Naturally occurring infections of cattle with Theileria lestoquardi and sheep with Theileria annulata in the Sudan.

Theileria annulata is endemic in northern Sudan, hindering all efforts at upgrading cattle for milk production. T. lestoquardi clinical cases occur throughout the year and causes annual outbreaks that result in substantial losses in sheep. In the northern Sudan both cattle and small ruminants are frequently raised together and/or share common grazing grounds at river banks. In an attempt to evaluate field cross infectivity of Theileria lestoquardi and T. annulata in cattle and sheep respectively, a PCR analysis was carried out on samples collected from closely reared sheep and cattle using both T. annulata and T. lestoquardi specific primers. A total of 19 sheep out of 51 (37.3%) were positive for T. lestoquardi while four sheep (7.8%) showed T. annulata specific amplicons. A total of 38 out of 52 (73.1%) surveyed cattle were PCR positive for T. annulata and only two (3.8%) showed T. lestoquardi specific bands. These findings indicate complex epidemiology of both infections in areas where both parasites are transmitted by the same vector and call for further investigations of this phenomenon.

Echinococcosis in sub-Saharan Africa: emerging complexity.

Cystic echinococcosis occurs in most regions of sub-Saharan Africa, but the frequency of this zoonosis differs considerably among and within countries. Especially human cases seem to be focally distributed. A number of environmental and behavioural factors partially explain this pattern, i.e. density of livestock, presence of dogs, uncontrolled slaughter, and hygiene. In addition, the various taxa of Echinococcus spp. are known to differ considerably in infectivity to different host species including humans. Genetic characterizations of isolates, which are necessary to evaluate the impact of this factor - so far done in only a few countries - indicate that the diversity of Echinococcus spp. in Sub-Saharan Africa is greater than on any other continent. The very incomplete data which are available show that sympatrical taxa may infect different hosts, others may be geographically restricted, some life cycles involve livestock, others wild animals. Possible implications of this complexity for public health, livestock economy and conservation are briefly discussed.

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.