Innate type 2 immunity controls hair follicle commensalism by Demodex mites.

Demodex mites are commensal parasites of hair follicles (HFs). Normally asymptomatic, inflammatory outgrowth of mites can accompany malnutrition, immune dysfunction, and aging, but mechanisms restricting Demodex outgrowth are not defined. Here, we show that control of mite HF colonization in mice required group 2 innate lymphoid cells (ILC2s), interleukin-13 (IL-13), and its receptor, IL-4Ra-IL-13Ra1. HF-associated ILC2s elaborated IL-13 that attenuated HFs and epithelial proliferation at anagen onset; in their absence, Demodex colonization led to increased epithelial proliferation and replacement of gene programs for repair by aberrant inflammation, leading to the loss of barrier function and HF exhaustion. Humans with rhinophymatous acne rosacea, an inflammatory condition associated with Demodex, had increased HF inflammation with decreased type 2 cytokines, consistent with the inverse relationship seen in mice. Our studies uncover a key role for skin ILC2s and IL-13, which comprise an immune checkpoint that sustains cutaneous integrity and restricts pathologic infestation by colonizing HF mites.

Lost companions: a new quill mite species and its possible coextinction with the Carolina parakeet.

Investigations of the parasites associated with extinct avian species provide unique insights into the ecology and evolution of both hosts and their parasitic counterparts. In the present paper, a new quill mite species, Peristerophila conuropsis sp. n., belonging to the family Syringophilidae (Prostigmata: Cheyletoidea) is described from the Carolina parakeet Conuropsis carolinensis Linnaeus (Psittaciformes: Psittacidae). This new species was collected from museum dry skin of the Carolina parakeet, the only native representative of the Psittacidae in the United States, which was an abundant resident of the southeastern and midwestern states and has been extinct in the beginning of the 20th century. Comment on the current taxonomic state and host associations of the genus Peristerophila are provided. Based on the host associations and habitats occupied by Peristerophila and related genera on parrots, it is hypothesized with the high probability that P. conuropsis has been extinct along with its host.

Parasite and virus dynamics in the honeybee Apis mellifera unicolor on a tropical island recently invaded by Varroa destructor.

In La Réunion, the established honeybee subspecies Apis mellifera unicolor, an endemic subspecies of African lineage, is facing considerable challenges. Since the introduction of the Varroa destructor mite in 2017 high colony losses have been recorded. We investigated the dynamics of V. destructor and two viruses, the Deformed Wing Virus (DWV), known to be transmitted by the mite, and the Chronic Bee Paralysis Virus (CBPV), in A. m. unicolor. Colonies from two apiaries located at 300 and 900 m a.s.l were monitored twice for one year without any acaricide treatment. The brood area, V. destructor infestation rates, DWV and CBPV prevalence and load were recorded monthly. A. m. unicolor maintained brood rearing throughout the year. Varroa destructor infestation resulted in high colony mortality (up to 85 %) and high phoretic mite rates (up to 52 mites per hundred bees). The establishment of DWV in colonies occurred after that of V. destructor and the mite infestation rate had a significant effect on the virus prevalence and load. CBPV appeared only transiently throughout the surveys. The data showed that, in tropical colonies with permanent brood rearing, V. destructor and DWV can reach high levels, but are still subject to seasonal variations that appear to be influenced by environmental conditions. This suggests that beekeeping practices could be adapted by favouring sites and periods for transhumance or acaricide treatment.

First report on the occurrence of psoroptic mange in llamas (Lama glama) of the Andean region.

An outbreak of Psoroptes sp.-caused mange was detected in a llama herd of Larcas, Jujuy province, Argentina. Infested llamas showed alopecia, erythema, hyperpigmentation, hyperkeratosis, and inflammation of the ear pinnae, as well as crusts and serous, serosanguineous, or purulent drainage with unpleasant smell in the external ear canal. Microscopic evaluation of skin scrapings revealed 0.5- to 0.7-mm-long acari identified as Psoroptes sp. based on their morphology. Histology showed a typical allergic reaction with perivascular to periadnexal mixed inflammatory infiltrate. Phylogenetic tree analysis showed that the cytochrome c oxidase subunit I gene sequences analyzed from the sampled acari clustered into a single P. ovis clade including sequences isolated from rabbits and bighorn sheep, with P. natalensis as a sister taxon that infested bighorn sheep from the USA. Phylogenetic analysis of cytochrome b sequences showed three well-supported clades, one of which contained the sequences of the Larcas llamas and US bighorn sheep isolates. This is the first report on P. ovis infestation of llamas raised in their original location. Investigations on mange etiological agents acting on South American camelids and their distribution are necessary to implement control strategies to mitigate the negative impacts of these parasitic infections.

Hematology of Liolaemus pacha (Iguania: Liolaemidae) and its relationship with mite infestation, reproductive period and body condition.

Variations in hematological profile in reptiles can be caused by multiple factors, including parasites presence. Our goals were to identify and morphologically describe blood cells of Liolaemus pacha and analyze their relationship with sex, body condition, individual reproductive/post-reproductive period and mite infestation. Blood smear analyses do not indicate the presence of hemoparasites, suggesting that the mites Neopterygosoma do not serve as vectors for these organisms, as has been proposed for other genera of ectoparasitic mites. In post-reproductive period, there was a reduction in specimens' body condition and a higher leukocyte count in uninfected lizards. This could be a consequence of the testosterone effects, in higher concentration during the reproductive season, which can increase the metabolic rate, decreasing feeding rate. Infested and non-infested lizards showed no differences in body condition, as well as in leukocyte count, hence the host's immune system could be developing infestation tolerance. Infested specimens had a higher count of monocytes, thrombocytes, heterophils and lymphocytes. Based on cells function, mites' effect could be associated with inflammatory processes, allergic reactions or infectious diseases. These results suggested a complex interaction between lizards' hematological parameters and factors associated to ectoparasites or body conditions. We consider this work as a diagnostic tool for genus Liolaemus, to evaluate health quality, with relevance to the conservation or management of this lizard's genus.

Analysis of Varroa Mite Colony Infestation Level Using New Open Software Based on Deep Learning Techniques.

Varroa mites, scientifically identified as Varroa destructor, pose a significant threat to beekeeping and cause one of the most destructive diseases affecting honey bee populations. These parasites attach to bees, feeding on their fat tissue, weakening their immune systems, reducing their lifespans, and even causing colony collapse. They also feed during the pre-imaginal stages of the honey bee in brood cells. Given the critical role of honey bees in pollination and the global food supply, controlling Varroa mites is imperative. One of the most common methods used to evaluate the level of Varroa mite infestation in a bee colony is to count all the mites that fall onto sticky boards placed at the bottom of a colony. However, this is usually a manual process that takes a considerable amount of time. This work proposes a deep learning approach for locating and counting Varroa mites using images of the sticky boards taken by smartphone cameras. To this end, a new realistic dataset has been built: it includes images containing numerous artifacts and blurred parts, which makes the task challenging. After testing various architectures (mainly based on two-stage detectors with feature pyramid networks), combination of hyperparameters and some image enhancement techniques, we have obtained a system that achieves a mean average precision (mAP) metric of 0.9073 on the validation set.

Feline straelensiosis: Clinical and histopathological description of a case and first genetic characterisation of Straelensia cynotis.

Straelensia cynotis is a trombidioid mite that causes painful, usually nonpruritic nodular dermatitis mainly in the dorsal region of dogs. This case report describes the first observation of feline straelensiosis in Europe with clinicopathological findings. Molecular characterisation of the parasite was performed and compared with mites collected from dogs.

Straelensia cynotis est un acarien trombidioïde qui provoque une dermatite nodulaire douloureuse, généralement non prurigineuse, principalement dans la région dorsale des chiens. Ce cas constitue la première observation de straelensiose féline en Europe avec des données clinicopathologiques. L'identification moléculaire du parasite a été réalisée et comparée à celle d'acariens prélevés sur des chiens.

Straelensia cynotis es un ácaro trombidioide que causa dermatitis nodular dolorosa, generalmente no pruriginosa, principalmente en la región dorsal de los perros. Este informe de caso describe la primera observación de estraelensiosis felina en Europa con hallazgos clínico-patológicos. Se realizó la caracterización molecular del parásito y se comparó con ácaros recolectados de perros.

Straelensia cynotis é um ácaro trombiculídeo que causa dermatite nodular dolorosa e geralmente não pruriginosa principalmente na região dorsal de cães. Este relato de caso descreve a primeira observação de stralensiose felina na Europa com achados clinicopatológicos. A caracterização molecular do parasita foi realizada e comparada com ácaros coletados de cães.

Psoroptes cuniculi infestation in pet rabbits in Tabasco, Mexico, 2021-2022.

BACKGROUND: Rabbits are an important worldwide meat- and fibre-producing animal, and they are popular pets. The rabbit ear mite, Psoroptes cuniculi, causes severe dermatological disease. Epidemiological data on P. cuniculi infestations are important for public health. OBJECTIVE: The objective of the study was to determine the frequency of P. cuniculi infestation in pet rabbits and evaluate epidemiological factors associated with infestation. ANIMALS: Two hundred pet rabbits presented for veterinary care between 2021 and 2022. MATERIALS AND METHODS: Physical examination, otoscopy and microscopy were used for ear mite identification. Association with age, sex, body mass index (BMI), breed, feeding and housing management was analysed. RESULTS: Of the 200 rabbits, 59 (29.5%) were positive for P. cuniculi. Only female sex had a positive association with P. cuniculi. CONCLUSIONS AND CLINICAL SIGNIFICANCE: Psoroptes cuniculi in pet rabbits has a similar frequency to that reported in meat-producing rabbits, and female sex had a positive association.

Brevipalpus yothersi Baker (Tenuipalpidae) development in sweet orange plants is influenced by previous mite infestation and the presence of shelters.

Citrus leprosis is the most important viral disease affecting citrus. The disease is caused predominantly by CiLV-C and is transmitted by Brevipalpus yothersi Baker mites. This study brings some insight into the colonization of B. yothersi in citrus [(Citrus × sinensis (L.) Osbeck (Rutaceae)] previously infested by viruliferous or non-viruliferous B. yothersi. It also assesses the putative role of shelters on the behavior of B. yothersi. Expression of PR1 and PR4 genes, markers of plant defense mechanisms, were evaluated by RT-qPCR to correlate the role of the plant hormonal changes during the tri-trophic virus-mite-plant interplay. A previous infestation with either non-viruliferous and viruliferous mites positively influenced oviposition and the number of adult individuals in the resulting populations. Mite populations were higher on branches that had received a previous mite infestation than branches that did not. There was an increase in the expression of PR4, a marker gene in the jasmonic acid (JA) pathway, in the treatment with non-viruliferous mites, indicating a response from the plant to their feeding. Conversely, an induced expression of PR1, a marker gene in the salicylic acid (SA) pathway, was observed mainly in the treatment with viruliferous mites, which suggests the activation of a plant response against the pathogen. The earlier mite infestation, as well as the presence of leprosis lesions and a gypsum mixture as artificial shelters, all fostered the growth of the B. yothersi populations after the second infestation, regardless of the presence or absence of CiLV-C. Furthermore, it is suggested that B. yothersi feeding actually induces the JA pathway in plants. At the same time, the CiLV-C represses the JA pathway and induces the SA pathway, which benefits the mite vector.

Morphological changes in plasma-exposed poultry red mites (Dermanyssus gallinae) using high-resolution video camera and optical coherence tomography (OCT).

Dermanyssus gallinae, the poultry red mite (PRM), is a hematophagous temporary ectoparasite that causes serious economic losses and animal health impairment on laying hen farms worldwide. Control is limited by the parasite's hidden lifestyle, restrictions on the use of chemical acaricides and the development of resistance against certain drug classes. As a result, research was conducted to explore alternative control methods. In recent years, atmospheric pressure plasma has been increasingly reported as an alternative to chemical acaricides for pest control. This physical method has also shown promising against PRM under laboratory conditions. However, the detailed mechanisms of action have not yet been elucidated. In the present study, the effects of cold atmospheric pressure plasma on PRM were investigated using digital videography and optical coherence tomography (OCT), an imaging technique that visualizes the topography of surfaces and internal structures. Digital videography showed that a redistribution of the contents of the intestinal tract and excretory organs (Malpighian tubules) occurred immediately after plasma exposure. The body fluids reached the distal leg segments of PRM and parts of the haemocoel showed whiter and denser clumps, indicating a coagulation of the haemocoel components. OCT showed a loss of the boundaries of the hollow organs in transverse and sagittal sectional images as well as in the three-dimensional image reconstruction. In addition, a dorso-ventral shrinkage of the idiosoma was observed in plasma-exposed mites, which had shrunk to 44.0% of its original height six minutes after plasma exposure.

Africanized honey bee colonies in Costa Rica: first evidence of its management, brood nest structure and factors associated with varroa mite infestation.

Management, brood nest structure and factors associated with varroa mite infestation were studied in 60 apiaries of Africanized honey bees in the northwest region of the Central Valley of Costa Rica. Apiaries were monitored two times. The first monitoring was taken forward during the rainy season between May and November 2019. The second monitoring during the dry season between February and March 2020. Information about the beekeepers, apiaries and management was collected through a survey. Amount of open and capped brood, honey and pollen were measured in the field. The infestation rate of varroa (IRV) was quantified using standard laboratory methods. A determination of multi-residue pesticides in bee bread was made through GC-MS/MS and LC-MS/MS techniques. According to the results, most of the beekeepers produce honey (96.7%), participate in training activities (82.2%), and change the bee queens annually (70%). The first monitoring was characterized by a lower amount of capped brood and honey reserves compared to the second one. IRV was significantly higher in the first monitoring (6.0 ± 0.4) in comparison with the second one (3.0 ± 0.3) (U Mann-Whitney p < 0.001). The maximum value for the first monitoring exceeds 40%, while this value was close to 25% in the second monitoring. Mite infestation exposed significant differences in relation to the variables associated to the beekeeper's management, i.e., change of bee queen (p = 0.002) or when beekeepers monitor varroa mites (p = 0.004). Additionally, the IRV had inverse correlations (p < 0.01) with the number of comb sides with capped brood (Spearman's rho coefficient = - 0.190), and honey reserves (Spearman's rho coefficient = - 0.168). Furthermore, 23 of 60 bee bread samples presented one to five pesticide residues, being the most frequent antifungal agrochemicals.

Parasite infestation patterns differ between ticks and chigger mites on two rodent host species in Taiwan.

Parasites are typically concentrated on a few host individuals, and identifying the mechanisms underlying aggregated distribution can facilitate a more targeted control of parasites. We investigated the infestation patterns of hard ticks and chigger mites on two rodent species, the striped field mouse, Apodemus agrarius, and the lesser ricefield rat, Rattus losea, in Taiwan. We also explored abiotic and biotic factors that were important in explaining variation in the abundance of ticks and chiggers on rodent hosts. Ticks were more aggregated than chiggers on both rodent species. Factors important for the variation in parasitic loads, especially biotic factors, largely differed between ticks and chiggers. Variation partitioning analyses revealed that a larger proportion of variation in chiggers than in ticks can be explained, especially by abiotic factors. If, as proposed, the higher number of parasites in males is due to a larger range area or immunity being suppressed by testosterone, when A. agrarius males host more ticks, they are expected to also host more chiggers, given that chiggers adopt a similar host finding approach to that of ticks. Instead, the similar abundance of chiggers in male and female A. agrarius implies that a large home range or suppressed immunity does not predispose males to inevitably host more parasites. More variations were explained by abiotic than biotic factors, suggesting that controlling practices are more likely to be successful by focusing on factors related to the environment instead of host traits. Our study indicated that the extent of parasitism is rarely determined by a sole factor, but is an outcome of complex interactions among animal physiology, animal behavior, characteristics of parasites, and the environments.

Bacterial pathogens' screening in Brazilian chigger mites (Trombidiformes: Trombiculidae), with the first report of 'Candidatus Rickettsia colombianensi'-like in avian-associated chiggers.

Chiggers are larval ectoparasites of the Trombiculidae that can transmit pathogens to their hosts. In this study, chiggers collected from birds in Brazil were morphologically identified as Blankaartia sinnamaryi, Eutrombicula batatas, Eutrombicula daemoni, Eutrombicula goeldii, Eutrombicula tinami, and Parasecia gilbertoi. For these specimens, a beginning attempt at molecular identification were also provided, as well as, were genetically screened to detect bacterial pathogens. The species B. sinnamaryi and E. tinami were positive for Rickettsia felis-like and 'Candidatus Rickettsia colombianensi'-like, respectively. For the other agents (Anaplasmataceae, Borrelia spp. and Orientia tsutsugamushi), the tests were negative. This is the first report of 'Ca. R. colombianensi'-like and the second record of R. felis-like in chigger collected on birds from Brazil.

Variation of bacterial community assembly over developmental stages and midgut of Dermanyssus gallinae.

Bacterial microbiota play an important role in the fitness of arthropods, but the bacterial microflora in the parasitic mite Dermanyssus gallinae is only partially explored; there are gaps in our understanding of the microbiota localization and in our knowledge of microbial community assembly. In this work, we have visualized, quantified the abundance, and determined the diversity of bacterial occupancy, not only across developmental stages of D. gallinae, but also in the midgut of micro-dissected female D. gallinae mites. We explored community assembly and the presence of keystone taxa, as well as predicted metabolic functions in the microbiome of the mite. The diversity of the microbiota and the complexity of co-occurrence networks decreased with the progression of the life cycle. However, several bacterial taxa were present in all samples examined, indicating a core symbiotic consortium of bacteria. The relatively higher bacterial abundance in adult females, specifically in their midguts, implicates a function linked to the biology of D. gallinae mites. If such an association proves to be important, the bacterial microflora qualifies itself as an acaricidal or vaccine target against this troublesome pest.

Attractant Activity of Host-Related Chemical Blends on the Poultry Red Mite at Different Spatial Scales.

Many blood-feeding arthropods use volatile organic compounds (VOCs) to detect their vertebrate hosts. The role of chemical interactions in mediating the behavior of hematophagous insects and ticks has been investigated before but remains poorly understood in hematophagous mesostigmatic mites. The poultry red mite Dermanyssus gallinae is an obligatory blood-sucking mesostigmatic mite that feeds on birds and causes damage in poultry farms. We characterized the attractive response of D. gallinae to candidate VOCs previously reported from the odor emitted by living hens. We performed in-vitro choice-test bioassays as well as semi-field and field trials using baited and unbaited traps, in the presence and absence of hens. Among different tested combinations of VOCs, a blend of 5 VOCs (mix1.0) was significantly attractive to our reference population of D. gallinae in vitro, whereas the same individual compounds tested alone were not attractive. Ammonia was attractive on its own and increased the mix1.0 attractiveness. The attractiveness of mix1.0 was confirmed at 'natural' spatial scales in the absence of hens both at the lab and on the farm that provided the reference population. The presence of hens inhibited the mix1.0 attractiveness. The attractive power of mix1.0 was not found in other farms. This research is an important step to advance our understanding of host-parasite interactions in hematophagous mesostigmatic mites and paves the way for developing alternative control tools against D. gallinae by interfering with chemical interactions. Moreover, it underlines the importance of assessing kairomonal activity on different pest populations when developing attract-and-kill systems.

Demodex murilegi and Demodex obliquus, two new specific skin mites from domestic cat Felis catus, with notes on parasitism.

The Demodecidae are skin and tissue parasites of mammals with high host, topical, and topographic specificity. They may cause a demodecosis, typically observed in pets and humans. Numerous mammal species have been found to have several, specific demodecids, which inhabit different microhabitats. Thus far, two species have been known from the domestic cat, namely Demodex cati Megnin, 1877 (Acariformes: Demodecidae) and D. gatoi Desch and Stewart, 1999; however, there have been indications for the presence of other demodecid mites in this host. Presently, two other species are described, D. murilegi sp. nov. associated primarily with the skin from the area of lips and nose, and D. obliquus sp. nov. associated with the skin of the lower part of the limb. They exhibit morphological discreteness in terms of qualitative traits significant for Demodecidae taxonomy. Demodex murilegi sp. nov. is larger than both known species, and D. obliquus sp. nov. is intermediate in length between them. It is likely that infection with different Demodex species may result in variable symptoms and courses of demodecosis; however, a correct identification of the species causing the parasitosis is needed to confirm this. Thus, the present study compares the taxonomic traits of four cat demodecid mites.

A rapid diagnosis and treatment of Ornithonyssus bacoti infection.

Mites serve as pathogens, allergens, or microbial containers, which can seriously damage the health of humans and animals. The substantial amount of mite species and their similar morphology make it complicated to identify and classify. Our mouse breeder incidentally noticed papular-type erythema with itching and peeling of the skin in several places, and an investigation revealed that this symptom was caused by an uncommon parasite that appeared on the skin and around the nest of the mice. By morphological observation, DNA extraction, PCR amplification, and DNA sequencing, we roughly identified the category of the parasite as a mite. Then, we designed a specific primer cox1, amplified and sequenced the mitochondrial cox1 gene fragment of the mite, calculated the intraspecific and interspecific differences, and reconstructed the phylogenetic tree for sequence alignment. Finally, this species was identified and named this Ornithonyssus bacoti-KF. According to the ivermectin gradient test, we found that 0.1 mg/mL concentration of ivermectin solution was the most effective for mite removal in the bath, with no recurrence after 6 months of treatment. Ornithonyssus bacoti, diagnosed by microscopic exam and confirmed by PCR amplification sequencing, was treated with ivermectin to control the rodent-borne parasite effectively.

Pigeon mite: An underdiagnosed cause of papular urticaria.

BACKGROUND: Dermanyssus gallinae, known as bird mite, generally lives on nestlings' featherless skin. Humans are accidentally infected, and itchy dermatitis is induced when the mites are unable to use birds' blood. The diagnosis is difficult due to the very small size and rapid movement of the mites, which make them hard to spot. CASE PRESENTATION: A 14-year-old male and his mother were referred to the allergy clinic complaining of a 2-week generalized itchy cutaneous papular lesion, unresponsive to antihista-mines, with the feeling of an insect moving on the surface of the skin. Due to the history of recently hatched pigeons nesting on their balcony and finding very small bugs, diagnosed as D. gallinae, they were instructed to clean the pigeon's nest as the source of these parasites, which successfully solved the problem. CONCLUSION: Bird mite infestation should be considered in the differential diagnosis of recurrent pruritus and urticaria, refractory to conventional treatments. Physicians should be aware of this mite infestation in approach to any patient with papular urticaria.

Macrophage Migration Inhibitory Factor in Psoroptes ovis: Molecular Characterization and Potential Role in Eosinophil Accumulation of Skin in Rabbit and Its Implication in the Host-Parasite Interaction.

Psoroptes ovis, a common surface-living mite of domestic and wild animals worldwide, results in huge economic losses and serious welfare issues in the animal industry. P. ovis infestation rapidly causes massive eosinophil infiltration in skin lesions, and increasing research revealed that eosinophils might play an important role in the pathogenesis of P. ovis infestation. Intradermal injection of P. ovis antigen invoked massive eosinophil infiltration, suggesting that this mite should contain some relative molecules involved in eosinophil accumulation in the skin. However, these active molecules have not yet been identified. Herein, we identified macrophage migration inhibitor factor (MIF) in P. ovis (PsoMIF) using bioinformatics and molecular biology methods. Sequence analyses revealed that PsoMIF appeared with high similarity to the topology of monomer and trimer formation with host MIF (RMSD = 0.28 angstroms and 2.826 angstroms, respectively) but with differences in tautomerase and thiol-protein oxidoreductase active sites. Reverse transcription PCR analysis (qRT-PCR) results showed that PsoMIF was expressed throughout all the developmental stages of P. ovis, particularly with the highest expression in female mites. Immunolocalization revealed that MIF protein located in the ovary and oviduct of female mites and also localized throughout the stratum spinosum, stratum granulosum, and even basal layers of the epidermis in skin lesions caused by P. ovis. rPsoMIF significantly upregulated eosinophil-related gene expression both in vitro (PBMC: CCL5, CCL11; HaCaT: IL-3, IL-4, IL-5, CCL5, CCL11) and in vivo (rabbit: IL-5, CCL5, CCL11, P-selectin, ICAM-1). Moreover, rPsoMIF could induce cutaneous eosinophil accumulation in a rabbit model and increased the vascular permeability in a mouse model. Our findings indicated that PsoMIF served as one of the key molecules contributing to skin eosinophil accumulation in P. ovis infection of rabbits.

Species diversity and related ecology of chiggers on small mammals in a unique geographical area of Yunnan Province, southwest China.

Chiggers are common ectoparasites and the exclusive vector of scrub typhus. Based on previous investigations from a unique geographical area in Yunnan Province of southwest China, the Three Parallel Rivers Area, we retrospectively studied the species diversity and related ecology of chiggers on rodents and other small mammals. A very high species diversity of 120 chigger species was identified. Five dominant chigger species accounted for 59.4% (5238/8965) of total chiggers, and among them Leptotrombidium scutellare is the second major vector of scrub typhus in China. Species diversity of the chigger community fluctuates greatly in different altitudinal and latitudinal gradients. There are significant differences in species composition, species diversity and dominant species of chiggers among hosts with apparent community heterogeneity. Based on the species abundance distribution, the expected total number of chigger species was estimated to be 170, 50 more than the number of actually collected species; this further indicates a very high chigger species diversity in this area. The bipartite ecological network analysis revealed the intricate relationships between chigger and host species-positive and negative correlations existed among some species of dominant and vector chiggers.