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Nature Communications Jun 2024Multi-host parasites pose greater health risks to wildlife, livestock, and humans than single-host parasites, yet our understanding of how ecological and biological...
Multi-host parasites pose greater health risks to wildlife, livestock, and humans than single-host parasites, yet our understanding of how ecological and biological factors influence a parasite's host range remains limited. Here, we assemble the largest and most complete dataset on permanently parasitic mammalian mites and build a predictive model assessing the probability of single-host parasites to become multi-hosts, while accounting for potentially unobserved host-parasite links and class imbalance. This model identifies statistically significant predictors related to parasites, hosts, climate, and habitat disturbance. The most important predictors include the parasite's contact level with the host immune system and two variables characterizing host phylogenetic similarity and spatial co-distribution. Our model reveals an overrepresentation of mites associated with Rodentia (rodents), Chiroptera (bats), and Carnivora in the multi-host risk group. This highlights both the potential vulnerability of these hosts to parasitic infestations and the risk of serving as reservoirs of parasites for new hosts. In addition, we find independent macroevolutionary evidence that supports our prediction of several single-host species of Notoedres, the bat skin parasites, to be in the multi-host risk group, demonstrating the forecasting potential of our model.
Topics: Animals; Host Specificity; Mites; Host-Parasite Interactions; Phylogeny; Mammals; Chiroptera; Ecosystem; Rodentia; Mite Infestations; Carnivora
PubMed: 38926409
DOI: 10.1038/s41467-024-49515-3 -
Zhongguo Dang Dai Er Ke Za Zhi =... Jun 2024To investigate the efficacy and safety of subcutaneous immunotherapy (SCIT) using dust mites in children with allergic asthma. (Randomized Controlled Trial)
Randomized Controlled Trial
OBJECTIVES
To investigate the efficacy and safety of subcutaneous immunotherapy (SCIT) using dust mites in children with allergic asthma.
METHODS
In a prospective randomized controlled study, 98 children with dust mite-induced allergic asthma were randomly divided into a control group (=49) and an SCIT group (=49). The control group received inhaled corticosteroid treatment, while the SCIT group additionally received a standardized three-year SCIT regimen. The two groups were compared based on peripheral blood eosinophil percentage, visual analogue score (VAS), total medication score, Asthma Control Test/Childhood Asthma Control Test scores, fractional exhaled nitric oxide (FeNO), and lung function before treatment, and at 6 months, 1 year, 2 years, and 3 years after treatment. Adverse reactions were recorded post-injection to evaluate the safety of SCIT.
RESULTS
Compared with pre-treatment levels, the SCIT group showed a significant reduction in the percentage of peripheral blood eosinophils, VAS, total medication score, and FeNO, while lung function significantly improved, and asthma control levels were better 3 years after treatment (<0.05). Compared with the control group, the SCIT group showed more significant improvement in all evaluated indicators 3 years after treatment (<0.05). A total of 2 744 injections were administered, resulting in 157 cases (5.72%) of local adverse reactions and 4 cases (0.15%) of systemic adverse reactions, with no severe systemic adverse events.
CONCLUSIONS
SCIT is an effective and safe treatment for allergic asthma in children.
Topics: Humans; Asthma; Male; Child; Female; Animals; Prospective Studies; Injections, Subcutaneous; Pyroglyphidae; Child, Preschool; Desensitization, Immunologic; Adolescent
PubMed: 38926371
DOI: 10.7499/j.issn.1008-8830.2309137 -
Proceedings of the National Academy of... Jul 2024Asthma is a widespread airway disorder where GATA3-dependent Type-2 helper T (Th2) cells and group 2 innate lymphoid cells (ILC2s) play vital roles. Asthma-associated...
Asthma is a widespread airway disorder where GATA3-dependent Type-2 helper T (Th2) cells and group 2 innate lymphoid cells (ILC2s) play vital roles. Asthma-associated single nucleotide polymorphisms (SNPs) are enriched in a region located 926-970 kb downstream from GATA3 in the 10p14 (hG900). However, it is unknown how hG900 affects the pathogenesis of allergic airway inflammation. To investigate the roles of the asthma-associated GATA3 enhancer region in experimental allergic airway inflammation, we first examined the correlation between GATA3 expression and the activation of the hG900 region was analyzed by flow cytometry and ChIP-qPCR. We found that The activation of enhancers in the hG900 region was strongly correlated to the levels of GATA3 in human peripheral T cell subsets. We next generated mice lacking the mG900 region (mG900KO mice) were generated by the CRISPR-Cas9 system, and the development and function of helper T cells and ILCs in mG900KO mice were analyzed in steady-state conditions and allergic airway inflammation induced by papain or house dust mite (HDM). The deletion of the mG900 did not affect the development of lymphocytes in steady-state conditions or allergic airway inflammation induced by papain. However, mG900KO mice exhibited reduced allergic inflammation and Th2 differentiation in the HDM-induced allergic airway inflammation. The analysis of the chromatin conformation around by circular chromosome conformation capture coupled to high-throughput sequencing (4C-seq) revealed that the mG900 region interacted with the transcription start site of with an influencing chromatin conformation in Th2 cells. These findings indicate that the mG900 region plays a pivotal role in Th2 differentiation and thus enhances allergic airway inflammation.
Topics: GATA3 Transcription Factor; Animals; Th2 Cells; Mice; Cell Differentiation; Asthma; Enhancer Elements, Genetic; Humans; Mice, Knockout; Inflammation; Hypersensitivity; Polymorphism, Single Nucleotide; Mice, Inbred C57BL
PubMed: 38923989
DOI: 10.1073/pnas.2320727121 -
Parasitology Research Jun 2024Hyperparasitism is defined as the interaction where one parasite is infected by another parasite. In bat flies (Streblidae and Nycteribiidae), both hyperparasites and...
Hyperparasitism is defined as the interaction where one parasite is infected by another parasite. In bat flies (Streblidae and Nycteribiidae), both hyperparasites and microparasites (bacteria, viruses, fungi, and arthropods such as mites) have been documented. Fungi belonging to the order Laboulbeniales are microscopic parasites of a wide diversity of arthropod hosts. Three genera exclusively target bat flies: Arthrorhynchus, which parasitizes species within Nycteribiidae in the Eastern Hemisphere, while genus Gloeandromyces and Nycteromyces parasitize Streblidae in the Western Hemisphere. Among the hyperparasitic arthropods, mites of family Neothrombidiidae, particularly the monospecific genus Monunguis, are known to parasitize bat flies. Here we present the first records of the hyperparasites Monunguis streblida and Gloeandromyces pageanus f. polymorphus parasitizing Streblidae bat flies in Colombia and a summary of these hyperparasitic interactions in the Neotropics. We detected fungi and mites parasitizing bat flies that were collected in the Magdalena River Basin, Colombia, in field expeditions in 2018, 2022, and 2023. We identified 17 bat flies and two species of hyperparasites, specifically M. streblida and the fungi Gloeandromyces. Our search for reports of these interactions in the Neotropics revealed that seven species of Trichobius (Streblidae) are parasitized by M. streblida, whereas Paratrichobius longicrus (Streblidae) is parasitized by Gloeandromyces pageanus f. polymorphus. These interactions have been reported in 11 countries, but our records are the first of M. streblida and Laboulbeniales fungi parasitizing bat flies in Colombia. So far, a total of 14 species of fungi and one species of mite have been associated with 19 species of bat flies, which in turn, are linked to 15 species of Neotropical bats.
Topics: Animals; Diptera; Chiroptera; Colombia; Mites; Host-Parasite Interactions
PubMed: 38922514
DOI: 10.1007/s00436-024-08221-1 -
Insects Jun 2024are predaceous mites that feed on phytophagous mites, pollens, and plant exudates and are known as one of the most potent biological pest management agents. is a...
are predaceous mites that feed on phytophagous mites, pollens, and plant exudates and are known as one of the most potent biological pest management agents. is a global mite that is difficult to manage because of its high population growth rates, necessitating alternative management measures like biological control. Regarding the functional response, the effects of temperature and prey density are some of the essential behaviors of natural enemies. This study investigates the effect of varying temperatures and prey densities on , a biological control agent for . The present results demonstrated the change in the functional response estimates when was reared at various temperatures and different prey densities. The results of the estimates regarding the searching efficiency () showed the highest value ( = 0.919) at 26 °C and the lowest value ( = 0.751) at 14 °C. The handling time per prey item () for the predatory mites changed with the temperature and prey density, showing the shortest handling time at 26 °C ( = 0.005) and the highest value at 14 °C ( = 0.015). The functional response curves matched the type II functional response model, demonstrating the inverse dependence of temperatures and prey density with a positive quadratic coefficient. The predation curves for showed a significant difference between the mean numbers of consumed at various prey densities and temperatures, illustrating a relationship between and Therefore, the results of this research may be utilized to forecast the behavior of and its usefulness in controlling populations.
PubMed: 38921159
DOI: 10.3390/insects15060444 -
Insects Jun 2024Implementation of marker-assisted selection (MAS) in modern beekeeping would improve sustainability, especially in breeding programs aiming for resilience against the...
Implementation of marker-assisted selection (MAS) in modern beekeeping would improve sustainability, especially in breeding programs aiming for resilience against the parasitic mite . Selecting honey bee colonies for natural resistance traits, such as brood-intrinsic suppression of varroa mite reproduction, reduces the use of chemical acaricides while respecting local adaptation. In 2019, eight genomic variants associated with varroa non-reproduction in drone brood were discovered in a single colony from the Amsterdam Water Dune population in the Netherlands. Recently, a new study tested the applicability of these eight genetic variants for the same phenotype on a population-wide scale in Flanders, Belgium. As the properties of some variants varied between the two studies, one hypothesized that the difference in genetic ancestry of the sampled colonies may underly these contribution shifts. In order to frame this, we determined the allele frequencies of the eight genetic variants in more than 360 colonies across the European continent and found that variant type allele frequencies of these variants are primarily related to the subspecies or phylogenetic honey bee lineage. Our results confirm that population-specific genetic markers should always be evaluated in a new population prior to using them in MAS programs.
PubMed: 38921134
DOI: 10.3390/insects15060419 -
Insects May 2024Thrips biocontrol research in greenhouse crops has focused primarily on western flower thrips (WFT; ). However, recent outbreaks of onion thrips (OT; ) in Ontario,...
Thrips biocontrol research in greenhouse crops has focused primarily on western flower thrips (WFT; ). However, recent outbreaks of onion thrips (OT; ) in Ontario, Canada, demonstrate that biocontrol-based IPM programs for WFT do not control OT sufficiently to prevent crop losses. A lack of comparative studies makes it difficult to determine which program components for WFT are failing for OT. We conducted several laboratory trials examining the extent to which commercial biocontrol products kill OT compared to WFT. These included phytoseiid mites (, , , ), a large generalist predator (), an entomopathogenic fungus strain GHA), and entomopathogenic nematodes (, , ). In no-choice trials, and consumed more OT than WFT (first instars and adults, respectively). In choice trials, , , and consumed more OT than WFT. caused higher mortality in OT than WFT. There was no difference in mortality between thrips species exposed to other biocontrol agents. This suggests available tools have the potential to manage OT as well as WFT. Possible explanations why this potential is not realized in commercial settings are explored.
PubMed: 38921115
DOI: 10.3390/insects15060400 -
Insects May 2024The mechanisms of action behind decreased mite reproduction (DMR) are still unknown, but current hypotheses state that DMR is the result of brood-intrinsic and/or...
The mechanisms of action behind decreased mite reproduction (DMR) are still unknown, but current hypotheses state that DMR is the result of brood-intrinsic and/or external disturbances in the -honey bee pupa signal interactions. For accurate and precise DMR phenotyping, sufficient single infested honey bee brood cells are required (e.g., 35), which requires extensive labor and time and may exclude many samples not reaching the threshold. We defined a new comprehensive trait called the 'mean reproduction rate' (mVR), which describes the mean number of offspring mites per infested cell in the sample while compensating for the reduced number of offspring with increasing multiple infested cells. We found a significant correlation between mVR and DMR, allowing for an estimation of DMR based on the mVR only. When the mVR was calculated with 10 infested cells, we found an average variation in mVR of 16.8%. For the same variation in DMR determination, 40 single infested cells are required. This broader look at resistance phenotyping can improve the applicability and effectiveness of traits related to reproduction in honey bee breeding programs.
PubMed: 38921112
DOI: 10.3390/insects15060397 -
Insects May 2024Resistance against amitraz in mite populations has become a subject of interest in recent years due to the increasing reports of the reduced field efficacy of amitraz...
Resistance against amitraz in mite populations has become a subject of interest in recent years due to the increasing reports of the reduced field efficacy of amitraz treatments, especially from some beekeepers in France and the United States. The loss of amitraz as a reliable tool to effectively reduce mite infestation in the field could severely worsen the position of beekeepers in the fight to keep infestation rates in their colonies at low levels. In this publication, we present data from French apiaries, collected in the years 2020 and 2021. These data include the field efficacy of an authorized amitraz-based treatment (Apivar ,Véto-pharma, France) and the results of laboratory sensitivity assays of mites exposed to the reference LC concentration of amitraz. In addition, a total of 240 mites from Eastern, Central, and Southern regions in France that were previously classified as either "sensitive" or "resistant" to amitraz in a laboratory sensitivity assay were genotyped. The genetic analyses of mite samples are focused on the β-adrenergic-like octopamine receptor, which is considered as the main target site for amitraz in mites. Special attention was paid to a single-nucleotide polymorphism (SNP) at position 260 of the gene that was previously associated to amitraz resistance in French mites, . Our findings confirm that amitraz resistance occurs in patches or "islands of resistance", with a less severe reduction in treatment efficacy compared to pyrethroid resistance or coumaphos resistance in mites. The results of our genetic analyses of mites call into question the hypothesis of the SNP at position 260 of the gene being directly responsible for amitraz resistance development.
PubMed: 38921105
DOI: 10.3390/insects15060390 -
Insects May 2024The dispersal strategies of a species can affect its invasion success. Investigations into the dispersal strategies of invasive species in relation to different factors...
The dispersal strategies of a species can affect its invasion success. Investigations into the dispersal strategies of invasive species in relation to different factors help improve our understanding of invasion mechanisms and provide knowledge for population management and invasion evaluation. Zacher (Acari: Tetranychidae) is an invasive species which is native to Europe but is now cosmopolitan. Here, we examined the effects of age and density on dispersal in mated females. Our results show that older females that are capable of producing more eggs within 24 h were more likely to disperse and moved longer distances than younger ones with fewer eggs. Older females spread most of their eggs out of their natal habitats and over longer distances, which reduced competition and increased offspring fitness. Females exhibited significantly increased dispersal probability and distances with an increase in population density to avoid crowding. The synchronization of dispersal and reproduction, along with the positive density-dependent dispersal strategy, may facilitate the habitat colonization and invasion speed of .
PubMed: 38921102
DOI: 10.3390/insects15060387