Species Of Chigger Mites Research Articles

Infestation and distribution of chigger mites on Brown rat (Rattus norvegicus) in Yunnan Province, Southwest China.

Chigger mites is a group of arthropods and some of them are vectors of scrub typhus. As a common synanthropic rodent species, the Brown rat (Rattus norvegicus) often harbors lots of ectoparasites including chigger mites. According to some "data mining" strategies, the present study took the advantage of the abundant original data from a long-term field ecological investigation between 2001 and 2015 to make a detailed analysis of chigger mites on R. norvegicus in Yunnan Province, Southwest of China. From 18 of 33 investigated counties, only 1414 chigger mites were collected from 1113 Brown rats with relatively low infestations. The 1414 individual chigger mites were identified as comprising 61 species, 11 genera and 2 subfamilies of the family Trombiculidae with a high species diversity (S=61, H'=3.13). Of 61 mite species, there were four main species, Walchia ewingi, Ascoschoengastia indica, W. koi and A. rattinorvegici, which accounted for 44.41% of the total mites. All the chigger mites were of aggregated distribution among different individuals of R. norvegicus. The Brown rats in the outdoor habitats harbored much more individuals and species of chigger mites with a higher mean abundance (MA=1.46) and mean intensity (MI=12.53) than in the indoor habitats (P<0.05). The overall infestation of the rats was significantly higher in the mountainous landscapes than in the flatland landscapes (P<0.001). The species similarity (Css) of the mites on the male and female rats reached 64.44% with sex biased infestations. The male rats harbored more species and individuals of the mites than the female rats. The adult rats harbored more species and individuals of the mites than the juvenile rats. The species abundance distribution of the mites was successfully fitted by Preston's lognormal model with ŝ(R)=15e-[0.31(R-1)]2 (α=0.31, R2=0.95). On the basis of fitting the theoretical curve by Preston's model, the total mite species on R. norvegicus was estimated to be 86 species, and 25 rare mite species were missed in the sampling field investigation. The curve tendency of the species-plot relationship indicates that R. norvegicus have a great potential to harbor many species of chigger mites, and more species of the mites would be collected if more rats are sampled.

&lt;p class="Body"&gt;&lt;strong&gt;Three new species of chigger mites (Acariformes: Trombiculidae) from the Galápagos Islands&lt;/strong&gt;&lt;/p&gt;

Three new species of chigger mites are described from two species of iguana endemic to the Galápagos Islands. Odontacarus cruzi sp. nov. and Schoengastia galapa sp. nov. are found on the marine iguana, Amblyrhynchus cristatus Bell, and Eutrombicula pachytrichia sp. nov. is found on the Santa Fe land iguana, Conolophus pallidus Heller. All these mite species were collected, identified, and named by P.H. Vercammen-Grandjean, but remained undescribed until the present.

Chigger Mites (Acariformes: Trombiculidae) of Chiloé Island, Chile, With Descriptions of Two New Species and New Data on the Genus Herpetacarus.

Three species of chigger mites are recorded in our collections from four species of cricetid rodents on Chiloé Island (southern Chile, Los Lagos Region), an area endemic to scrub typhus (Orientia sp.). Two species are described as new-Herpetacarus (Abonnencia) eloisae sp. nov. and Quadraseta chiloensis sp. nov. One species, Paratrombicula goffiStekolnikov and González-Acuña 2012, is for the first time recorded on a mammal host (one species of cricetid rodent), and its distribution is extended to the Los Lagos Region of Chile. The genus ProschoengastiaVercammen-Grandjean, 1967 is synonymized with the subgenus Herpetacarus (Abonnencia)Vercammen-Grandjean, 1960, and four new combinations are established: Herpetacarus (Abonnencia) herniosa (Brennan and Jones, 1961), comb. nov., Herpetacarus (Abonnencia) insolita (Brennan and Jones, 1961), comb. nov., Herpetacarus (Abonnencia) macrochaeta (Brennan and Jones, 1961), comb. nov., and Herpetacarus (Abonnencia) antarctica (Stekolnikov and Gonzalez-Acuña, 2015), comb. nov.

Potential zoonotic hosts and vectors of scrub typhus in Sri Lanka: A preliminary report

Background: Scrub typhus is an acute febrile disease caused by a Gram-negative, obligate intracellular bacterium Orientia tsutsugamushi, transmitted to humans following an accidental bite by an infected larval trombiculid mite commonly known as chiggers. Chiggers are a group of ectoparasites prevalent on a variety of mammals, mainly small mammals like rodents. Clinical cases of scrub typhus are documented in almost all ecological zones including both rural and urban Sri Lanka. They occur as year-round sporadic cases or as outbreaks mainly during the drier months of the year. However, their reservoir hosts and transmitting vector species are yet to be identified in Sri Lanka. Such knowledge is important for effective implementation of control measures of this re-emerging infection. Therefore, this study was designed to live capture small rodent/mammal hosts and identify chigger mite species present in the country. Methods & Materials: Traps designed to live capture small rodents/mammals were placed in peri-domestic areas of clinically confirmed scrub typhus patients in southern province, Sri Lanka. Traps baited with fried coconut were placed around residences and in pre-selected sites with scrubby vegetation and rodent burrows, one hour before sun set and were retrieved the next day morning. The captured animals were anaesthetized with ketamine/xylazine and inspected for the presence of vector mites. Collected mites were preserved in 70% alcohol and identified by microscopy using standard morphological keys. Collected data were analyzed using chi square test, MINITAB 17 statistical software. Results: Rodents belonging to Rattus norvegicus (n = 15, 56.%), Rattus rattus (n = 10, 37%) and shrews of Suncus murinus (n = 2, 7.4%) were captured during the study over 6 months and a total of 147 mites were isolated. Isolated chigger mites belonged to genus Leptotrombidium (n = 90, 67%), Eutrombicula (n = 31, 23%), Helenicula (n = 24, 17%), and species Leptotrobidium lagone (n = 2, 1.5%). Majority were potential vectors for Orientia tsutsugamushi. Conclusion: It is noted that Rattus norvegicus harbored significantly high amount of chigger mites (Per individual n = 7, χ2 = 110.35, p < 0.001] compared to other species captured. We are currently in the process of molecular speciation of sampled chigger mites and molecular detection of Orientia tsutsugamushi in sampled mites indicating their vectorial capacity.

Detection of DNA of Rickettsia and Orientia tsutsugamushi in rodents and ectoparasites in Ha Giang province

Rickettsial fever is one of a zoonotic disease which is caused by bacteria genus Rickettsia. The ectoparasites such as ticks, mites, fleas, lice... were demonstrated as the main transmited vectors through host reservoirs are rodents and small animals including mice, squirrels, mink... In this study, the rodents and ectoparasites species were identified. The molecular detection of Rickettsia was also performed. In 2018, 83 rats were trapped in 2 villages Thanh Duc and Phu Linh, Vi Xuyen district, Ha Giang province, in which 48.2% mice were found as house mice Rattus flavipectus, 21.7% was forest mice R. rattus, 12% was R. fulvescens, 8.4% was R. nitidus, the remaining rates were R. bowersi, Mus. pahari, Leopoldamys sabanus, Mus musculus and R. niviventer, accounting for 1.2% - 3.6%. The ectoparasites survey found 5 chigger mite species including Leptotrombidium (Leptotrombidium) deliense, Ascoschoengastia (Laurentella) indica, Garhliepia (Walchia) rustica, Lorilutum oreophilum and Shunsenia sp as well as 3 gamasid mite species such as Laelaps (Echidninus) sedlaceki, Laelaps (Laelaps) nuttali and Lenstivalius klossi bispiniformis. The result indicated that 19.3% and 10.8% mice were positive with Ricketsia spotted fever group (SFG) and Rickettsia typhi, respectively by real-time PCR. The nested PCR result showed that 19.4% R. flavipectus mice and 10% L. (L.) deliense chigger mites were positive with Orientia tsutsugamushi.

Bimonthly surveillance of wild rodents and chigger mites in urban parks in Daegu from 2018 to 2019

AbstractTsutsugamushi disease is caused by Orientia tsutsugamushi, which is transmitted to humans via chigger mites in wild rodents, among other animal hosts. It has become a recurring health problem in South Korea with increasing numbers of cases since 2010s and most cases occurring in October through December. However, studies on chigger mites and wild rodents in urban areas in South Korea are inadequate. Thus, this study aimed to analyze the species composition of chigger mites and wild rodents, their seasonal distribution, and pathogen rates of chigger mites via a 2‐year surveillance study at six urban parks in Daegu. Monthly surveillance of wild rodents and chigger mites was conducted at urban parks in Daegu from 2018 to 2019. Chigger mites were isolated from the collected rodents bimonthly. A total of 31 rodents were collected, with a trap rate and percentage of chigger mite infection of 0.52 and 61.3%, respectively. A total of 273 chigger mites were collected, with a chigger index (CI) of 14.4. Six species of chigger mites from two genera were collected, with Leptotrombidium pallidum being the most common (n = 127, 31.8%). Chigger mites were most frequent at riverside parks (n = 95, 34.8%). To detect O. tsutsugamushi in chigger mites, 40 pools of chigger mites (n = 273) were analyzed. All analyzed pools showed negative results. In conclusion, the populations of chigger mites and wild rodents in the six parks surveyed were smaller than those in the other regions in South Korea. Both the population and minimum positive rates of chigger mites in urban Daegu indicated a low threat of Tsutsugamushi disease. However, attention should still be paid to preventing this disease.

Rudnicula goffi n. sp. (Acariformes: Trombiculidae) from the diadem leaf-nosed bat Hipposideros diadema (Geoffroy) (Chiroptera: Hipposideridae) on Bali, Indonesia.

A new species of chigger mite, Rudnicula goffi n. sp., is described from the diadem leaf-nosed bat Hipposideros diadema (Geoffroy) (Hipposideridae) caught in the Goa Peteng Cave on Bali (Indonesia). The new species differs from the closely related species by the presence of scutum with AL windows, lateral scutal margins with cuticular striations and fSt = 2 + 2 + 2. A list of all available records of Rudnicula species is provided. The genus is restricted to the tropics of Southeast Asia, Australia, Melanesia, and the subtropics of eastern Asia. A key to the known species of Rudnicula based on the morphology of the larvae is also provided.

&lt;p class="Body"&gt;&lt;strong&gt;Host selection and seasonal fluctuation of &lt;em&gt;Leptotrombidium deliense &lt;/em&gt;(Walch, 1922) (Trombidiformes: Trombiculidae) at a localized area of southern Yunnan, China&lt;/strong&gt;&lt;/p&gt;

As an independent species of chigger mites, Leptotrombidium deliense (Walch 1922) is the most important and powerful vector of scrub typhus (tsutsugamushi disease) in the south of China. Located in the southwest of China, Yunnan province, especially southern Yunnan, is an important focus of scrub typhus. A localized area, Jingha village in southern Yunnan, was chosen as the target site and a field investigation at the village was carried out for 12 consecutive months from April 2016 to March 2017. The investigation is an attempt to illustrate the small mammals host selection and seasonal fluctuation of L. deliense at a fixed geographical site within the focus of scrub typhus, and the selected localized area makes this possible. A total of 2,434 hosts were captured and examined, including rodents and some other “rodent-like” small mammals. Of the identified 15 host species, L. deliense was found on 73.33% of them (11 species of hosts), but 88.61% of the mites were from the Southeast Asian house rats, Rattus brunneusculus. Of 10 genera, 5 families and 4 orders of identified hosts, more than 80.00% of them were infested with L. deliense with a prominent cross infestation among different taxonomic categories of hosts, but the majority of the mites (96.60%) were collected from rodents (the order Rodentia), especially the rats in the genus Rattus (92.95%). It suggests that L. deliense prefers rodents (especially the Rattus rats) to some other small mammals although it has a low host specificity. Rattus brunneusculus is the major host of the mite in the investigated site. The female R. brunneusculus rats harbored more L. deliense mites than the male rats (P&lt;0.01). The spatial distribution pattern of L. deliense on the hosts was determined as aggregated distribution. L. deliense mites were collected every month with two peaks (in July and October), belonging to the summer-autumn type. The first peak in July was much higher than the second peak in October. The monthly fluctuation of L. deliense was highly in accordance with that of the rainfall, which suggests the summer season with plentiful rainfall benefits the occurrence of this powerful vector of scrub typhus, L. deliense.

A new species of Schoutedenichia Jadin & Vercammen-Grandjean, 1954 from Madagascar and a re-description of S. dutoiti (Radford, 1948) from South Africa (Acariformes: Trombiculidae).

A new chigger mite species, Schoutedenichia microcebi n. sp. is described from the grey mouse lemur Microcebus murinus (J.F. Miller) from Madagascar. The new species is closely related to S. dutoiti (Radford, 1948), a species described from a single specimen collected on a rodent in South Africa. Examination of the holotype and new material on S. dutoiti from South Africa enabled us to re-describe this species and provide new data on its hosts and geographical distribution.

A new species of chigger mite (Acariformes: Trombiculidae: Leeuwenhoekiinae) collected from a scorpion in Iran

ABSTRACTA new species of chigger mite, Odontacarus scorpionivorus Stekolnikov and Saboori sp. nov., is described from a scorpion Mesobuthus eupeus (Koch) in the West Azerbaijan Province of Iran. It is the tenth known case of a chigger parasitizing an arthropod. The new species is similar to Odontacarus paradoxus (André) described from a scorpion host in Greece and to a group of Odontacarus species from Transcaucasia, Middle Asia, and China.http://www.zoobank.org/urn:lsid:zoobank.org:pub:DE9359A1-F0E8-47AA-B2C4-3708D1C1B73F

&lt;p class="Body"&gt;Six new and one little known species of chigger mites (Acariformes: Trombiculidae) from South Africa

Six new chigger mite species were described from rodents of South Africa: Ascoschoengastia ueckermanni sp. nov., Schoutedenichia horaki sp. nov., Herpetacarus octosetosus sp. nov., Herpetacarus decasetosus sp. nov., Microtrombicula graphiuri sp. nov. and Trombicula walkerae sp. nov. The genus Trombicula Berlese, 1905 sensu stricto, which is known from South Asia and Australia, is recorded on the African continent for the first time. Two new species of Herpetacarus Vercammen-Grandjean, 1960 present an example of closely related sympatric chigger species that occur on the same host individual.

A New Species of Morelacarus (Acariformes: Prostigmata: Leeuwenhoekiidae) Associated with Sceloporus grammicus (Squamata: Phrynosomatidae) from the Mexican Plateau, Zacatecas, Mexico

A new species of chigger mites, Morelacarus uazi n. sp., parasitizing lizards of the species Sceloporus grammicus from Mazapil, Zacatecas, Mexico, is described and illustrated. This new taxon differs from other species of the genus by having a palpal claw with 4 subequal paired prongs, and it can be further distinguished by the combination of the following characters: presence of onychotriches and mastitarsala III, absence of mastitibiala III, subterminala I, and parasubterminala I, and the palpal setal formula B/B/BBb. Additionally, an identification key for the species of the genus Morelacarus is presented. The new species represents the seventh species assigned to the genus and the first species described from a Mexican lizard.

Blankaartia sinnamaryi (Trombidiformes: Trombiculidae) parasitizing birds in southeastern Brazil, with notes on Rickettsia detection.

The larvae of the family Trombiculidae are ectoparasites of vertebrates, including birds. The bite of some species can cause deep lesions and severe skin reactions in the host, these can lead to dermatitis, popularly known as trombiculiasis. A morphological study of chiggers collected on birds from the state of Minas Gerais in Southeastern Brazil discovered Blankaartia sinnamaryi-infestation on Passeriformes birds. Molecular studies of the disclosed the 18S rDNA sequences of the mite, and the detection of a Rickettsia sp. in this chigger mite species.

Research Progress on Leptotrombidium deliense.

This article reviews Leptotrombidium deliense, including its discovery and nomenclature, morphological features and identification, life cycle, ecology, relationship with diseases, chromosomes and artificial cultivation. The first record of L. deliense was early in 1922 by Walch. Under the genus Leptotrombidium, there are many sibling species similar to L. deliense, which makes it difficult to differentiate L. deliense from another sibling chigger mites, for example, L. rubellum. The life cycle of the mite (L. deliense) includes 7 stages: egg, deutovum (or prelarva), larva, nymphochrysalis, nymph, imagochrysalis and adult. The mite has a wide geographical distribution with low host specificity, and it often appears in different regions and habitats and on many species of hosts. As a vector species of chigger mite, L. deliense is of great importance in transmitting scrub typhus (tsutsugamushi disease) in many parts of the world, especially in tropical regions of Southeast Asia. The seasonal fluctuation of the mite population varies in different geographical regions. The mite has been successfully cultured in the laboratory, facilitating research on its chromosomes, biochemistry and molecular biology.

The First Record of a Chigger Mite of the Genus Neotrombicula (Acariformes: Trombiculidae) in the Northwest of European Russia

A chigger mite species, Neotrombicula absoluta Schluger, 1966, previously known only from its type locality in Transcarpathian Region of Ukraine, was found in the vicinity of Kurgolovo Village (Kingisepp District, Leningrad Province, Russia). A single specimen of this species was collected off the common shrew Sorex araneus L. This is the first record of the genus Neotrombicula (which includes the most usual causative agents of trombiculiasis of humans and domestic animals in Europe) in the northwestern part of European Russia.

Landscapes with different biodiversity influence distribution of small mammals and their ectoparasitic chigger mites: A comparative study from southwest China

From a previous field investigation in Yunnan, southwest China between 2001 and 2015, we selected two types of landscapes to make a retrospectively comparative study on the distribution of small mammals and their ectoparasitic chigger mites. One landscape is “mountainous uncultivated land (MUL)” with higher biodiversity, which is located in a famous “World Nature Heritage Site”, the Three-Parallel-Rivers Region in the northwest of Yunnan. The other is “cultivated flatland landscape (CFL)” with lower biodiversity, which is located in the south of Yunnan. The landscapes with different biodiversity apparently influenced the distribution of small mammals and their ectoparasitic chigger mites. Much more species of small mammals and mites were found in MUL than in CFL. A total of 3,177 small mammals captured from MUL were identified as 55 species, 30 genera and 10 families in five orders. From these small mammal hosts, 5,882 chigger mites were collected and identified as 127 species, 15 genera and 3 subfamilies in two families. A total of 1,112 small mammals captured from CFL were identified as 19 species, 12 genera and 5 families in three orders. From these hosts, 17,742 chiggers were collected and identified as 86 species, 12 genera and 3 subfamilies in two families. Both the species diversity (S = 55) and community diversity (H = 2.673) of small mammals in MUL were much higher than those in CFL (S = 19; H = 0.926). There were also higher values of β diversity in MUL than in CFL. Different main reservoir rodent hosts of zoonoses (including tsutsugamushi disease) were found in two types of landscapes. Rattus tanezumi (one main reservoir host) was most abundant in CFL, which accounted for 80.22% of all the small mammals. Another two main reservoir hosts, Eothenomys miletus and Apodemus chevrieri were the dominant species in MUL, but they were not as abundant as R. tanezumi in CFL. Different vector species of chigger mites also existed in MUL and CFL. Leptotrombidium deliense (a main and powerful vector of tsutsugamushi disease in China) and Ascoschoengastia indica (a potential vector of tsutsugamushi disease) were the dominant species of chigger mites in CFL (Cr = 25.81% for A. indica; Cr = 23.47% for L. deliense). Leptotrombidium scutellare (also a main vector of tsutsugamushi disease in China) was the dominant chigger species in MUL (Cr = 26.09%). Higher infestation of vector mites on small mammals was found in the simple landscape with lower biodiversity (CFL) than in the complex landscape with higher biodiversity (MUL). The overall prevalence (P), mean abundance (MA) and mean intensity (MI) of chigger mites on small mammals were much higher in CFL than in MUL. The main vector mite species on their main rodent hosts also showed a higher P, MA and MI in CFL than in MUL.

Species diversity of ectoparasitic chigger mites (Acari: Prostigmata) on small mammals in Yunnan Province, China.

Chigger mites are a large group of arthropods and the larvae of mites are ectoparasites. Some species of ectoparasitic mites (larvae) can be the transmitting vectors of tsutsugamushi disease (scrub typhus). Yunnan Province is located in the southwest of China with complicated topographic landform and high biodiversity, where there are five zoogeographical subregions. Rodents and some other small mammals were trapped and examined for ectoparasitic chigger mites in 29 investigation sites in Yunnan during 2001-2013. From 13,760 individuals and 76 species of small mammal hosts, we collected 274 species of mites, which were identified as comprising 26 genera in two families. The species diversity of chigger mites (274 species) in the present study were not only much higher than that from other provinces of China but also largely exceeded that recorded from other regions and countries in the world. Of the five zoogeographical subregions, both the species diversity and Shannon-Weiner's diversity of mites were the highest in subregion II (southern subregion of Hengduan Mountains) with middle altitudes and middle latitude. Both the species diversity of mites and Shannon-Wiener diversity index showed a parabolic tendency from the low altitude (<500m) to the high altitude (>3500m) along the vertical gradients with the peak occurring in the middle-altitude regions (2000-2500m). Of four dominant hosts, the species richness of mites was highest on Eothenomys miletus (S = 165) and Shannon-Wiener diversity index was highest on Rattus norvegicus (H = 3.13). Along latitude gradients, species richness of chigger mites increased first and then decreased, peaking at 25° to 26° N with 193 mite species. The geographical location, complex topography, and landscape with diverse small mammal hosts in Yunnan Province have contributed to the extremely high species diversity of mites in the province. The large sampling size of small mammal hosts in a wide geographical scope within a long time span also made it possible to have collected so many species of chigger mites.

An updated distribution and hosts: trombiculid mites (Acari: Trombidiformes) associated with small mammals in Yunnan Province, southwest China.

Trombiculid mites (or chigger mites) are a large group of arthropods, and some of these species are vectors of Orientia tsutsugamushi, the causative agent of tsutsugamushi disease (scrub typhus). Yunnan Province is situated in the southwest of China, and its complicated topography, special altitude gradients, and high biodiversity have aroused the interest of many scientists to study the fauna and species diversity of plants and animals. To replenish our former faunal study, this paper listed all the scientific names of trombiculid mites in Yunnan Province, together with their hosts and collection sites (geographical distribution). A total of 120,138 individuals of trombiculid mites were collected from the body surface of 13,760 small mammal hosts (89.06% of them are rodents) in 29 collection sites (counties) of Yunnan Province from 2001 to 2013. The 120,138 mites were identified as comprising 2 families (Trombiculidae and Leeuwenhoekiidae), 26 genera, and 274 species. The genus Leptotrombidium had the most abundant species (109 species) of 26 genera. Of the six main vectors of scrub typhus in China, five of them were found in Yunnan. Of the 274 chigger mite species, 23 were determined as the newly recorded species (new records), which were found in Yunnan Province for the first time. The identified 274 species of trombiculid mites in the present paper are much more than those from other provinces in China and even largely exceeded the species of trombiculid mites recorded from some other regions and countries in the world. Based on the formula of Chao 1, the total number of chigger mite species in Yunnan was approximately estimated to be 346 species, and about 72 species might have been missed in our sampling process.

A Revised Checklist of Chigger Mites (Acari: Trombiculidae) From Thailand, with the Description of Three New Species

Chigger mites of Thailand were studied on the basis of larvae collected from 19 small mammal species (17 species of Rodentia, 1 species of Erinaceomorpha, and 1 species of Scandentia) and revision of published data. Samples of 38 trombiculid species were collected from 11 provinces. Three new species were described: Trombiculindus kosapani sp. nov., Helenicula naresuani sp. nov., and Walchia chavali sp. nov. Ten species were recorded in Thailand for the first time: Leptotrombidium sialkotense Vercammen-Grandjean and Langston, 1976; Leptotrombidium subangulare Wen and Xiang, 1984; Leptotrombidium tenompaki Stekolnikov, 2013; Leptotrombidium turdicola Vercammen-Grandjean and Langston, 1976; Leptotrombidium yunlingense Yu, Yang, Zhang and Hu, 1981; Lorillatum hekouensis Yu, Chen and Lin, 1996; Helenicula pilosa (Abonnenc and Taufflieb, 1957); Gahrliepia xiaowoi Wen and Xiang, 1984; Walchia minuscuta Chen, 1978; and Walchia ventralis (Womersley, 1952). In all, 99 chigger mite species were considered; the presence of 93 species was established in Thailand by original data or properly documented records in the scientific literature. Evidence for 64 species records of 147 from a previous checklist of Thai chiggers (Tanskul 1993) remains unknown. Distribution of chigger species by geographical regions of Thailand is discussed.

Ectoparasitic chigger mites on large oriental vole (Eothenomys miletus) across southwest, China.

An investigation of chigger mites on the large oriental vole, Eothenomys miletus (Rodentia: Cricetidae), was conducted between 2001 and 2013 at 39 localities across southwest China, and 2463 individuals of the vole hosts were captured and examined, which is a big host sample size. From the body surface of E. miletus, 49,850 individuals of chigger mites were collected, and they were identified as comprising 175 species, 13 genera, and 3 subfamilies in 2 families (Trombiculidae and Leeuwenhoekiidae). The 175 species of chigger mites from such a single rodent species (E. miletus) within a certain region (southwest China) extremely exceeded all the species of chigger mites previously recorded from multiple species of hosts in a wide region or a whole country in some other countries, and this suggests that E. miletus has a great potential to harbor abundant species of chigger mites on its body surface. Of 175 mite species, Leptotrombidium scutellare was the most dominant species, which has been proved as one of the main vectors of scrub typhus and the potential vector of haemorrhagic fever with renal syndrome (HFRS) in China. The patchiness index (m*/m) was used to measure the spatial patterns of the dominant chigger mite species, and all the three dominant mite species (L. scutellare, Leptotrombidium sinicum, and Helenicula simena) showed aggregated distributions among the different host individuals. The coefficient of association (V) was adopted to measure the interspecies interaction between the dominant mite species and a slightly positive association existed between L. scutellare and L. sinicum (V = 0.28, P < 0.01), which implies that these two mite species can co-exist on the same species of the host, E. miletus. The tendency curve of species abundance showed that the number of chigger mite species gradually decreased with the increase of mite individuals, and this revealed that most chigger mite species were rare with very few individuals, but few dominant species had abundant individuals. The species-sample relationship indicated that the number of chigger mite species increased with the increase of the host samples. The results suggest that a big host sample size over a wide realm of geographical regions is needed in the field investigation in order to obtain a true picture of species diversity and species composition.