Current situation of Echinococcus infection in different hosts in Qinghai plateau

Abstract

Objective To analyze Echinococcus infection in definitive and intermediate hosts in different zones of Qinghai plateau,Qinghai southern plateau,Qilian mountain-Hehuang valley and Chaidamu basin,and to provide a scientific basis for developing control strategies against Echinococcosis infection. Methods Echinococcosis infection in definitive hosts,dogs and foxes,was identified by morphological observation; in domesticated and wild intermediate host animals was identified by anatomy and pathology; some of the suspected samples were further identified by molecular biological methods.Results Stray dogs in different zones of Qinghai plateau were infected with Echinococcus granulosus,the infection rates were 38.71％(300/775),49.60％(124/250),and 9.76％(4/41 ) in Qinghai southem plateau,Qilian mountain-Hehuang valley and Chaidamu basin,respectively,and the difference was statistically significant(x2 =25.72,P ＜ 0.01 ).in addition,only Qinghai southern plateau dogs were infected with Echinococcus multiloularis,and the infection rate was 16.04％(98/611).The infection rates of fox with Echinococcus multilocularis were 22.89％(38/166) and 30.77％(12/39) in Qinghai southern plateau and Qilian mountain-Hehuang valley,respectively,and wolves were also found to be infected with Echinococcus granulosus in the same areas.The infection rates of domesticated sheep,yaks,goats and pigs with Echinococcosis were significantly different statistically in those different areas(x2 =82.70,41.82,212.63,194.58,all P ＜ 0.01 ).The infection rates of sheep and yaks were higher[43.43％(5664/13 042),49.47％(2917/5896),52.99％ (887/1674),42.18％ (779/1847),50.70％ (1049/2069),52.90％ (685/1295) ] in three areas.The infection rates of goats and pigs [3.26％ (7/215),0.00％ (0/108)] in Qinghai southern plateau were lower than that of other two areas[ 19.51％(119/610),26.91％(43/1598),47.91％(343/716),21.91％(71/324)].The infection rates of Ochotona curzoniae with Echinococcosis were 6.21％ (243/3910),1.80％ (3/167) and 0.00％ (0/199) in Qinghai southern plateau,Qilian mountain-Hehuang valley and Chaidamu basin,respectively,and the difference was statistically significant (x2 =18.50,P ＜ 0.01 ).Moreover,wild intermediate hosts of Echinococcosis,such as Microtus fuscus,Lepus oiostolus,Pseudois nayaur,Procapra picticaudata,and Prodorcas gutturosa were found to be infected only in Qinghai southern plateau.Conclusions Human is faced with a threat of Echinococcosis infection from various definitive hosts in different zones of Qinghai plateau.And stray dogs are the most crucial factor.The life-cycles of Echinococcus are very complicated in Qinghai plateau.Qinghai plateau is a key area in prevention and control of Echinococcosis infection in China. Key words: Qinghai; Host-parasite relations; Echinococcus multilocularis; Echinococcus granulosus; Echinococcosis