Species Of Chigger Mites Research Articles

Discovery of a novel spotted fever group Rickettsia, "Candidatus Rickettsia kedanie," in unfed larval chigger mites, Leptotrombidium scutellare.

Spotted fever group (SFG) rickettsia, the causative agent of SFG rickettsiosis, is predominantly carried by ticks, whereas Orientia tsutusgamushi, the causative agent of scrub typhus, is primarily transmitted by chigger mites in Japan. In this study, we attempted to isolate intracellular eubacteria from Leptotrombidium scutellare, a major vector of O. tsutsugamushi; moreover, we isolated an SFG rickettsia using a mosquito-derived cell line. Draft genome sequences of this unique isolate, by applying criteria for species delimitation, classified this isolate as a novel strain, proposed as "Rickettsia kedanie." Further genetic analysis identified conserved virulence factors, and the isolate successfully propagated in mammalian cells, suggesting its ability to cause diseases in humans. The presence of SFG rickettsia in unfed larvae implies potential dual-pathogen carriage and reflects a symbiotic relationship similar to that between the mites and O. tsutsugamushi, indicating possibility of its transovarial transmission from female adults. Furthermore, conserved genomic similarity of the novel isolate to known SFG rickettsia suggests potential multiple hosts, including chiggers and ticks. In the natural environment, ticks, chigger mites, and wild animals may carry new isolates, complicating the infection cycle and increasing the transmission risks to humans. This discovery challenges the conventional association of SFG rickettsia with ticks, emphasizing its implications for research and disease control. However, this study was confined to a particular species of chigger mites and geographic area, underscoring the necessity for additional studies to comprehend the ecological dynamics, host interactions, and health implications linked to this newly identified SFG rickettsia.

The Distribution and Host-Association of the Vector Chigger Species Leptotrombidium imphalum in Southwest China.

Leptotrombidium imphalum is a species of chigger mites, and it can serve as a transmitting vector of scrub typhus. Southwest China is an important focus of scrub typhus. Based on the field investigation in southwest China from 2001 to 2022, this article presents the first report on the distribution and infestation of L. imphalum on rodents and other sympatric small mammals in the region. A total of 2161 L. imphalum were identified from 218 small mammal hosts in 21 of 114 survey sites. The 17 host species of L. imphalum crossed 13 genera and 5 families in 3 orders (Rodentia, Eulipotyphla, and Scandentia), indicating the low host specificity of the mite. The Asian house rat (Rattus tanezumi) was the dominant host species in the 21 sites where L. imphalum were collected, and 49.38% of mites were found on R. tanezumi. Different small mammals had different susceptibility to the infestation of L. imphalum. The prevalence (PM = 27.66%), infestation mean abundance (MA = 6 mites/per examined host), and mean intensity (MI = 21.69 mites/per infested host) for L. imphalum on the shrew gymnure (Neotetracus sinensis) were much higher than those on other host species (p < 0.05), indicating N. sinensis had a high susceptibility to the infestation of L. imphalum. The infestation indices for L. imphalum on small mammal hosts varied along different altitude and latitude gradients (p < 0.05), indicating the environmental heterogeneity of the mite infestation. Leptotrombidium imphalum exhibited an aggregated distribution among different individuals of its hosts. Besides the low host specificity of L. imphalum, the prevalence of the mite was positively correlated with the occurrence of scrub typhus, indicating the potential risk of the mite.

A NEW SPECIES OF CHIGGER MITE AND THE RECORD OF A GASTROINTESTINAL NEMATODE IN SCELOPORUS CAUTUS (SQUAMATA: PHRYNOSOMATIDAE) FROM THE CHIHUAHUAN DESERT PROVINCE IN COAHUILA, MEXICO.

The chigger species Acomatacarus coahuilensis n. sp. (Acariformes: Trombidiformes: Leeuwenhoekiidae) inhabiting the neck scales of the wary spiny lizard Sceloporus cautus Smith, 1938 (Squamata: Iguania: Phrynosomatidae), from Chihuahuan Desert Province, Coahuila, Mexico, is described herein. The new mite species is assigned to the genus AcomatacarusEwing, 1942, based on a palptarsus with 6 branched setae plus the tarsala (ω). This new species can be separated from the other species in this genus mainly based on the combination of the following characters: presence of mastisetae (MTa) on tarsus III and tibiala (φ) on tibia III, subterminala (ζ1), parasubterminala (z), and pretarsala (ζ2) on tarsus I, 2 genualae (σ1-2) on genu I, onychotriches and claw-like empodium of legs I-III, and absence of mastisetae on tibia III. In addition to the new species, the gastrointestinal nematode Skrjabinoptera phrynosoma (Ortlepp, 1922) Schulz, 1927 (Physalopteridae), was also found, which represents a new host record in the wary spiny lizard. This study reports the third species of the genus Acomatacarus recorded from Mexico and the first record of chigger mites and helminth parasites associated with Sc. cautus.

New data on the distribution of chigger mites (Acariformes: Trombiculidae) associated with small mammals in Vietnam.

The study of chigger mites of Vietnam is based on the material collected during fieldworks in 20112019 and examination of small mammal samples deposited in museum collections. A total 59 small mammals species were examined (49 species of Rodentia, 8 species of Eulipotyphla, and 2 species of Scandentia). On them, 79 species of chigger mites were collected, of which 44 species are recorded in Vietnam for the first time. Thus, the list of chigger mite species reported in Vietnam has been extended to 122 species belonging to 16 genera and 3 subfamilies. Most recorded species belong to the genera Leptotrombidium and Walchia. New hosts have been recorded for 48 trombiculid species. The study showed that the diversity of trombiculids of various regions of Vietnam has been studied unevenly.

Multiplex PCR assay for identifying five species of chigger mites in the Republic of Korea

AbstractChigger mites (Trombiculidae), which are known vectors of Orientia tsutsugamushi, have significantly fewer molecular data available than other known species, with a focus on morphological species identification rather than molecular species identification. However, chigger mites are easily damaged because of small size. In addition, natural variation and adult similarity would interrupt accurate classification and identification. Therefore, in this study, a multiple polymerase chain reaction (PCR) method using the internal transcribed spacer (ITS) region of five frequently occurring species (Euschoengastia koreaensis, Leptotrombidium orientale, Leptotrombidium pallidum, Leptotrombidium palpale, and Leptotrombidium scutellare) among eight species known to mediate the spread of is presented. This is the first report using molecular species identification for the classification method of chigger mites, which was only possible with morphological species identification, and is expected to be used as basic data for vector surveillance.

ПАРАЗИТАРНАЯ СИСТЕМА ЛИХОРАДКИ ЦУЦУГАМУШИ: КРАСНОТЕЛКОВЫЕ КЛЕЩИ (ACARIFORMES, TROMBICULIDAE) – ПЕРЕНОСЧИКИ И РЕЗЕРВУАРЫ ИНФЕКЦИИ В ЮГО-ВОСТОЧНОЙ АЗИИ

This review is dedicated to chigger mites (Trombiculidae) as vectors and reservoirs of infection in scrub typhus foci in South East Asia. Here we review biology, infection rates in natural and anthropurgic foci of scrub typhus. Vector competence of chigger mite species were summarized. Key words: scrub typhus, Orientia tsutsugamushi, Trombiculidae, vectors.

Contribution to the fauna of chiggers (Acariformes: Trombiculidae) parasitizing bats in Spain

Four chigger mite species were collected from different bat hosts in several provinces of Spain. Leptotrombidium europaeum (Daniel and Brelih, 1959) and Ascoschoengastia latyshevi (Schluger, 1955) has been recorded for the first time on bats; Leptotrombidium russicum (Oudemans, 1902), A. latyshevi and Willmannium cavus moldaviensis Kudryashova, 1992 have been recorded for the first time from Spain. The latter record represents also the first finding of the genus Willmannium Vercammen-Grandjean and Langston, 1976 in Western Europe.

Ectoparasites Diversity on Rodents and Shrews at Scrub Typhus Endemic Vellore District of Tamil Nadu, India.

Rodents and shrew living in the vicinity of human beings perform significant role to harbor different species of ectoparasites and thus act as the reservoir host for the spread of diseases to human and animals. This study was undertaken to determine the species composition of the medically important ectoparasites present in the scrub typhus affected places of Vellore District using wonder and Sherman traps for trapping of live Rodent/Shrew during September 2017 to August 2018. Rodent/shrew hosts belonged to two Families, three sub families and five genera and five different species. These animals carried 23 species of ectoparasites including 17 trombiculid mites, two non-trombiculid mites, two ticks and two fleas. A total of 940 chigger mites were collected which belonged to three Tribes, six Genera, two Subgenera and 17 species. Adult mites collected belonged to two families, three genera and three species. Ticks collected were classified under one family, two genera and two species. Fleas fall under one family, one subfamily, one tribe, one genus and two species. This is the first record of 14 species of chigger mites and three species of adult mites from Vellore District, Tamil Nadu. Surveillance of these keystone ectoparasites helped to identify the medically important disease vectors causing acari-borne zoonotic diseases.

Research history and progress of six vector chigger species of scrub typhus in China

Scrub typhus (tsutsugamushi disease) is caused by the causative agent, Orientia tsutsugamushi, and it is a widespread zoonosis and vector-borne disease. Chigger mites (trombiculid mites) are the exclusive vectors of this disease. To date, more than 500 species of chigger mites have been documented in China, and six of them have been proved to be the main effective vector species of scrub typhus: Leptotrombidium deliense, L. scutellare, L. rubellum, L. sialkotense, L. wenense and L. insulare. The present paper reviewed the research history and progress of the six vector chigger species in China, which covered their history of nomenclature, vector roles, morphological identification, life cycle, distribution, host selection and seasonal fluctuation, etc.

Genetic variation of chigger mites in the Republic of Korea

AbstractThe chigger mite is a known vector for the zoonotic disease, Tsutsugamushi, which affects more than 4,000 patients each year in the Republic of Korea (ROK) since 2004. However, molecular data is only available for a few species of chigger mite, compared to the numbers of known species. This study focused on securing molecular data for six species (Leptotrombidium pallidum, Leptotrombidium scutellare, Leptotrombidium palpale, Leptotrombidium orientale, Neotrombicula gardellai, and Euschoengastia koreaensis) of chigger mites in the ROK from cytochrome c oxidase subunit I (COI) and internal transcribed spacer 2 (ITS2). In the results, there were each two genotypes in L. pallidum and L. palpale, and three genotypes in L. scutellae in the COI, whereas the ITS2 sequence was identical within the species. The other three species were identical from COI and ITS2. This study first revealed the genetic variation in the COI sequences of chigger mites in the ROK. Further studies could determine how this variation is related to ecological behavior and disease transmission.

A new genus and two new species of chigger mites (Trombidiformes: Leeuwenhoekiidae) from Brazilian caves with notes about the genus Whartonia Ewing, 1944

ABSTRACT The family Leeuwenhoekiidae has a worldwide distribution. In Brazil, it is represented by five genera and 10 species parasitising all groups of terrestrial vertebrates. Examination of material housed in the Acari Collection of the Instituto Butantan revealed undescribed species belonging to this family. In the present study, we describe a new genus, Caramuruacarus gen. nov., with the type species Caramuruacarus carnavalesca sp. nov. from the Minas Gerais State and a new species for the genus Whartonia, Whartonia parauapebensis sp. nov., from Pará State, both from the soil of Brazilian caves. In addition, a discussion of the genus Whartonia and its subgenera is provided. http://www.zoobank.org/urn:lsid:zoobank.org:pub:B4D09A27-D163-4772-B4FA-79949D5FEC9F http://www.zoobank.org/urn:lsid:zoobank.org:pub:F3533B72-8643-467F-A348-63534EB67AAA http://www.zoobank.org/urn:lsid:zoobank.org:pub:3BC85F16-1E6D-4FFB-9B71-465A2689D9EE

A new genus and species of bat chiggers (Acariformes: Trombiculidae) from Kenya

A new genus and species of chigger mites, Minteracarus mombasa n. gen., n. sp., has been described from the heart-nosed bat, Cardioderma cor (Peters) (Chiroptera: Megadermatidae) in Mombasa, Kenya. The description was based on the material identified as a new species of the genus Trombicula Berlese, 1905 by P.H. Vercammen-Grandjean, but remained undescribed until the present.

Infestation and distribution of chigger mites on Chevrieri's field mouse (Apodemus chevrieri) in Southwest China.

Based on a long-term field investigation on chigger mites in southwest China from 2001 to 2019, the present study analyzed the infestation and distribution of chigger mites on the Chevrieri's field mouse (Apodemus chevrieri) in the region. A total of 12,516 individuals of chigger mites were collected from 1981 A. chevrieri mice, and 12,281 chiggers were identified as 107 species, 11 genera and 3 subfamilies in 2 families, which revealed a high species diversity of the mites on A. chevrieri mice. Of 1981 A. chevrieri mice, 633 ones were infested with chiggers with a relatively high overall prevalence (PM = 31.95%), mean abundance (MA = 6.32) and mean intensity (MI = 19.77). Of the 107 chigger species identified from A. chevrieri mice, three ones were the most dominant and they were Leptrombidium scutellare, L. densipunctatum and L. cricethrionis, which showed aggregated distribution among different individuals of the mice. A slightly positive association existed between every two dominant chigger species, which implied that the dominant chigger species tend to co-exist on A. chevrieri. The infestations of A. chevrieri with chiggers varied in different latitudes, altitudes and landscapes and they showed some heterogeneity along different environmental gradients. The logistic regression analysis showed that the risk factors for chigger infestations on A. chevrieri were landscapes, ages and altitudes, which implied that the environmental factors and host ages could influence the infestations of the mice with the mites. A theoretical curve of the species abundance distribution of chigger mites on A. chevrieri was successfully fitted by Preston's lognormal model, suggesting that the species abundance distribution conforms to the lognormal distribution pattern. The expected total species of chigger mites on A. chevrieri was roughly estimated to be 136 species and about 29 rare chigger species were probably missed in the sampling field investigation.

Distribution of chigger mites (Acari: Trombiculidae) over hosts, parasitopes, collection localities, and seasons in northern Iran

We studied the distribution of chigger mite species over mammal hosts, attachment sites on the host body, habitats, and seasons in Iran. The study was based on 2155 specimens of 36 chigger species collected from 10 species of Muridae, Cricetidae, and Soricidae across six provinces of northern Iran. A high level of mixed infestation by chiggers was recorded-76% of hosts parasitized by chiggers were infested by more than one (2-8) species. Statistically significant differences in the preference for anterior and posterior parts of the host body were found. Three species-Neotrombicula lubrica, N. delijani, and Cheladonta firdousii-preferred the posterior part of the host body; 12 species were characterized by the occurrence in the anterior part and differed from one another by the frequency of presence in the posterior part. One species, Hirsutiella alpina, was found only in the anterior part of the host body (inside the ears of rodents). The most diverse chigger fauna was on the fringe of Golestan National Park (species richness = 21, Shannon-Wiener index = 2.823). The chigger fauna of the high-mountain localities on the Alborz Range was the least diverse (species richness = 16, Shannon-Wiener index = 2.439). The seasonal aspect of activity was evident for Neotrombicula elegans, which exposed the autumn-winter period of the occurrence on hosts, and N. vernalis, with the winter-spring peak of abundance.

Geographical Distribution and Epidemiologic Factors of Chigger Mites on Apodemus agrarius during Autumn in Korea.

A nationwide survey of chigger mites causing scrub typhus and an investigation of epidemiologic factors for chigger mites was conducted at 16 localities in 8 provinces in Korea during autumn 2009, 2012, and 2013. A total of 233 Apodemus agrarius were captured, and all were infested with chigger mites. The chigger index was highest in Chungcheongbuk-do in 2009 (358.3) and 2012 (290.1) and Chungcheongnam-do in 2013 (294.4). The predominant chigger mite species was Leptotrombidium pallidum in the northern and central parts and L. scutellare in the southern and western parts, Korea. L. pallidum was not found in Jellanam-do and Gyeongsangnam-do and the distribution of L. scutellare had been expanded in the northern parts of Korea. The chigger index of L. pallidum was positively correlated with temperature and negatively correlated with humidity. The incidence of scrub typhus is dependent on L. scutellare index. These findings could be helpful to monitor the distribution of chigger mites and to develop a preventive measures for scrub typhus in Korea.

Contribution to the taxonomy of human-infesting chiggers (Acariformes: Trombiculidae) in Europe

Three species of chigger mites, which are supposed to be agents of human trombiculiasis in Europe, have been studied based on museum collections and specimens collected by the authors. Trombicula toldti Winkler, 1953 has been transferred to the monotypic genus Blanciella Vercammen-Grandjean, 1960. The type species of this genus, Blanciella deschiensi (Vercammen-Grandjean, 1956), was synonymized with Blanciella toldti comb. nov., and B. toldti was re-described. Lectotype of B. toldti was designated based on the type material donated to Zoological Institute RAS (St. Petersburg, Russia). The lectotype of Kepkatrombicula desaleri (Methlagl, 1928) was found in Muséum National d’Histoire Naturelle (Paris, France), and the previously designated neotype of K. desaleri has been set aside. Both B. toldti and K. desaleri have been recorded for the first time in Switzerland infesting goats (Capra hircus L., 1758). Human parasitism by Neotrombicula inopinata (Oudemans, 1909) in the UK has been confirmed for the first time with an examined museum specimen.

Infestation and Related Ecology of Chigger Mites on the Asian House Rat (Rattus tanezumi) in Yunnan Province, Southwest China.

This paper is to illustrate the infestation and related ecological characteristics of chigger mites on the Asian house rat (Rattus tanezumi). A total of 17,221 chigger mites were collected from 2,761 R. tanezumi rats, and then identified as 131 species and 19 genera in 2 families. Leptotrombidium deliense, the most powerful vector of scrub typhus in China, was the first major dominant species on R. tanezumi. All the dominant mite species were of an aggregated distribution among different individuals of R. tanezumi. The species composition and infestations of chiggers on R. tanezumi varied along different geographical regions, habitats and altitudes. The species-abundance distribution of the chigger mite community was successfully fitted and the theoretical curve equation was Ŝ (R)=37e−(0.28R)². The total chigger species on R. tanezumi were estimated to be 199 species or 234 species, and this further suggested that R. tanezumi has a great potential to harbor abundant species of chigger mites. The results of the species-plot relationship indicated that the chigger mite community on R. tanezumi in Yunnan was an uneven community with very high heterogeneity. Wide geographical regions with large host samples are recommended in the investigations of chigger mites.

New locality and host records of two chigger mite species (Acariformes: Trombiculidae) from Morocco

Two chigger mite species, Ericotrombidium tarentolae (Vercammen-Grandjean and Langston, 1976) and Neotrombicula orycti Taufflieb, 1960, have been recorded outside their type localities and on two species of geckos from the genus Quedenfeldtia Boettger for the first time. One new subjective synonym has been established on the base of examination of type specimens and additional materials — Neotrombicula orycti Taufflieb, 1960 (syn.: Neotrombicula lemni Taufflieb, 1960, n. syn.).

Redescriptions of ten chigger mite species (Acariformes: Trombiculidae) from Vietnam.

Ten species of chigger mites from the genera Gahrliepia Oudemans, 1912, Walchia Ewing, 1931, Cheladonta Lipovsky, Crossley and Loomis, 1955, Doloisia Oudemans, 1910, Schoutedenichia Jadin and Vercammen-Grandjean, 1954, and Microtrombicula Ewing, 1950, incompletely described by Schluger et al. (1960a, c, 1961, 1963) from rodents in North Vietnam, are redescribed based on type series. Lectotypes and paralectotypes have been designated for all species. A new synonymy has been established: Walchia delicatula (Schluger, Grochovskaja, Ngu, Hoe and Tung, 1960) (= Walchia tianguangshanensis Zhao, 1981 syn. nov.).

A new genus and species of chigger mites (Acariformes: Trombiculidae) from Madagascar

ABSTRACT A new genus and species of chigger mites, Sambonacarus nesomysi gen. et sp. nov., is described from a Madagascan endemic Nesomys rufus Peters, 1870 (Rodentia: Nesomyidae). The mite specimens are deposited in the Natural History Museum (London, UK) and were presumably collected from an alcohol-fixed specimen of island mouse deposited in the same museum. The new genus is similar to the genera Eutrombicula Ewing, 1938 and Microtrombicula Ewing, 1950 within the Eutrombicula generic complex. http://zoobank.org/urn:lsid:zoobank.org:pub:A373C8A7-9284-45FA-8559-DEDCD4197C32