Present situation of cystic echinococcosis in Central Asia

Abstract

Cystic echinococcosis (CE) caused by Echinococcus granulosus has always been an endemic disease in central Asia. During the period of Soviet Administration up to 1991, human surgical incidence rates tended to be relatively low with perhaps at most 1-5 cases per 100,000 per year. Following the collapse of the Soviet Union and the emergence of the New Independent States there has been profound economic and social changes. Associated with this has been a serious epidemic of CE throughout the region. In many areas figures suggest the surgical incidence is now greater than 10 cases per 100,000. Furthermore, official government figures are believed to substantially under report the extent of the problem. For example, official figures in Uzbekistan reported 819 cases of CE surgically treated in 2001. However, a detailed analysis of hospital records suggests that the true figure was 4089, more than 4 fold higher. The latter figure represents an annual surgical incidence rate of nearly 25 cases/100,000 per year. Similarly high endemic areas are seen in southern Kazakhstan, Kyrgystan and Tadjikistan with incidence rates of up to 13 cases/100,000, 20 cases/100,000 and 27 cases/100,000 respectively. A disproportionate number of cases are in children and the unemployed. The rates of infection have also increased in major livestock species such as sheep with a doubling of reported prevalence in some areas. In the dog population, independent studies in Uzbekistan and Kazakhstan have demonstrated that the rural dog population, closely associated with the sheep industry, is highly infected, with prevalences approaching 25%. Village and urban dogs have a considerably lower prevalence.