ISSN 1003-8280 CN 10-1522/R 中国疾病预防控制中心 主办
Objective To determine the host selection and distribution of Ascoschoengastia indica on different small mammal hosts in different areas of Yunnan province. Methods A field survey was carried out in 19 counties of Yunnan province. The small mammal hosts were captured with mice cages and traps with baits. The chigger mites on the surface of two auricles were scraped off by a bistoury and then preserved in 70% ethanol. Species of each specimen of the chigger mites was identified using microscopy. Conventional statistical Methods were adopted to calculate the constituent ratios of A. indica on different hosts and in different areas, together with its prevalence and mean abundance on different hosts. Results A total of 1267 individuals of A. indica (1.36% of the total chigger mite species) were collected from the body surface of 3224 individual small mammal hosts of 7 species. The host specificity of A. indica was relatively high compared to that of other species of chigger mites, of which 94.40% were collected from the body surface of Rattus tanezumi. Conclusion The A. indica species are mainly distributed in southern and midwestern Yunnan with a high abundance, mostly on the body surface of R. tanezumi, a major reservoir host of tsutsugamushi disease.
The mite?borne hemorrhagic fever with renal syndrome (HFRS) has been attracting domestic and foreign controversies in recent years. Based on a large number of field investigation and experimental studies, Chinese scholars have proved the existence of the mite vector of HFRS and its possible role. This paper reviews the epidemiologic, experimental and molecular biologic basis of the HFRS of Apodemus type and Rattus type transmitted by gamasid mites, as well as the research advance in the animal hosts.
Objective To determine the niche breadth and overlap in eleven dominant species of gamasid mites parasitic on 39 species of small?mammal hosts around Biluoxueshan Mountain in Weixi, Yunnan. Methods The niche breadth was determine using the Levins model, the niche overlap the Colwell?Futuyma model, based on which the systematic grouping of niche overlap for all gamasid mites was completed by cluster analysis. Results (1) Eulaelaps huzhuensis and Hypoaspis pavlovskii had the widest niche breadth (0.1067 and 0.1044), while Laclaps traubi Domrow and Haemogamasus sanxiaensis had the narrowest (0.0390 and 0.0365). (2)L. traubi Domrow and L. turkestanicus shared a highly similar population distribution with L. chin, Ha. oliviformis and Hy. pavlovskii. Conclusion The niche breadth could be used as an index for evaluating the host specificity of gamasid mites, whose similarity in population distribution was largely related to that of their hosts, as well as their taxonomic distance.
【Abstract】 Objective To investigate the geographical distribution, habitat, dominant hosts and population spatial distribution patterns of Ornithonyssus bacoti in Yunnan province. Methods A total of 28 counties in five zoogeographical sub?regions were chosen as the investigated sites. Each investigated site was divided into two habitats (indoors and outdoors) and then small mammal hosts were randomly captured by mouse traps. All the gamasid mites from the body surface of the hosts were collected and preserved in 70% ethanol. Hoyer’s medium was used to mount the mites onto glass slides and each mite specimen was finally identified by microscope. The spatial pattern of the mite was analyzed by K?value of negative binomial distribution, patchiness index, Taylor’s power function and Iwao’s model. Results A total of 3339 O. bacoti were collected from 11 560 captured small mammal hosts which belonged to 3 orders 4 families 8 genera and 15 species. Of the investigated 28 counties, O. bacoti was found in 21 counties and the mites were collected from 15 species of small mammal hosts. O.bacoti mainly distributed in Southwest region (accounted for 90% of the total), and the quantity of O. bacoti in indoors (2914, 87.27%) were obviously higher than that in outdoors (425, 12.73%). 90% mites mainly parasitized on the body surface of Rattus norvegicus and R. tanezumi which were the dominant host of mites. The results showed that the spatial pattern of O. bacoti was an aggregated distribution. Conclusion O. bacoti widely distributes in Yunnan province and mainly parasitizes on the body surface of R. norvegicus and R. tanezumi. It is of aggregated distribution among its main hosts.
【Abstract】 Objective To investigate the community structure of fleas on small mammals in eight counties of southern mountainous areas in Yunnan. Methods Small mammal hosts were captured from eight counties selected randomly in southern mountainous areas and fleas were collected from the body surface of each host. Richness (S), Shannon?Wiener’s diversity index (H′), evenness (J′) and dominance index (C′) were used to measure the community structure of fleas on the hosts. Results There were 3184 small mammals captured, which belonged to 21 species,13 genera, 5 families and 4 orders. A total of 1767 fleas were collected from the small mammal hosts and were classified into 15 species, 13 genera and 5 families. There were seven dominant small mammals like Rattus tanezumi, Mus caroli, M.pahari, R.norvegicus, Suncus murinus, R.rattus sladeni and Niniventer fulvescens, and the dominant fleas were Xenopsylla cheopis, Nosopsyllus (Nosopsyllus) wualis and Leptopsylla segnis. Conclusion There are few fleas in the southern mountainous areas of Yunnan which biodiversity is lower than that in others.
【Abstract】 Objective To understand the ectoparasite communities in a population of Eothenomys miletus in the surrounding areas of Erhai Lake and describe the importance of them in the medicinel and veterinary. Methods Investigation sites were randomly selected at different direction of surrounding areas of Erhai Lake in Yunnnan. Small mammals were captured by live traps with baits. The live traps were examined and the baits were changed each morning. Trapped small mammals were brought to the laboratory to identify according to their body shape, size and color, and some measurements such as body length, ear length and hind feet length, and ectoparasites were collected. Ectoparasites were identified under a microscope after mounting, clearity and desiccation. The constituent ratio (C), prevalence (P) and average ectoparasite abundance (A) were used to reflect the prevalence and density of ectoparasites. Non-parametric Mann-Whitney U-tests were used to test differences in the abundance and richness of ectoparasites between female and male hosts. Spearman correlation analysis was used to analyze the relationship between ectoparasites and the body parameters of hosts. Results There were 916 E.miletus caught. Of which, a total of 756 were infested by ectoparasite, and the infestation rate was 83%. A total of 86 species of ectoparasite were collected, including 51 species of chigger mite, 23 species of gamasid mite, 7 species of flea and 5 species of sucking louse. Seventeen species were proved to be the main vectors of human disease. Conclusion There was very high diversity of ectoparasites parasitized on E.miletus, and some species had been reported to be associated with human disease. E.miletus could be a natural reservoir of plague bacilli, epidemic haemorrhagic fever (korean haemorrhagic fever) viruses and scrub typhus.
【Abstract】 Objective To illustrate the similarity, transitional tendency and classification of gamasid mite communities in the surrounding areas of Biluoxueshan in Weixi county of Yunnan province. Methods System clustering analysis was used in this study. Results In 1560 small mammals captured, the dominant species of mites from Apodemus draco, Eothenomys miletus, Niviventer confucianus, Ap.chevrieri, Ap.peninsulae, Rattus norvegicus and R.tanezumi were Laelaps jingdongensis(Dr=41.32), L.chin(Dr=41.87), L.traubi (Dr=63.51) and L.turkestanicus (Dr=24.78), L.traubi(Dr=18.82), Eulaelaps huzhuensis(Dr=14.11) and L.chin(Dr=11.76), E.huzhuensis(Dr=25.00), E.huzhuensis(Dr=23.61) and Haemogamasus oliviformis(Dr=16.67), Ornithonyssus bacoti(Dr=71.73) and O.bacoti(Dr=98.82), respectively. The result of system clustering analysis indicated that there was prominent similarity between the gamasid mite from R.norvegicus and R.tanezumi, secondly it was the similarity among the mites from Ap.draco, Ap.peninsulae and Ap.chevrieri. Conclusion The taxonomic relations of mite hosts was nearer, the communities similarity of gamasid mite was higher. The habits distribution of hosts had an effect on communities type of parasitic gamasid mite.
【Abstract】 Objective To study the distribution and its ecological charateristics of medical gamasid mites in the surrounding areas of Biluoxueshan in Yunnan province, China. Methods Some small mammals were captured by mouse traps (or mouse clips) in the surrounding areas of Biluo snow mountain located in Weixi county of Yunnan province. The ectoparasitic gamasid mites were all collected from the body surface of small mammal hosts. The community structure of gamasid mites were illustrated with richness (S), Shannon?Wiener’s diversity index(H′), evenness(J′) and dominance index(C′). The spatial distribution patterns of some dominant species of gamasid mites were measured by disperse coefficient, clumping index, Cassie index and patch index. Results There were 1560 small mammals belonging to 40 species captured, and 35 species of gamasid mites were collected from the body of small mammals. Of which, 8 species were not identified. The community of gamasid mites showed a high diversity with abundant species. The dominant species of gamasid mite were Laclaps traubi, Laelaps chin, Laelaps jingdongensis, Laclaps turkestanicus and Ornithonyssus bacoti. The distribution patterns of 5 dominant gamasid mite species on the body of small mammals were of aggregated distribution. Of the 5 dominant species, the female ratios of most mite species (96.84%, 87.94%, 92.78%, 95.77%) were much higher than the males, but Os.bacoti was an exception (37.25%). For most mites species, the proportion of the larvae and nympha was much lower with the exception of Os.bacoti Hirst (54.51%). Conclusion The community of gamasid mites in the surrounding areas of Biluo snow mountain was relatively complicated with abundant species. The spatial distribution of dominant mite species was of aggregated distribution pattern.