The parasitological, immunological, and molecular diagnosis of human taeniasis with special emphasis on Taenia solium taeniasis

Human neurocysticercosis, caused by the larval stage of the tapeworm Taenia solium, is an important neurological disorder reported as a major cause of epilepsy. An important risk factor for neurocysticercosis is the presence of human T. solium carriers who, upon open defecation, disseminate tapeworm eggs, which are infective to both humans and pigs. In the latter, infection also results in cysticercosis, with associated health and economic consequences. Control of T. solium therefore depends greatly on accurate detection and treatment of carriers. However, the currently available direct diagnostic tests depend on detection, in feces, of either parasite stages or parasite antigens and genetic material. The former are low cost but lack adequate sensitivity and specificity; the latter are too expensive to be routinely utilized in endemic communities. Indirect tests based on antibody detection may only show exposure and not active infection. An ideal diagnostic test should be one that is low cost and is able to quickly and reliably detect tapeworm carriers so that appropriate treatment can be prescribed in order to eliminate the source of infection. Such a test remains elusive. Efforts should, therefore, be directed at formulation of a test that is not only sensitive and specific but also affordable for use in endemic countries.http://link.springer.com/journal/404752015-12-31hb201

Effects of ‘The Vicious Worm’ educational software on Taenia solium knowledge among key pork supply chain workers in Zambia

The neglected zoonotic cestode Taenia solium is endemic in many low- and middle-income countries, including Zambia. The parasite infects humans and pigs, inflicting high socioeconomic and disease burdens in endemic areas. Health education is regarded as an important component in T. solium control and previous studies indicate that ‘The Vicious Worm’ may be an effective T. solium health education tool for Tanzanian medical and agricultural professionals and Zambian primary school students. This study aimed to assess the effects of health education using ‘The Vicious Worm’ among Zambian pork supply chain workers, because the pork supply chain greatly influences food safety and security in Zambia. Half-day educational workshops using ‘The Vicious Worm’ and subsequent follow-up sessions were organized in the Lusaka and Katete districts of Zambia in March and April 2019. Questionnaires were administered before, after, and three weeks after the use of ‘The Vicious Worm’ to assess the program’s impact on knowledge uptake and short-term retention. Focus group discussions were conducted to assess the program’s user experience and the participants’ beliefs, attitudes, and insights. In total, 47 pork supply chain workers participated: 25 from Lusaka and 22 from Katete. Overall, knowledge about T. solium was significantly higher (p<0.001) both immediately after, and three weeks after the use of ‘The Vicious Worm’ compared to baseline knowledge. Focus group discussions indicated incipient attitudinal and behavioral change, as well as a positive reception of the software; with participants describing the software as simple, educative, and useful to share knowledge. The study results indicate that workshops using ‘The Vicious Worm’ may be effective for short-term T. solium health education among key pork supply chain workers. Follow-up studies are required to assess long-term effects, transfer of knowledge and behavioral change. However, educational interventions with ‘The Vicious Worm’ could be considered for integrated T. solium control programs in sub-Saharan Africa, especially if the educational content is further simplified and clarified

Perceptions and acceptability of piloted Taenia solium control and elimination interventions in two endemic communities in eastern Zambia

Infections with Taenia solium cause significant public health and economic losses worldwide. Despite effective control tools, long‐term sustained control/elimination of the parasite has not been demonstrated to date. Success of intervention programs is dependent on their acceptability to local communities. Focus group discussions (FGDs) and questionnaires (QS) were conducted in two study communities in eastern Zambia to assess local perceptions and acceptance of two piloted intervention strategies: one targeting pigs only (‘control’ study arm), and one integrated human‐ and pig‐based (‘elimination’) strategy. QS (n = 227) captured data regarding participation in project activities, knowledge and perceptions of T. solium and of the interventional drugs used in the study. FGDs (n = 18) discussed perceived advantages and disadvantages of the interventions and of the project's delivery and value. QS data revealed 67% of respondents participated in at least one educational activity, and 80% correctly identified at least one disease targeted by the education. All elimination study arm respondents (n = 113) had taken the human treatment, and 98% intended to do so next time. Most (70%) indicated willingness to pay for future treatments (median 0.20 USD per dose). Of pig‐owning respondents, 11/12 (92%) had allowed their pigs to be treated/vaccinated and all intended to do so again next time. Four pig owners indicated willingness to pay 0.10–0.50 USD per dose of treatment or vaccine. FGD feedback revealed positive perceptions of interventions; people reported improved health in themselves and their pigs, and fewer cysticerci in pork. Latrine use, hand washing, meat inspection and proper cooking of pork had reportedly increased since the program's inception. Preliminary assessment indicates that the piloted intervention methods are generally acceptable to the communities. The reported willingness of many respondents to pay for the medications would contribute to the feasibility of long‐term, government‐led T. solium intervention programs in future

Effects of ‘The Vicious Worm’ educational tool on Taenia solium knowledge retention in Zambian primary school students after one year

Background: Taenia solium is a neglected zoonotic parasite endemic throughout many low-income countries worldwide, including Zambia, where it causes human and pig diseases with high health and socioeconomic burdens. Lack of knowledge is a recognized risk factor, and consequently targeted health educational programs can decrease parasite transmission and disease occurrence in endemic areas. Preliminary assessment of the computer-based education program The Vicious Worm' in rural areas of eastern Zambia indicated that it was effective at increasing knowledge of T. solium in primary school students. The aim of this study was to evaluate the impact of The Vicious Worm' on knowledge retention by re-assessing the same primary school students one year after the initial education workshops. Methodology/Principal findings: Follow-up questionnaires were administered in the original three primary schools in eastern Zambia in 2017, 12 months after the original workshops. In total, 86 pupils participated in the follow-up sessions, representing 87% of the initial workshop respondents. Knowledge of T. solium at follow-up' was significantly higher than at the initial pre' questionnaire administered during the Vicious Worm workshop that took place one year earlier. While some specifics of the parasite's life cycle were not completely understood, the key messages for disease prevention, such as the importance of hand washing and properly cooking pork, remained well understood by the students, even one year later. Conclusions/Significance: Results of this study indicate that The Vicious Worm' may be an effective tool for both short- and long-term T. solium education of rural primary school students in Zambia. Inclusion of educational workshops using The Vicious Worm' could be recommended for integrated cysticercosis control/elimination programs in sub-Saharan Africa, particularly if the content is simplified to focus on the key messages for prevention of disease transmission. Author summary The zoonotic parasite Taenia solium, commonly known as the pork tapeworm, causes substantial public health and economic losses worldwide. It is commonly found in low-income countries where pigs are raised in areas of poor sanitation, including Zambia. The links between the parasite and its different disease forms in humans and pigs are not very well known, and ignorance of the parasite is a known risk factor for infection. Health education can significantly increase knowledge and awareness of the parasite and can inspire behavioral change that reduces disease transmission. The Vicious Worm' is a computer-based program designed to provide T. solium education in a fun and interactive way. We conducted educational workshops in three primary schools in rural areas of eastern Zambia, and preliminary assessment indicated that the Vicious Worm' educational content significantly improved students' knowledge of T. solium. We also conducted follow-up studies in the same students one year later, and discovered that the students' knowledge was still significantly higher than at baseline. We conclude that The Vicious Worm' may be a useful educational component to enable targeting of school students, and would recommend its inclusion in integrated T. solium control programs in future

An epidemiological study of human tapeworm infections in the Eastern Province of Zambia

Neurocysticercosis is an important neglected parasitic zoonoses caused by the metacestode stage of Taenia solium. The infection is endemic in most developing countries of Africa, Asia and Latin America. Most studies on the parasite in endemic regions of sub-Saharan Africa have been carried out in pigs with little or no data available on human taeniosis/cysticercosis. The aim of this thesis was to provide an understanding of the epidemiology of human taeniosis/cysticercosis in the Eastern province of Zambia where porcine cysticercosis is endemic, and to assess the performance of the existing diagnostic tests under field conditions. Community-based cross sectional and longitudinal studies (Chapters 3 and 4 respectively) were carried out in two rural communities of Eastern Zambia to obtain the prevalence of taeniosis/cysticercosis and incidence of cysticercosis respectively as well as to study related risk factors. Given the constraints associated with blood collection in epidemiological studies, the use of urine, which is better accepted by communities, as a diagnostic specimen for human cysticercosis in field conditions, was evaluated (Chapter 6). Furthermore, three techniques, coproscopy, copro-Ag ELISA and copro-PCR, for the detection of taeniosis in stool samples were compared (Chapter 7). Prevalences of 6.3% (45/718) and 5.8% (41/708) were determined for taeniosis based on copro-Ag ELISA and cysticercosis using Ag-ELISA assays, respectively in the study area in Petauke district with an increased frequency of cysticercosis positive individuals from the age of 30 onwards. In a neighbouring district, Katete, higher prevalences of 12.0% (27/227) and 14.5% (155/1069) were determined for taeniosis and cysticercosis using the same tests, respectively, but no significant relationship with age could be identified. A higher prevalence rate of cysticercosis based on sero-Ab analysis (EITB) ranging between 33.5 (54/161) and 38.5% (62/161) was recorded in the Katete study. The overall incidence rate for cysticercosis in Katete was determined to be 6.2% after 12 months. The longitudinal study revealed that even though many people were exposed to the infection as indicated by the antibody and antigen presence, few actually established active infections. This highlighted the importance of a multitude of factors, and not just exposure, that play a role in the establishment of infection and/or symptomatology. Classification and regression analyses (CART) revealed that older individuals and those that came from households with many inhabitants were associated with higher prevalence rates of infection, listing these disease determinants as being very important for infection, and as such potential focus points of control programmes. Moreover, the CART highlighted differences in important disease determinants in neighbouring endemic areas, indicating the complexity of identifying optimal control measures. Evaluation of the urine Ag-ELISA revealed a lower specificity as compared to the serum Ag-ELISA which was more pronounced testing the Zambian samples (78.6%) than the Ecuadorian samples (88.4%). Therefore, aspects of specificity have to be addressed for urine to be used as a sample in field conditions. Comparison of three different diagnostic tests for taeniosis showed coproscopy to be the least sensitive (52.5%) and the copro-PCR the most specific (99.6%). Given the findings of this study, control of the tapeworm remains a challenge. It is proposed that, as there is a lack of knowledge of the parasite at all levels; health education should always be included in control programmes. It would be the best option in the long term, and would also determine the success of other more short term control measures as the more people get to know about the importance of the parasite the more they will accept control measures such as improved sanitation, vaccination and/or treatment of pigs and treatment of adult tapeworm carriers. Chapters 3, 4 and 5 of this thesis demonstrated that human T. solium taeniosis/cysticercosis is endemic in the study area. It also indicated the need for further studies on transmission dynamics and burden of disease on the local people, as well as further improvement of diagnostic techniques. Finally, given the complexity of the disease determinants, as highlighted in chapter 5, the control of T. solium in our study area depends on multi-sectoral collaboration including the medical, veterinary and other relevant sectors as well as effective engagement of the affected communities.Thesis (PhD)--University of Pretoria, 2012.Veterinary Tropical DiseasesPhDUnrestricte