Helminth parasites of pigs and humans in North Central Nigeria, with a particular focus on Taenia solium

Abstract

The pork tapeworm Taenia solium causes neuro-cysticercosis, a parasitic zoonosis that is becoming increasingly important globally as a re-emerging disease and is typically associated with poor marginalized people in low-income countries. Various gastrointestinal parasites of pigs also present threats to human health and pig production in these countries. The study (ii) Determine the gastrointestinal parasites present in north central Nigeria among pigs and pig farmers, and improve understanding of risk factors for infection; (iii) Study the epidemiology of T. solium cysticercosis in pigs and humans commercial antibody-detecting enzyme-linked immune-assays (ELISAs) using crude antigen and electro-transfer blot and elucidate significant risk factors and practices associated with infection. A cross sectional survey was conducted in three pig producing states in north central Nigeria, from March 2012 to November 2013. A total of 767 and 510 faecal samples were collected from pigs, respectively before and one year after anthelmintic treatment. Blood samples from 556 pigs and 1266 humans were serologically screened for evidence of T. solium infection. Questionnaires on pig management, human behaviour and socio-demographic factors were completed to provide information on risk factors for infection. Coprological examination of the 767 pigs before and 510 after interventions indicated that 78 % and 49 %, respectively, excreted parasite eggs, and 9 parasite taxa were observed. Significant predictors of gastrointestinal parasite infection in pigs were management practices and type of feed given to pigs. Most farmers practiced a semi intensive system of management, under which the pigs find most of their food through scavenging and in the process become exposed to parasite eggs they pick up while grazing on the fields. The majority of the feed offered to pigs was kitchen waste and concentrates containing lots of fibre, favouring the development of Oesophagostomum spp. Of the 754 and 512 human faecal samples examined before and after the intervention, 8 different types of parasite ova, with a prevalence of 27 % and 15 % was obtained, respectively. Out of the 556 serum samples screened by crude antigen, 51 (9.2 %) of pigs were seropositive to porcine cysticercosis. There was a significant relationship between porcine cysticercosis and the month pigs were sampled (April and October) and the age group (5-8 months). Serum from 47 of the ELISA-positive pigs was tested by electro-transfer blot (EITB), of which 4 (8.5%) showed the presence of a band of 6 kDa, indicating active cysticercosis. Out of the 1266 human serum samples screened for T. solium antibodies using crude antigen, none were seropositive; and none of 24 samples screened by EITB, therefore no cases of active cysticercosis were identified. Results of this study indicate that conditions for transmission of gastrointestinal helminths and porcine cysticercosis are present in the study area and larger, more detailed studies should be carried out in order to underpin holistic control strategies to reduce economic loss to the farmers and the risk of zoonotic disease.

Date of Award	23 Jan 2020
Original language	English
Awarding Institution	The University of Bristol
Supervisor	Eric R Morgan (Supervisor) & Mark C Eisler (Supervisor)