Re-visiting the detection of porcine cysticercosis based on full carcass dissections of naturally Taenia solium infected pigs

Abstract

Background Taenia solium is a neglected zoonotic parasite. The performances of existing tools for the diagnosis of porcine cysticercosis need further assessment, and their shortcomings call for alternatives. The objective of this study was to evaluate the performance of tongue palpation and circulating antigen detection for the detection of porcine cysticercosis in naturally infected pigs of slaughter age compared to full carcass dissections (considered the gold standard). Additionally, alternative postmortem dissection procedures were investigated. A total of 68 rural pigs of slaughter age randomly selected in the Eastern Province of Zambia were dissected. Dissections were conducted on full carcasses (or half carcass in case cysticerci were already detected in the first half), including all the organs. Total cysticercus counts, location and stages were recorded and collected cysticerci were identified morphologically and molecularly. All sera were analysed with the B158/B60 antigen detecting ELISA (Ag-ELISA).ResultsKey findings were the high occurrence of T. solium infected pigs (56%) and the presence of T. solium cysticerci in the livers of 26% of infected animals. More than half of the infected carcasses contained viable cysticerci. Seven carcasses had T. hydatigena cysticerci (10%), out of which five carcasses were co-infected with T. hydatigena and T. solium; two carcasses (3%) had only T. hydatigena cysticerci. Compared to full carcass dissection, the specificity of the Ag-ELISA to detect infected carcasses was estimated at 67%, the sensitivity at 68%, increasing to 90% and 100% for the detection of carcasses with one or more viable cysticerci, and more than 10 viable cysts, respectively. Tongue palpation only detected 10% of the cases, half carcass dissection 84%.Selective dissection of the diaphragm, tongue and heart or masseters can be considered, with an estimated sensitivity of 71%, increasing to 86% in carcasses with more than 10 cysticerci.ConclusionsDepending on the aim of the diagnosis, a combination of Ag-ELISA and selective dissection, including investigating the presence of T. hydatigena, can be considered. Full carcass dissection should include the dissection of the liver, kidneys, spleen and lungs, and results should be interpreted carefully, as small cysticerci can easily be overlooked.

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

“…These data are consistent with the tissue distribution of T. solium cysticerci in many previous studies, including the comprehensive investigations undertaken by Boa et al [21] on naturally infected pigs in Tanzania, the majority of which were heavily infected. These data, however, contrast with those reported by Chembensofu et al [20], who found large numbers of viable, DNA-confirmed cysticerci in the liver, lungs and kidneys of many pigs from Zambia. There is no clear explanation for this discrepancy.…”

“…Identification of infected animals by slicing muscles only from one side of the carcase, rather than the entire carcase musculature, would have missed 25% of the infected animals (2 of 8 infected). Chembensofu et al [20] found that slicing predilection sites plus only one side of the carcase musculature would have missed 16% of the infected animals in their study undertaken with naturally infected pigs in Zambia.…”

Performance of a Sandwich Antigen-Detection ELISA for the Diagnosis of Porcine Taenia solium Cysticercosis

“…Cross-reaction with T. hydatigena has been previously described by Dorny et al 30 and demonstrated in assays with HP10 Ag-ELISA 31 and B158/ B60 Ag-ELISA. 23 The present study confirms the crossreactivity, with 20 of the 22 T. hydatigena-infected pigs (90.9%) testing positive in 158C11/60H8 Ag-ELISA, 13 of which had saturating OD results (59.1%).…”

“…Many diagnostic studies of porcine cysticercosis to date have been performed in rural community settings where anecdotal evidence has suggested the presence of cysticercosis, but without a confirmation of cysts observed in pig carcass dissection, 22 or without enzyme-linked immunoelectrotransfer blot (EITB) antibody assessments. 23 In Latin America, there has been no prior in-depth study testing B158/B60 Ag-ELISA. Therefore, the aim of the present study was to assess the sensitivity, specificity, and Taenia hydatigena cross-reactivity of the B158/ B60 Ag-ELISA diagnostic test in pigs in a controlled environment by using MoAb IgG (158C11/60H8) to capture ES antigens in well-defined porcine serum samples.…”

Carotid Taenia solium Oncosphere Infection: A Novel Porcine Neurocysticercosis Model

“…Sera aliquots were evaluated for the presence of antibodies by LLGP-EITB, 25,26 and circulating parasite antigens by the B158/B160 monoclonal antibody-based enzyme-linked immunosorbent assay. 32 Antibody levels were expressed as the number of LLGP-EITB bands visualized, with the presence of one or more bands considered as positive. Antigen levels were expressed as the ratio of the optical density of the sample to a cutoff defined by negative control sera; antigen ratios > 1 were considered positive for the presence of circulating antigen.…”