A molecular survey of cystic echinococcosis in Sudan

A survey of cystic echinococcosis in livestock was conducted from May 2001 to July 2003 in central, western and southern Sudan. Hydatid cysts were present in 59% (466/779) of camels, 6% (299/4893) of cattle, 11% (1180/10,422) of sheep and 2% (106/5565) of goats, with little variation among different geographical areas. 532 of these cysts were examined by PCR and could be overwhelmingly (98.7%) allocated to Echinococcus canadensis G6/7 (all of 215 cysts from camels, 112 of 114 cysts from cattle, 134 of 138 cysts from sheep, and all of 65 cysts from goats); the genotype G6 was identified by sequencing 13 of these isolates. Only 2 cysts from cattle belonged to Echinococcus ortleppi. The mean number of cysts per infected animal was much higher in camels (5.1) than in the other species (1.0–1.3), and cyst fertility was higher in camels and cattle (74% and 77%) than in goats and sheep (31% and 19%). Fertile cysts from five human patients from hospitals in Khartoum and Juba belonged to E. canadensis (G6). This study confirms the predominance of the ‘camel strain’ in Sudan and the infectivity of this strain for humans. This is the first genetic characterization of human CE in Sudan.