Host selection and niche differentiation in sucking lice (Insecta: Anoplura) among small mammals in southwestern China

(1) Background: As a species of gamasid mite, the tropical rat mite (Ornithonyssus bacoti) is a common ectoparasite on rodents and some other small mammals. Besides stinging humans to cause dermatitis, O. bacoti can be a vector of rickettsia pox and a potential vector of hemorrhagic fever with renal syndrome (HFRS). (2) Objective: The present study was conducted to understand the host selection of O. bacoti on different animal hosts and the distribution in different environmental gradients in Yunnan Province of Southwest China. (3) Methods: The original data came from the investigations in 39 counties of Yunnan, between 1990 and 2015. The animal hosts, rodents and some other small mammals were mainly trapped with mouse traps. The O. bacoti mites on the body surface of animal hosts were collected and identified in a conventional way. The constituent ratio (Cr), prevalence (PM), mean abundance (MA) and mean intensity (MI) were used to reflect infestations of animal hosts with O. bacoti mites. The patchiness index and Taylor’s power law were used to measure the spatial distribution pattern of O. bacoti mites on their hosts. (4) Results: A total of 4121 tropical rat mites (O. bacoti) were identified from 15 species and 14,739 individuals of hosts, and 99.20% of them were found on rodents. More than half of O. bacoti mites (51.78%) were identified from the Asian house rat (Rattus tanezumi), and 40.09% of the mites from the Norway rat (R. norvegicus) (p < 0.05). The infestations of R. tanezumi (PM = 7.61%, MA = 0.40 and MI = 5.31) and R. norvegicus (PM = 10.98, MA = 1.14 and MI = 10.39) with O. bacoti mites were significantly higher than those of other host species (p < 0.05). The infestations of two dominant rat hosts (R. tanezumi and R. norvegicus) with O. bacoti mites varied in different environmental gradients (latitudes, longitudes, altitudes, landscapes and habitats) and on different sexes and ages of the hosts. The prevalence of juvenile R. norvegicus rats with O. bacoti mites (PM = 12.90%) was significantly higher than that of adult rats (PM = 9.62%) (p < 0.05). The prevalence (PM = 38.46%) and mean abundance (MA = 2.28 mites/host) of R. tanezumi rats with O. bacoti mites in the high latitude were higher than those in the low latitudes (p < 0.05). The majority of the total collected 4121 O. bacoti mites was found in the flatland landscape (91.28%) and indoor habitat (73.48%) (p < 0.05). The PM (10.66%) and MA (0.49 mites/host) of R. tanezumi rats with O. bacoti mites were significantly higher in the indoor habitat than in the outdoor habitat (p < 0.05). The tropical rat mites showed an aggregated distribution pattern on their first dominant host, R. tanezumi. Conclusion: The tropical rat mite (O. bacoti) is a widely distributed species of gamasid mite in Yunnan Province, Southwest China, and its dominant hosts are two synanthropic species of rats, R. tanezumi and R. norvegicus. It is mainly distributed in the flatland landscape and indoor habitat. It has some host-specificity, with a preference to rodents, especially R. tanezumi and R. norvegicus. The O. bacoti mites are of aggregated distribution on R. tanezumi rats.

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Niche differentiation among small mammals of the Alexander Archipelago in southeastern Alaska

Journal of Mammalogy ◽

10.1093/jmammal/gyx141 ◽

2017 ◽

Vol 99 (1) ◽

pp. 108-116 ◽

Cited By ~ 2

Author(s):

Shannon L O’Brien ◽

Joseph A Cook ◽

Seth D Newsome

Keyword(s):

Small Mammals ◽

Niche Differentiation ◽

Alexander Archipelago

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Infection of Borrelia burgdorferi sensu lato of small mammals in Yunnan Province, China

10.1101/714980 ◽

2019 ◽

Author(s):

Zhi-hai He ◽

Bao-gui Jiang ◽

Zi-hou Gao ◽

Zong-ti Shao ◽

Yun Zhang ◽

...

Keyword(s):

Genetic Diversity ◽

Lyme Disease ◽

Borrelia Burgdorferi ◽

Small Mammals ◽

Yunnan Province ◽

Wide Distribution ◽

Southwestern China ◽

23S Rrna ◽

Prevalence Rates ◽

Landscape Types

AbstractBackgroundLyme disease is caused by Borrelia burgdorferisensulato (BBSL) which is usually found in wild and domestic mammals worldwide. Human cases of B. burgdorferi infections have been identified in China, but little direct surveillance of potential rodent reservoirs has been performed in Yunnan Province, Southwestern China. Yunnan Province is a tropical area with a diverse topographic range and sustains a high biodiversity of small mammals that could potentially play an important role in the transmission of a variety of B. burgdorferigenospecies.Methods3659 small mammals were captured in 159 sample siteslocated 23 countries inYunnan Province and screened for BBSL infection by nested PCR based on 5S-23S rRNA intergenic spacer gene of BBSL.Univariate and multivariate forward stepwise logistic regression analysis was used to access the association between infections and related risk factors.ResultsInfection with BBSL was confirmed in 3.99%(146/3659) of small mammals. Significant differences in prevalence rates of BBSL were observed at varying landscape types and altitudes.Small mammals in forested areas had higher prevalence rates than other landscape types as did small mammals found at altitudes greater than 2500 meters. The 5S-23S rRNA intergenic spacergene revealed that there were 5 genotype of BBSL, including B. afzelii, B. burgdorferisensustricto, B.japonica, B.gariniiand B.valaisiana, which demonstrate the genetic diversity and regional distribution.ConclusionsThere exists a wide distribution and genetic diversity of endemic BBSL in Southwestern China, warranting further investigations and monitoring of clinical disease in individuals presenting with symptoms of Lyme disease in these areas.Author summaryLyme disease is caused by Borrelia burgdorferi sensu lato (BBSL) which is usually found in wild and domestic mammals worldwide. Human cases of Borrelia burgdorferi sensu lato infections have been identified in China, but little direct surveillance of potential rodent reservoirs has been performed in Southwestern China. This study documents potential small mammal reservoir hosts collected from a large of sample sites from different landscape types and altitudes, with PCR and sequencing identifying the wide distribution and genetic diversity of endemic Borrelia burgdorferi sensu lato in Southwestern China. This was the first report that B. japonica was detected in Apodemus draco and Niviventer excelsior in China. This study adds to body of literature on Borrelia burgdorferi sensu lato in China. This work will provide insight regarding small mammals to target for surveillance and we access the association between gender, developmental stage of rodents, environmental landscape and altitude to better prevent human exposure.

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Host selection and seasonal fluctuation of Leptotrombidium deliense (Walch, 1922) (Trombidiformes: Trombiculidae) at a localized area of southern Yunnan, China

Systematic and Applied Acarology ◽

10.11158/saa.24.11.15 ◽

2019 ◽

Vol 24 (11) ◽

pp. 2253-2271 ◽

Cited By ~ 1

Author(s):

Yan Lv ◽

Xianguo Guo ◽

Daochao Jin ◽

Wenyu Song ◽

Rong Fan ◽

...

Keyword(s):

Small Mammals ◽

Host Selection ◽

Scrub Typhus ◽

Seasonal Fluctuation ◽

Field Investigation ◽

Male Rats ◽

Tsutsugamushi Disease ◽

Two Peaks ◽

The Village ◽

Taxonomic Categories

As an independent species of chigger mites, Leptotrombidium deliense (Walch 1922) is the most important and powerful vector of scrub typhus (tsutsugamushi disease) in the south of China. Located in the southwest of China, Yunnan province, especially southern Yunnan, is an important focus of scrub typhus. A localized area, Jingha village in southern Yunnan, was chosen as the target site and a field investigation at the village was carried out for 12 consecutive months from April 2016 to March 2017. The investigation is an attempt to illustrate the small mammals host selection and seasonal fluctuation of L. deliense at a fixed geographical site within the focus of scrub typhus, and the selected localized area makes this possible. A total of 2,434 hosts were captured and examined, including rodents and some other “rodent-like” small mammals. Of the identified 15 host species, L. deliense was found on 73.33% of them (11 species of hosts), but 88.61% of the mites were from the Southeast Asian house rats, Rattus brunneusculus. Of 10 genera, 5 families and 4 orders of identified hosts, more than 80.00% of them were infested with L. deliense with a prominent cross infestation among different taxonomic categories of hosts, but the majority of the mites (96.60%) were collected from rodents (the order Rodentia), especially the rats in the genus Rattus (92.95%). It suggests that L. deliense prefers rodents (especially the Rattus rats) to some other small mammals although it has a low host specificity. Rattus brunneusculus is the major host of the mite in the investigated site. The female R. brunneusculus rats harbored more L. deliense mites than the male rats (P<0.01). The spatial distribution pattern of L. deliense on the hosts was determined as aggregated distribution. L. deliense mites were collected every month with two peaks (in July and October), belonging to the summer-autumn type. The first peak in July was much higher than the second peak in October. The monthly fluctuation of L. deliense was highly in accordance with that of the rainfall, which suggests the summer season with plentiful rainfall benefits the occurrence of this powerful vector of scrub typhus, L. deliense.

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Microbiome of Co-cultured Fish Exhibits Host Selection and Niche Differentiation at the Organ Scale

Frontiers in Microbiology ◽

10.3389/fmicb.2019.02576 ◽

2019 ◽

Vol 10 ◽

Cited By ~ 3

Author(s):

Zhimin Zhang ◽

Dapeng Li ◽

Weitong Xu ◽

Rong Tang ◽

Li Li

Keyword(s):

Host Selection ◽

Niche Differentiation ◽

Cultured Fish

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