Modelling Taenia saginata epidemiology and control in Belgium

Taenia saginata (beef tapeworm) is a worldwide occurring zoonotic cestode, of which the adult tapeworm resides in the intestinal lumen of the human _nal host (taeniasis). Humans get infected by consuming raw or undercooked infected beef. Eggs and proglottids are expelled with the stool or through active migration of the proglottids. On average more than 150000 eggs can be expelled daily. Cattle are infected by ingesting these eggs, e.g. through infected feed or contaminated meadows/water. Inside the intestines, the oncosphere larva (already present in the egg), will free itself, penetrate the intestinal wall and translocate to the (skeleton and cardiac) muscles through the blood ow. Here, they will develop into metacestodes (cysticerci)(bovine cysticercosis, BCC), that will become infective to humans after 10 weeks. Viable cysticerci consist of a transparent capsule with an invaginated scolex. When cysts die, they undergo a degeneration, followed by calci_- cation. Only consumption of viable cysts can lead to the development of a tapeworm in humans [Murrell, 2005]. The impact of tapeworm infections on public health has not yet been determined, but the yearly incidence in Belgium is estimated at 11000 cases, based on the number of cestodicides sold (estimated prevalence: 0.1%). Most infections cause no to very few symptoms with the most common complaint being the unpleasant feeling in the anal region when proglottides actively leave the body [Murrell, 2005]. BCC is responsible for important economic losses in the meat sector, especially concerning beef cattle [Wanzala et al., 2002, Scandrett et al., 2009]. In Belgium, one third of the 29000 beef cattle companies has taken an interest in insurances for BCC, since carcasses of heavily infected animals will be condemned and those of lightly infected animals will loose almost half their value due to the obligatory freezing treatment. Diagnosis of BCC is currently based on o_cial meat inspection (MI) according to EC directive 854/2004, which has a known low sensitivity (

Trefwoorden:B780-tropische-geneeskunde