Inefficient mechanical transmission of Langat (tick-borne encephalitis virus complex) virus by blood-feeding mites (Acari) to laboratory mice.
Durden L A,Turell M J
Journal of medical entomology
One day after feeding on a viremic mouse, tropical rat mites, Ornithonyssus bacoti (Hirst), transmitted Langat (tick-borne encephalitis virus complex) virus to a naive suckling mouse in one of four trials. However, no transmissions to naive mice by O. bacoti were recorded either immediately after the viremic blood meal (0/4 trials) or on days 4-18 (0/20 trials). After feeding on a viremic mouse, chicken mites, Dermanyssus gallinae (De Geer), failed to transmit Langat virus to naive suckling mice in any trials (0/24). Although virus failed to replicate in either species of mite, it was detectable in 20% (2/10) of O. bacoti individuals 1 d after a viremic blood meal, but only immediately after the viremic blood meal in 20% (2/10) of D. gallinae mites. Neither mite appears to be an efficient vector of Langat virus.
Two new species of Litomosoides (Nematoda: Filarioidea) in Sigmodontines (Rodentia: Muridae) from Rio de La Plata marshland, Argentina.
Notarnicola J,Bain O,Navone G T
The Journal of parasitology
Two new species of coelomic filarioid belonging to Litomosoides are described from sigmodontine murids from the Rio de La Plata marshland, Argentina. Litomosoides bonaerensis n. sp., a parasite of Oligoryzomys delticola, belongs to the carinii group and is close to L. silvai, which differs by the head and tail papillae, buccal capsule and cavity, area rugosa, and morphology of the microfilaria. Litomosoides oxymycteri n. sp., from Oxymycterus rufus, belongs to the sigmodontis group. Differential diagnosis is based on the morphology of the buccal capsule, the head and tail papillae, and microfilaria. The ectoparasitic gamasid Ornithonyssus bacoti, in which several Litomosoides species develop, has been recovered from sigmodontines trapped in the study.
Outbreak of rat mite dermatitis in medical students.
Chung S L,Hwang S J,Kwon S B,Kim D W,Jun J B,Cho B K
International journal of dermatology
BACKGROUND:The tropical rat mite, Ornithonyssus bacoti (0. bacoti), is an ectoparasite on many rodents, but when the rodent is not available, humans may become the victim of the mite's bite. The bite induces a nonspecific dermatitis; therefore, it is not easy to diagnose rat mite dermatitis unless the parasites are found. MATERIALS AND METHODS:Ten cases of rat mite dermatitis were found in medical students who had studied in the same room of the library. Their nonspecific dermatitis consisted of small papules, and parasites were found in the skin or in the environment. The mites were collected and identified as O. bacoti, female. Histopathologic studies showed moderate perivascular lymphohistiocytic infiltrations intermingled with some eosinophils. The presence of rodents in or around the room was confirmed by the students, but there had been no preceding rodent eradication. Although the rats were not captured in the library, insecticides were sprayed, and no further problem with either mites or dermatitis developed during the follow-up period. CONCLUSIONS:Rat mite dermatitis can occur in clusters that involve a common source of exposure to the rat mite epidemiologically. Prompt identification of rat mites and the eradication of mites and rodents from the environment can prevent further spreading of the disease.
New building, old parasite: Mesostigmatid mites--an ever-present threat to barrier facilities.
Mesostigmatid mites are blood-sucking parasitic mites found in wild rodent populations. Periodically they can also become a problem for laboratory rodent colonies, particularly when building construction or renovations disturb colonies of commensal (building) rodents that had been acting as hosts. Mesostigmatid mites infest both rats and mice and, unlike the more common rodent fur mites (Myobia, Myocoptes, and Radfordia sp.), can survive for long periods in the environment and travel considerable distances in search of new hosts. They easily penetrate barrier caging systems, including individually ventilated cages, thus circumventing the usual precautions to protect rodents from infection. The two mites reported in laboratory rodent colonies, Ornithonyssus bacoti and Laelaps echidnina, also bite humans and have the potential to transmit zoonotic diseases. Once the mites gain access to a colony, eradication requires elimination of commensal rodent reservoirs in addition to insecticide treatment of both the laboratory rodents and the environment. In view of the undesirability of insecticide use in the animal facility, it is advisable to investigate the effectiveness of preventive treatments, such as environmental application of insect growth regulators or silica-based products. This article summarizes available information on mesostigmatid mites and their laboratory incursions, and provides suggestions for diagnosis, treatment, and control based on the authors experience with several outbreaks at a large academic institution..
Infection of the intermediate mite host with Wolbachia-depleted Litomosoides sigmodontis microfilariae: impaired L1 to L3 development and subsequent sex-ratio distortion in adult worms.
Arumugam Sridhar,Pfarr Kenneth M,Hoerauf Achim
International journal for parasitology
The rodent filaria Litomosoides sigmodontis harbour Wolbachia, endosymbionts essential for worm embryogenesis, larval development and adult survival. To study the effect of tetracycline, which depletes Wolbachia, on the development of microfilariae (L1s, MF) to L3 in the intermediate host Ornithonyssus bacoti, and to observe the development of Wolbachia-depleted L3s in Mongolian gerbils (Meriones unguiculatus); microfilaremic gerbils were treated orally with tetracycline for 6 weeks (primary infected Tet) or untreated (primary Con). Treatment resulted in a significant reduction of Wolbachia per MF in primary Tet gerbils. Naïve mites then fed on the primary Tet and primary Con gerbils in the week after treatment ended, when MF levels were not significantly different, and used to infect new gerbils (secondary infected ) Tet, secondary Con) via natural infection. The infection rate from dissected mites was 9% and 54% (primary Tet and primary Con, respectively). After 3 months, worms were isolated from secondary gerbils. Significantly fewer female worms developed in secondary Tet gerbils. In contrast, there was no difference in the number of male worms that developed in secondary gerbils, resulting in a male biased sex-ratio. Although secondary Tet male worms had fewer Wolbachia than secondary Con males, development was not impaired. Female worms that developed from Wolbachia-depleted MF had Wolbachia levels equivalent to worms from secondary Con animals. Thus, tetracycline pre-treatment selected for female worms with high numbers of Wolbachia, whereas male worms had median Wolbachia levels significantly lower than secondary Con males. Therefore, female worms require a higher threshold of Wolbachia for their development. The worms analysed were only exposed to tetracycline as MF, ruling out direct effects of tetracycline during larval development in the mites or secondary gerbils, suggesting that the depletion of Wolbachia in MF was the cause of impaired larval development.
Ectoparasite fauna of rodents and shrews from four habitats in Kuala Lumpur and the states of Selangor and Negeri Sembilan, Malaysia and its public health significance.
Paramasvaran S,Sani R A,Hassan L,Krishnasamy M,Jeffery J,Oothuman P,Salleh I,Lim K H,Sumarni M G,Santhana R L
A total of 204 rodents comprising 14 host species from four different habitats were examined. Nine rodent species were trapped from the forest and another five species were trapped from the coastal, rice field and urban habitats. Rattus rattus diardii (67%) was the predominant rodent species examined. Fifty six (47.3%) rodents and shrews were found to be infested with at least one of the 20 species of ectoparasite recovered. Mites belonging to the family Trombiculidae were the predominant ectoparasite species recovered. Ticks belonging to the family Ixodidae were recovered mainly from the forest dwelling rodents. Polyplax spinulosa and Hoplopleura pacifica were the common lice species found infesting the urban rodents. Xenopsylla cheopis was the only flea species recovered. The following ecto-parasites have been incriminated as important vectors or as mechanical carriers for the transmission of zoonotic diseases: Ixodes granulatus, Dermacentor sp. Haemaphysalis sp., Amblyomma sp. Ascoschoengastia indica, Leptotrombidium deliense, Ornithonyssus bacoti, Laelaps nuttalli, H. pacifica, P. spinulosa and Xenopsylla cheopis. Urban and forest rodents were significantly higher in ecto-parasitic infestation, compared to rats from the other two habitats. However, there was no significant statistical association between male and female rodents infested with ectoparasites.
Litomosoides sigmodontis: a simple method to infect mice with L3 larvae obtained from the pleural space of recently infected jirds (Meriones unguiculatus).
Hübner Marc P,Torrero Marina N,McCall John W,Mitre Edward
Litomosoides sigmodontis is a filarial nematode that is used as a mouse model for human filarial infections. The life cycle of L. sigmodontis comprises rodents as definitive hosts and tropical rat mites as alternate hosts. Here, we describe a method of infecting mice with third stage larvae (L3) extracted from the pleural space of recently infected jirds (Meriones unguiculatus). This method enables infection of mice with a known number of L3 larvae without the time-consuming dissection of L3 larvae from mites and results in higher worm recovery and patency rates than conventional methods. Additionally, this method allows for geographical separation of the facility maintaining the L. sigmodontis life cycle from the institution at which mice are infected.
The infective larva of Litomosoides yutajensis Guerrero et al., 2003 (Nematoda: Onchocercidae), a Wolbachia-free filaria from bat.
Guerrero R,Bain O,Attout T,Martin C
Parasite (Paris, France)
The infective larva of Litomosoides yutajensis Guerrero et al., 2003, a parasite of the bat Pteronotus pamellii, is described; it is distinct from congeneric infective larvae by the absence of caudal lappets. The life cycles of five other species of Litomosoides are known; three are parasites of rodents, one of a marsupial and one of a bat. As with these species, the experimental vector of L. yutoajensis used was the macronyssid mite Ornithonyssus bacoti. In nature, the main vectors are probably other macronyssids but transmission by O. bacoti, with its large host-range, could account for the characteristic host-switchings in the evolution of Litomosoides. Unlike the murine model L. sigmodontis Chandler, 1931, L. yutajensis is devoid of the endosymbiontic bacteria Wolbachia and may be of great interest.
Fitness cost of Litomosoides sigmodontis filarial infection in mite vectors; implications of infected haematophagous arthropod excretory products in host-vector interactions.
Nieguitsila Adélaïde,Frutos Roger,Moulia Catherine,Lhermitte-Vallarino Nathaly,Bain Odile,Gavotte Laurent,Martin Coralie
BioMed research international
Filariae are a leading cause of infections which are responsible for serious dermatological, ocular, and vascular lesions. Infective third stage larvae (L3) are transmitted through the bite of a haematophagous vector. Litomosoides sigmodontis is a well-established model of filariasis in the mouse, with the vector being the mite Ornithonyssus bacoti. The aim of the study was to analyse the filarial infection in mites to determine the consequences of filarial infection in the blood-feeding and the reproduction of mites as well as in the regulation of vector-induced inflammation in the mouse skin. Firstly, L3 are unevenly distributed throughout the host population and the majority of the population harbours a moderate infection (1 to 6 L3). Filarial infection does not significantly affect the probing delay for blood feeding. The number of released protonymphs is lower in infected mites but is not correlated with the L3 burden. Finally, induced excreted proteins from infected mites but not from uninfected mites stimulate TNF- α and the neutrophil-chemoattractant KC production by antigen-presenting cells (APCs). Altogether, these results describe the modification of the mite behavior under filarial infection and suggest that the immunomodulatory capacity of the mite may be modified by the presence of the parasite, hindering its defensive ability towards the vertebrate host.
Study on the Relationship Between Microbial Composition and Living Environment in Important Medical Mites Based on Illumina MiSeq Sequencing Technology.
Guo Yijie,Wang Ruiling,Zhao Yae,Niu Dongling,Gong Xiaojuan,Hu Li
Journal of medical entomology
The microbiota of mites is closely related to their growth, development, and pathogenicity. Therefore, it is necessary to study the bacteria in mites. Here, for the first time, based on 16s rRNA V3-V4 region, the microbiota of 45 samples of nine species in six families of medically important mites were analyzed using Illumina MiSeq sequencing technique. The results showed that, at the phylum level, Proteobacteria (56.20-86.40%) were the dominant, followed by Firmicutes (6.41-19.43%), Bacteroidetes (5.56-13.38%) and Actinobacteria (1.93-28.07%). But at the genera the microbiota of mites are different, showing four characteristics: 1) The microbiota is related to the parasitic host. Demodex folliculorum (Acariforms: Demodicidae) and D. brevis (Acariforms: Demodicidae), both parasitizing humans, showed similar microbial composition, as did D. canis (Acariforms: Demodicidae) and Sarcoptes scabiei canis (Acariforms: Sarcoptidae) parasitizing dogs, but D. caprae (Acariforms: Demodicidae) parasitizing sheep showed unique microbial community; 2) The microbiota is related to mite's species. Dermatophagoides farinae and Cheyletus malaccensis (Acariforms: Cheyletidae), both collecting from flour, show respective microbial composition; 3) The microbiota is related to the life stage. There were differences in microbiota between adults and larvae of D. farinae, but no differences observed in Psoroptes cuniculi (Acariforms: Psoroptidae); and 4) The microbiota is related to the blood-feeding state. The microbiota of blood-fed Ornithonyssus bacoti (Parasitiformes: Macronyssidae) adults was significantly higher than that of unfed adults. This indicates that the microbiota of mites is affected by mite species, parasitic host, growth stage and habitat. Therefore, understanding these influencing factors will have a very important guiding significance for the prevention and control of mite-borne diseases.
Observations on the micromorphology of the tropical rat mite Ornithonyssus bacoti (Hirst) as revealed by scanning electron microscopy.
Green E D,Baker C
Journal of the South African Veterinary Association
Ornithonyssus bacoti (Hirst) is an important parasite of rodents. The characteristic shape of the dorsal and sternal shields and gnathosoma used as taxonomic characteristics was confirmed by scanning electron microscopy. The anal plate is distinctly pear-shaped with a pair of adanal setae lateral to the anal valves, a single postanal seta and a distinct dentate cribrum formed by peg-like projections. In the adult mites a peritreme extends anteriorly to the 1st coxa from the spiracle situated laterally between the 3rd and 4th coxa. The peritreme is an open canal protected by an overhanging dorsal ridge and lined with short peg-like aciculae. The gnathosoma includes a pair of pedipalps, a pair of protrusile chelicerae retracted into the hypostoma, and a serrate tritosternum ventrally. A unique feature to the normal setae of the pedipalps is a golf club-shaped seta which is found medially on the palp genu. A distinctive double-bladed 'palpal claw' or apotele is directed medially from the palp tibia. The pincer-like chela consists of a spear-like prong forming the moveable digit and a curved stylus-like fixed digit used to pierce the skin. Each leg ends with a pair of hooked tarsal claws and a pair of lateral comblike pretarsal appendages adjacent to the pulvillus. The pulvillus may be retracted, allowing the pretarsal operculum to function as a 'clasping organ' that enables the mite to clasp the hairs of the host during feeding.
Analysis of ectoparasites (chigger mites, gamasid mites, fleas and sucking lice) of the Yunnan red-backed vole (Eothenomys miletus) sampled throughout its range in southwest China.
Peng P-Y,Guo X-G,Song W-Y,Hou P,Zou Y-J,Fan R,He X-S
Medical and veterinary entomology
The Yunnan red-backed vole Eothenomys miletus (Rodentia: Cricetidae) is an endemic rodent species and reservoir host of zoonoses in southwest China. Based on a large host sample (2463 voles collected from 39 localities between 2001 and 2013), a general analysis of four categories of ectoparasite (fleas, sucking lice, chigger mites and gamasid mites) on E. miletus across its entire range of distribution was made. This analysis identified a total of 71 895 ectoparasites belonging to 320 species (30 species of flea, 9 of sucking louse, 106 of gamasid mite and 175 of chigger mite) with a high prevalence (87%), mean abundance (29.19) and mean intensity (33.69). Of the 18 vector species of zoonoses found on E. miletus, the flea Ctenophthalmus quadratus (Siphonaptera: Hystrichopsyllidae) and chigger mite Leptotrombidium scutellare (Trombidiformes: Trombiculidae) were the dominant species; these are the main vectors of zoonoses in China. All of the dominant parasite species showed an aggregated distribution pattern. Male voles harboured more species of parasite than females. Chigger mites represented the most abundant species group on voles and their prevalence was positively correlated with mean abundance (r = 0.73; P < 0.05). As a single rodent species, E. miletus has a high potential to harbour abundant ectoparasites with high species diversity and high rates of infestation. The sex of the vole affects ectoparasite infestation.
Outbreak and Eradication of Tropical Rat Mite (Acari: Macronyssidae) in a European Animal Facility.
Brito-Casillas Yeray,Díaz-Sarmiento Mercedes,García-Arencibia Moisés,Carranza Cristina,Castrillo Antonio,Fernández-Pérez Leandro,Zumbado-Peña Manuel,González Jorge F,Wägner Ana M
Journal of medical entomology
A zoonotic, opportunistic out-break of tropical rat mite Ornithonyssus bacoti [Acari: Macronyssidae; Ornithonyssus bacoti (Hirst)] in an animal facility, is described. Immunocompetent mice [Mus musculus (Linnaeus)] and rat [Rattus norvegicus (Berkenhout)] strains in a conventional health status facility suffered from scratching and allopecia and staff members suffered from pruritic, erythemato-papular lesions, presumed to be allergic in origin. O. bacoti was identified and treatment with a 0.1% ivermectin solution led to its complete erradication. Safety assessment revealed no signs of acute toxicity in any animal strain. Following this inexpensive strategy, 7 wk after the initial dose, samples were negative for the presence of acari. At the time of this report, 26 months after diagnosis, O. bacoti remains undetected.
Morphological and molecular analysis of Ornithonyssus spp. (Acari: Macronyssidae) from small terrestrial mammals in Brazil.
Nieri-Bastos Fernanda A,Labruna Marcelo B,Marcili Arlei,Durden Lance A,Mendoza-Uribe Leonardo,Barros-Battesti Darci M
Experimental & applied acarology
Based on chaetotaxy of the dorsal shield, the taxonomic status of many species of Ornithonyssus has been considered invalid, resulting in the synonymy of all Brazilian Ornithonyssus from small terrestrial wild mammals into one of the following four species: Ornithonyssus bacoti (Hirst, 1913), Ornithonyssus matogrosso (Fonseca, 1954), Ornithonyssus pereirai (Fonseca, 1935) or Ornithonyssus wernecki (Fonseca, 1935). Despite the revision of this genus in 1980, including all known species worldwide, the knowledge of Ornithonyssus in Brazil has not progressed for more than 40 years. Considering the potential importance of these haematophagous mites in transmitting rickettsial disease agents to animals and humans, we have revised Ornithonyssus species collected from small mammals in Brazil by means of morphological and molecular studies. Types and other material deposited in the Acari Collection of the Instituto Butantan (IBSP) were examined in addition to recently collected specimens. Morphological and genetic analysis of the 16S rDNA mitochondrial gene revealed that small terrestrial mammals in Brazil are parasitized by six species of Ornithonyssus mites: Ornithonyssus brasiliensis (Fonseca, 1939), O. matogrosso, O. monteiroi (Fonseca, 1941), O. pereirai, O. vitzthumi (Fonseca, 1941), and O. wernecki. An illustrated key to females of the valid Brazilian species of Ornithonyssus is included, based on optical and scanning electron microscopy.
Outbreak of tropical rat mite (Ornithonyssus bacoti) dermatitis in a home for disabled persons.
Baumstark J,Beck W,Hofmann H
Dermatology (Basel, Switzerland)
Five mentally handicapped individuals living in a home for disabled persons in Southern Germany were seen in our outpatient department with pruritic, red papules predominantly located in groups on the upper extremities, neck, upper trunk and face. Over several weeks 40 inhabitants and 5 caretakers were affected by the same rash. Inspection of their home and the sheds nearby disclosed infestation with rat populations and mites. Finally the diagnosis of tropical rat mite dermatitis was made by the identification of the arthropod Ornithonyssus bacoti or so-called tropical rat mite. The patients were treated with topical corticosteroids and antihistamines. After elimination of the rats and disinfection of the rooms by a professional exterminator no new cases of rat mite dermatitis occurred. The tropical rat mite is an external parasite occurring on rats, mice, gerbils, hamsters and various other small mammals. When the principal animal host is not available, human beings can become the victim of mite infestation.
Bartonella henselae infections in an owner and two Papillon dogs exposed to tropical rat mites (Ornithonyssus bacoti).
Bradley Julie M,Mascarelli Patricia E,Trull Chelsea L,Maggi Ricardo G,Breitschwerdt Edward B
Vector borne and zoonotic diseases (Larchmont, N.Y.)
After raccoons were trapped and removed from under a house in New York, the owner and her two Papillon dogs became infested with numerous rat mites (Ornithonyssus bacoti). Two weeks later, both dogs developed pruritus, progressively severe vesicular lesions, focal areas of skin exfoliation, swelling of the vulva or prepuce, abdominal pain, and behavioral changes. Two months after the mite infestation, the owner was hospitalized because of lethargy, fatigue, uncontrollable panic attacks, depression, headaches, chills, swollen neck lymph nodes, and vesicular lesions at the mite bite sites. Due to ongoing illness, 3 months after the mite infestation, alcohol-stored mites and blood and serum from both dogs and the owner were submitted for Bartonella serology and Bartonella alpha Proteobacteria growth medium (BAPGM) enrichment blood culture/PCR. Bartonella henselae DNA was amplified and sequenced from blood or culture specimens derived from both dogs, the owner, and pooled rat mites. Following repeated treatments with doxycycline, both dogs eventually became B. henselae seronegative and blood culture negative and clinical signs resolved. In contrast, the woman was never B. henselae seroreactive, but was again PCR positive for B. henselae 20 months after the mite infestation, despite prior treatment with doxycycline. Clinicians and vector biologists should consider the possibility that rat mites may play a role in Bartonella spp. transmission.
Occurrence of a house-infesting Tropical rat mite (Ornithonyssus bacoti) on murides and human beings.
Travel medicine and infectious disease
In Germany there is little information available about the distribution of the Tropical rat mite (Ornithonyssus bacoti) in rodents. A few case reports show that this haematophagous mite species may also cause dermatitis in man. All developmental stages are exclusively bloodfeeder. Three children (4, 11 and 15 years old) of a family and a 23-year-old medical student were attacked by the Tropical rat mite. Prior to the consultation of our institution, the patients' conditions had been diagnosed as allergic dermatitis of unclear origin and treated by several antiphlogistic agents, however without success. The conclusive diagnosis, Tropical rat mite dermatitis, was based on the identification of the arthropod Ornithonyssus bacoti in the flats of the patients (husbandry of gerbils, etc.). The diagnosis of a Rat mite dermatitis requires the detection of the parasite, which is more likely to be found in the environment of its host than on the hosts' skin itself.
Pet hamsters as a source of rat mite dermatitis.
Creel Naomi B,Crowe Mark A,Mullen Gary R
Rat mite dermatitis is characterized by pruritic papules in a patient exposed to the tropical rat mite Ornithonyssus bacoti. We report a case of a woman with rat mite dermatitis who developed this eruption after exposure to her pet hamster. Mites were collected from the hamster and identified as O bacoti. Reported sources of rat mites, as well as avian mites and other mites that bite humans, are reviewed.
[Mites as a cause of zoonoses in human beings].
Beck Wieland,Pfister Kurt
Wiener klinische Wochenschrift
Different mite species occurring in animals may infest humans temporarily. Such agents should be considered a possible cause of erythemateous and sometimes pruritic skin reactions of unclear origin. Pseudoscabies is a common problem in occupationally exposed humans, e.g. farmers, veterinarians or pet owners. Those selflimiting dermatoses may often be misdiagnosed. Several species including Sarcoptes scabiei, Notoedres cati, Cheyletiella spp., Dermanyssus gallinae, Ornithonyssus bacoti, Ophionyssus natricis and Neotrombicula autumnalis may infest human skin, causing symptoms.
Prevalence and zoonotic risk of tropical rat mite (Ornithonyssus bacoti) in exotic companion mammals in southern Italy.
d'Ovidio Dario,Noviello Emilio,Santoro Domenico
BACKGROUND:Exotic companion mammals are popular pets worldwide. They are a potential source of zoonotic infections transmissible to their owners. HYPOTHESIS/OBJECTIVES:To determine the prevalence and zoonotic risks of tropical rat mite (Ornithonyssus bacoti) in exotic companion mammals in Italy. ANIMALS:The records of 782 exotic pet mammals seen in multiple veterinary clinics (n = 20), pet shops (n = 10) and private breeders (n = 2) around Naples (Italy) were searched. METHODS AND RESULTS:The isolation of O. bacoti was the only inclusion criterion. Relative (in the subgroups) and absolute prevalence (in the entire population sampled) of clinical signs in pets and owners were calculated. The prevalence of clinical signs in pets and their owners was also calculated based on their housing (pet shops versus private housing) using Fisher's exact test. A P-value < 0.05 was considered significant. Seventy seven records (9.8%) of animals infested were identified. Of those, 33.8% (26 of 77) were hamsters, 25.9% (20 of 77) gerbils, 11.7% (nine of 77) guinea pigs, 7.8% (six of 77) rabbits, 7.8% (six of 77) degus, 5.2% (four of 77) kangaroo mice, 2.6% (two of 77) hedgehogs, 2.6% (two of 77) squirrels and 2.6% (two of 77) were sugar gliders. The frequency of owners affected by the rat mite dermatitis was very high in gerbils (20 of 20), hamsters (21 of 26) and guinea pigs (seven of nine). CONCLUSIONS AND CLINICAL IMPORTANCE:The results of the present survey indicate that exotic pet mammals may serve as an active reservoir for O. bacoti infestation. The results of this study also suggest a lack of species specificity for O. bacoti when favourable conditions are present (overcrowding).
ERADICATION OF A TROPICAL RAT MITE ( ORNITHONYSSUS BACOTI) INFESTATION FROM A CAPTIVE COLONY OF ENDANGERED AMARGOSA VOLES ( MICROTUS CALIFORNICUS SCIRPENSIS).
Mantovani Sarah,Allan Nora,Pesapane Risa,Brignolo Laurie,Foley Janet
Journal of zoo and wildlife medicine : official publication of the American Association of Zoo Veterinarians
Staff at a university laboratory responsible for management of a captive insurance colony of endangered Amargosa voles ( Microtus californicus scirpensis) discovered an outbreak of tropical rat mites ( Ornithonyssus bacoti) infesting 106 voles. This bloodsucking mesostigmatid mite typically occurs in laboratory settings and can cause weight loss, wounds, or other negative impacts on health. The source of the infestation was likely feral rodents, and the route was suspected to be straw bedding. Twenty-nine of the 106 (27.4%) infested voles developed ulcerated dorsal skin lesions that resolved when treated with topical selamectin. A triad approach was implemented to eradicate the mites, consisting of environmental management, individual animal treatment, and training. Voles were moved individually into a clean room containing only autoclaved materials (including straw), cages were treated with permethrin-impregnated cotton, treatment order was instituted to avoid transferring mites, and voles coming from outside were quarantined. All animals in an infested room were treated with topical selamectin, and personnel were trained on risks and new procedures. No adverse effects from the use of selamectin were identified, and this efficient protocol does not require the long-term use of acaricides. This report documents infestation of an endangered rodent with an exotic parasite, safe use of permethrin and selamectin in this species, and comprehensive management to manage a large infestation.
[Cumulation of Ornithonyssus bacoti (tropical rat mite) infestations of pet rodents and their owners in the Canton of Zürich and Graubünden].
Fiechter R,Grimm F,Müller G,Schnyder M
Schweizer Archiv fur Tierheilkunde
In spring 2009 several cases of infestation with Ornithonyssus bacoti («tropical rat mite») in pet rodents have been diagnosed at the Institute of Parasitology, University of Zurich. Although adequate animal hosts were present, owners also became victims of mite infestation. The owners presented cutaneous lesions such as pruritic red papules partly with a central vesicle, predominantly disposed in groups. Particularly children with close body contact to their pet rodents were strongly affected. Because the definite diagnosis was usually yielded at a late time-point, the medical treatment remained unsatisfactory in some cases. The mite-infestation of the pets was mostly detected after the owners also became affected. The owners noticed merely non-specific signs such as increased restlessness, itching and shaggy coat on their animals. Efficient healing was achieved only if the parasites were completely eliminated, i.e. also the pets were treated, the cages cleaned and the apartments professionally disinfested. A definite diagnosis of «Infestation with Ornithonyssus bacoti» is only possible by means of morphological identification on an isolated mite, which is most likely to be found in the environment of the animals. Pet owners should be informed about the zoonotic potential of O. bacoti.
De Novo RNA-seq and Functional Annotation of Haemaphysalis longicornis.
Niu DongLing,Zhao YaE,Yang YaNan,Yang Rui,Gong XiaoJuan,Hu Li
PURPOSE:Haemaphysalis longicornis (Neumann) is a hematophagous tick widely distributed in northern China. It not only causes enormous economic loss to animal husbandry, but also as a vector and reservoir of various zoonotic pathogens, it spreads natural focal diseases, such as severe fever with thrombocytopenia syndrome, seriously threatening human health. Lack of transcriptomic and genomic data from H. longicornis limits the study of this important medical vector. METHODS:The engorged female H. longicornis from Gansu, China, was used for RNA extraction, de novo RNA-seq, functional annotation, and ORF prediction. RESULTS:As a result, 53.09 million clean reads (98.88%) with a GC content of 54.29% were obtained. A total of 65,916 Unigenes were assembled, of which 34.59% (23,330) were successfully annotated. Of these Unigenes, 22,587 (34.27%) were annotated to species by NCBI non-redundant protein (nr). Ixodes scapularis, Limulus polyphemus, Parasteatoda tepidariorum, Stegodyphus mimosarum, and Metaseiulus occidentalis were the top BLAST hit species, accounting for 47.23%, 9.58%, 4.11%, 3.50%, and 2.69%, respectively. A total of 29,182 ORFs were predicted, and 35 complete ORFs for functional genes were identified, including ORFs involved in digestion (14), stress responses (8), anticoagulation (3), reproduction (3), antimicrobial (2), drug resistance (2), movement (2), autophagy (1), and immunity (1), respectively. The Unigene ORFs encoding cathepsin and heat shock proteins were further analyzed phylogenetically. CONCLUSION:De novo RNA-seq and functional annotation of H. longicornis were successfully completed for the first time, providing a molecular data resource for further research on blood-sucking, pathogen transmission mechanisms, and effective prevention and control strategies.
[Zoonoses transmitted by mouse and rat maintained as laboratory or pet animals].
Bleich André,Nicklas Werner
Berliner und Munchener tierarztliche Wochenschrift
Large numbers of mice (Mus spp.) and rats (Rattus spp.) are maintained for scientific reasons and as pet animals in Germany. While laboratory animals are monitored for pathogenic agents, the hygienic status of pet animals is usually completely unknown. Despite great efforts, zoonotic infections were reported even in laboratory settings, e.g. with Hantavirus (Seoul virus), Streptobacillus moniliformis, and Trichphyton mentagrophytes. However, in current reports, zoonotic infections were transmitted by mice and rats maintained as pet animals. This includes infections by Lymphocytic choriomeningitis virus, Leptospira interrogans, Streptobacillus moniliformis, Salmonella enterica, Trichophyton mentagrophytes, and Ornithonyssus bacoti. Furthermore, entero-hepatic Helicobacter spp. of rats and mice are currently discussed to be involved in the etiology of hepatobiliary diseases. Pasteurella spp. of mice and rats do not present a risk for human disease comparable to those species that are transmitted by dogs or cats and might induce serious disease after bites. Altogether, this article lists potential zoonotic agents that were detected in mice and rats and are present in Germany, as well as agents that were reportedly transmitted by mice and rats maintained as laboratory or pet rodents.
Tropical rat mites (Ornithonyssus bacoti) - serious ectoparasites.
Beck Wieland,Fölster-Holst Regina
Journal der Deutschen Dermatologischen Gesellschaft = Journal of the German Society of Dermatology : JDDG
In Germany there is limited information available about the distribution of the tropical rat mite (Ornithonyssus bacoti) in rodents. A few case reports show that this hematophagous mite species may also cause dermatitis in man. Having close body contact to small rodents is an important question for patients with pruritic dermatoses. The definitive diagnosis of this ectoparasitosis requires the detection of the parasite, which is more likely to be found in the environment of its host (in the cages, in the litter or in corners or cracks of the living area) than on the hosts' skin itself. A case of infestation with tropical rat mites in a family is reported here. Three mice that had been removed from the home two months before were the reservoir. The mites were detected in a room where the cage with the mice had been placed months ago. Treatment requires the eradication of the parasites on its hosts (by a veterinarian) and in the environment (by an exterminator) with adequate acaricides such as permethrin.
Rickettsial pathogens in the tropical rat mite Ornithonyssus bacoti (Acari: Macronyssidae) from Egyptian rats (Rattus spp.).
Reeves Will K,Loftis Amanda D,Szumlas Daniel E,Abbassy Magda M,Helmy Ibrahim M,Hanafi Hanafi A,Dasch Gregory A
Experimental & applied acarology
We collected and tested 616 tropical rat mites (Ornithonyssus bacoti (Hirst)) from rats (Rattus norvegicus (Berkenhout) and R. rattus (Linnaeus)) throughout 14 governorates in Egypt and tested DNA extracts from pools of these mites for Bartonella spp., Coxiella burnetii, and Rickettsia spp. by PCR amplification and sequencing. Three different mite-associated bacterial agents, including one Bartonella and two Rickettsia spp., were detected in eight pools of mites. Further research could demonstrate the vector potential of mites and pathogenicity of these agents to humans or animals.
Use of scanning electron microscopy to confirm the identity of tropical rat mite (Ornithonyssus bacoti): the cause of rat mite dermatitis.
Nath Anjan Jyoti,Islam Saidul,Sahu Samyak
Journal of parasitic diseases : official organ of the Indian Society for Parasitology
Cutaneous lesions in human patient due to the bite of rat mite Ornithonyssus bacoti are frequently misdiagnosed as allergies, fungal infection, or bacterial infection. Bite lesions in the personnel working in a Laboratory Animal facility which was infested with O. bacoti is reported here along with its therapeutic management. Diagnosis of the parasites obtained from the clothing of the personnel and later from the infested mice colony was based on preliminary light microscopy and confirmed by scanning electron microscopy. The mean length and breadth of adult female mite were 1.13 mm × 0.63 mm. The body is hairy, unsegmented and has four pairs of legs. The gnathostoma has long pointed chelicerae and pedipalp. The dorsal surface has one dorsal shield, and the ventral surface has three shields- sternal, genital and anal shield. Treatment of dermatitis involved antihistaminic drugs for a period of 3-5 days. The skin lesion, characterized by papular erythema, tends to disappear within a period of 4-5 days of antihistaminic treatment. In untreated cases, the lesions disappeared within 7-10 days. Tropical rat mite O. bacoti Hirst, 1931 was identified to be the cause of infestation in the laboratory mice colony of Pasteur Institute of India, Coonoor, Tamil Nadu, predisposing the animal handlers to be temporary host.
De novo RNA-seq and functional annotation of Ornithonyssus bacoti.
Niu DongLing,Wang RuiLing,Zhao YaE,Yang Rui,Hu Li
Experimental & applied acarology
Ornithonyssus bacoti (Hirst) (Acari: Macronyssidae) is a vector and reservoir of pathogens causing serious infectious diseases, such as epidemic hemorrhagic fever, endemic typhus, tularemia, and leptospirosis. Its genome and transcriptome data are lacking in public databases. In this study, total RNA was extracted from live O. bacoti to conduct RNA-seq, functional annotation, coding domain sequence (CDS) prediction and simple sequence repeats (SSRs) detection. The results showed that 65.8 million clean reads were generated and assembled into 72,185 unigenes, of which 49.4% were annotated by seven functional databases. 23,121 unigenes were annotated and assigned to 457 species by non-redundant protein sequence database. The BLAST top-two hit species were Metaseiulus occidentalis and Ixodes scapularis. The procedure detected 12,426 SSRs, of which tri- and di-nucleotides were the most abundant types and the representative motifs were AAT/ATT and AC/GT. 26,936 CDS were predicted with a mean length of 711 bp. 87 unigenes of 30 functional genes, which are usually involved in stress responses, drug resistance, movement, metabolism and allergy, were further identified by bioinformatics methods. The unigenes putatively encoding cytochrome P450 proteins were further analyzed phylogenetically. In conclusion, this study completed the RNA-seq and functional annotation of O. bacoti successfully, which provides reliable molecular data for its future studies of gene function and molecular markers.
Record of Tropical Rat Mite, Ornithonyssus bacoti (Acari: Mesostigmata: Macronyssidae) from Domestic and Peridomestic Rodents (Rattus rattus) in Nilgiris, Tamil Nadu, India.
Bhuyan Pranab Jyoti,Nath Anjan Jyoti
Journal of arthropod-borne diseases
BACKGROUND:Tropical rat mite (Ornithonyssus bacoti) is reported from many parts of the world and is considered important in transmitting rickettsial pathogens. There have been scanty reports on prevalence of this parasite from India. Following a recent report of O. bacoti infestation in a laboratory mice colony from Nilgiris, Tamil Nadu, India, attempts were made to detect the parasite in its natural reservoir, ie the domestic and peridomestic rats (Rattus rattus). METHODS:The National Centre for Disease Control, Coonoor is involved in screening plague in domestic and peridomestic rats in Nilgiris and erstwhile plague endemic areas of Southern India. The parasite samples were identified based on the morphological characteristics attributable to O. bacoti and as per description of published literature. RESULTS:Seven mite samples identified as O. bacoti based on morphological characteristics were isolated incidentally from domestic and peridomestic rodents in and around the hilly districts of Nilgiris, Southern India, during the routine plague surveillance programme. The identification was based on the morphological characteristics attributable to O. bacoti observed under a low power microscope. CONCLUSION:In India, this is probably the first record of isolation of O. bacoti from domestic and peridomestic rodents. Prevalence of such parasite in domestic and peridomestic rats necessitates further investigation on monitoring and surveillance of rickettsial diseases in the locality, as these parasites are considered to be potential vector of transmitting rickettsial pathogens.