Influence of livestock husbandry on schistosomiasis transmission in mountainous regions of Yunnan Province.

An investigation was conducted in the highly endemic areas of schistosomiasis japonica in Weishan and Eryuan counties, Yunnan Province. The results are summarized as follows: 1) the number of domestic animals was increasing annually; 2) the proportion of animal husbandry gains in the total agriculture income had a yearly escalating tendency; 3) the infection rate of inhabitants was upgrading as a result of the development of and the prevalence in domestic animals in the recent decades. Owing to frequent migration of domestic animals, serious spread of infection sources and high prevalence of schistosomiasis japonica occurred. It is suggested that more attention should be paid to the control of schistosomiasis japonica in mountainous endemic regions during the course of economic development, especially in the development of domestic animals.

Analysis of social factors and human behavior attributed to family distribution of schistosomiasis japonica cases.

An investigation of family distribution patterns of schistosomiasis japonica was carried out in four pilot villages in Yunnan Province. Family clustering of the disease was present in Bihuayuan Village before and after economic reform (site A); however, such clustering did not occur in Tuanshan and Liantie Villages (sites B and C) in the same periods. Being contrary to the stage prior to economic reform family clustering existed in Zhonghe Village (site D) after the reform. The results obtained from single- and multifactor analysis showed that the main human behavior related to family distribution of schistosomiasis in mountainous regions of Yunnan Province included the frequency of laborer migration, contact with cercariae-infested water in public places or family microenvironments with a high transmission potential, promiscuous defecation and status of cattle grazing. The frequency of laborer migration and human contact with cercariae-infested water in public places in sites B and C without family clustering was higher than that in sites A and D with family clustering. Place for promiscuous defecation and cattle grazing in site A converged compared with that in sites B and C.