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Graphical abstract, Highlights • The prevalence of porcine cysticercosis was determined in pigs from the Banke District of Nepal. • Slaughter-age animals were selected at random and underwent detailed necropsy examination. • Thirty two of 110 animals were found to harbour T. solium cysticerci. • This is one of the highest levels of porcine cysticercosis described for any region in the world. • Measures are warranted to control this zoonotic disease in Nepal., Neurocysticercosis is a major cause of epilepsy in countries where Taenia solium is endemic and the parasite is a major cause of food-borne disease globally. Pigs are the natural intermediate host involved in transmission of the parasite. T. solium is known to be endemic in Nepal, however there is limited reliable data about the prevalence of the disease in Nepal. The aim of this study was to determine accurately the prevalence of porcine cysticercosis in slaughter age pigs in an area of Nepal where pigs are known to be free-roaming. Pigs were obtained from the Udaypur Village Development Committee (VDC) and Hirminiya & Betahani VDC of the Banke district in Nepal. One hundred and ten animals of slaughter age (approximately 8–16 months old) were purchased, slaughtered and the heart, liver, brain and half the body skeletal musculature were sliced using hand knives and the number and viability of T. solium cysts determined. Thirty two of the 110 animals were found to harbour T. solium cysticerci (29%), of which 30 (27%) were found to have viable cysticerci (93% of the infected animals). This is one of the highest prevalences of porcine cysticercosis that has been reported to date from the results of necropsy on randomly selected animals. This study highlights a high rate of transmission of T. solium in the Banke District of Nepal. It encourages further investigation of human and porcine cysticercosis in Nepal, as well as implementation of efforts to reduce transmission of the parasite and the associated human disease.

Taenia solium is a zoonotic cestode parasite which causes human neurocysticercosis. Pigs transmit the parasite by acting as the intermediate host. An intervention was implemented to control transmission of T. solium by pigs in Dalit communities of Banke District, Nepal. Every 3 months, pigs were vaccinated with the TSOL18 recombinant vaccine (Cysvax, IIL, India)) and, at the same time, given an oral treatment with 30mg/kg oxfendazole (Paranthic 10% MCI, Morocco). The prevalence of porcine cysticercosis was determined in both an intervention area as well as a similar no intervention control area, among randomly selected, slaughter-age pigs. Post mortem assessments were undertaken both at the start and at the end of the intervention. Participants conducting the post mortem assessments were blinded as to the source of the animals being assessed. At the start of the intervention the prevalence of porcine cysticercosis was 23.6% and 34.5% in the control and intervention areas, respectively. Following the intervention, the prevalence of cysticercosis in pigs from the control area was 16.7% (no significant change), whereas no infection was detected after complete slicing of all muscle tissue and brain in animals from the intervention area (P = 0.004). These findings are discussed in relation to the feasibility and sustainability of T. solium control. The 3-monthly vaccination and drug treatment intervention in pigs used here is suggested as an effective and practical method for reducing T. solium transmission by pigs. The results suggest that applying the intervention over a period of years may ultimately reduce the number of tapeworm carriers and thereby the incidence of NCC., Author summary Neurocysticercosis is a disease caused by a parasitic infection of the brain. The parasite responsible, Taenia solium, is transmitted by pigs where human sanitation is poor and pigs roam freely. Neurocysticercosis is responsible for many cases of epilepsy in people living in poor, developing countries. The feasibility and sustainability of implementing control measures have been major impediments to reducing the incidence of neurocysticercosis. Recently, two new commercial products have become available which together offer the possibility of interrupting the parasite’s transmission by pigs–the TSOL18 vaccine (Cysvax, IIL, India) and an oxfendazole formulation (Paranthic 10%, MCI, Morocco) licensed for use in pigs for the treatment of cysticercosis. Here we describe the impact of implementing vaccination plus drug treatment of pigs in the Banke district of Nepal. The intervention eliminated the risk of transmission of T. solium by the animals vaccinated and treated during the trial. Application of the vaccination and drug treatment program used here, possibly with strategic use of anthelmintics also in the human population, is an effective option for reducing the incidence of neurocysticercosis in Nepal and elsewhere.