Risk Factors of Porcine Cysticercosis in the Eastern Cape Province, South Africa

There is a high prevalence of Taenia solium taeniosis/cysticercosis in humans and pigs in the Eastern Cape Province (ECP) of South Africa. The objective of this study was to identify risk factors of porcine cysticercosis in select districts of the ECP. Data were collected in 2003 by interviewing 217 pig producers from the area. Blood samples were collected from 261 of their pigs, which were tested using two enzyme-linked immunosorbent assays (ELISA) for the presence of antibodies to cysticercosis. Frequencies of both owner- and pig-level characteristics were determined. For pig-level analysis, all bivariable and multivariable associations were determined using the surveylogistic procedure of the SAS/STAT® software to accommodate for the intraclass correlation that exists for clusters of pigs within one owner and for clusters of owners within a district. All tests for significance were performed at the α = 0.05 level, and adjusted odds ratios (aOR) and 95% confidence intervals (CI) were determined. Among the respondents, 48% of their households lacked a latrine, 98% slaughtered pigs at home, and 99% indicated that meat inspection services were not available. On bivariable analysis, there was a significant association between porcine infection and district (p = 0.003), breed (p = 0.041) and the absence of a latrine (p = 0.006). On multivariable analysis, the absence of a latrine was the only variable significantly associated with porcine infection (aOR = 1.89; 95% CI = 1.07, 3.35) (p = 0.028). The increased odds of porcine infection with households lacking a latrine contributes to our understanding of the transmission of this parasite in the ECP. Determining and addressing the risk factors for T. solium infection can potentially lower the very high prevalence in humans and pigs in this endemic area

Final multivariable model for the association between owner/pig characteristics and cysticercosis¹ infection in pigs from Eastern Cape Province (South Africa) (N = 256)².

1<p>Determined using two enzyme-linked immunosorbent assays (B158/B60 Ag-ELISA <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0037718#pone.0037718-Dorny1" target="_blank">[18]</a> and HP10 Ag-ELISA <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0037718#pone.0037718-Harrison1" target="_blank">[19]</a>–<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0037718#pone.0037718-Harrison2" target="_blank">[20]</a>). Infection was defined as a positive result on either of these two ELISA tests.</p>2<p>Analyses were performed using the surveylogistic procedure of the SAS/STAT® software to simultaneously adjust for clusters of pigs within one owner and for clusters of owners within district of residence.</p>3<p>CI = Confidence interval.</p>4<p>Had missing values for n = 7.</p>5<p>Had missing values n = 2. Other includes other pure bred breeds.</p

Bivariable associations between owner/pig characteristics and cysticercosis¹ infection in pigs from Eastern Cape Province (South Africa) (N = 256)².

§<p>- not determined, due to cells with zero counts.</p>‵1<p>Determined using two enzyme-linked immunosorbent assays (B158/B60 Ag-ELISA <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0037718#pone.0037718-Dorny1" target="_blank">[18]</a> and HP10 Ag-ELISA <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0037718#pone.0037718-Harrison1" target="_blank">[19]</a>–<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0037718#pone.0037718-Harrison2" target="_blank">[20]</a>). Infection was defined as a positive result on either of these two ELISA tests.</p>2<p>Analyses were performed using the survey logistic procedure of the SAS/STAT® software to adjust for clusters of pigs within one owner.</p>3<p>(%) refers to row percentages.</p>4<p>CI = Confidence interval.</p>5<p>Type 3 wald statistic had a <i>p</i>-value of 0.003.</p>6<p>Type 3 wald statistic had a <i>p</i>-value of 0.041. Had missing values for n = 7. Other includes other pure bred breeds.</p>7<p>Had missing values for n = 2.</p>8<p>Had missing values for n = 1.</p>9<p>Had missing values for n = 3. Measles are cysts, from the larvae of <i>Taenia solium</i>, observed in pig meat.</p>10<p>Had missing values for n = 2.</p>11<p>Had missing values for n = 8.</p>12<p>Had missing values for n = 2.</p>13<p>Had missing values for n = 2.</p><p>Note: no significant associations (<i>p</i>≥0.10) were found between porcine infection and owner or household variables (sex, age, education, years of experience managing pigs, keeping pigs for home consumption), or with awareness questions (knowing what cysts in pork were, knowing how pigs acquired tapeworm, knowing how humans were infected with tapeworm or how to recognize infection, or had heard of persons in the village suffering with epilepsy, headache, or madness).</p