Chigger mites are parasites of rodents and other vertebrates, invertebrates, and other arthropods, and are the only vectors of scrub typhus, in addition to other zoonoses. Therefore, investigating their distribution, diversity, and seasonal abundance is important for public health. Rodent surveillance was conducted at 6 districts in Shandong Province, northern China (114–112°E, 34–38°N), from January to December 2011. Overall, 225/286 (78.7%) rodents captured were infested with chigger mites. A total of 451 chigger mites were identified as belonging to 5 most commonly collected species and 3 genera in 1 family. Leptotrombidium scutellare and Leptotrombidium intermedia were the most commonly collected chigger mites. L. scutellare (66.2%, 36.7%, and 49.0%) was the most frequently collected chigger mite from Apodemus agrarius, Rattus norvegicus, and Microtus fortis, respectively, whereas L. intermedia (61.5% and 63.2%) was the most frequently collected chigger mite from Cricetulus triton and Mus musculus, respectively. This study demonstrated a relatively high prevalence of chigger mites that varied seasonally in Shandong Province, China.
Animals ; Arthropods ; Arvicolinae ; China* ; Cricetinae ; Cricetulus ; Humans ; Invertebrates ; Mice ; Mites* ; Murinae ; Neptune ; Parasites ; Prevalence ; Public Health ; Rats ; Rodentia* ; Scrub Typhus ; Seasons ; Trombiculidae* ; Vertebrates ; Zoonoses

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.
Animals ; Arvicolinae ; Chungcheongnam-do ; Globus Pallidus ; Gwangju* ; Hantavirus ; Korea* ; Leptospira ; Mammals* ; Mites ; Murinae ; Orientia tsutsugamushi* ; Polymerase Chain Reaction* ; Rickettsia ; Rodentia ; Sequence Homology ; Seroepidemiologic Studies ; Trombiculidae* ; Zoonoses*

Continuously growing incisors are common to all rodents, which include the Microtus genus of voles. However, unlike many rodents, voles also possess continuously growing molars. Here, we report spontaneous molar defects in a population of Prairie voles (Microtus ochrogaster). We identified bilateral protuberances on the ventral surface of the mandible in several voles in our colony. In some cases, the protuberances broke through the cortical bone. The mandibular molars became exposed and infected, and the maxillary molars entered the cranial vault. Visualisation upon soft tissue removal and microcomputed tomography (microCT) analyses confirmed that the protuberances were caused by the overgrowth of the apical ends of the molar teeth. We speculate that the unrestricted growth of the molars was due to the misregulation of the molar dental stem cell niche. Further study of this molar phenotype may yield additional insight into stem cell regulation and the evolution and development of continuously growing teeth.
Animals ; Arvicolinae ; anatomy & histology ; genetics ; Female ; Humans ; Male ; Molar ; diagnostic imaging ; growth & development ; Pedigree ; X-Ray Microtomography

This paper describes a new species of chigger mite (Acari: Trombiculidae), Gahrliepia cangshanensis n. sp., from rodents in southwest China. The specimens were collected from Yunnan red-backed voles, Eothenomys miletus (Thomas, 1914), and a Chinese white-bellied rat, Niviventer confucianus (Milne-Edwards, 1871) in Yunnan Province. The new species is unique mainly in its number of dorsal setae (n=21), and it has the following features: fT (formula of palpotarsus)=4B (B=branched), fp (formula of palpal seta)=B/N/N/N/B (N=naked), a broad tongue-shaped scutum with an almost straight posterior margin, and 17 PPLs (posterior posterolateral seta) with a length of 36-43 microm. This chigger mite may also infect other rodent hosts and may be distributed in other localities.
Animal Structures/anatomy & histology ; Animals ; Arvicolinae/*parasitology ; China ; Ectoparasitic Infestations/parasitology/*veterinary ; Microscopy ; Murinae/*parasitology ; Rodent Diseases/*parasitology ; Rodentia/*parasitology ; Trombiculidae/anatomy & histology/*classification

Animals ; Arvicolinae ; microbiology ; DNA Mutational Analysis ; Genes, Bacterial ; Mutation ; Yersinia pestis ; genetics

Altitude ; Animals ; Arvicolinae ; Gene Expression ; Hypoxia ; Rats ; Tumor Suppressor Protein p53 ; genetics

OBJECTIVETo study the pathogenic ecology characteristics of plague in Qinghai plateau.

METHODSApplied molecular biology techniques, conventional technologies and geographic information system (GIS) to study phenotypic traits, plasmid spectrum, genotype, infected host and media spectrum etc.of 952 Yersinia pestis strains in Qinghai plateau plague foci, which were separated from different host and media in different regions during 1954 to 2012.

RESULTSThe ecotypes of these strains were Qingzang plateau (91.49%, 871/952),Qilian mountain (6.41%, 61/952) and Microtus fuscus (1.26%, 12/952).83.6% (796/952) of these strains contained all the 4 virulence factors (Fr1, Pesticin1,Virulence antigen, and Pigmentation), 93.26% (367/392) were velogenic strains confirmed by virulence test.725 Yersinia pestis strains were separated from Qinghai plateau plague foci carried 9 kinds of plasmid, among which 713 strains from Marmot himalayan plague foci carried 9 kinds of plasmid, the Mr were 6×10(6), 7×10(6), 23×10(6), 27×10(6), 30×10(6), 45×10(6), 52×10(6), 65×10(6) and 92×10(6) respectively. 12 Yersinia pestis strains were separated from Microtus fuscus plague foci carried only 3 kinds of plasmid, the Mr were 6×10(6), 45×10(6), 65×10(6). Meanwhile, the strains carrying large plasmid (52×10(6), 65×10(6) and 92×10(6)) were only distributed in particular geographical location, which had the category property. The research also confirmed that 841 Yersinia pestis strains from two kinds of plague foci in Qinghai plateau had 11 genomovars. The strains of Marmot himalayan plague foci were given priority to genomovar 5 and 8, amounted to 611 strains, genomovar 8 accounted for 56.00% (471/841), genomovar 5 accounted for 23.07% (194/841). Besides, 3 new genomovars, including new 1(62 strains), new 2(52 strains), new 3(48 strains) were newly founded, and 12 strains of Microtus fuscus plague foci were genomovar 14.

CONCLUSIONThe main host and media of Qinghai plateau plague foci directly affected the spatial distribution regularities of plague epidemic and the pathogens characteristics, meanwhile the polymorphism of plague ecological geographic landscape leds to the complexity of Yersinia pestis' genotype.

Animals ; Arvicolinae ; microbiology ; China ; epidemiology ; Disease Reservoirs ; microbiology ; Ecology ; Genotype ; Marmota ; microbiology ; Plague ; epidemiology ; microbiology ; Virulence ; genetics ; Yersinia pestis ; genetics ; pathogenicity

BACKGROUNDThe rodentia and lagomorpha animals are the intermediate hosts of Echinococcus multilocularis, their distribution and infection of this parasite may facilitate the infection of definitive hosts such as dogs. The aim of this study was to determine the distribution of the intermediate hosts of Echinococcus multilocularis in Shiqu County, Sichuan, China.

METHODSA systematic sampling method was used to investigate the density of burrows of rodents and lagomorphs at 97 pasture sites in winter and summer pastureland and remote sensing (RS) technology was used to correlate their densities to the distribution of these animals in different landscape types.

RESULTSBased on the densities of Ochotona curzoniae, Microtus fuscus (dependent variable) and their burrow densities (independent variable) in survey points, regression equations were fitted respectively (Ochotona curzoniae, P < 0.0001, R(2) = 0.8705; Microtus fuscus, P < 0.0001, R(2) = 0.9736). Their burrow density in summer pastureland was higher than in winter pastureland (F = 36.65, P < 0.0001). The burrow densities of Ochotona curzoniae and Microtus fuscus in bareland and half-bareland are higher than in grassland (F = 7.73, P < 0.001).

CONCLUSIONSThe regression relationship between the densities of Ochotona curzoniae and Microtus fuscus and their burrow densities indicate that the burrow densities could reflect the animal densities and that the burrow density was greater in summer pastureland than in winter pastureland. The main distribution areas of the intermediate hosts were in bareland and half-bareland.

Animals ; Arvicolinae ; parasitology ; China ; Echinococcosis ; epidemiology ; transmission ; Echinococcus multilocularis ; pathogenicity ; Lagomorpha ; parasitology

Vascular endothelial growth factor (VEGF) plays an important role in tissues angiogenesis. The adaptation of animals to hypoxic environment is relative to the microvessel density (MVD) in tissues. To further explore the adaptation mechanisms of plateau zokor (Myospalax baileyi) to the hypoxic-hypercapnic burrows, the VEGF mRNA and the MVD in cerebral tissues of the plateau zokor were studied. Total RNA was isolated from liver, and VEGF cDNA was obtained by RT-PCR, then the VEGF cDNA was cloned and sequenced. The coding sequence of plateau pika (Ochotona curzniae), rat (Rattus norvegicus) and mouse (Mus musculus) VEGF cDNA are obtained from GenBank, and the nucleotide and amino acid sequence homology of plateau zokor VEGF cDNA coding sequence with that of plateau pika, rat and mouse were analyzed and compared by using of bioinformatics software. The VEGF mRNA was detected by real-time PCR, and the MVDs in cerebral tissues of the plateau zokor, plateau pika and Sprague-Dawley (SD) rat were measured by immunohistochemical staining. The results showed that the open reading frame of the plateau zokor VEGF was 645 bp, and the coding sequence of the plateau zokor VEGF cDNA shared 92.1%, 93.6% and 93.8% nucleotide sequence homology to that of the plateau pika, rat and mouse, respectively. The deduced amino acid sequence of the plateau zokor VEGF cDNA was composed of 188 amino acids and the amino acids from 1 to 26 were signal peptide sequence. The plateau zokor VEGF188 was 90.2%, 94.9% and 94.4% homologous to that of plateau pika, rat and mouse. The level of VEGF mRNA in brain of the plateau zokor was significantly lower than that of SD rat, but there was no obvious difference in VEGF mRNA level between plateau zokor and plateau pika. The MVD in brain of the plateau zokor was markedly higher than that of plateau pika and SD rat. In conclusion, plateau zokor enhances its adaptation to the hypoxic environment by increasing the MVD. The level of VEGF mRNA in the brain of plateau zokor is lower than that of SD rat, which may be as a result of inhibition by the higher concentration of carbon dioxide in the burrow.
Adaptation, Physiological ; physiology ; Amino Acid Sequence ; Animals ; Arvicolinae ; physiology ; Base Sequence ; Brain ; blood supply ; metabolism ; Hypoxia ; physiopathology ; Microvessels ; anatomy & histology ; Molecular Sequence Data ; RNA, Messenger ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley ; Species Specificity ; Vascular Endothelial Growth Factor A ; genetics ; metabolism

Mandarin vole (Lasiopodomys mandarinus) spends almost all of its life underground and must have evolved remarkable adaptations to cope with the subterranean hypoxic stress. The aim of present study is to explore the adaptation mechanism through the comparison of hemogram changes under chronic intermittent hypoxia in Mandarin vole and Kunming (KM) mouse (Mus musculus). Mandarin vole and KM mouse were treated with chronic intermittent hypoxia (10.0% oxygen), which was maintained by an oxygen cabin, for 4 h per day during four weeks. Then blood samples from the animals with and without hypoxia treatment were analyzed by a hematology analyzer. The results showed that under normoxic condition mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), white blood cell count (WBC) and platelet (PLT) in Mandarin vole were significantly lower than those in KM mouse. On the contrast, red blood cell count (RBC) and mean corpuscular hemoglobin concentration (MCHC) in Mandarin vole were higher than that in KM mouse. After four-week chronic intermittent hypoxia treatment, the hemogram changes were as following. MCV and HCT were elevated in Mandarin vole, not affected in KM mouse. Both hemoglobin (HGB) content and MCH in KM mouse increased, while only MCH increased in Mandarin vole. No obvious changes of WBC and PLT were found in two species. These results suggest that the adaptive mechanism of blood system in Mandarin vole responding to hypoxic conditions is different from that of KM mouse. As a subterranean vole, the Mandarin vole has a better tolerance to hypoxia.
Adaptation, Physiological ; physiology ; Animals ; Arvicolinae ; blood ; Chronic Disease ; Erythrocytes ; Hemoglobins ; Hypoxia ; blood ; Mice ; blood ; Species Specificity