Overlapping distributions of hosts and parasites are critical for successful completion of multi-host parasite life cycles and even small environmental changes can impact on the parasite's presence in a host or habitat. The generalist Cardiocephaloides longicollis was used as a model for multi-host trematode life cycles in marine habitats. This parasite was studied to quantify parasite dispersion and transmission dynamics, effects of biological changes and anthropogenic impacts on life cycle completion. We compiled the largest host dataset to date, by analysing 3351 molluscs (24 species), 2108 fish (25 species) and 154 birds (17 species) and analysed the resultant data based on a number of statistical models. We uncovered extremely low host specificity at the second intermediate host level and a preference of the free-swimming larvae for predominantly demersal but also benthic fish. The accumulation of encysted larvae in the brain with increasing fish size demonstrates that parasite numbers level off in fish larger than 140mm, consistent with parasite-induced mortality at these levels. The highest infection rates were detected in host species and sizes representing the largest fraction of Mediterranean fishery discards (up to 67% of the total catch), which are frequently consumed by seabirds. Significantly higher parasite densities were found in areas with extensive fishing activity than in those with medium and low activity, and in fish from shallow lagoons than in fish from other coastal areas. For the first time, C. longicollis was also detected in farmed fish in netpens. Fishing generally drives declines in parasite abundance, however, our study suggests an enhanced transmission of generalist parasites such as C. longicollis, an effect that is further amplified by the parasite's efficient host-finding mechanisms and its alteration of fish host behaviour by larvae encysted in the brain. The anthropogenic impact on the distribution of trophically-transmitted, highly prevalent parasites likely results in a strong effect on food web structure, thus making C. longicollis an ideal bioindicator to compare food webs in natural communities versus those impacted by fisheries and aquaculture.

• MeSH
• Ecosystem MeSH
• Snails parasitology   MeSH
• Host Specificity MeSH
• Trematode Infections parasitology   transmission   veterinary   MeSH
• Human Activities MeSH
• Mollusca classification   parasitology   MeSH
• Bird Diseases parasitology   transmission   MeSH
• Fish Diseases parasitology   transmission   MeSH
• Food Chain MeSH
• Birds MeSH
• DNA, Ribosomal chemistry   MeSH
• RNA, Ribosomal, 28S genetics   MeSH
• Fisheries MeSH
• Fishes anatomy & histology   classification   MeSH
• Sequence Analysis, DNA veterinary   MeSH
• Life Cycle Stages * MeSH
• Trematoda classification   genetics   growth & development   MeSH
• Body Size MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Geographicals
• Black Sea MeSH
• Mediterranean Sea MeSH

• MeSH
• Acquired Immunodeficiency Syndrome prevention & control   MeSH
• HIV Infections prevention & control   MeSH
• Delivery of Health Care MeSH
• Refugees MeSH
• Geographicals
• Africa South of the Sahara MeSH

• Conspectus
• Veřejné zdraví a hygiena
• NML Fields
• dermatovenerologie
• NML Publication type
• informační publikace

The tachinid fly Exorista larvarum (L.) (Diptera: Tachinidae) is a polyphagous larval endoparasitoid that deposits its eggs on the host exoskeleton of lepidopteran and tenthredinid larvae. The attachment of larval E. larvarum and the formation of the respiratory funnel were studied during infestation in the last larval instar of the wax moth, Galleria mellonella (L.) (Lepidoptera: Pyralidae). The tachinid larvae burrow through the host integument after hatching, using their robust cephalopharyngeal skeleton, leaving a dark spot at the point of their penetration as a result of host cuticle melanization. Endoparasitoid penetration induces the host cellular defence, resulting in the formation of a haemocyte capsule consisting of multi-cellular sheaths. This enveloping capsule later undergoes melanization, which is mostly obvious towards the posterior part of the endoparasitoid. The endoparasitoid uses the host encapsulation response to build a respiratory funnel from the modified host integument, leading to the host surface. The encapsulated larva remains attached to the respiratory funnel via an anal hook and cuticular spines until fully developed. Additional immunohistochemical analyses were used to study host-parasitoid interactions. Indirect immunofluorescence showed no labelling of potential tachinid antigens and confirmed no effect on the surrounding host tissues. A simulated parasitization with coated polybead microspheres revealed the mortal impact of tachinid antigens to the host. Hosts injected with antigen-coated polybeads died as a consequence of an acute and extensive immunological response to the tachinid antigens and not due to the trauma caused by foreign objects inside their body.

• MeSH
• Diptera physiology   MeSH
• Fluorescent Antibody Technique, Indirect MeSH
• Host-Parasite Interactions * MeSH
• Larva physiology   MeSH
• Microspheres MeSH
• Moths parasitology   MeSH
• Mice MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

Parasites with wide host spectra provide opportunities to study the ecological parameters of speciation, as well as the process of the evolution of host specificity. The speciose and cosmopolitan louse genus Menacanthus comprises both multi-host and specialised species, allowing exploration of the ecological and historical factors affecting the evolution of parasites using a comparative approach. We used phylogenetic analysis to reconstruct evolutionary relationships in 14 species of Menacanthus based on the sequences of one mitochondrial and one nuclear gene. The results allowed us to validate species identification based on morphology, as well as to explore host distribution by assumed generalist and specialist species. Our analyses confirmed a narrow host use for several species, however in some cases, the supposed host specialists had a wider host spectrum than anticipated. In one case a host generalist (Menacanthus eurysternus) was clustered terminally on a clade almost exclusively containing host specialists. Such a clade topology indicates that the process of host specialisation may not be irreversible in parasite evolution. Finally, we compared patterns of population genetic structure, geographic distribution and host spectra between two selected species, M. eurysternus and Menacanthus camelinus, using haplotype networks. Menacanthus camelinus showed limited geographical distribution in combination with monoxenous host use, whereas M. eurysternus showed a global distribution and lack of host specificity. It is suggested that frequent host switching maintains gene flow between M. eurysternus populations on unrelated hosts in local populations. However, gene flow between geographically distant localities was restricted, suggesting that geography rather than host-specificity is the main factor defining the global genetic diversity of M. eurysternus.

• MeSH
• Amblycera classification   genetics   physiology   MeSH
• Adaptation, Biological MeSH
• Biological Evolution * MeSH
• Phylogeography * MeSH
• Host Specificity MeSH
• Molecular Sequence Data MeSH
• Sequence Analysis, DNA MeSH
• Gene Flow MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

Pneumocystis is a genus of parasitic fungi infecting lung tissues in a wide range of mammal species, displaying a strong host specificity and patterns of co-speciation with their hosts. However, a recent study on Asiatic murids challenged these patterns reporting several Pneumocystis lineages/species shared by different host species or even genera in the Rattini and Murini tribes. Here we screened lung samples of 27 species of African rodents from five families for the presence of Pneumocystis DNA. Using reconstructed multi-locus phylogenies of both hosts and parasites, we tested the hypothesis of their co-evolution. We found that Pneumocystis is widespread in African rodents, detected in all but seven screened host species, with species-level prevalence ranging from 5.9 to 100%. Several host species carry pairs of highly divergent Pneumocystis lineages/species. The retrieved co-phylogenetic signal was highly significant (p = .0017). We found multiple co-speciations, sorting events and two host-shift events, which occurred between Murinae and Deomyinae hosts. Comparison of genetic distances suggests higher substitution rates for Pneumocystis relative to the rodent hosts on neutral loci and slower rates on selected ones. We discuss life-history traits and population dynamics factors which could explain the observed results.

• MeSH
• Biological Evolution MeSH
• Phylogeny MeSH
• Genes, Fungal MeSH
• Host-Pathogen Interactions MeSH
• Muridae microbiology   MeSH
• Lung microbiology   MeSH
• Pneumocystis classification   genetics   physiology   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Geographicals
• Africa MeSH

Infekcie močových ciest (IMC) patria medzi najčastejšie infekčné ochorenia. Uropatogénne kmene E. coli (UPEC) spôsobujú 70 – 95 % IMC. Obsahové látky brusnice veľkoplodej (proantokyanidíny) zabraňujú tak senzitívnym, ako aj multi-drug rezistentným kmeňom baktérií E. coli adherovať k slizničným bunkám urogenitálneho traktu. Celkovo in-vivo a in-vitro štúdie poukazujú, že používanie prípravkov z brusníc predstavuje zaujímavú a novú alternatívu s možnosťou prevencie opakovaných infekcií močových ciest.

A urinary tract infection (UTI) is one of the most prevalent bacterial infections. Uropathogenic strains of Escherichia coli (UPEC) are the primary cause of community-acquired UTI (70 – 95 %). Vaccinium macrocarpon (cranberry) and its constituents could prevent bacterial adhesion to host tissue against both sensitive as well as multi-drug resistant strains of E. coli. Overall, in-vivo and in-vitro studies suggested that consumption of cranberry preparations represents an interesting new strategy to prevent recurrent urinary tract infections.

Host size and distance from an infected plant have been previously found to affect mistletoe occurrence in woody vegetation but the effect of host plant competition on mistletoe infection has not been empirically tested. For an individual tree, increasing competition from neighbouring trees decreases its resource availability, and resource availability is also known to affect the establishment of mistletoes on host trees. Therefore, competition is likely to affect mistletoe infection but evidence for such a mechanism is lacking. Based on this, we hypothesised that the probability of occurrence as well as the abundance of mistletoes on a tree would increase not only with increasing host size and decreasing distance from an infected tree but also with decreasing competition by neighbouring trees. Our hypothesis was tested using generalized linear models (GLMs) with data on Loranthus europaeus Jacq., one of the two most common mistletoes in Europe, on 1015 potential host stems collected in a large fully mapped plot in the Czech Republic. Because many trees were multi-stemmed, we ran the analyses for both individual stems and whole trees. We found that the probability of mistletoe occurrence on individual stems was affected mostly by stem size, whereas competition had the most important effects on the probability of mistletoe occurrence on whole trees as well as on mistletoe abundance. Therefore, we confirmed our hypothesis that competition among trees has a negative effect on mistletoe occurrence.

• MeSH
• Quercus * MeSH
• Ecosystem * MeSH
• Forests * MeSH
• Mistletoe * MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Geographicals
• Czech Republic MeSH

Pathogen species often consist of genetically distinct strains, which can establish mixed infections or coinfections in the host. In coinfections, interactions between pathogen strains can have important consequences for their transmission success. We used the tick-borne bacterium Borrelia afzelii, which is the most common cause of Lyme disease in Europe, as a model multi-strain pathogen to investigate the relationship between coinfection, competition between strains, and strain-specific transmission success. Mus musculus mice were infected with one or two strains of B. afzelii, strain transmission success was measured by feeding ticks on mice, and the distribution of each strain in six different mouse organs and the ticks was measured using qPCR. Coinfection and competition reduced the tissue infection prevalence of both strains and changed their bacterial abundance in some tissues. Coinfection and competition also reduced the transmission success of the B. afzelii strains from the infected hosts to feeding ticks. The ability of the B. afzelii strains to establish infection in the host tissues was strongly correlated with their transmission success to the tick vector. Our study demonstrates that coinfection and competition between pathogen strains inside the host tissues can have major consequences for their transmission success.

• MeSH
• Borrelia burgdorferi Group * genetics   MeSH
• Ixodes * MeSH
• Coinfection * MeSH
• Lyme Disease * MeSH
• Mice MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Geographicals
• Europe MeSH

• MeSH
• Microbiology MeSH
• Mucous Membrane MeSH

• Conspectus
• Mikrobiologie
• NML Fields
• mikrobiologie, lékařská mikrobiologie
• patologie

Pathogen life history theory assumes a positive relationship between pathogen load in host tissues and pathogen transmission. Empirical evidence for this relationship is surprisingly rare due to the difficulty of measuring transmission for many pathogens. The comparative method, where a common host is experimentally infected with a set of pathogen strains, is a powerful approach for investigating the relationships between pathogen load and transmission. The validity of such experimental estimates of strain-specific transmission is greatly enhanced if they can predict the pathogen population strain structure in nature. Borrelia burgdorferi is a multi-strain, tick-borne spirochete that causes Lyme disease in North America. This study used 11 field-collected strains of B. burgdorferi, a rodent host (Mus musculus, C3H/HeJ) and its tick vector (Ixodes scapularis) to determine the relationship between pathogen load in host tissues and lifetime host-to-tick transmission (HTT). Mice were experimentally infected via tick bite with 1 of 11 strains. Lifetime HTT was measured by infesting mice with I. scapularis larval ticks on 3 separate occasions. The prevalence and abundance of the strains in the mouse tissues and the ticks were determined by qPCR. We used published databases to obtain estimates of the frequencies of these strains in wild I. scapularis tick populations. Spirochete loads in ticks and lifetime HTT varied significantly among the 11 strains of B. burgdorferi. Strains with higher spirochete loads in the host tissues were more likely to infect feeding larval ticks, which molted into nymphal ticks that had a higher probability of B. burgdorferi infection (i.e., higher HTT). Our laboratory-based estimates of lifetime HTT were predictive of the frequencies of these strains in wild I. scapularis populations. For B. burgdorferi, the strains that establish high abundance in host tissues and that have high lifetime transmission are the strains that are most common in nature.

• MeSH
• Borrelia burgdorferi * MeSH
• Ixodes * MeSH
• Larva MeSH
• Lyme Disease * MeSH
• Mice, Inbred C3H MeSH
• Mice MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH