Essentiality of wildlife studies in understanding the transmission mechanism of zoonoses in China
Résumé
More than 75% of human infectious diseases are zoonotic. Wildlife species occupy a great portion of these pathogenic infectious organisms. Since the beginning of the 21st century, the pandemic transmission of SARS and AIV have prompted China to establish a national wide infectious diseases control system to stop or limit the disease transmission in human societies. However, to many wildlife borne zoonotic diseases, epidemiological studies were mainly focused on humans and domestic animals in China. Limited information about biology, ecology, and epidemiology to the wildlife cycles caused knowledge of these zoonotic diseases incomplete, and high risks of outbreaks in human societies in China. Therefore, for a long time the animal ecology research group from ECNU has been focusing on studies to the wildlife epidemiology of AIV and echinococcosis, two zoonotic diseases involving complex wildlife host transmitting cycles.
(1)For a long time, eastern China has been judged as the origin area of the highly pathogenic avian influenza virus (HPAIV) in eastern Asia. Eastern China contains a series of important stopovers for migratory birds traveling along the eastern Asia-Australasia flyway. Migratory birds were strongly associated with the AIV geographic dissemination. However, without knowledge of the epidemiology of HPAIV in migratory birds, the role of migratory birds in the initial introduction and spread of HPAIV in China and other countries in the region is unclear. We studied the epidemiology of HPAI H5N8 strains in migratory birds sampled in Shanghai from October 2013 through December 2014. Accompanied with published materials, we showed the mechanism of migratory birds influencing the circulation of HPAIV along their flyways to spread the disease to different countries.
(2)Echinococcosis is a serious lethal zoonosis mainly endemic in the western part of China. The pastoral area of Tibetan plateau is a newly recognized endemic region with the highest human infection rates. However, compared with the fact that epidemiological studies mainly focused on humans and domestic animals (i.e., dogs), parasitological and ecological studies on Echinococcus in wildlife host species are still limited. Our study on the eastern Tibetan plateau is clarifying the composition of wildlife host species of echinococcus spp., especially small mammal intermediate host species. We found that the spatial distribution of wildlife cycles can be quite near to villages, which causes local people still susceptible to echinococcosis even when infection in dogs, the main domestic definitive host species, are careful controlled.