Ectoparasite communities of Niviventer confucianus (Rodentia: Muridae) in the surrounding areas of Erhai Lake in Yunnan.

Objective Niviventer confucianus(Milne-Eawards 1871) is the oriental species,not only have been believed to be an important pest for agriculture and forest but also have been suspected the reservoir of plague,scrub typhus and epidemic hemorrhagic fever(EHF) in the wild rodent-type plague focus of northwestern Yunnan province.This study is aimed to understand the diversity of ectoparasites in a population of Niviventer confucianus in the Surrounding areas of Erhai Lake.Ectoparasite communities of 89 Niviventer confucianus were studied.Methods Different oriented areas surrounding the Erhai Lake in Yunnan were selected as investigation spots.Small mammals were randomly captured with baited mouse cages and ectoparasites were collected form the animals.Ectoparasites were identified to species under a microscope.The constituent ratio(C),prevalence(P) and average ectoparasite abundance(A) were used to determine 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 is very high diversity of ectoparasites of Niviventer confucianus and some species of ectoparasites have been reported associated with human disease.A high proportion(79%) of 70 Niviventer confucianus was found to be infested with ectoparasites.A total of 51 species of ectoparasites,including 31 species of chigger mite,13 species of mesostigmatid(gamasid) mite,4 species of flea and 3 species of sucking louse were collected.Walchia ewingi fuller is the most abundant chigger mite species,accounting for 66.23% of all chigger mites.Laelaps turkestanicus lange is the most abundance gamasid mite species,accounting for 38.48% of all gamasid mites.Paradoxopsyllus custodies Jordan was the most abundance of the fleas observed,accounting for 42.86% of all fleas collected.Hoplopleura pacifica was the most abundance of the sucking lice observed,accounting for 80.07% of all sucking lice collected.Within this ectoparasite complex,11 species have previously been reported to be vectors of human diseases.Non-parametric Mann-Whitney Utests showed the species richness and abundance of total ectoparasites,chigger mites,sucking lice,fleas or gamasid mites had no significant differences between male and female hosts.Spearman correlation analysis showed that abundance and species of total ectoparasite,chigger mite,sucking louse,flea or gamasid mite were not correlated with the body weight of the host.Conclusions The community structure of ectoparasites of Niviventer confucianus is complex,which reflects a high species diversity of ectoparasites on Niviventer confucianus.11 species have previously been reported to be vectors of human diseases.Sucking lice,fleas,chiggers and gamasid mites are main ectoparasites.Niviventer confucianus would be a natural reservoir for pathogen on plague bacilli,epidemic haemorrhagic fever(korean haemorrhagic fever) viruses,and scrub typhus.