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South American chiggers have historically been poorly studied, and this has continued into present times. Of the 33 genera in the family Leeuwenhoekiidae Womersley, only Odontacarus Ewing and Sasacarus Brennan & Jones have been reported in Peru. Here, we describe a new genus, Peruacarus n. gen., and a new species, Peruacarus anthurium n. sp., parasitizing Koford's grass mouse, Akodon kofordi Myers & Patton, in Peru., (© The Author(s) 2021. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Leptotrombidium scutellare is one of the 6 main vectors of scrub typhus in China. It has been found in more than 15 provinces of China. Especially in Yunnan, it was found to be mainly distributed in some mountainous areas with high altitude, low temperature and low precipitation. Rodents and some other small mammals were the most common hosts of L. scutellare. To date, more than 40 host species of L. scutellare have been recorded with very low host specificity, and the main hosts varied in different geographical regions. L. scutellare had a strong resistance against the cold environment, and the temperature and humidity were 2 important factors affecting its growth and development. Among different individuals of their rodent hosts, L. scutellare mites often showed an aggregated distribution pattern, which reflected the interspecific cooperation of the mites. The chromosome karyotype of L. scutellare was 2n=16 and all the 8 pairs of chromosomes were short rod-shaped with metacentric or sub-metacentric types. The isozyme spectrum supported that L. scutellare, L. deliense and L. rubellum were in the same species group. Based on the natural infection, experimental transmission and epidemiological evidence, L. scutellare has been eventually confirmed as the second major vector of scrub typhus in China, which is second only to L. deliense.

The Piauí State, Brazil, has never had its chigger fauna recorded. In this study, we examined chiggers collected on marsupials, rodents, and lizards from the conservation unit Parque Nacional da Serra das Confusões (PNSC). Herein we describe four new species, Paraguacarus klompenin. sp., Neoschoengastia ochoain. sp., Quadraseta welbournin. sp., and Susa bauchanin. sp. Furthermore, an additional seven species are reported: Eutrombicula alfreddugesi (Oudemans, 1910), Microtrombicula brachytrichiaBrennan, 1971, Microtrombicula rhipidomysiGoff, Whitaker and Dietz, 1983, Parascoschoengastia aemulata (Brennan and Jones, 1964), Parasecia validaBrennan, 1969, Pseudochoengastia petrolinensis Jacinavicius, Bassini-Silva and Barros-Battesti 2019, and Quadraseta flochi (Brennan and Jones, 1960). This is the first report of chiggers in Piauí State, which includes one of the most biodiverse areas in the Caatinga biome and is of particular importance to conservation. The genera Paraguacarus Goff and Whitaker, 1984 and Susa Audy and Nadcharam, 1960 are reported here for the first time to Brazil., (© The Author(s) 2020. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

This study records the clinical findings in nine hunting dogs showing systemic illness associated with trombiculids and identifies the mite species involved. In fall, coinciding with the seasonality of mites, all dogs were infested with mites and had been in the risk area (Sierra Cebollera Natural Park, La Rioja, Spain) a few hours before the onset of symptoms. The symptoms included vomiting, anorexia, weakness and lethargy, diarrhea, and even stupor. The clinical picture was fast-acting and potentially fatal. The infestations varied from low to severe. Molecular analysis of mites that fed on the dogs confirmed that they were larvae of Neotrombicula inopinata (Oudemans, Acari, Trombiculidae). This is the first time that N. inopinata has been identified as feeding on dogs and implicated in canine systemic illness associated with trombiculids. In contrast to other chiggers, N. inopinata does not seem to cause dermatitis. Likewise, the clinical and epidemiological similarity between the clinical symptoms we describe herein and the occurrence of seasonal canine illness (SCI) led us to suspect that this illness may be caused by infestation with these mites. The condition could be the consequence of severe infestation from large numbers of feeding mites, especially N. inopinata. Whether or not the cases were due to a severe allergic host response to salivary proteins or the result of the transmission of a new or emerging trombiculid-borne pathogen is not known., (© The Author(s) 2019. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The chiggers (Acari: Trombiculidae) Blankaartia sinnamaryi (Floch et Fauran, 1956), Parasecia soucouyanti (Brennan et Yunker, 1966), Eutrombicula lipovskyana (Wolfenbarger, 1952) and Neoschoengastia dalmati Brennan, 1951 were found in Honduras on a total of twelve bird species. Parasecia soucouyanti was recorded parasitising birds for the first time. All these mites are here reported from Honduras for the first time.

Cases of co-invasion of various chigger species parasitizing murids and cricetids in various habitats were analysed using morphological and molecular approaches. Here we provide evidence for 25 new cases of co-parasitism of chigger mites on rodent hosts (Myodes glareolus, Apodemus flavicollis, Apodemus agrarius) accounting for 8.6% of all host-parasite associations observed in this study. The results confirm higher incidence of co-parasitism in vertebrate-associated Parasitengona mites compared to arthropod-associated ones. Among factors influencing the occurrence of co-parasitism in Trombiculidae the body constitution and year-round availability of hosts associated with lower host specificity of larvae should be considered.

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.

We document chigger mite (Acari: Trombiculidae) ectoparasitic infestation (prevalence and intensity) on a population of Catharus ustulatus (Turdidae) wintering at a site (PAD A) in southeastern Peru undergoing development for natural gas exploration. We compare prevalence (i.e., the proportion of individuals infested by chigger mites) and intensity (i.e., the average number of larvae and larvae clusters in infested individuals) at forest edge (<100 m) and interior (>100 m) from PAD A because variations in biotic (e.g., vegetation cover) and abiotic (e.g., relative humidity and temperature) factors are expected to influence chigger mite abundance. Chigger mite prevalence was 100%; all C. ustulatus captured were infested regardless of distance. The range of variation in larvae (2-72 larvae/individual) and cluster intensity (1-4 clusters/individual) did not differ between edge and interior ( P > 0.05), despite differences in herbaceous vegetation cover (U M-W = 180, n = 30, 31; P < 0.01). Ectoparasitic prevalence and intensity in long-distance migratory birds might add risks to an already hazardous journey; because ectoparasitic variation and other selective pressures experienced by individuals at each locality not only may be a cause of within-site mortality, but, by affecting the physical condition of birds, may be carried over to subsequent sites and affect reproductive success and survival. Documenting ectoparasitism at any phase of the life cycle of migrants could improve understanding of population declines of migratory birds.

Stylostomes (feeding tubes) of Hirsutiella zachvatkini (Schluger) (Trombiculidae), feeding on bank voles [Myodes glareolus (Schreber)], and of Trombidium holosericeum (L.) (Trombidiidae), feeding on larvae of Stenodemini sp. (Heteroptera, Miridae), were studied by TEM methods and on semi-thin sections. The stylostome of H. zachvatkini is a homogeneous structure of low electron density and without strict margins. It extends within the concave host epidermis, undergoing hyperplasia and hyperkeratosis. TEM does not reveal any obvious stratification in the stylostome walls. The cheliceral movable digits are moved apart by 5-6 µm and tightly applied/adhered to the stylostome substance. A local area beneath the open end of the stylostome canal is not empty but contains a nearly homogeneous substrate, which can pass into the central stylostome canal. The latter is mostly free of contents. In contrast to H. zachvatkini, larvae of T. holosericeum form a root-like stylostome chaotically branching within the clear space underneath the host cuticle free of tissue elements. Tubules of the distal stylostome branches become progressively thinner and disappear blindly. As in H. zachvatkini, the stylostome walls of T. holosericeum are devoid of stratification but show moderate to high electron density. The cheliceral movable digits are moved apart by the same distance, as in H. zachvatkini, and tightly applied to the stylostome substance. The lumen of the central canal is either electron lucent, in the distal portions, or filled with a fine granular or homogeneous substrate of low electron density in the proximal portions forming a type of ampoule. This study shows that Trombiculidae and Trombidiidae share similar initial stages of stylostome formation but the resultant stylostome of each family is distinctly different.

The poultry red mite, Dermanyssus gallinae, represents a key threat for the poultry industry worldwide. The control of D. gallinae is mainly achieved by continuous applications of acaricides. However, the fast-growing development of resistance, and the strict laws concerning chemicals admitted for treatments on food animals, highlighted the importance of alternative control tools. Here, we explored the potential of Artemisia sieberi essential oil against D. gallinae. In this study, the A. sieberi essential oil was analyzed using GC and GC-MS. The oil toxicity through contact and fumigant assays on adult mites was evaluated. The oil repellent activity was assessed on adult mites over different time intervals. Lastly, the residual toxicity of various doses of the oil was evaluated on D. gallinae until 14 days post treatment. GC and GC-MS showed that the oil was rich in α-thujone (31.5%), β-thujone (11.92%), camphor (12.3%), and 1,8-cineole (10.09%). Contact toxicity on adult mites showed 50% lethal concentration (LC 50 ), LC 90 , and LC 99 of 15.85, 26.63, and 35.42 μg/cm 3 , respectively. In fumigant assays, the oil was toxic on D. gallinae, and mortality was significantly higher in open containers over closed ones, underlining the key role of highly volatile constituents. Repellent assays showed that after 24 h from the treatment, all doses of the A. sieberi essential oil led to significant repellent activity over the control, except for 2 μg/cm 3 . After 48 h, A. sieberi essential oil tested at all doses led to significant repellent activity, if compared to the control. Residual toxicity assays showed that time exposure and concentration tested had a significant impact on mite mortality after 1, 2, 5, and 7 days from the treatment. Notably, mortality remained significantly higher over the control for 7 days after spraying with oil at 2%. Further field assays with selected molecules from the A. sieberi essential oil are ongoing, testing them in synergistic blends, as well as in microencapsulated formulations.

Climate change, by its influence on the ecology of vectors might affect the occurrence of vector-borne diseases. This study examines the effects of meteorological factors in Japan on the occurrence of scrub typhus, a mite-borne zoonosis caused by Orientia tsutsugamushi. Using negative binomial regression, we analysed the relationships between meteorological factors (including temperature, rainfall, snowfall) and spring-early summer cases of scrub typhus in Yamagata Prefecture, Japan, during 1984-2014. The average temperature in July and August of the previous year, cumulative rainfall in September of the previous year, snowfall throughout the winter, and maximum depth of snow cover in January and February were positively correlated with the number of scrub typhus cases. By contrast, cumulative rainfall in July of the previous year showed a negative relationship to the number of cases. These associations can be explained by the life-cycle of Leptotrombidium pallidum, a predominant vector of spring-early summer cases of scrub typhus in northern Japan. Our findings show that several meteorological factors are useful to estimate the number of scrub typhus cases before the endemic period. They are applicable to establish an early warning system for scrub typhus in northern Japan.

The chigger mite genus Blankaartia includes 28 known species, of which 10 are distributed in the Nearctic and Neotropical regions. These species preferentially parasitize birds, but occasionally they can also be found on rodents, bats, and reptiles, showing low host selectivity. In the present study, we report the presence of this genus in Brazil for the first time, including the first report of Blankaartia sinnamaryi (Floch and Fauran) and the description of a new species of Blankaartia collected from birds (Order Passeriformes)., (© The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com Version of Record, first published online October 5, 2016 with fixed content and layout in compliance with Art. 8.1.3.2 ICZN.)

Serosurveillance for zoonotic diseases in small mammals and detection of chiggers, the vector of Orientia tsutsugamushi, were conducted from September 2014 to August 2015 in Gwangju Metropolitan Area. Apodemus agrarius was the most commonly collected small mammals (158; 91.8%), followed by Myodes regulus (8; 4.6%), and Crocidura lasiura (6; 3.5%). The highest seroprevalence of small mammals for O. tsutsugamushi (41; 26.3%) was followed by hantaviruses (24; 15.4%), Rickettsia spp. (22; 14.1%), and Leptospira (2; 1.3%). A total of 3,194 chiggers were collected from small mammals, and 1,236 of 3,194 chiggers were identified with 7 species of 3 genera: Leptotrombidium scutellare was the most commonly collected species (585; 47.3%), followed by L. orientale (422; 34.1%), Euchoengastia koreaensis (99; 8.0%), L. palpale (58; 4.7%), L. pallidum (36; 2.9%), Neotrombicula gardellai (28; 2.3%), and L. zetum (8; 0.6%). L. scutellare was the predominant species. Three of 1,236 chigger mites were positive for O. tsutsugamushi by PCR. As a result of phylogenetic analysis, the O. tsutsugamushi strain of chigger mites had sequence homology of 90.1-98.2% with Boryong. This study provides baseline data on the distribution of zoonotic diseases and potential vectors for the development of prevention strategies of vector borne diseases in Gwangju metropolitan area.

Background: Co-infection with multiple parasite species is commonly observed in nature and interspecific interactions are likely to occur in parasite infracommunities. Such interactions may affect the distribution of parasites among hosts but also the response of infracommunities to perturbations. However, the response of infracommunities to perturbations has not been well studied experimentally for ectoparasite communities of small mammal hosts., Methods: In the current study we used experimental perturbations of the ectoparasite infracommunity of sengis from Africa. We suppressed tick recruitment by applying an acaride and monitored the effects on the ectoparasite community., Results: Our treatment affected the target as well as two non-target species directly. The experimental removal of the dominant tick (Rhipicephalus spp.) resulted in increases in the abundance of chiggers and lice. However, while these effects were short-lived in chiggers, which are questing from the environment, they were long-lasting for lice which spend their entire life-cycle on the host. In addition, the recruitment rates of some ectoparasite species were high and did not always correspond to total burdens observed., Conclusion: These findings indicate that infracommunity interactions may contribute to patterns of parasite burdens. The divergent responses of species with differing life-history traits suggest that perturbation responses may be affected by parasite life-history and that the ectoparasite infracommunity of sengis may lack resilience to perturbations. The latter observation contrasts with the high resilience reported previously for endoparasite communities and also suggests that anti-parasite treatments can affect the distribution of non-target species.

A total of 12 chigger species (Acariformes: Trombiculidae) occurred on 7 bird species in Vietnam. Two new species, namely Neoschoengastia vietnamensis sp. nov. and Hypogastia stekolnikovi sp. nov. are described, figured and compared with similar species placed in relevant genera using differential diagnoses of related species. Figures and diagnosis of Leptotrombidium taiyuanense Tian and Wen, 1984 are added. Odontacarus audy (Radford, 1946), Leptotrombidium allosetum Wang, Liao and Lin, 1981, L. taiyuanense, Leptotrombidium hanseni Traub and Lakshana, 1966, Leptotrombidium kunshui Wen and Xiang, 1984, Leptotrombidium paradux Vercammen-Grandjean and Langston, 1976, Leptotrombidium turdicola Vercammen-Grandjean and Langston, 1976, Neotrombicula elegans Schluger, 1966 and Neoschoengastia longitar-salis Schluger and Belskaya, 1966 were recorded in Vietnam for the first time.

Examination of host-associated variation in the chigger mite Hirsutiella zachvatkini (Schluger) revealed morphological differences among larvae infesting sympatric hosts: Apodemus agrarius, Apodemus flavicollis and Myodes glareolus. The analysis included 61 variables of larvae obtained from their gnathosoma, idiosoma and legs (measurements and counts). Statistically significant differences were observed for metric characters of the legs as opposed to the scutum. In view of the conspecificity of the mites, supported by comparison of COI gene products obtained from larvae and laboratory-reared deutonymphs, the observed variation is attributed to phenotypic plasticity. The knowledge of larval morphology, including intraspecific variation of metric characters, supported by molecular and host range data, places H. zachvatkini among the most comprehensively defined members of Trombiculidae.

The prosomal salivary glands of the unfed larvae Leptotrombidium orientale (Schluger) were investigated using transmission electron microscopy. In total, four pairs of the prosomal glands were identified--three pairs, the lateral, the medial and the anterior, belong to the podocephalic system, and one pair, the posterior, is separate having an own excretory duct. All glands are simple alveolar/acinous with prismatic cells arranged around a relatively small intra-alveolar lumen with the duct base. The cells of all glands besides the lateral ones contain practically mature electron-dense secretory granules ready to be discharged from the cells. The secretory granules in the lateral glands undergo formation and maturation due to the Golgi body activity. The cells of all gland types contain a large basally located nucleus and variously expressed rough endoplasmic reticulum. Specialized duct-forming cells filled with numerous freely scattered microtubules are situated in the middle zone of each gland's acinus and form the intra-alveolar lumen and the duct base. Both the acinar (secretory) and the duct-forming cells contact each other via gap junctions and septate desmosomes. Axons of nerve cells come close to the basal extensions of the duct-forming cells where they form the bulb-shaped synaptic terminations. The process of secretion is under the control of the nerve system that provides contraction of the duct-forming cells and discharge of secretion from the secretory cells into the intra-alveolar lumen and further to the exterior. Unfed larvae of L. orientale, the potential vector of tsutsugamushi disease agents, contain the most simply organized salivary secretory granules among known trombiculid larvae, and this secretion, besides the lateral glands, does not undergo significant additional maturation. Thus, the larvae are apparently ready to feed on the appropriate host just nearly after hatching.

A new genus and species of chigger mites, Diaguitacarus choapensis gen. et sp. nov., is described from four lizard species of the genus Liolaemus in Choapa Province of Chile. Eight new chigger species are described from lizards of the genera Liolaemus, Phymaturus (Squamata: Liolaemidae), and Microlophus (Squamata: Tropiduridae), in Arica and Parinacota, Atacama, Coquimbo, Valparaíso, and Biobío Regions: Eutrombicula nerudai sp. nov., Eutrombicula mistrali sp. nov., Eutrombicula picunche sp. nov., Microtrombicula mapuche sp. nov., Parasecia molini sp. nov., Paratrombicula philippii sp. nov., Morelacarus jorgei sp. nov., and Morelacarus camanchaca sp. nov. A new species Proschoengastia antarctica sp. nov., which is described from American mink Neovison vison on Navarino Island (Region of Magallanes and Antártica Chilena), is the most southerly chigger species, found at the distance of about 1000 km from the continent of Antarctica. Whartonacarus chaetosus (Brennan and Jones, 1961) comb. nov., which was described from Peru, is for the first time recorded in Chile (Atacama Region) and on Microlophus atacamensis. A new combination Proschoengastia macrochaeta (Brennan and Jones, 1961) comb. nov. is established. The genus Morelacarus Vercammen-Grandjean, 1973 previously known from Mexico and southwestern USA is for the first time recorded in Chile. A review of all previously described Chilean chiggers and a key to Eutrombicula species from Chile are provided. In all, 22 species from 13 genera were recorded in Chile, of which only one species (Whartonacarus chaetosus) is known outside the country.

Leptotrombidium chiangraiensis Tanskul & Linthicum, and Leptotrombidium imphalum Vercammen-Grandjean are important vectors of scrub typhus in rice field habitats in northern Thailand. The developmental biology of all stages of the life cycle of two generations of these species of mites infected with Orientia tsutsugamushi (Hayashi) and uninfected mites is reported. The development of the infected lines of both F1 and F2 L. chiangraiensis were significantly longer than their respective uninfected lines (P < 0.05). The developmental times of uninfected and infected F1 lines of L. imphalum were not significantly different; however, F2 infected lines took significantly longer to develop (P < 0.05). Both F1 and F2 generations of infected L. imphalum and L. chiangraiensis oviposited on average >150 fewer eggs than uninfected mites.

This paper describes two experiments conducted to examine the acaricidal potential of spinosad against the poultry red mite, Dermanyssus gallinae (De Geer), a serious ectoparasitic pest of laying hens. Spinosad is a natural product derived from the fermentation of the micro-organism Saccharopolyspora spinosa. In vitro testing confirmed that, when applied to a galvanised metal plate to the point of run-off, spinosad was toxic to adult female D. gallinae and suggested that at an application rate of 3.88 g/L a significant residual toxicity of spinosad could be achieved for up to 21 days. A subsequent in vivo experiment in a conventional cage housing system for laying hens demonstrated the acaricidal activity and residual toxicity to D. gallinae of a single application of spinosad when applied at either 1.94 or 3.88 g/L. Residual toxicity of spinosad at both of these application rates was maintained throughout the course of the 28 day post-spray study period, with a peak in product efficacy seen 14 days after spraying. The results suggest that the greater the D. gallinae population the greater will be the toxic effect of spinosad. Although the exact reasons for this are unclear, it can be speculated that conspecifics spread the product between each other more efficiently at higher mite population densities. However, further study is warranted to confirm this possibility. Application of spinosad in vivo had no effect on hen bodyweight or egg production parameters (number and weight), suggesting that this product could be used to effectively control D. gallinae infestations whilst birds are in lay. This paper also describes a novel method for effectively and efficiently achieving replication of treatments in a single poultry house, previously unpopulated with D. gallinae. Individual groups of conventional cages were stocked with hens, seeded with D. gallinae and used as replicates. Independence of replicates was achieved by isolating cage groups from one another using a non-drying glue barrier to minimise D. gallinae migration. Creating isolated populations (replicates) of D. gallinae within a single poultry house thus represents a novel and efficient means of screening other potential acaricides under field conditions., (Copyright © 2010 Elsevier B.V. All rights reserved.)

Chigger mites of Afghanistan were studied on the base of collections made in Eastern and Central Hindu Kush, Kabul, and some other localities. Fifteen chigger species parasitizing nine species of Rodentia, two species of Lagomorpha, and one species of Soricomorpha were found, including 13 species which were not previously recorded in Afghanistan. Eco-geographical variability is observed in Shunsennia oudemansi: Individuals of this species from high-mountain localities of Eastern Hindu Kush are characterized by larger values of most morphometric characters than the specimens collected in Kabul. Vertical and horizontal distribution of chiggers and chigger-host relationships in Eastern Hindu Kush is discussed. Comparison of our data with that on chigger fauna in the region of Tirich Mir clearly demonstrates the role of the Eastern Hindu Kush main ridge as a border between different chigger faunas.

Stylostomes of the trombiculid mite larvae Neotrombicula pomeranzevi (Schluger), Hirsutiella zachvatkini (Schluger), Miyatrombicula esoensis (Sasa and Ogata) and Euschoengastia rotundata (Schluger) (Acariformes: Trombiculidae), formed in the host skin during feeding of the parasites on their natural hosts (voles) were studied histologically and histochemically. A stylostome is a variously shaped tube formed of solidified mite saliva that extends from the mouthparts of the parasite through the epidermis into the dermis of the host, and allows the mite to obtain its liquid food. The first step of stylostome formation is deposition of an eosinophilic cone, to which the larva's chelicerae are glued. Organization of the stylostome depends on the mite species, and its walls may show weakly expressed longitudinal or transverse stratification. Histochemically, the stylostome is composed of complex glycoprotein with varying tinctorial properties through the width or the length of the stylostome's walls. Beneath the distal end of the stylostome, irrespectively of its localization either in the epidermis or in the dermis of the host, a feeding cavity is formed as a result of the action of the hydrolytic components of the mite's saliva forced through the stylostome into the wound. An inflammatory dermal reaction of moderate intensity is evolved during larval feeding and stylostome formation. It is manifested by the infiltration of the foci with neutrophiles, lymphocytes and macrophages and by dilation of capillaries of the terminal vessel bed and filling them by erythrocytes and other blood elements. Around the stylostome, necrosis of the epidermal cells occurs, leucocytes come to the damaged area and fuse with the necrotic epidermal cells, leading to the formation of the large scabs on the surface of the host's skin. In the case of E. rotundata, single capsules having a terminal opening and containing feeding larva are formed on the abdomen of the hosts. The walls of the capsules are composed of the mite's saliva flowing upon the surface of the host's skin. At the bottom of the capsule, a stylostome perforating the epidermis is also present.

Skin lesions on the ears and inguinal and axillary regions of a number of adult animals within a captive population of the endangered bridled nailtail wallaby (Onychogalea fraenata) were associated with the trombiculid mite, Eutrombicula hirsti. The local inflammatory response of these Australian marsupials is described.

Three new species of chigger mites, Neotrombicula kounickyi sp. n., Leptotrombidium angkamii sp. n., and Doloisia vlastae sp. n., are described from two species of small mammals collected in the Barun Glacier Valley, Makalu region, Nepal Himalaya. Two species, Trombiculindus mehtai Fernandes et Kulkarni, 2003 and Cheladonta ikaoensis (Sasa et al., 1951) are recorded for the first time in Nepal. Data on altitude distribution of chiggers and their host preferences are given.

The aim of this study was to investigate the prevalence of Demodex spp. in the eyelash follicles obtained from patients seen in our ophthalmology clinic, to define the symptoms of this infestation, and to examine the effectivity of the therapy. This study was conducted in Department of Ophthalmology and Parasitology, Dokuz Eylül University, School of Medicine. Our study included 82 cases that were seen in the Ophthalmology Department and Parasitology Department for various reasons. We have also observed that the presence of Demodex spp. provokes itching and redness in the eyes and that using baby shampoo for cleansing the face reduces the risk of infestation. After the treatment of 32 cases with 4% pilocarpin HCl gel, we achieved a total cure in 12 eyes (37.5%), partial improvement in 13 eyes (40.6%), (making a total of 25 eyes, 78.1%). The treatment was unsuccessful in 7 eyes (21.9%). In patients with Demodex spp. cleansing with baby shampoo and treating by pilocarpin gel may be used in treatment.

Demodex folliculorum (D. folliculorum) is a human ectoparasite that resides in the pilosebasceous skin unit. Common sites of predilection are the skin of cheeks, forehead, nose, nasolabial fold and eyelids. Genital D. folliculorum inoculation case reports are extremely rare and depend on investigation of skin lesions. There is no study of genital skin without lesions, and, as far as we know, there is no literature on D. folliculorum prevalence in male genital skin. We examined D. folliculorum prevalence on the healthy scrotum and male perineum. One hundred males were examined for D. folliculorum on facial and genital skin. Samples were taken from cheek, forehead, scrotum and perineum by standard skin surface biopsy (SSSB) or hair epilation. The mean age was 53.5+/-13.0 (24-70) years. Eight percent of males had D. folliculorum on their facial skin. Mean Demodex density (Dd) of men with D. folliculorum positivity was 5.1+/- 2.9/ cm (2)(2-9/cm(2)). Diagnostic results of both sampling methods were similar. No D. folliculorum was demonstrated on genital skin.

With this case report, we describe Trombiculidae larvae (Neotrombicula autumnalis) infestation in a Little Bittern (Ixobrychus minutus) which was brought to our clinics by the Directorship of Environmental and Forestry authorities of Samsun, Turkey in April, 2007. The male Little Bittern (I. minutus), with a black back and crown, and black wings with a large white patch on each wing, had thick Trombiculidae larvae infestation both on its legs. There were neither dermatological nor general conditional changes observed, except its superficial larval attachments to the skin. To our knowledge, this is the first report of Trombiculidae larvae (N. autumnalis) infestation in a Little Bittern (I. minutus) in Turkey.

Chigger mites were collected from 1,080 wild birds of 37 species at Certak (Czech Republic), in the western Carpathian Mountains, from 29 July to 24 September 2005. The prevalence of infestation with chigger larvae was 7%. A total of 325 chigger specimens from 10 bird species was identified and three chigger species were found: Neotrombicula autumnalis, N. carpathica, and N. inopinata, the latter two species being reported on new hosts. Neotrombicula carpathica is reported in the Czech Republic for the first time. A total of 509 chigger larvae found on 79 host specimens were examined by polymerase chain reaction (PCR) for the presence of Borrelia burgdorferi s.l. DNA (fragments of the rrf (5S)--rrl (23S) intergenic spacer), and Anaplasma phagocytophilum DNA (epank1 gene). A fragment of specific Borrelia DNA was amplified through PCR in one sample, and the PCR product was further analyzed by reverse line blotting assay, whereby both genospecies of B. garinii and B. valaisiana were proved. This sample pooled five chigger larvae collected from one Sylvia atricapilla on 11 August 2005. No A. phagocytophilum DNA was amplified. We conclude that larvae of the genus Neotrombicula can be infected with Borrelia genospecies originated from their present or former hosts.

Nodular trombiculinosis has been reported in Brazil in chickens [Torres, S., Braga, W., 1939. Apolonia tigipioensis, g. e sp. n. (Trombiculinae) parasito de Gallus gallus dom. Chave para determinação de gêneros. Boletim da S.A.I.C. 4, 37-44] and humans [Carneiro, L.S., 1952. Uma nova acaríase humana - Contribuição ao seu estudo. Imprensa Industrial, Recife. Faculdade de Medicina da Universidade do Recife, Tese Livre Docência, p. 56]. In this report, a juvenile ostrich and a house sparrow, both originating from a riverside property in the town of Petrolina in the state of Pernambuco, presented 87 and eight nodules, respectively, on various locations of their bodies. Physical expression of the nodules liberated parasites that were morphologically identified as mites from the family Trombiculidae. The mites were further identified as Apolonia tigipioensis by the presence of an elongated body form and transversely striated, three pairs of long legs each with seven segments, primary coxae with a single seta, each tarsus terminating with three claws, and a scutum with an anteromedian projection and paired anteromedian setae. Histopathologic examination of skin biopsies from these birds, stained with hematoxilin-eosin, revealed acute parasitic cystic lymphoplasmacytic dermatitis.

Ectoparasites of an urban population of big brown bats (Eptesicus fuscus) in Fort Collins, Colorado, were investigated during summers 2002, 2003, and 2004. Eleven species of ectoparasites were found (the macronyssid mite Steatonyssus occidentalis, the wing mite Spinturnix bakeri, the myobiid mites Acanthophthirius caudata and Pteracarus aculeus, the chirodiscid mite Alabidocarpus eptesicus, the demodicid mite Demodex sp., the chigger Leptotrombidium myotis, the soft tick Carios kelleyi, the batfly Basilia forcipata, the batbug Cimex pilosellus, and the flea Myodopsylla borealis). Five species were analyzed by prevalence and intensity (C. pilosellus, M. borealis, L. myotis, S. bakeri, and S. occidentalis) based on 2161 counts of 1702 marked individual bats over the 3 summer study periods. We investigated 4 factors potentially influencing prevalence and intensity: age class of the host, reproductive status of adult female hosts, roosts in which the hosts were found, and abiotic conditions during the year sampled. The macronyssid mite, S. occidentalis, was the most prevalent and abundant ectoparasite. Adult big brown bats had more ectoparasites than volant juveniles for most of the species analyzed. In a sample of known age bats at 1 large colony, bats of 4 yr of age or greater had higher ectoparasite loads of S. occidentalis and S. bakeri when compared with younger bats. Lactating female bats had the highest prevalence and intensities of most ectoparasites. Annual differences in ectoparasite prevalence and intensity were related to temperature and humidity, which can affect the nidicolous species of ectoparasites. Residents of 2 buildings sprayed insecticides in response to Cimex sp., and this appeared to reduce ectoparasitism of S. occidentalis and C. pilosellus present at these buildings. Intensity of S. occidentalis had no influence on annual survival of big brown bats.

Parasitism is not well documented for birds found in tropical habitats. Long-distance migratory birds may face additional risks to an already hazardous journey when infected. This study explores the ecology of an ectoparasite infestation in Chiapas, Mexico. During a mist-netting project in 2 different coffee management systems, chigger mites (Acarina: Trombiculidae), ectoparasitic during the larval stage, were found on both resident and migratory birds. Using a rapid assessment protocol, it was observed that 17 of 26 species of long-distance migrants and 33 of 71 resident species had at least 1 infested individual. Infestation prevalences were unexpectedly high on some long-distance migrants, as high as 0.73 for Swainson's thrush (Catharus ustulatus), a value on par with heavily infested resident species. Prevalence was highest during winter sampling: 0.18 overall, 0.16 of migrants, and 0.23 of residents. Prevalence was 0.14 for resident birds during the summer breeding season. Mean abundance and mean intensity of infestation are reported for 97 species captured and inspected during the course of this study. In this region, chigger mite larvae are relatively common on birds and their abundance varies seasonally. High prevalence for some migratory birds suggests that more research and monitoring of ectoparasites are needed, especially in light of emerging diseases.

Larvae of the trombiculid mite Neotrombicula autumnalis were collected at 18 sites in and around Bonn, Germany, to be screened for infection with Borrelia burgdorferi s.l. by means of PCR. Questing larvae numbering 1380 were derived from the vegetation and 634 feeding ones were removed from 100 trapped micromammals including voles, mice, shrews and hedgehogs. In a laboratory infection experiment, a further 305 host-seeking larvae from the field were transferred onto Borrelia-positive mice and gerbils, and examined for spirochete infection at various intervals after repletion. In three cases borrelial DNA could be amplified from the mites: (1) from a larva feeding on a wild-caught greater white-toothed shrew (Crocidura russula), (2) from a pool of four larvae feeding on a B. garinii-positive laboratory mouse, and (3) from a nymph that had fed on a B. afzelii-positive laboratory gerbil as a larva. In the first case, borrelial species determination by DNA hybridization of the PCR product was only possible with a B. burgdorferi complex-specific probe but not with a species-specific one. In the second case, probing showed the same borrelial genospecies (B. garinii) as the laboratory host had been infected with. In the latter case, however, DNA hybridization demonstrated B. valaisiana while the laboratory host had been infected with B. afzelii. Subsequent DNA sequencing confirmed much higher similarity of the PCR product to B. valaisiana than to B. afzelii indicating an infection of the mite prior to feeding on the laboratory host. The negligible percentage of positive mites found in this study suggests that either the uptake of borrelial cells by feeding trombiculids is an extremely rare event or that ingested spirochetes are rapidly digested. On the other hand, the results imply a possible transstadial and transovarial transmission of borreliae once they are established in their trombiculid host. However, unless the transmission of borreliae to a given host is demonstrated, a final statement on the vector competence of trombiculid mites is not possible.

Large-bodied Demodex mites were detected in 4 dogs. The mites were readily detected in material obtained via deep skin scrapings and were most commonly found on the trunk. The mites were distinguishable from D. canis, because adult males were approximately 100% longer and adult females were approximately 50% longer than adult male and female D. canis mites, respectively. The large-bodied mites were found in the hair follicles, sebaceous ducts, and sebaceous glands in histologic sections of skin from 2 dogs. All dogs had adult-onset generalized demodicosis. Two dogs had coexistent iatrogenic hypercortisolism, 1 dog had hypothyroidism, and 1 dog did not have coexistent disease. Infestations responded to miticidal therapy, control of the coexistent disease, or both.

The red poultry mite, Dermanyssus gallinae, is one of the most economically deleterious ecto-parasites of layer hens worldwide. D. gallinae is difficult to eliminate from infested poultry farms, and even to study, because it resides on the host only during the bloodmeal at night, and hides in the crevices of poultry houses during the day. Here, the life-cycle of D. gallinae was reproduced entirely in vitro. Mites were incubated in a glass pipette at 30 degrees C, 60-95 degrees relative humidity and total darkness. A feeding apparatus, composed of a membrane, reservoir and blood was fitted on the pipette during bloodmeals. We tested feeding rates on blood mixed with 1 of 3 anti-coagulants (EDTA, heparin and trisodium citrate) at different concentrations, and biological and artificial membranes. The best engorgement and survival rates for all 3 haematophagous life-stages of the parasite were observed in 1-day-old chick membranes and heparinized (0.02 mmo/ml) blood. We then describe the steps in developing a complete self-sustaining in vitro life-cycle. A colony of mites was maintained in vitro for 7 generations. Losses in the first generation were heavy, but survival had multiplied 5-fold by the fifth generation. We hypothesize that heavy mortality rates during the first life-cycle correspond to selective pressure: only the mites which fed and survived in vitro were able to reproduce.

The distribution of unengorged larvae of Leptotrombidium pallidum, L. fuji and L. kitasatoi in and around 12 rodent-nest holes in Oita Prefecture, Japan was studied using the Tullgren funnel apparatus. Soil was taken from each nest hole, and the ground-surface soil and litter from the surrounding area A (an inner quadrate of 20 cm x 20 cm except the nest hole), and also from the outer area B (an outer quadrate of 40 cm x 40 cm excluding A and the nest hole) were sampled, separately. The numbers (% of the total) of L. pallidum collected from soil samples of the nest holes and areas A and B were 38 (19.0), 111 (55.5) and 30 (15.0); those of L. fuji were 171 (58.8), 104 (35.7) and 14 (4.8); those of L. kitasatoi were 35 (77.9), 7 (15.6) and 3 (6.7), and those of G. saduski were 20 (50.0), 17 (42.5) and 3 (7.5). The larvae recovered from litter samples were few, representing 0-8.5% of the total. It is shown that unengorged larvae of these species are distributed not only in the nest holes but also in the nearby areas, and exist mainly on (or in) the soil.

We found trombiculid mite (Trombiculidae) infestations in 32 of 101 (32%) freeranging Florida black bears (Ursus americanus floridanus) live-captured or necropsied in Florida from January 1999 to April 2000. Prevalence of chigger infestation was greatest in June with no infestations seen October to March. Chigger infestations were recognized as accumulations of bright orange granular material usually associated with hair shafts. Mites were found in clusters of one to 102 (mean +/- SD = 8.5+/-19.5) and were distributed primarily over the ventral abdomen and thorax, inguinal and axillary regions, and proximal medial aspect of the extremities. Mites were identified as larval Eutrombicula splendens. Cutaneous lesions were seen in two of 32 (6%) infested bears.

Leptotrombidium subqunadratum larvae were collected for the first time in 1994 from dogs in Bloemfontein. The larvae have been collected annually, during the summer months, over a period of 6-7 years. Previously the only known hosts were scrub hare (Lepus saxatilis) (locality unknown) and short-snouted elephant shrew (Elephantulus brachyrhynchus) (Kruger National Park). These mites cause severe itching and dermatitis in humans and dogs.

The ultrastructure of the integument of the quiescent reduced tritonymph of the trombiculid mite Hirsutiella zachvatkini (Schluger) was investigated by means of transmission electron microscopy. Mites were investigated daily during the 14-16 day tritonymphal period (imagochrysalis). This period includes the deutonymphal moult (1-3 days), the quiescent tritonymph period (2-4 days), and the tritonymphal moult into the adult mite (6-10 days). A distinct recognizable feature of the tritonymphal moulting cycle is a sequence of events independent of precise time intervals. This process involves partial destruction and reorganization of the hypodermis of the previous instar, and formation of a new hypodermis of the subsequent instar from islands of rudimentary hypodermal cells. The integument of the reduced tritonymph differs greatly from that of both larva and active deutonymph and adult. It consists of a simply organized hypodermal layer of varying thickness and a thick clear poorly lamellate cuticle with curved pore canals, and lacking setae. The epicuticle is very thin and without a clear protein layer. The tritonymphal instar as such with its own cuticle situated near the hypodermis is encased within the detached covering of the previous active deutonymph, and may be considered a calyptostasic and entirely pharate instar. There is a tendency for reduced tritonymphal stage to be eliminated from ontogenesis and this stage is not homologous to the pupa of insects.

1. The dynamics of the poultry red mite, Dermanyssus gallinae, in aviary systems for layers were studied in an empirical study in Sweden between 1994 and 1997. Fluctuations were monitored with mite traps at monthly intervals during 3 laying cycles at each of 2 commercial poultry farms. 2. When mites were first detected in the system it then took about 5 months for the populations to reach equilibrium levels around which they fluctuated. Within flocks when the population growth was unaffected by temporary control activities, it was demonstrated that the mite populations were significantly denser in summer than in winter. 3. Current control methods had limited effects as mite populations were only temporarily suppressed. One exception was the control achieved with permethrin impregnated plastic strips, which reduced the population at equilibrium level to approximately 22%, compared with the previous flock. 4. The distribution of mites was patchy horizontally, along the aviary system, at low burden wlhereas it became more evenly dispersed at equilibrium. 5. Significant differences in vertical mite distributions that correlated with the hybrids used and their rearing conditions were also observed. In flocks with brown hens, mites gathered at the lower tiers, whereas they were found at the highest tiers in association with white hens. As the hens are attacked mainly at night-time the most likely explanation is that the mites adjust their behavioural pattern to the birds' roosting behaviour.

A morphological expression of quiescent nymphal instars (calyptostases) in trombiculid mites (Trombiculidae) is analysed. The analysis takes into consideration ontogenetic functions of different instars during the individual development of these mites, which includes an alternation of active and regressive quiescent instars. Cyclic start and blocking of different integumental differentiation programs in Trombiculidae is caused by the cyclic reduction and renewal of particular functions of respective instars, whereas internal organs of these mites do not transform significantly during the life cycle. The reduction of some functions, particularly the locomotion and feeding, in the quiescent nymphal instars with changed integumental function has an inevitable result in a complication and prolongation of the moulting process. The moulting of these instars begins at once after finishing the previous moulting cycle, i.e. it is realized in "automatic pattern" without the intermoult phase. In general, the organization of both quiescent proto- and tritonymph is the same, because it expresses concordant morphological correlations and synchronous reductions of certain functions and structures in these instars during the evolutionary process. At the same time, the trombiculid mites and, perhaps, other representatives of Parasitengona reveal the most generalized type of ontogenesis in Acariformes within the "alternating calyptostasy" phenomenon.

In colonies of Leptotrombidium fletcheri mites infected with Orientia tsutsugamushi (Ot), the agent of scrub typhus, males rarely appear. In the present study, the development of a high ratio of males was observed after introduction of minocycline (MC). A high dose of MC was injected subcutaneously into a mouse, and by feeding unfed larvae from an infected mite colony on this mouse, the Ot in the mites were successfully killed. Of a total of 130 unfed larvae attached to the mouse, 29 developed into females; of these, 9 laid an average of 112.4 eggs/female. Unfed larvae in the succeeding generations were attached to untreated mice. All adults in the P and F1 generation were females, and males started to appear at the F2 generation. The ratio of males to females was 332:7, 108:13, 263:61 and 71:9 at the F2, F3, F4 and F5 generations, respectively. These data suggest that Ot in the ovary or gonad may suppress the development of males.

Engorged larvae of Leptotrombidium akamushi (Brumpt), a vector of scrub typhus, were reared in small plastic containers placed on the ground and fed fresh eggs of the collembolan Sinella curviseta Brook. Engorged larvae obtained in October developed into deutonymphs through protonymphs approximately 1 mo before winter and became dormant in the cold winter season (approximately 3 mo). Most deutonymphs developed into tritonymphs in April and adults in May. Females began laying eggs in mid-June and the numbers of unfed larvae showed a peak in August. The mites reared from July rapidly developed into adults by August, and laid eggs in September. Larvae were most abundant in October, and adults became dormant in the winter. The same adults laid eggs from early May to late June and, upon hatching, the larval population peaked in early July of the 2nd summer. Most larvae died before the 2nd winter. Eggs hatched approximately 3 wk after oviposition and longevity of unfed larvae was 2 mo. Because of this very short incubation period, L. akamushi larvae occur in the summer, whereas L. pallidum Nagayo, Miyagawa, Mitamura & Tamiya, and L. scutellare Nagayo, Miyagawa, Mitamura, Tamiya & Tenjin occur in the autumn, although 3 species lay eggs from May to August.

Effects of low temperature (-30 degrees C) on the different life stages of Dermatophagoides pteronyssinus (Trouessart) were studied. Humid cold air at -30 degrees C killed all stages of mites except eggs after 10 min; after 35 min exposure, 20% of the eggs hatched after the incubation period. Dry, cold air at -30 degrees C killed 40% of all stages of mites except eggs after 4 min and 100% after 5 min; all eggs died after 1 min exposure.

Engorged larvae of Leptotrombidium pallidum Nagayo, Miyagawa, Mitamura & Tamiya, the vector mite of scrub typhus in Japan, were reared by feeding them with fresh eggs of the collembolan Sinella curviseta Brook while confined in small plastic containers under natural conditions in a copse. The larvae were collected from wild rodents (Apodemus speciosus) in autumn 1985 and spring 1986. Adults were kept alive for 2 yr or longer. The larvae obtained in autumn became dormant in the cold winter season, and growth recommenced in the spring. Thus, the development of mites collected in April became synchronized with that of larvae obtained in the autumn. Most larvae developed into protonymphs in May, deutonymphs in June, tritonymphs in July, and adults in August. The females laid eggs in two consecutive summers. Some larvae collected in autumn were kept in a refrigerator until the following summer. They developed into deutonymphs, tritonymphs, or adults and then became dormant in the winter. Development restarted the next spring and all became adult by summer, when the females laid eggs. Under experimental conditions, all larvae are hatched in the autumn, unlike the natural situation in which two peaks of larval occurrence on wild rodents are observed in autumn and spring.

On the basis of literary data and original investigations some phylogenetic, ecological and morphological aspects of the origin of parasitism in trombiculid mites are carefully considered for the first time. It is shown that parasitism in this group of trombidiform mites is a relatively young historical phenomenon and was formed after their ontogenesis had differentiated into active and quiescent stages. Therefore, in the life pattern of trombiculid mites the character of individual development, that defines their biotopical restriction, is much more important than the phase parasitism. Primitive organization of the digestive system and extraintestinal digestion, so characteristic of this group, are one of the main reasons of the origin of their parasitism. Under pasture conditions trombiculid mites, that initially were predators-entomophages with bite-sucking mouth parts, pass easily to parasitism on vertebrate animals and become primary lymphophages. They use the vertebrate host's organism exclusively as a source of food and by the extent of polyphagia are very close to free-living blood-sucking insects. Stylostome, that develops during feeding of trombiculid larvae and some other closely related groups of trombidiform mites, is a universal structure for achieving a large amount of food on a wide range of animals during a relatively short period of time and reflects wide host-parasite specificity of these parasitic mites. From the historical view the larvae of trombiculid mites did not pass from one group of hosts to the others, but owing to morphological preadaptation to parasitism passed in a definite historical period, not earlier than Paleogene, to parasitism on all classes of terrestrial vertebrates, especially on mammals, their primary hosts.

In four villagers parasitic prurigo caused by the autumnal chigger (Neotrombicula autumnalis) was diagnosed. The clinical picture consisted of intensely itchy, erythematous papules, at sites where clothes fitted tightly or in body folds. Further investigation in the village revealed that in 16 of the 48 homes at least one person in the preceding two months had suffered from prurigo possibly caused by the autumnal chigger. The characteristics of the parasite, the clinical picture, treatment and prevention are discussed.

The life cycle of 5 generations of Leptotrombidium (L.) fletcheri infected with Rickettsia tsutsugamushi and reared under ambient temperatures in Malaysia was presented and compared with a colony reared at a constant 27 degrees C (Neal and Barnett, 1961). In general our colony had a longer generation time (average of 54 days from engorged larvae to adult compared with 37 days) and produced fewer eggs (average of 127.9 compared with 900.0) than the comparison colony. Possible factors causing these differences are discussed.