-
Trends in Parasitology Aug 2023'Chiggers' (trombiculid mite larvae) are best known as vectors of rickettsial pathogens, Orientia spp., which cause a zoonosis, scrub typhus. However, several other... (Review)
Review
'Chiggers' (trombiculid mite larvae) are best known as vectors of rickettsial pathogens, Orientia spp., which cause a zoonosis, scrub typhus. However, several other pathogens (e.g., Hantaan orthohantavirus, Dabie bandavirus, Anaplasma spp., Bartonella spp., Borrelia spp., and Rickettsia spp.) and bacterial symbionts (e.g., Cardinium, Rickettsiella, and Wolbachia) are being reported from chiggers with increasing frequency. Here, we explore the surprisingly diverse chigger microbiota and potential interactions within this microcosm. Key conclusions include a possible role for chiggers as vectors of viral diseases; the dominance in some chigger populations of unidentified symbionts in several bacterial families; and increasing evidence for vertical transmission of potential pathogens and symbiotic bacteria in chiggers, suggesting intimate interactions and not simply incidental acquisition of bacteria from the environment or host.
Topics: Humans; Animals; Trombiculidae; Orientia tsutsugamushi; Scrub Typhus; Rickettsia; Zoonoses
PubMed: 37270375
DOI: 10.1016/j.pt.2023.05.002 -
Cellular & Molecular Immunology Nov 2023Aeroallergen sensitization, mainly mediated by lung epithelium and dendritic cells (DCs), is integral to allergic asthma pathogenesis and progression. IL-10 has a dual...
Aeroallergen sensitization, mainly mediated by lung epithelium and dendritic cells (DCs), is integral to allergic asthma pathogenesis and progression. IL-10 has a dual role in immune responses, as it inhibits myeloid cell activation but promotes B-cell responses and epithelial cell proliferation. Here, we report a proinflammatory function of B-cell-derived IL-10 modulated by Bcl-3 in allergic asthma. Specifically, Bcl-3 mice showed elevated IL-10 levels and were found to be highly vulnerable to allergic asthma induced by house dust mites (HDMs). IL-10 had a positive correlation with the levels of the DC chemoattractant CCL-20 in HDM-sensitized mice and in patients with asthma and induced a selective increase in CCL-20 production by mouse lung epithelial cells. Blockade of IL-10 or IL-10 receptors during sensitization dampened both HDM-induced sensitization and asthma development. IL-10 levels peaked 4 h post sensitization with HDM and IL-10 was primarily produced by B cells under Bcl-3-Blimp-1-Bcl-6 regulation. Mice lacking B-cell-derived IL-10 displayed decreased lung epithelial CCL-20 production and diminished DC recruitment to the lungs upon HDM sensitization, thereby demonstrating resistance to HDM-induced asthma. Moreover, responses to HDM stimulation in Bcl-3 mice lacking B-cell-derived IL-10 were comparable to those in Bcl-3 mice. The results revealed an unexpected role of B-cell-derived IL-10 in promoting allergic sensitization and demonstrated that Bcl-3 prevents HDM-induced asthma by inhibiting B-cell-derived IL-10 production. Thus, targeting the Bcl-3/IL-10 axis to inhibit allergic sensitization is a promising approach for treating allergic asthma. IL-10 is released rapidly from lung plasma cells under Bcl-3-Blimp-1-Bcl-6 regulation upon house dust mite exposure and amplifies lung epithelial cell (EC)-derived CCL-20 production and subsequent dendritic cell (DC) recruitment to promote allergic sensitization in asthma.
Topics: Animals; Humans; Mice; Allergens; Asthma; Dendritic Cells; Disease Models, Animal; Interleukin-10; Lung; Pyroglyphidae; Th2 Cells
PubMed: 37653127
DOI: 10.1038/s41423-023-01079-w -
Journal of the European Academy of... Dec 2023Rosacea is a common chronic inflammatory skin condition that is often refractory to treatment, with frequent relapses. Alterations in the skin immunological response and...
BACKGROUND
Rosacea is a common chronic inflammatory skin condition that is often refractory to treatment, with frequent relapses. Alterations in the skin immunological response and Demodex mite infestation are the primary aetiologic factors targeted for treatment. Transient receptor potential cation channel subfamily V member 1 (TRPV1) is a nociceptive cation channel that plays a role in cutaneous neurogenic pain and can be activated by various rosacea triggers.
OBJECTIVES
We investigated the effects of TRPV1 modulation in rosacea, focussing on Demodex mite colonization and cutaneous neurogenic inflammation.
METHODS
We examined mRNA expression levels according to Demodex population counts. An in vitro study using capsazepine as a TRPV1 antagonist was performed to assess the influence of TRPV1 in keratinocytes. A rosacea-like mouse model was generated by the injection of the 37-amino acid C-terminal cathelicidin peptide (LL37), and changes in the skin, dorsal root ganglion (DRG) and ears were examined.
RESULTS
Increased Demodex mite population counts were associated with increased expression levels of TRPV1, tropomyosin receptor kinase A (TrkA) and nerve growth factor (NGF), and these levels could be reduced by capsazepine treatment in keratinocytes. In an in vivo study, the downstream effects of TRPV1 activation were investigated in the skin, DRG and ears of the rosacea-like mouse model.
CONCLUSIONS
The findings of this study are instrumental for understanding the underlying causes of rosacea and could potentially lead to the development of new treatments targeting the NGF-TrkA-TRPV1 pathway. The identification of this pathway as a therapeutic target could represent a major breakthrough for rosacea research, potentially resulting in more effective and targeted rosacea treatments. This study contributes to an improved understanding of rosacea pathophysiology, which may lead to the development of more effective treatments in the future.
Topics: Animals; Mice; Neurogenic Inflammation; Nerve Growth Factor; Mites; Rosacea; Mite Infestations; TRPV Cation Channels
PubMed: 37606610
DOI: 10.1111/jdv.19449 -
The Journal of Allergy and Clinical... Jan 2024Allergen immunotherapy is highly effective for seasonal pollinosis. Three years of treatment results in long-term efficacy. This disease modification is accompanied by... (Randomized Controlled Trial)
Randomized Controlled Trial
Allergen immunotherapy is highly effective for seasonal pollinosis. Three years of treatment results in long-term efficacy. This disease modification is accompanied by downregulation of allergen-specific Th2 responses and the induction of persistent specific IgG- and IgA-associated IgE-blocking activity. In children with seasonal rhinitis, both subcutaneous and sublingual pollen immunotherapy have been shown to reduce the development of asthma symptoms and asthma medication requirements. House dust mite tablet allergen immunotherapy has been shown to be effective for perennial mite-driven rhinitis in adults and children and may suppress asthma exacerbations, whereas its long-term efficacy has yet to be explored. The success of primary prevention of peanut allergy in childhood by introduction of peanut into the diet during infancy provides a strong rationale to explore whether primary prevention of inhalant allergies and asthma may also be possible. House dust mite allergy is a major risk factor for developing asthma. Preliminary data in at-risk children suggest that sublingual house dust mite immunotherapy initiated during infancy could reduce the onset of multiple allergen sensitizations and prevent the development of asthma at age 6 years. This possibility should now be explored in an adequately powered, prospectively randomized controlled trial.
Topics: Child; Adult; Animals; Humans; Hypersensitivity; Desensitization, Immunologic; Asthma; Allergens; Rhinitis, Allergic, Seasonal; Rhinitis; Respiration Disorders; Pyroglyphidae; Sublingual Immunotherapy
PubMed: 37844847
DOI: 10.1016/j.jaip.2023.10.013 -
Plant Physiology Nov 2023Composite generalist herbivores are comprised of host-adapted populations that retain the ability to shift hosts. The degree and overlap of mechanisms used by...
Composite generalist herbivores are comprised of host-adapted populations that retain the ability to shift hosts. The degree and overlap of mechanisms used by host-adapted generalist and specialist herbivores to overcome the same host plant defenses are largely unknown. Tetranychidae mites are exceptionally suited to address the relationship between host adaptation and specialization in herbivores as this group harbors closely related species with remarkably different host ranges-an extreme generalist the two-spotted spider mite (Tetranychus urticae Koch [Tu]) and the Solanaceous specialist Tetranychus evansi (Te). Here, we used tomato-adapted two-spotted spider mite (Tu-A) and Te populations to compare mechanisms underlying their host adaptation and specialization. We show that both mites attenuate induced tomato defenses, including protease inhibitors (PIs) that target mite cathepsin L digestive proteases. While Te solely relies on transcriptional attenuation of PI induction, Tu and Tu-A have elevated constitutive activity of cathepsin L proteases, making them less susceptible to plant anti-digestive proteins. Tu-A and Te also rely on detoxification of tomato constitutive defenses. Te uses esterase and P450 activities, while Tu-A depends on the activity of all major detoxification enzymatic classes to disarm tomato defensive compounds to a lesser extent. Thus, even though both Tu-A and Te use similar mechanisms to counteract tomato defenses, Te can better cope with them. This finding is congruent with the ecological and evolutionary times required to establish mite adaptation and specialization states, respectively.
Topics: Animals; Tetranychidae; Host Adaptation; Cathepsin L; Plants; Biological Evolution; Herbivory
PubMed: 37437113
DOI: 10.1093/plphys/kiad412 -
Molecules (Basel, Switzerland) Sep 2023Mites have been a persistent infectious disease affecting both humans and animals since ancient times. In veterinary clinics, the primary approach for treating and... (Review)
Review
Mites have been a persistent infectious disease affecting both humans and animals since ancient times. In veterinary clinics, the primary approach for treating and managing mite infestations has long been the use of chemical acaricides. However, the widespread use of these chemicals has resulted in significant problems, including drug resistance, drug residues, and environmental pollution, limiting their effectiveness. To address these challenges, researchers have shifted their focus towards natural products that have shown promise both in the laboratory and real-world settings against mite infestations. Natural products have a wide variety of chemical structures and biological activities, including acaricidal properties. This article offers a comprehensive review of the acaricidal capabilities and mechanisms of action of natural products like plant extracts, natural compounds, algae, and microbial metabolites against common animal mites.
Topics: Animals; Humans; Acaricides; Biological Products; Tick Control; Mites; Mite Infestations
PubMed: 37836661
DOI: 10.3390/molecules28196818 -
The Journal of Allergy and Clinical... Aug 2023
Topics: Humans; Animals; Dopamine; Lung; Asthma; Th2 Cells; Cytokines; Pyroglyphidae; CD4-Positive T-Lymphocytes
PubMed: 37315810
DOI: 10.1016/j.jaci.2023.06.002 -
American Journal of Ophthalmology Jan 2024To determine the association between ocular and facial demodicosis, and the effect of facial treatment on ocular demodicosis.
PURPOSE
To determine the association between ocular and facial demodicosis, and the effect of facial treatment on ocular demodicosis.
DESIGN
Prospective clinical cohort study.
METHODS
Ocular demodicosis outpatients from a tertiary medical center were enrolled from April to December 2020. The diagnosis was based on epilation of 4 eyelashes from each upper eyelid. High ocular Demodex load (ODL) was defined as ≥8 mites per eye. Facial infestation was assessed by direct microscopic examination, with facial Demodex overgrowth (FDO) defined as a density >5 mites/cm. All patients were prescribed 3 months of ocular treatment, and FDO patients received dermatologic treatment.
RESULTS
Eighty-nine patients were enrolled. Among those that completed the treatment course, 39 presented high ODL. Lower cylindrical sleeve counts were found in low ODL patients (low ODL vs high ODL: 8 vs 14, P = .009). FDO was less prevalent in this group (49% vs 77%, P = .012). The Ocular Surface Disease Index score decreased in patients without FDO (20.0 ± 17.1 to 14.0 ± 16.6, P = .027) after 3 months of topical tea tree oil treatment. Topical ivermectin treatment on the facial skin provided a higher ocular Demodex eradication rate in FDO patients (76% vs 16%, P < .001).
CONCLUSION
Concurrence of ocular and facial demodicosis is common, especially in cases of severe ocular demodicosis. Although ocular treatment alone is effective for patients with ocular demodicosis only, cotreatment with topical ivermectin on the facial skin enhances ocular Demodex eradication in patients with comorbid facial Demodex overgrowth.
Topics: Animals; Humans; Mite Infestations; Ivermectin; Prospective Studies; Cohort Studies; Mites; Eyelashes; Comorbidity; Blepharitis; Eye Infections, Parasitic
PubMed: 37739203
DOI: 10.1016/j.ajo.2023.09.010 -
Dermatology (Basel, Switzerland) 2024Rosacea is a chronic inflammatory dermatological condition in humans, and its pathogenesis remains unclear. However, the development of rosacea is suspected to be... (Review)
Review
BACKGROUND
Rosacea is a chronic inflammatory dermatological condition in humans, and its pathogenesis remains unclear. However, the development of rosacea is suspected to be related to Demodex, a microscopic commensal organism that resides in or near hair follicles and sebaceous glands. Although Demodex is known to be a host-specific, obligate commensal organism, it is currently difficult to be cultured in vitro to parasitize and infect other animal hosts. Therefore, direct evidence for a pathogenic role of Demodex in rosacea is currently lacking.
SUMMARY
As circumstantial evidence, non-invasive skin-detecting techniques have shown abnormally elevated numbers of Demodex in rosacea patients. Increased cytokine levels such as IL-10, IL-8, and IL-12p70 have been observed in human sebocytes following the Demodex challenge, and acaricides have been found to be effective in rosacea therapy, all point to a close relationship between Demodex and rosacea. Based on these findings, we conducted a comprehensive literature review to summarize the current state of knowledge, research insights, and clinical treatment recommendations for Demodex-associated rosacea, with the ultimate goal of improving patient outcomes.
Topics: Animals; Humans; Mite Infestations; Mites; Rosacea; Skin; Sebaceous Glands
PubMed: 37848012
DOI: 10.1159/000534245 -
Integrative Zoology May 2024Honeybees are the most critical pollinators providing key ecosystem services that underpin crop production and sustainable agriculture. Amidst a backdrop of rapid global... (Review)
Review
Honeybees are the most critical pollinators providing key ecosystem services that underpin crop production and sustainable agriculture. Amidst a backdrop of rapid global change, this eusocial insect encounters a succession of stressors during nesting, foraging, and pollination. Ectoparasitic mites, together with vectored viruses, have been recognized as central biotic threats to honeybee health, while the spread of invasive giant hornets and small hive beetles also increasingly threatens colonies worldwide. Cocktails of agrochemicals, including acaricides used for mite treatment, and other pollutants of the environment have been widely documented to affect bee health in various ways. Additionally, expanding urbanization, climate change, and agricultural intensification often result in the destruction or fragmentation of flower-rich bee habitats. The anthropogenic pressures exerted by beekeeping management practices affect the natural selection and evolution of honeybees, and colony translocations facilitate alien species invasion and disease transmission. In this review, the multiple biotic and abiotic threats and their interactions that potentially undermine bee colony health are discussed, while taking into consideration the sensitivity, large foraging area, dense network among related nestmates, and social behaviors of honeybees.
Topics: Bees; Animals; Stress, Physiological; Mites; Introduced Species; Climate Change; Pollination
PubMed: 37427560
DOI: 10.1111/1749-4877.12752