MeSH
- Schistosoma physiology MeSH
- Schistosomiasis * epidemiology veterinary MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Systematic Review MeSH
- Geographicals
- Democratic Republic of the Congo MeSH
One of the key factors that determine the interaction between hosts and their parasites is the frequency of their interactions, which depends on the locomotory behavior of both parts. To address host behavior we used natural infections involving insect pathogenic nematodes and Drosophila melanogaster larvae as hosts. Using a modified version of a recently described method (FIMTrack) to assess several parameters in larger sets of animals, we initially detected specific differences in larval food searching when comparing Drosophila strains. These differences were further influenced by the presence of nematodes. Given a choice, Drosophila larvae clearly avoided nematodes irrespective of their genetic background. Our newly developed methods will be useful to test candidate genes and pathways involved in host/pathogen interactions in general and to assess specific parameters of their interaction.
- MeSH
- Drosophila melanogaster growth & development parasitology physiology MeSH
- Host-Parasite Interactions MeSH
- Larva parasitology physiology MeSH
- Locomotion MeSH
- Rhabditida physiology MeSH
- Feeding Behavior MeSH
- Gene Expression Regulation, Developmental MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
