Risk factors associated with human cystic echinococcosis in Jordan: results of a case-control study

The parasites causing cystic echinococcosis (CE) are transmitted to man and domestic animals either directly or indirectly from dogs. High levels of human infection have been frequently described in sheep-rearing areas of the world, where the infection cycles between dogs and sheep through the use of working dogs and the feeding of sheep offal to dogs. A case-control study was undertaken in northern Jordan to examine the epidemiological characteristics of echinococcosis in a Muslim community. Forty-four indigenous Jordanians who had been treated for CE between 1990 and 1996 were contacted and three controls for each case, matched for sex and age, were selected from the Jordanian population. The most important single factor associated with treatment for CE was the main source of domestic water; 42 (95%) of the cases but only 81 (61%) of the controls reported that they used a public, piped, water supply as their principal source of household water [odds ratio (OR) = 13.22; 95% confidence interval (CI) = 2.91-83.7]. The keeping of dogs or close association with dogs or farm animals was not associated with any increased risk of CE. However, individuals who grew their own vegetables had a significantly decreased risk of acquiring CE (OR = 0.30; CI = 0.08-0.98). There was evidence of widespread ignorance of the disease and how it is transmitted.