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Nine species-level taxa of bat ectoparasites, three chigger mites (Trombiculidae), three hard (Ixodidae), and one soft tick (Argasidae) species, as well as two bug (Cimicidae) species from nine bat species hosts were detected in the Eastern Palaearctic. Trombiculid larvae of Leptotrombidium schlugerae, Leptotrombidium album, and Ascoschoengastia latyshevi were first recorded on bats in the temperate zone of eastern Russia. L. schlugerae was more abundant than A. latyshevi in the same study sites in Eastern Siberia, and the main hosts of both chigger species were Plecotus ognevi and Eptesicus nilssonii. Ixodid ticks Dermacentor marginatus, Ixodes simplex, and Ixodes sp. were sampled from bats in Kazakhstan, the Far East, and Eastern Siberia, respectively. Phylogenetic analysis based on Cox1, 16S rDNA, and ITS2 sequences of I. simplex showed that the specimens from the Far East grouped into a clade distributed in the Eastern Palaearctic and India. In turn, the specimen of Ixodes sp. from Eastern Siberia was most closely related to Ixodes soricis and Ixodes angustus with p-distance of 9.8–10.7% (Cox1), suggesting that this tick probably belongs to a new species. Argas vespertilionis larvae were collected from three widespread bat species in Kazakhstan. Two bug species, Cimex pipistrelli and Cimex aff. lectularius, were recorded in the Far East and Eastern Siberia, respectively. Specimens from Transbaikalia were morphologically identified as Cimex lectularius. However, they differed from the latter by 12.5–12.9% of Cox1 sequences, indicating that C. aff. lectularius may be a new species. [ABSTRACT FROM AUTHOR]

Drivers of patterns of ectoparasitism in rodents in patchy Mojave Desert wetlands were investigated. A total of 1,571 ectoparasites in Mesostigmata, Trombidiformes, Siphonaptera and Ixodida were collected from 341 rodents (Microtus californicus scirpensis, Mus musculus, Reithrodontomys megalotis, Peromyscus eremicus, and Neotoma lepida) at eleven marshes. Trombiculids accounted for 82.5% of mites, followed by the mesostigmatid Ornithonyssus bacoti (17.5%), with chiggers predominating on voles and harvest mice. There were at least three genera of chiggers (Eutrombicula alfreddugesi, Euschoengastia sp. novel, and Blankaartia sp. novel). Fleas included Orchopeas leucopus (90.3% of all fleas) and O. sexdentatus (9.7%), and ticks were the novel endemic Ixodes mojavensis (82.1% of ticks) and Dermacentor similis (17.9%). On all hosts and at all marshes, coverage-based rarefaction sampling was over 96%, indicating coverage sufficient for analysis. Dissimilarities in ectoparasite community structure were driven mainly by chiggers, I. mojavensis and O. leucopus. Northern marshes were dominated by chiggers; central marshes by I. mojavensis; and southern marshes by O. leucopus. Primary determinants of ectoparasite community structure were host species, patch size, and parasite interspecific interactions. Host species richness and environmental factors such as patch distance and water and plant availability were not significantly associated with patterns of ectoparasitism. There were nine (60%) significant negative pairwise associations between ectoparasite taxa and no significant positive relationships. Ixodes mojavensis had the highest number of negative associations (with five other species), followed by chiggers and O. bacoti with two negative associations each. The study area is among the most arid in North America and supports numerous rare and endemic species in increasingly isolated wetland habitat patches; knowledge of ectoparasite ecology in this region identifies potential ectoparasite vectors, and provides information needed to design and implement programs to manage vector-borne diseases for purposes of wildlife conservation.

Based on a long-term field investigation in the five provincial regions of Southwest China between 2001 and 2019, the present paper studied the infestation and related ecology of chigger mites (chiggers) on the large Chinese vole (Eothenomys miletus), an endemic and dominant rodent species in the regions. A total of 52331 chiggers were collected from 2661 voles, and 52261 mites were identified as 185 species and 13 genera in the family Trombiculidae with very high species diversity. The identified 185 chigger species on E. miletus (a single rodent species) even exceeded those recorded in some countries. The overall infestation prevalence (Pm = 53.96%), mean abundance (MA = 19.64) and mean intensity (MI = 36.39) on E. miletus were much higher than those on some other rodent species in the same regions. Although the species composition showed a moderate similarity (J = 0.63) between male and female hosts (E. miletus), the infestation indices (Pm = 56.25%, MA = 21.67) of chiggers on male hosts were higher than those on the females (Pm = 51.23%, MA = 17.09) (P

The family Trombiculidae encompasses numerous and widespread mites, the larvae of which are obligatory parasites of vertebrates. Our research objective was to assess how trombiculid burdens on rodents inhabiting three forested and one open area in NE Poland vary in relation to host identity, sex and body size, and how they are influenced by qualities of the habitat. Trapped rodents (n = 240) were measured, weighted and screened for ectoparasites. Apodemus flavicollis (n = 42) and Myodes glareolus (n = 173) harbored a total of 4652 Hirsutiella zachchvatkini larvae. Statistical tests revealed that both prevalence and abundance were significantly higher in voles (93%, 27 larvae/ind.) than in mice (14%, 0.24 larvae/ind.) but there was no effect of host sex. Among the localities, H. zachvatkini was most prevalent (98%) and abundant (41 larvae/ind.) in rodents from the deciduous mixed forest in Tałty compared to fallow land (2.6%, 0.13 larvae/ind.). The highest prevalence and abundance were found in bank voles; in this host species in Tałty, prevalence reached 100% and the mean abundance was >42 larvae/ind. Significant positive correlations were found between the body mass and body length of voles and the number of attached larvae. Our results confirm the sylvan nature of H. zachvatkini and its preference for bank voles inhabiting deciduous forests with rich and humid undergrowth. The lack of a sex bias and the moderate correlation between mite burden and host size are in line with observations already made on other rodent-associated Trombiculidae. [ABSTRACT FROM AUTHOR]

Introduction: Scrub typhus is transmitted by the bite of the larva (chigger) of a microscopic trombiculidae mite (Leptotrombidium) found in moist areas and vegetation, which serves as both vector and reservoir. Scrub typhus is an often neglected and misdiagnosed febrile illness; clinical suspicion is the only key to diagnosis. Aim: To study clinicolaboratory profile and outcome of serologically confirmed scrub typhus in children from sub Himalayan tribal district of India. Materials and Methods: This cross-sectional observational study was conducted in Department of Paediatrics at Government District Hospital, Chamba, Himachal Pradesh, India, from May 2019 to April 2020. Children upto 18 years admitted with positive Immunoglobulin M (IgM) antibodies for scrub typhus were enrolled. The observational data including detail history and examination, relevant laboratory investigation and treatment was analysed by Statistical Package for Social Sciences (SPSS) software version 18.0 and Chi-square test with p-value

Based on a long-term field investigation in the five provincial regions of Southwest China between 2001 and 2019, the present paper studied the infestation and related ecology of chigger mites (chiggers) on the large Chinese vole (Eothenomys miletus), an endemic and dominant rodent species in the regions. A total of 52331 chiggers were collected from 2661 voles, and 52261 mites were identified as 185 species and 13 genera in the family Trombiculidae with very high species diversity. The identified 185 chigger species on E. miletus (a single rodent species) even exceeded those recorded in some countries. The overall infestation prevalence (P m = 53.96%), mean abundance (MA = 19.64) and mean intensity (MI = 36.39) on E. miletus were much higher than those on some other rodent species in the same regions. Although the species composition showed a moderate similarity (J = 0.63) between male and female hosts (E. miletus), the infestation indices (P m = 56.25%, MA = 21.67) of chiggers on male hosts were higher than those on the females (P m = 51.23%, MA = 17.09) (P < 0.05). Two dominant chigger species, Leptotrombidium scutellare (C r = 19.17%) and L. sinicum (C r = 11.06%), showed an aggregated distribution pattern among different individuals of their host E. miletus , and a relatively high degree of positive association existed between the two dominant chigger species with PCC = 0.57, DI = 0.60 and OI = 0.62 (x 2 = 857.46, P < 0.001). Leptotrombidium d ensipunctatum , Walchia koi , Helenicula hsui , L. scutellare and W. ewingi showed a high degree of environmental adaptability to their environments with high niche breadths. The theoretical curve of the species abundance distribution of chigger community on E. miletus was successfully fitted with Preston's lognormal distribution model. Based on the theoretical curve fitting, the expected total number of chigger species on E. miletus was roughly estimated to be 223 species, and 38 chigger species were probably missed in the sampling investigation. [Display omitted] • Chiggers are the common ectoparasites of rodents and vector of scrub typhus, Eothenomys miletus is the reservoir host and infectious source of zoonoses. • The dominant chigger specie, Leptotrombidium scutellare , is one of the main and powerful vectors of scrub typhus in China. • To study the chigger mites of E. miletus voles in such a wide geographical region. [ABSTRACT FROM AUTHOR]

Larvae of the chigger mite Leptotrombidium album (Kamo, Kawashima & Nishimura, 1957) (Acariformes, Trombiculidae) are found in Kunashir island and recognized as parasites of bats Barbastella pacifica (Kruskop, Kawai & Tiunov, 2019) for the first time. Larvae were measured and photographed using SEM and DIC approaches. A stylostome is described in bats for the first time by histological with additional CLSM, DIC and polarized light methods. The stylostome belongs to the mesenchymal type and penetrates deep into the host dermis perpendicular to the skin surface. The stylostome is a straight relatively wide (80 µm) tube and may reach 250 µm long in the maximum development. The axial stylostome canal varies from 7.5 to 20 µm wide and distally is opened to the subjacent host tissue. A particular eosinophil cone of a gel consistency to which the larval cheliceral blades are tightly cemented represents the proximal stylostome portion. The main stylostome portion usually remains unstained and also shows a gel-like consistency. The distal stylostome portion—supposedly a fresh saliva portion—is typically stained by Azur in blue and seems to be a transitional condition between sol to gel. No birefringent components are found in the stylostome substance. The stylostome may immediately contact host tissues or may be surrounded by a mixed eosinophil substance composed of destroyed inflammatory cells. If present, this substance is tightly associated with the stylostome walls and may be considered as an analog of scab but distributed not on the surface but inside the skin. The stylostome formation is accompanied by a generalized inflammatory reaction with the predominance of neutrophil leukocytes. The activity of basophils, lymphocytes, macrophages and mast cells is relatively weak. A particular tissue sinus filled with inflammatory cells, an analog of the feeding cavity, situates underneath the stylostome. The disclosed stylostome organization confirms its species-specific character. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Infection with severe fever with thrombocytopenia syndrome (Bandavirus dabieense) virus poses a substantial public health threat because of its high mortality rates and severe complications. The virus is prevalent in Asia, although data from Thailand are scarce. Our study confirmed the virus in 1.6% of acute febrile illness patients and specific antibodies in 3% of archived samples since 2015 in Thailand. Nationwide zoonotic surveillance identified the virus in 8 rodent species and 4 chigger genera. Our findings underscore the importance of raising awareness among healthcare providers and the general public about the symptoms, risks, and prevention strategies associated with severe fever with thrombocytopenia syndrome virus infection. Ongoing surveillance of the virus in human and animal populations is essential for monitoring its prevalence, distribution, and potential for emergence.

Introduction: Scrub typhus is transmitted by the bite of the larva (chigger) of a microscopic trombiculidae mite (Leptotrombidium) found in moist areas and vegetation, which serves as both vector and reservoir. Scrub typhus is an often neglected and misdiagnosed febrile illness; clinical suspicion is the only key to diagnosis. Aim: To study clinicolaboratory profile and outcome of serologically confirmed scrub typhus in children from sub Himalayan tribal district of India. Materials and Methods: This cross-sectional observational study was conducted in Department of Paediatrics at Government District Hospital, Chamba, Himachal Pradesh, India, from May 2019 to April 2020. Children upto 18 years admitted with positive Immunoglobulin M (IgM) antibodies for scrub typhus were enrolled. The observational data including detail history and examination, relevant laboratory investigation and treatment was analysed by Statistical Package for Social Sciences (SPSS) software version 18.0 and Chi-square test with p-value <0.05 was considered statistically significant. Results: There were total 55 patients with scrub typhus, mean age was 9.2 years, most common age group was 7-12 years, 51% were male. Fever was most common complaint, followed by vomiting (27.3%), abdomen pain (25.4%), respiratory (1.8%), and rash (9%). Clinical examination findings were generalised lymphadenopathy in 46 (83.6%) patients and splenomegaly in 29 (52.7%). Eight patients presented with respiratory signs and tachypnea at the time of admission. Eschar was present in only 3 (5.5%) patients. Sign of meningeal irritation was present in 4 (7.3% cases and low GCS score (below 9) observed in 7 (12.7%) patients. Eight patients required mechanical ventilatory support. Nineteen patients were prescribed doxycycline alone; while 34 were given both azithromycin and doxycycline. There were total five deaths; on multivariate logistic regression, respiratory complaint, need for mechanical ventilation, pain abdomen with liver damage, history of seizures and duration of fever more than 4 days before presentation to hospital were associated with adverse outcome. Conclusion: The prevalence of scrub typhus is considerably high during rainy season, and should be considered as a differential diagnosis of fever among children in this period regardless of the presence of an eschar. Immediate medical care, treatment with doxycycline with early defervescence of fever reduce mortality. [ABSTRACT FROM AUTHOR]

The genus Rickettsia is the causative agent of several rickettsial diseases that are primarily transmitted by hard ticks. The occurrence of Rickettsia in chigger mites, which are vectors of scrub typhus in the western Pacific region, has been infrequently investigated. We identified Rickettsia spp. in chiggers collected from small mammals in six counties of Taiwan. Moreover, by capitalising on parallel Rickettsia detections on small mammals and their infested ticks and fleas, we were able to identify Rickettsia spp. that suggested more intimate associations with chigger mites. Rickettsia detection rates in 318 pools of chiggers were 21.7% and 22.3% when based on the ompB and gltA gene, respectively. Overall, we identified six (based on the ompB gene) and eight (gltA gene) Rickettsia species. Approximately half of the sequenced species were most similar to Rickettsia sp. clone MB74‐1 (ompB gene) and Rickettsia sp. TwKM02 (gltA gene). Furthermore, both species were either infrequently or never identified in small mammals, ticks and fleas, which suggests that chigger mites might be the primary host of both rickettsiae. Whether both species are pathogenic to humans remains to be studied. They may also be microbial endosymbionts of chigger mites, with their potential effects on the pathogenicity of the aetiologic agent of scrub typhus deserving further investigations. [ABSTRACT FROM AUTHOR]

Rock lizards of the genus Darevskia are interesting research models due to their asexual reproduction. Ectoparasitic mites and ticks of these lizards are poorly known, despite some of these chelicerates being vector pathogens of humans and wildlife. Here we document and curate previously known data on ectoparasitic Acari of rock lizards and, based on our extensive survey, provide an annotated list of these ectoparasitic arthropods (six tick species, one macronyssid species, and seven chigger species). We also provide new host records (Ixodes ricinus on Darevskia caucasica, D. dryada, D. mixta, and D. szczerbaki; Haemaphysalis sulcata on D. rudis; Odontacarus saxicolis on D. brauneri); and new geographical records (O. saxicolis in Russia and Georgia). [ABSTRACT FROM AUTHOR]

Background: Mites are among the smallest arthropods that can be seen without magnification, were the use of dermatoscopy is an invaluable tool. They are a cosmopolitan pest, and at the moment more than 250 species have been shown to produce problems for humans and animals alike. These mites are capable of producing a wide array of clinical signs and symptoms, from local to systemic, from mild to severe, as well as transmitting pathogens. This study aimed to provide an update to the clinical impact on human health, the distribution and species involved in the clinical conditions produced by trombiculids through a systematic review. Background: Mites are among the smallest arthropods that can be seen without magnification, were the use of dermatoscopy is an invaluable tool. They are a cosmopolitan pest, and at the moment more than 250 species have been shown to produce problems for humans and animals alike. These mites are capable of producing a wide array of clinical signs and symptoms, from local to systemic, from mild to severe, as well as transmitting pathogens. This study aimed to provide an update to the clinical impact on human health, the distribution and species involved in the clinical conditions produced by trombiculids through a systematic review. Methods: A systematic literature review was conducted in Medline, Lilacs, Redalyc, Scopus, SciELO and Google Scholar, were we use as a threshold of publication date the year 2008. We limited the search strategy to articles published in Portuguese, French, English and Spanish. Eligible studies were case reports and case series that reported outcomes in humans caused by trombiculid bites. Patient-level and study-level information was extracted. Results: The literature search yielded 832 studies; 13 were case reports, 4 case series and 2 descriptive studies reporting a total of 49 cases. Most patients were male, and the median age was 33.7±6.4 years old. The most frequently reported symptoms were local erythema, pruritus and papules. No deaths were documented. Trombiculids from the genera Trombicula, Eutrombicula and Leptotrombidium appear to be the most commonly reported. Discussion: Trombiculiasis is an infestation caused by the larval stage of various types of mites, known as chiggers, they belong to the class Arachnida and the family Trombiculidae. This systematic review provides an overview of the trombiculids of clinical importance, their distribution and effects of the bite on human health. Our results show that there are different species of mites that can have important consequences for human health. No fatal cases owere registered.Even so, the transmission of scrub typhus is important and remains one of the most life-threatening rickettsial infections in some regions of Asia. Conclusions: The bite of different species of trombiculids around the world can cause a wide array of clinical consequences to human health. Even as mortality appear to be nonexistent, trombiculid bites must be adequately diagnosed and treated properly: A systematic literature review was conducted in Medline, Lilacs, Redalyc, Scopus, SciELO and Google Scholar, were we use as a threshold of publication date the year 2008. We limited the search strategy to articles published in Portuguese, French, English and Spanish. Eligible studies were case reports and case series that reported outcomes in humans caused by trombiculid bites. Patient-level and study-level information was extracted. Results: The literature search yielded 832 studies; 13 were case reports, 4 case series and 2 descriptive studies reporting a total of 49 cases. Most patients were male, and the median age was 33.7±6.4 years old. The most frequently reported symptoms were local erythema, pruritus and papules. No deaths were documented. Trombiculids from the genera Trombicula, Eutrombicula and Leptotrombidium appear to be the most commonly reported. Discussion: Trombiculiasis is an infestation caused by the larval stage of various types of mites, known as chiggers, they belong to the class Arachnida and the family Trombiculidae. This systematic review provides an overview of the trombiculids of clinical importance, their distribution and effects of the bite on human health. Our results show that there are different species of mites that can have important consequences for human health. No fatal cases owere registered.Even so, the transmission of scrub typhus is important and remains one of the most life-threatening rickettsial infections in some regions of Asia. Conclusions: The bite of different species of trombiculids around the world can cause a wide array of clinical consequences to human health. Even as mortality appear to be nonexistent, trombiculid bites must be adequately diagnosed and treated properly.

The study aims to register Hannemania larvae in Leptodactylus luctator and their infestation rates in an area of the Pampa biome at the extreme south of Brazil. Forty-six specimens of L. luctator (25 females: 21 males) collected in an urban area of the state of Rio Grande do Sul were examined. The prevalence of mites was 93.5%, and 4207 larvae were collected. The mean intensity of infestation was 97.8 mites/host (6-379). There were no significant differences in the prevalence and mean intensity of infestation between male and female hosts. There was no relationship between abundance of larvae and size of anurans. The study increases knowledge of the parasitic fauna and its parasitological indices in anurans from extreme south of Brazil. [ABSTRACT FROM AUTHOR]

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This diagnostic survey of chigger mites of the family Trombiculidae was conducted across 26 provinces of Turkey during 2015 - 2016. A total of eight species of chigger mites from 5 genera were collected from 7 different host species of wild rodents and soricomorphs. The chigger species were as follows: Brunehaldia brunehaldi (Vercammen-Grandjean, 1956), B. bulgarica (Vercammen-Grandjean and Kolebinova, 1966), Cheladonta sp., Kepkatrombicula kudryashovae (Stekolnikov, 2001), K. serbovae (Kolebinova, 1972), Neotrombicula sympatrica (Stekolnikov, 2001), N. vulgaris (Schluger, 1955) and Schoutedenichia krampitzi (Willmann, 1955). The overall prevalence of infestation of the individual, captured rodents and soricomorphs by one or more chigger mites was 12.3% (88/716). The moderately prevalence of chigger species demonstrated in the present study suggests that Turkey is an endemic region for chiggers due to the widespread presence of a number of potential hosts that include rodents and soricomorphs.

We studied chigger and gamasid mite loads on small mammals during the dry season in Vietnam and used both our field data and museum collections to estimate the influence of environmental factors on mite abundance and prevalence. Generalized linear (mixed effect) models were used to analyze the data. We examined 1,239 small mammal individuals, which were obtained from field expeditions and museum collections belonging to 59 species. In different localities, Rattus Fischer (Rodentia: Muridae), Niviventer Marshall (Rodentia: Muridae), and Maxomys Sody (Rodentia: Muridae) were the most common animals captured. The prevalence of chigger and gamasid mites in our expedition data was high: 72% and 62%, respectively. We found differences in the abundance of chigger mites between different populations of the same species of small mammals. Season and locality were the main factors that influenced chigger mite abundance and prevalence. The best model that predicted the abundance and prevalence of chigger mites included geography (province) as a predictor and host species and season as random effects. For the first time, we analyzed factors connected with climate and weather affecting chigger mites of small mammals in Vietnam., (© The Author(s) 2024. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Chiggers, the larval Trombiculid mites are the vectors for scrub typhus. Rodents and shrews are the preferred host. Study made at different habitats of chiggers collected in rodents and shrews, revealed more number to Rattus rattus 95(63%) and Suncus murinus 33(22%). Rattus rattus 31(54%) and Suncus murinus 17(30%) alone contributed more in chigger positivity. Chigger mites belonged to eight species under five genera. Leptotrombidium deliense (66%), Schoengatiella ligula (15%), and other chiggers (9%) were collected from 57 positive rodents. Seasonally, there was a significant difference in rodent positivity, and there was no significant difference in the number of chiggers collected. The study indicated the prevalence of chiggers in the various hosts and their variation in rodent/shrew hosts. R. rattus 31(54%) and S. murinus 17(30%) contributed more in chiggers infestation and seasonally wet-cool months favored more chiggers and host positivity from different habitats. [ABSTRACT FROM AUTHOR]

Post-larval life cycle, larval morphology and histology of the sites of the larvae feeding were investigated in the trombiculid mite Hirsutiella hexasternalis (Kudryashova, 1998) based on the material firstly collected from West Siberia (Tyumen province) from the voles Myodes rutilus (Pallas, 1779). Duration of the nymphal developmental stages generally corresponds to those of other trombiculid mites with the average values of 19 and 13 days for proto- and tritonymphs, respectively. Duration of active deutonymphal stage varies greatly and allocated between 12 and 31 days. Adult mites live much longer, up to eleven months. Larval morphological characters studied by SEM correspond to those of the first descriptions of this species. The stylostome developed in the host skin during larval feeding was investigated using histological methods. The stylostome belongs to the epidermal type and its characters do not correspond to stylostomes studied so far in other trombiculid species. The stylostome is a uniformly wide whitish structure with neither longitudinal nor transverse stratification. It may demonstrate pale-pink staining along the central canal and at the proximal and the distal ends. The central canal opens freely to the underlying tissue and may contain cell debris. Beneath the stylostome, a differently developed feeding cavity containing lymphoid cells may be observed. The host skin demonstrates thickening of the epidermis at the site of attachment, hyperkeratosis as well as dilation of the terminal blood vessels. The characteristics of this trombiculid species are discussed. It is shown, in particular, that morphologically closed species of trombiculid mites reveal noticeable differences in the characters of the life cycle as well as in the stylostome formation.

Purpose: Larval stages of trombiculid mites infest a wide variety of wild and domestic animals. The most common clinical signs related with the presence of these parasites are alopecia, crusts, erythema, excoriation, erosion, papules, pustules and vesicles. Most of trombiculid infestations may not be perceived by the clinician due to their small size. Although Ericotrombidium ibericense has been recorded on cats, it has not been found on dogs. Methods: In August 2019, three domestic dogs presenting pruritic dermatological lesions in the ventral area of the body and interdigital spaces were presented at a veterinary clinic in Santarém, central Portugal. Trombiculid mites were extracted from the skin and preserved in 70% ethanol. Specimens were prepared in slides with Hoyer's medium and observed with optical microscopy. Results: After morphological examination of the specimens, mites were identified as E. ibericense (Acariformes: Trombiculidae). Conclusions: Most of the trombiculids recorded in European clinical practice are generally identified as Neotrombicula autumnalis by default, since, in most cases, mites are not examined morphologically. This is the first record of E. ibericense in domestic dogs. More studies are needed to evaluate the distribution of these mites in Portugal. Veterinary clinicians must be aware of this parasitosis, as trombiculids can cause exuberant clinical signs, but are often misdiagnosed. [ABSTRACT FROM AUTHOR]

This diagnostic survey of chigger mites of the family Trombiculidae was conducted across 26 provinces of Turkey during 2015 - 2016. A total of eight species of chigger mites from 5 genera were collected from 7 different host species of wild rodents and soricomorphs. The chigger species were as follows: Brunehaldia brunehaldi (Vercammen-Grandjean, 1956), B. bulgarica (Vercammen-Grandjean and Kolebinova, 1966), Cheladonta sp., Kepkatrombicula kudryashovae (Stekolnikov, 2001), K. serbovae (Kolebinova, 1972), Neotrombicula sympatrica (Stekolnikov, 2001), N. vulgaris (Schluger, 1955) and Schoutedenichia krampitzi (Willmann, 1955). The overall prevalence of infestation of the individual, captured rodents and soricomorphs by one or more chigger mites was 12.3% (88/716). The moderately prevalence of chigger species demonstrated in the present study suggests that Turkey is an endemic region for chiggers due to the widespread presence of a number of potential hosts that include rodents and soricomorphs. [ABSTRACT FROM AUTHOR]

The chigger, Euschoengastia pipistrelli Brennan, is a trombiculid mite that infests a variety of vespertilionid bats in North America. It has been reported from at least 9 species of bats from 18 U.S. states. However, nothing is available on the actual in situ infestation and ultrastructure of this chigger. Here we document some stereoscopic photographs of the infestation as well as a scanning electron micrograph of the mite from a common bat species. We also provide a summation of host and state records for this chigger. [ABSTRACT FROM AUTHOR]

Abstract Background Ectoparasitic infections are of particular interest for endangered wildlife, as ectoparasites are potential vectors for inter- and intraspecific pathogen transmission and may be indicators to assess the health status of endangered populations. Here, ectoparasite dynamics in sympatric populations of two Malagasy mouse lemur species, Microcebus murinus and M. ravelobensis, were investigated over an 11-month period. Furthermore, the animals’ body mass was determined as an indicator of body condition, reflecting seasonal and environmental challenges. Living in sympatry, the two study species experience the same environmental conditions, but show distinct differences in socioecology: Microcebus murinus sleeps in tree holes, either solitarily (males) or sometimes in groups (females only), whereas M. ravelobensis sleeps in mixed-sex groups in more open vegetation. Results Both mouse lemur species hosted ticks (Haemaphysalis sp.), lice (Lemurpediculus sp.) and mites (Trombiculidae gen. sp. and Laelaptidae gen. sp.). Host species, as well as temporal variations (month and year), were identified as the main factors influencing infestation. Tick infestation peaked in the late dry season and was significantly more often observed in M. murinus (P = 0.011), while lice infestation was more likely in M. ravelobensis (P < 0.001) and showed a continuous increase over the course of the dry season. Genetic analyses identified Lemurpediculus sp. infesting both mouse lemur species. Ticks morphologically conform to H. lemuris, but genetic analysis showed a clear differentiation of the specimens collected in this study, suggesting a potentially new tick species. Host body mass decreased from the early to the late dry season, indicating nutritional stress during this period, which may render individuals more susceptible to parasitic infections. Conclusions Seasonal differences and species-specific variations in sleeping site ecology in terms of sleeping site type and sociality were determined as key factors influencing ectoparasitism in M. murinus and M. ravelobensis. This needs to be taken into account when evaluating ectoparasite infestations at a given time point. The detection of the same parasite species on two closely related and sympatric host species furthermore indicates a potential pathway for disease transmission, not only within but also between lemur species.

Background--The study aims to assess the efficacy of a permethrin 54.5%-fipronil 6.1%-based spot-on solution in dogs naturally infested with Neotrombicula in an open-label controlled study. Methods--Ten naturally infested dogs received one drop per affected site on day (D) 0, and on D14, the rest of the pipette was applied on the skin between the shoulders. Five dogs served as sentinels. Parasite score (0-3), skin lesions (0-4), and investigator pruritus scale (0-4) were assessed on D0, D1, D14, and D28. Results--No treated dogs developed adverse reactions. Parasite score of sentinel dogs was maintained between 1.8 (D0, D1, and D28) and 2.2 (D14). In treated dogs, D0 parasite score was 2.4. It was significantly reduced from D1 (0.5; p < 0.002) to D28 (0.1; p < 0.002). The lesion score was 2.9 on D0 and D1; it was significantly reduced on D14 (0.6; p < 0.002) and D28 (0.1; p < 0.002). Similarly, investigator pruritus scale (D0, 2.2) scores significantly decreased on D14 (0.4; p < 0.004) and D28 (0.2; p < 0.002). Conclusions--The combination permethrin-fipronil appears to be well-tolerated, rapidly and durably effective in the control of localized canine harvest mite infestation. [ABSTRACT FROM AUTHOR]

Scrub typhus is caused by Orientia tsutsugamushi (formerly Rickettsia) and is transmitted to humans by an arthropod vector of the Trombiculidae family (Leptotrombidium deliense and L. akamushi). It is the most common re-emerging Rickettsial infection in India and many other South East Asian countries. In fact, scrub typhus is confined geographically to the Asia Pacific region, a billion people are at risk and nearly a million cases are reported every year. Scrub typhus appears particularly to be distributed in the tsutsugamushi triangle which is distributed over a very wide area of 13 million km2 bound by Japan in the east, through China, the Philippines, tropical Australia in the south, and west through India, Pakistan, possibly to Tibet to Afghanistan, and southern parts of the USSR in the north. Eschar is the characteristic lesion that starts as a vesicular lesion at the site of mite feeding. Later, an ulcer forms with black necrotic center and an erythematous border along with regional lymphadenopathy. Other features are fever, maculopapular rash starting from the trunk, and spreading to the limbs. It may affect the central nervous system, cardiovascular system, renal, respiratory, and gastrointestinal systems. Serious complication in the form of myocarditis, pneumonia, meningoencephalitis, acute renal failure, gastrointestinal bleeding, and even acute respiratory distress syndrome may develop. Tetracycline or chloramphenicol remains the main stay of therapy.

Chiggers, the larvae of trombiculid mites, parasitize a wide variety of terrestrial vertebrates worldwide. Their bites cause seasonal trombiculiasis in humans and animals. Affected canines can have a variety of digestive and systemic clinical signs. We describe a case of canine trombiculiasis in a dog exhibiting severe neurologic symptoms.

Two new chigger species, Leptotrombidium mondulkiri sp. nov. and Walchia keoseima sp. nov., and one new subspecies, Leptotrombidium pilosum cambodiensis subsp. nov., are described from Cambodia. Three species, Walchia lupella (Traub and Evans, 1957), W. micropelta (Traub and Evans, 1957), and W. kritochaeta (Traub and Evans, 1957), are for the first time reported from the country. A redescription of W. lupella is given based on new materials from Cambodia and Thailand.

The red palm mite Raoiella indica Hirst, 1924 (Acari: Tenuipalpidae) is an important pest of the coconut palm Cocos nucifera L. (Arecaceae) and has caused problems in coconut production worldwide. Research has been carried out aiming at controlling the mite through chemical, biological, alternative, and host plant resistance methods. Identifying coconut palm cultivars resistant to R. indica is important to reduce the problems caused to plantations. Therefore, the objective of this work was to evaluate the performance of R. indica in six dwarf coconut palm cultivars, to identify sources of resistance. The cultivars of the sub-varieties green, red, and yellow evaluated were Brazilian Green Dwarf-Jiqui (BGDJ), Brazilian Red Dwarf-Gramame (BRDG), Cameroon Red Dwarf (CRD), Malayan Red Dwarf (MRD), Brazilian Yellow Dwarf-Gramame (BYDG), and Malayan Yellow Dwarf (MYD). Confinement and free choice tests of R. indica on the cultivars were performed, in which biological parameters and preference were evaluated. Mite performance was different in the cultivars evaluated. In the confinement bioassay, R. indica had the worst performance in the cultivar BGDJ, the best performance in CRD, MRD, and BRDG, and intermediate performance in BYDG and MYD. In the free choice test, the cultivars MRD and MYD were preferred in relation to BGDJ, and CRD was less preferred in relation to BGDJ. Therefore, we considered that the cultivar BGDJ is the most resistant to R. indica, by antibiosis and antixenosis; CRD has resistance by antixenosis; and MRD, BRDG, BYDG, and MYD are susceptible., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Few studies have been carried out on the Ecuadorian chigger fauna. In this study, we are describing a new species of Eutrombicula from the Galápagos Islands. Also, we provide an updated checklist of Ecuadorian and Galápagos Islands chiggers, including a new host association and locality record for Eutrombicula nerudai Stekolnikov and González-Acuña., (© 2023. The Author(s), under exclusive licence to Springer Nature B.V.)

Background: Orientia tsutsugamushi is a zoonotic intracellular pathogen that requires parasitism in eukaryotic cells to reproduce. In recent years, tsutsugamushi disease reported in many places nationwide has crossed the Yangtze River, continuously, spreading to the North China. Now this phenomenon has aroused people's attention. Materials and Methods: In this study, meta-analysis was used to analyze the infection of rodents (vectors) in China, to clarify the transmission rule of O. tsutsugamushi . Results: This study included literature from six databases (PubMed, Web of Science, Science Direct, Wanfang, CNKI, and VIP). A total of 55 articles were included in the study from 610 retrieved articles. The total infection rate of O. tsutsugamushi in rodents was 5.5% (1206/20,620, 95% confidence interval [CI]: 0.0553-0.0617). The prevalence of O. tsutsugamushi in rodents before 2013 (7.73%, 95% CI: 4.11-12.37) was higher than after 2013 (2.11%, 95% CI: 0.64-4.41). O. tsutsugamushi spread among a variety of rodents, among which Rattus losea (13.3%, 95% CI: 4.33-26.26), Rattus tanezumi (5.69%, 95% CI: 1.37-12.72), and Apodemus agrarius (5.32%, 95% CI: 2.26-9.58) infection rate was higher. Kawasaki (8.32%, 95% CI: 1.42-20.17), Karp (7.36%, 95% CI: 2.62-14.22), Kato (2.54%, 95% CI: 0.08-8.28), and Gilliam (2.13%, 95% CI: 0.42-5.09) were the main prevalent genotypes in China. The prevalence of O. tsutsugamushi in rodents was seasonal, increasing gradually in summer (2.39%, 95% CI: 0.46-5.77), peaking in autumn (4.59%, 95% CI: 1.15-10.16), and then declining. The positive rate of immunofluorescence assay (25.07%, 95% CI: 8.44-46.88) was the highest among the detection methods, and it was statistically significant ( p  < 0.05). Based on the subgroup of geographical factors and climatic factors, the probability of O. tsutsugamushi infection in rodents was the highest when the temperature >19℃ (8.20%, 95% CI: 1.22-20.52), the altitude <100 millimeters (7.23%, 95% CI: 3.45-12.26), the precipitation >700 millimeters (12.22%, 95% CI: 6.45-19.50), and the humidity 60-70% (7.80%, 95% CI: 4.17-12.44). Conclusions: Studies have shown that rodents carrying O. tsutsugamushi are common. People should prevent and control rodents in life and monitor rodents carrying O. tsutsugamushi for a long time.

Determining the factors that influence parasite load is a fundamental goal of parasitology. Body size often influences parasite load in reptiles, but it is unclear whether higher levels of parasitism are a result of greater surface area of individuals (a function of size) or of longer periods of exposure to parasites (a function of age). Using skeletochronology in a wild population of Clark's Spiny Lizards (Sceloporus clarkii Baird and Girard, 1852), we tested the hypotheses that (i) larger individuals have higher parasite loads due to increased surface area available for colonization by parasites and their vectors and that (ii) older individuals have higher parasite loads because they have had longer exposure to parasites and their vectors. Males harboured more ectoparasites than females. Males and females differed in how body size influenced chigger (Acari: Trombiculidae) load; larger males harboured more chiggers than smaller males, but this was not the case in females. Age did not affect ectoparasite load in either sex. These results emphasize the importance of disentangling the effects of size and age in models of parasitism to gain a clearer understanding of intraspecific variation in parasite load. [ABSTRACT FROM AUTHOR]

Six new chigger mite species were described from rodents of South Africa: Ascoschoengastia ueckermannisp. nov.,Schoutedenichia horakisp. nov.,Herpetacarus octosetosussp. nov.,Herpetacarus decasetosussp. nov.,Microtrombicula graphiurisp. nov. and Trombicula walkeraesp. 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. [ABSTRACT FROM AUTHOR]

Yuma Ridgway's Rails (Rallus obsoletus yumanensis) are federally endangered birds endemic to wetlands throughout the Lower Colorado River Basin in Nevada, California, Arizona, and Mexico. The U.S. population has declined in recent years for unknown reasons. We documented a novel and severe chigger mite infestation in the Yuma Ridgway's Rails in southwestern Arizona in 2017. Prevalence of the infestation was spatially heterogeneous: 92% (48 of 52) of the Yuma Ridgway's Rails that we captured at Imperial National Wildlife Refuge were infested, whereas only 11% (2 of 18) of the Yuma Ridgway's Rails at Cibola National Wildlife Refuge were chigger infested. We know little about the origin of this infestation or the impacts of the parasites on the behavior and fitness of Yuma Ridgway's Rails. However, ectoparasite infestations in other species have caused population declines and the intensity and novelty of this ectoparasite infestation, combined with population status of this species, warrants immediate attention to this issue and further study of these ectoparasites. [ABSTRACT FROM AUTHOR]

Trombiculosis has been reported in some wild ruminant species. We investigated the occurrence of trombiculosis in the northern chamois (Rupicapra rupicapra rupicapra) in the Western Italian Alps, and we describe the related histopathologic changes. Superficial scrapes and skin samples were taken from 191 chamois from the Lombardy and Piedmont regions during the hunting season in September-December 2015. Numbers of eosinophils, mast cells, cluster of differentiation (CD)3-, CD79α-, CD68-positive cells were determined on immunohistochemically stained skin sections using a semiautomatic analysis system. Forty (20.9, 40/191) chamois were positive for trombiculid larvae on skin scrapings. Of the positive animals, 15 were from Lombardy and 25 from Piedmont, with similar prevalences. Macroscopic lesions were light with involvement of body regions that had contact with the ground, especially head (pinnae and areas around eyes and mouth) and limbs, where stylostome was easily formed due to thin skin. Histologically, trombiculosis caused a focal moderate dermatitis with epidermal necrosis, thin crusts, and hyperkeratosis. Inflammatory infiltrates were suggestive of a granulomatous reaction centered on a stylostome, formed by mite saliva and necrotic host tissue debris. However, we detected some difference in cutaneous immune response with some chamois showing a prevalent T-cell response and others having an increased Bcell count associated with a higher number of eosinophils, mast cells and a lower number of T cells. [ABSTRACT FROM AUTHOR]

Scrub typhus is a mites-borne rickettsiosis caused by the obligate intracellular Gram-negative bacterium Orientia tsutsugamushi. The disease is potentially life threatening and is prevalent in tropical Asia, islands of the western Pacific Ocean and northern Australia where an estimated one million cases occur annually. Orientia tsutsugamushi is transmitted by the bite of larval mites in the genus Leptotrombidium. In the present study, the composition of the microbiome in larvae, deutonymphs and adult males and females from laboratory colonies of L. imphalum that were infected as well as uninfected with O. tsutsugamushi were investigated by high-throughput sequencing of the bacterial 16S rRNA gene. Notably, the bacterial microbiomes of infected adult females were dominated by sequences of O. tsutsugamushi and an unidentified species of Amoebophilaceae, which together comprised 98.2% of bacterial sequences. To improve the taxonomic resolution of the Amoebophilaceae OTU a nearly full length sequence of the 16S rRNA gene was amplified, cloned, and Sanger sequenced. Infected female mites had 89 to 92% nucleotide identity with the Amoebophilaceae family, indicating that the bacterium was likely to be a species of a novel genus. The species composition of bacterial communities varied between mite life stages regardless of their infection status. Uninfected adults exhibited greater species diversity than adults infected with O. tsutsugamushi. In the infected colony, the rate of filial infection with Orientia was less than 100%. Larval and male mites that were PCR-negative for Orientia contained low numbers of sequences of Amoebophilaceae (0.01 and 0.06%, respectively) in their taxonomic profiles, suggesting that a mutualistic relationship exists between the novel species of Amoebophilaceae and O. tsutsugamushi. Our study findings provide the basis for further research to determine the influence of the novel Amoebophilaceae species on the bacterial microbiome and on vector susceptibility to and transovarial transmission of O. tsutsugamushi. [ABSTRACT FROM AUTHOR]

Scrub typhus, a disease caused by Orientia tsutsugamushi, affects more than one billion people globally with an average fatality rate of 6%. Humans are accidentally infected through the bite of trombiculid mite larvae (chiggers). Chiggers feed on hosts’ extracellular fluid for survival and development. O. tsutsugamushi is maintained throughout the chigger’s lifespan and over several generations. Although disease-related knowledge is essential in designing effective control strategies, many personnel in related sectors are unfamiliar with this disease and its vector. To tackle this issue, we developed a distance learning tool using educational videos on scrub typhus- and vector-related topics. The learning method is facilitated online, and students and tutors are not required to be physically present at the same place and time, thus allowing flexibility and accessibility. Knowledge improvement of 34 participants from related sectors was evaluated by pre- and post-test questionnaires. Although 54% of participants had prior knowledge of scrub typhus, 76.5% still lack basic knowledge of vector identification. After the distance learning, the average score increased significantly from the baseline (p < 0.05). Most participants showed interest in the topic and learning method. These results suggest that the distance learning method was promising in distributing health-related information and might be applied to other diseases and communities.