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

Rosina Claudia Krecek,Peter Mullineaux Schantz,Lulama Ntanjana,Stephen Rakem Werre,Arve Lee Willingham,Lynne Margaret Michael,Hamish Mohammed,Liesl Morey,Charles Jonathan Woodrow

doi:10.1371/journal.pone.0037718

Abstract

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.

Highlights

A high prevalence of Taenia solium taeniosis/cysticercosis is reported from some countries in Africa whereas limited or no information is available from others [1,2]
South Africa has the largest number of pigs in southern Africa, and human and porcine cysticercosis has been recognized as a problem in the country for many decades [2,4,5,6,7]
When we employed a Bayesian approach to estimate the true prevalence of porcine cysticercosis in the Eastern Cape Province (ECP), we found the level to be very high [10]

Summary

Introduction

A high prevalence of Taenia solium taeniosis/cysticercosis is reported from some countries in Africa whereas limited or no information is available from others [1,2]. Humans and pigs acquire cysticercosis by ingesting T. solium eggs. South Africa has the largest number of pigs (most being raised under commercial conditions) in southern Africa, and human and porcine cysticercosis has been recognized as a problem in the country for many decades [2,4,5,6,7]. An extensive national abattoir study in 1937 reported a prevalence of 25% of porcine cysticercosis and an incidence of 10% in the Eastern Cape Province (ECP) of South Africa [1,2]. The number of pigs continues to increase throughout southern Africa [3,4,5,6,7]. Projections for pork consumption in the developing regions of the world for the period 1993–2020 are anticipated to double (39 to 81 million tonnes) compared to a marginal increase in developed regions (38 to 41 million tonnes) [8]

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