Implementation of a practical and effective control program for Taenia solium in the Banke District of Nepal

Abstract

19Taenia solium is a zoonotic cestode parasite which causes human neurocysticercosis. Pigs 20 transmit the parasite by acting as the intermediate host. An intervention was implemented in 21 pigs to control transmission of T. solium in Dalit communities of Banke District, Nepal. 22Every 3 months, pigs were vaccinated with the TSOL18 recombinant vaccine (Cysvax TM , 23 IIL, India)) and, at the same time, given an oral treatment with 30mg/kg oxfendazole 24 (Paranthic 10%™, MCI, Morocco). The prevalence of porcine cysticercosis was determined 25 in both an intervention area as well as a similar no intervention control area, among randomly 26 selected, slaughter-age pigs. Post mortem assessments were undertaken both at the start and 27 at the end of the intervention. Participants conducting the post mortem assessments were 28 blinded as to the source of the animals being assessed. At the start of the intervention the 29 prevalence of porcine cysticercosis was 23.6% and 34.5% in the control and intervention 30 areas, respectively. Following the intervention, the prevalence of cysticercosis in pigs from 31 the control area was 16.7% (no significant change), whereas no infection was detected after 32 complete slicing of all muscle tissue and brain in animals from the intervention area 33 (P=0.004). These findings are discussed in relation to the feasibility and sustainability of T. 34 solium control. The 3-monthly vaccination and drug treatment intervention in pigs used here 35 is suggested as an effective and practical method for reducing T. solium transmission, thereby 36 reducing the incidence of human neurocysticercosis. 37 Author summary 38 Neurocysticercosis is a disease caused by a parasitic infection of the brain. The parasite 39 responsible, Taenia solium, is transmitted by pigs where human sanitation is poor and pigs 40 roam freely. Neurocysticercosis is responsible for many cases of epilepsy in people living in 41 poor, developing countries. The feasibility and sustainability of implementing control 42 measures have been major impediments to reducing the incidence of neurocysticercosis. 43 Recently, two new commercial products have become available for pigs which together offer 44 the possibility of interrupting the parasite's transmission -the TSOL18 vaccine (Cysvax TM , 45 IIL, India) and an oxfendazole formulation (Paranthic 10% TM , MCI, Morocco) licensed for 46 use in pigs for the treatment of cysticercosis. Here we describe the impact of implementing 47 vaccination plus drug treatment of pigs in the Banke district of Nepal. The intervention 48 eliminated the risk of transmission of T. solium by the animals vaccinated and treated during 49 the trial. Application of the vaccination and drug treatment program used here, possibly with 50 strategic use of anthelmintics also in the human population, is an effective option for 51 reducing the incidence of neurocysticercosis in Nepal and elsewhere. 53 Neurocysticercosis is a serious medical condition caused by infection in the brain or ot...