Implementation of a practical and effective pilot intervention against transmission of Taenia solium by pigs in the Banke district of Nepal

The Frequency of Porcine Cysticercosis and Factors Associated with Taenia solium Infection in the Municipality of Tuchín-Córdoba, Colombia

Taeniasis and cysticercosis are parasitic infections that affect humans and pigs. Their global distribution constitutes a serious public health issue with significant implications for pork production. The purpose of this study was to evaluate the presence of porcine cysticercosis in backyard swine from 42 indigenous communities throughout Tuchín-Córdoba, Colombia. Between December 2020 and March 2021, free-range pigs (n = 442) were assessed using the ELISA cysticercosis Ag test; 85 pigs were examined through sublingual visual evaluation, and 4 slaughtered pig carcasses were subjected to standard operation inspection. The collected cysticercus underwent histological and PCR analysis. Furthermore, 192 surveys of knowledge, attitudes, and practices (KAP) were used to identify the factors that facilitate infection transmission. Serological investigation revealed that 9.7% (46/472) of the animals were positive for cysticerci Ag. Sublingual inspection identified cysticercus in 28.7% (25/87) of the animals, while PCR analysis indicated that cysticercus corresponded to the T. solium American/African genotype. The factors associated with T. solium infection in the pigs in the surveyed areas numbered 14. The majority are associated with factors that promote the active persistence of Taenia solium's life cycle in an area, such as lack of environmental sanitation, a lack of coverage or care for drinking water and wastewater treatment services, and no solid waste disposal.

Recent history of Veterinary Immunology in Australia

This Commentary article reviews the history of veterinary immunology in Australia from the 1980s and discusses the key people and areas of research during this period.

Insights into the diagnosis, vaccines, and control of Taenia solium, a zoonotic, neglected parasite

Taenia solium taeniasis/cysticercosis (TSTC) is a foodborne, zoonotic neglected tropical disease affecting predominately low- and middle-income countries. Humans are definitive hosts for T. solium, whereas pigs act as intermediate hosts. Taeniasis, i.e. intestinal infection with adult T. solium in the human host, occurs through ingestion of undercooked pork infected with the larval stage (porcine cysticercosis, PCC). Human cysticercosis occurs after humans ingest T. solium eggs, acting as accidental intermediate hosts. Migration of cysticerci to the human brain results in neurocysticercosis (NCC), manifesting in a variety of clinical symptoms, most notably epilepsy. NCC is the leading cause of acquired epilepsy cases in endemic areas. PCC results in reduced pork value because of condemnation or the risk of condemnation of the meat. Available serological diagnostic tests for porcine and human cysticercosis are characterized by low sensitivity and are not cost-effective. An effective vaccine for T. solium cysticercosis in pigs has been developed, although it is not yet commercially available in all endemic countries, and still no vaccine is available for use in humans. This primer highlights the recent development in the field of diagnostic tests and vaccine production and explores possible strategies for future control and eradication of T. solium. In the absence of highly specific diagnostic tests and human vaccines, treatment of infected pigs and tapeworm carriers and prevention of disease transmission remain the principal means to interrupt the zoonotic cycle of T. solium in endemic countries.

Aggregation of Taenia solium cysticerci in pigs: Implications for transmission and control

Parasite aggregation within hosts is a fundamental feature of parasite distributions, whereby the majority of parasites are harboured by a minority of hosts. Parasite aggregation can influence their transmission and hence control. In this narrative review, possible sources of aggregation of Taenia solium cysticerci in pigs are discussed, along with implications for control of the parasite. While heavy T. solium infections in pigs could most likely be associated with ingestion of high doses of infective parasite eggs, consistent with coprophagic behaviour of pigs, lighter infections indicate a role of indirect routes of transmission to pigs, mostly from lower infection doses. Light infections are likely to be missed by commonly used diagnostic methods - tongue examination or meat inspection - and end up in the food chain. Hence, they entail a 'hidden' risk and are of a particular public health concern, especially in areas where meat is consumed raw or undercooked. To be effective and sustainable, control strategies against T. solium likely require a broader understanding of, and consideration for parasite transmission dynamics. More importantly, a holistic One Health approach incorporating interventions on humans, pigs and the environment will likely have a larger, more successful and sustainable impact.

Food safety interventions in low- and middle-income countries in Asia: A systematic review

Effective and sustainable interventions are necessary for long-term improvement of food safety. This review provides a summary of food safety interventions evaluated in selected low- and middle-income countries in Asia between 2000 and 2020. A systematic screening of published articles from PubMed and CabDirect databases was carried out with the aid of Rayyan QCRI software. A total of 25 studies were considered in the review. A 'before and after' study design was the most frequently used design (64%), while five studies (20%) used a randomized control trial (RCT) design. Interventions applied focused on training to improve knowledge, attitudes, and practices (KAP) towards safe food (60%) or on specific technologies (40%). Nine of the 25 studies were specific on the value chain considered: cattle (1), poultry (1), pigs (4) and fish value chains (3). Except for one study, all interventions reported some level of success; 17 were rated as having a high level of success, defined differently across studies. However, there is a clear evidence gap for the efficacy and cost-effectiveness of food safety interventions in market settings, both consumer- and vendor-facing. A rigorous and standardized assessment of intervention effectiveness and sustainability is recommended, to not only identify areas of improvement, but also to ensure scaling of interventions with demonstrated evidence of success and sustainability.

Neurocysticercosis control for primary epilepsy prevention: a systematic review

Neurocysticercosis (NCC) is a leading cause of preventable epilepsy in lower- and upper- middle-income countries (LMICs/UMICs). NCC is a human-to-human transmitted disease caused by ingestion of Taenia solium eggs from a Taenia carrier. T. solium infection control is the key to reduce NCC incidence. This systematic review aims to identify T. solium control programs that can provide frameworks for endemic areas to prevent NCC-related epilepsy. A systematic search was conducted in PubMed/Medline, Embase, Web of Science, and Cochrane Library databases in March 2021. After title and abstract review, full texts were screened for qualitative analysis. Additional articles were identified via citation search. Of 1322 total results, 34 unique studies were included. Six major intervention types were identified: national policy (8.8%), community sanitation improvement (8.8%), health education (8.8%), mass drug administration (29.4%), pig vaccination and treatment (32.4%), and combined human and pig treatment (11.8%). Overall, 28 (82.4%) studies reported decreased cysticercosis prevalence following the intervention. Only health education and combined human and pig treatment were effective in all selected studies. NCC causes preventable epilepsy in LMICs/UMICs and its incidence can be reduced through T. solium control. Most interventions that disrupt the T. solium transmission cycle are effective. Long-term sustained results require comprehensive programs, ongoing surveillance, and collaborative effort among multisectoral agencies.

Neurocysticercosis: an update on diagnosis, treatment, and prevention

Neurocysticercosis (NCC) is an important cause of neurological disease worldwide, including imported cases in nonendemic countries.

PURPOSE OF REVIEW

The purpose of this review is to update information on diagnosis, management, and prevention of neurocysticercosis.

RECENT FINDINGS

WHO and Infectious Diseases Society of America/American Society of Tropical Medicine and Hygiene guidelines emphasize the importance of corticosteroids and antiparasitic drugs for viable parenchymal disease and single enhancing lesions. Subarachnoid NCC is associated with a high fatality rate unless optimally treated. Advances in subarachnoid NCC include use of prolonged antiparasitic and anti-inflammatory courses and the increasing use of antigen-detection and quantitative PCR assays in diagnosis and follow-up. Emerging data support the safety and efficacy of minimally invasive surgery in ventricular cases. Calcified neurocysticercosis continues to be associated with a high burden of disease. Field studies are demonstrating the feasibility of eradication using a combination of mass chemotherapy for human tapeworms and vaccination/treatment of porcine cysticercosis.

SUMMARY

NCC remains an important and challenging cause of neurological disease with significant morbidity despite advances in treatment and prevention.

Advances in the treatment, diagnosis, control and scientific understanding of taeniid cestode parasite infections over the past 50 years

In the past 50 years, enormous progress has been made in the diagnosis, treatment and control of taeniid cestode infections/diseases and in the scientific understanding thereof. Most interest in this group of parasites stems from the serious diseases that they cause in humans. It is through this lens that we summarize here the most important breakthroughs that have made a difference to the treatment of human diseases caused by these parasites, reduction in transmission of the taeniid species associated with human disease, or understanding of the parasites' biology likely to impact diagnosis or treatment in the foreseeable future. Key topics discussed are the introduction of anti-cestode drugs, including benzimidazoles and praziquantel, and the development of new imaging modalities that have transformed the diagnosis and post-treatment monitoring of human echinococcoses and neurocysticercosis. The availability of new anti-cestode drugs for use in dogs and a detailed understanding of the transmission dynamics of Echinococcus granulosus sensu lato have underpinned successful programs that have eliminated cystic echinococcosis in some areas of the world and greatly reduced the incidence of infection in others. Despite these successes, cystic and alveolar echinococcosis and neurocysticercosis continue to be prevalent in many parts of the world, requiring new or renewed efforts to prevent the associated taeniid infections. Major advances made in the development of practical vaccines against E. granulosus and Taenia solium will hopefully assist in this endeavour, as might the understanding of the parasites' biology that have come from an elucidation of the nuclear genomes of each of the most important taeniid species causing human diseases.

Vaccine for a neglected tropical disease Taenia solium cysticercosis: fight for eradication against all odds

INTRODUCTION

Taenia solium infection is among the 17 most neglected tropical diseases identified by World Health Organization and to be eradicated by 2030. This parasite infects the central nervous system (Neurocysticercosis [NCC]) and intestine [Taeniasis]). NCC is the most frequent cause of acquired epilepsy in endemic regions and Taeniasis is responsible for the widespread malnutrition and abdominal discomfort among children. Epilepsy caused by T. solium is preventable and the total elimination of NCC can be achieved by good hygiene, mass therapy, and most importantly vaccination of pigs or humans. Vaccine for pig is available but not widely in use and for humans it's still elusive.

AREA COVERED

Several vaccine candidates for porcine cysticercosis have been tried like TSOL18, SP3Vac, KETc7, TSOL45, etc. with good success in the limited field trial. This review highlights some seminal contributions for the anti-cestode vaccine, the associated challenges, current status, suggestive future directions, and the need of vaccine for human use.

EXPERT OPINION

Though several vaccines are available, none is being widely used due to lack of awareness, economic constraints, accessibility, etc. Hence, there is a need for a newer, economic, and reliable vaccine for humans or pigs use to reduce the disease burden.

Demand for Taenia solium Cysticercosis Vaccine: Lessons and Insights From the Pig Production and Trading Nodes of the Uganda Pig Value Chain

Taenia solium cysticercosis disease remains a key challenge to the pig sector in low- and middle-income countries in sub-Saharan Africa, Latin America and South East Asia, resulting in both economic losses and public health impacts. The World Health Organization has ranked it first on the global scale of foodborne parasites. A One Health approach has been recommended for reduction of infection pressure and eradication in the longer term. A new vaccine TSOL18 (Cysvax™), applied in combination with oxfendazole (Paranthic 10%™), a dewormer drug has been developed and field tested for the control of T. solium cysticercosis, with high potential to break the disease cycle. It is however unclear whether the products can be marketed through a market driven approach, and if smallholder pig farmers would be willing to take up and pay for the vaccine–oxfendazole combination. A choice experiment methodology was used to assess the potential demand and willingness to pay for the vaccine—oxfendazole combination by Ugandan smallholder pig farmers, and demand for vaccinated pigs by pig traders. The results showed that farmers highly valued quality assurance attributes and were not keen on the vaccine if there were no associated returns in the form of premium price for vaccinated pigs during sales. They were willing to pay US$ 2.31 for the vaccine if it resulted in a premium price for vaccinated pigs. Furthermore, they preferred an accompanying vaccine viability detector as part of its quality assurance. The pig traders on the other hand preferred high carcass weight of pigs, potentially achieved by using oxfendazole. The results show that unless the pig market systems pay a premium price for vaccinated pigs, and quality assurance systems guarantee quality vaccine, uptake of the TSOL18 vaccine and oxfendazole by farmers through market mechanisms may be unsuccessful. The current pig marketing system does not reward food safety, the focus is mainly on carcass weight. Alternative delivery mechanisms for the vaccine through a mix of private–public investments needs to be explored, as the benefits of vaccinated pigs are societal and include reduction and elimination of neurocysticercosis in the long run.

Taenia solium taeniasis/cysticercosis: From parasite biology and immunology to diagnosis and control

Infection with the pork tapeworm (Taenia solium) is responsible for a substantial global burden of disease, not only restricted to its impact on human health, but also resulting in a considerable economic burden to smallholder pig farmers due to pig cysticercosis infection. The life-cycle, parasitology and immunology of T. solium are complex, involving pigs (the intermediate host, harbouring the larval metacestode stage), humans (the definitive host, harbouring the adult tapeworm, in addition to acting as accidental intermediate hosts) and the environment (the source of infection with eggs/proglottids). We review the parasitology, immunology, and epidemiology of the infection associated with each of the T. solium life-cycle stages, including the pre-adult/adult tapeworm responsible for human taeniasis; post-oncosphere and cysticercus associated with porcine and human cysticercosis, and the biological characteristics of eggs in the environment. We discuss the burden associated, in endemic settings, with neurocysticercosis (NCC) in humans, and the broader cross-sectoral economic impact associated both with NCC and porcine cysticercosis, the latter impacting food-value chains. Existing tools for diagnostics and control interventions that target different stages of the T. solium transmission cycle are reviewed and their limitations discussed. Currently, no national T. solium control programmes have been established in endemic areas, with further work required to identify optimal strategies according to epidemiological setting. There is increasing evidence suggesting that cross-sectoral interventions which target the parasite in both the human and pig host provide the most effective approaches for achieving control and ultimately elimination. We discuss future avenues for research on T. solium to support the attainment of the goals proposed in the revised World Health Organisation neglected tropical diseases roadmap for 2021-2030 adopted at the 73rd World Health Assembly in November 2020.

Control trial of porcine cysticercosis in Uganda using a combination of the TSOL18 vaccination and oxfendazole

Background

Neurocysticercosis caused by Taenia solium when the parasite lodges in the central nervous system, is an important cause of human seizures and mortality in sub-Saharan Africa. The parasite is prevalent in many regions of Uganda. Pigs are intermediate hosts for T. solium, and we evaluated a T. solium control program in pigs, involving vaccination of pigs with the TSOL18 vaccine and treatment with oxfendazole.

Methods

The study was conducted in two districts of Eastern Uganda involving the rural village communities of Bukedea (intervention area) and Kumi (control area) during 2016–2017. Seven hundred and thirty-four households were enrolled in the study. Pigs in the intervention area received intramuscular immunizations with TSOL18 (Cysvax™) and an oral medication with 30 mg/kg oxfendazole (Paranthic™) at approximately 3-monthly intervals for 18 months. Porcine cysticercosis was evaluated by post-mortem examination. At the beginning of the study, 111 pigs were examined. In an interim evaluation in the intervention area, 55 pigs were evaluated 12 months after starting the project. At the end of the study approximately 3 months after the final intervention, 55 pigs from the intervention area and 56 pigs from the control area were evaluated.

Results

The prevalence of porcine cysticercosis for the two sites was 16.2% at the beginning of the study (17.2% in the intervention area and 15.1% in the control area) with no statistically significant difference (P = 0.759) between the two study sites. Among the 110 animals assessed from the intervention site (55 at the interim evaluation and 55 at the final evaluation), no pig with viable T. solium cysts was found. There was a statistically significant difference between the prevalence at baseline (17.2%) and at the end of the study (0%) in the intervention area (P = 0.001) and a statistically significant difference between the intervention (0%) and control areas (5.4%) (P = 0.041) at the end of the study.

Conclusions

Three-monthly concurrent vaccination of pigs with the TSOL18 vaccine and medication with oxfendazole eliminated T. solium transmission by the animals involved in the study. Application of vaccination with medication in pigs has the potential to reduce transmission of T. solium in Uganda and other endemic countries.

Socio-economic and health costs of porcine/human cysticercosis, neurocysticercosis and epilepsy to small-scale pig producers in Tanzania

BACKGROUND

Porcine cysticercosis, human cysticercosis, neurocysticercosis, and epilepsy pose a serious public health risk and lead to economic losses to the small-scale pig farmers in Tanzania's rural areas. It also resulted in lowering the pig's prices, high treatment expenses, lower labour productivity, and social discrimination. In Tanzania, small-scale pig producers are unaware of the methods that are used to manage and prevent the diseases associated with Taenia solium.

MAIN BODY

The main goal of the reviewed article was to investigate the socio-economic and health costs of porcine/human cysticercosis, neurocysticercosis, and epilepsy on small-scale pig producers in Tanzania. Several search engines yielded 80 peer-reviewed publications, 44 of which were considered to be relevant to the study. Taenia solium cysticercosis has been reported to cause huge financial losses in the management of pigs posing a burden in terms of vaccination and treatment.

CONCLUSION

The information on porcine/human cysticercosis, neurocysticercosis, and epilepsy is still insufficient in Tanzania. Poor habits, negative perceptions, and attitudes are the result of this misinformation. This review suggests that health education should be emphasized as one of the intervention methods for eliminating all forms of cysticercosis and epilepsy in Tanzania to promote and increase awareness about all forms of cysticercosis and epilepsy in rural areas.

Zoonotic Taenia infections with focus on cysticercosis due to Taenia solium in swine and humans

Zoonotic taeniasis caused by the adult stage of Taenia solium, Taenia saginata or Taenia asiatica are considered neglected tropical diseases by the World Health Organization. The life cycle of these 3 metazoan species is very similar and includes an intermediate host: pigs in the case of T. solium and T. asiatica, and cattle in the case of T. saginata. By eating meat (pork/T. solium, T. asiatica; beef/T. saginata) containing live cysticerci, humans develop taeniasis, which is practically asymptomatic but is the main risk factor for intermediate hosts to become infected. T. saginata causes bovine cysticercosis, while T. solium and T. asiatica cause swine cysticercosis, of veterinary and economic importance. T. solium cysticerci cause neurological disease in humans: neurocysticercosis. Cysticerci develop after ingesting microscopic eggs released from a human tapeworm carrier. Here we describe the life stages of the parasites, diagnosis, pathogenesis, symptomatology of neurocysticercosis, and prevention and control measures. Highlighting the need to validate diagnostic tools, treatments and vaccination in endemic areas, with the challenge of addressing the most vulnerable populations that lack resources. If people understand the transmission route, avoid eating uncooked or insufficiently cooked meat and have adequate hygienic habits, the life cycle of the 3 zoonotic Taenia species may be interrupted. In addition, we describe the growing field of immune response and immunomodulation elicited by the parasites, which may provide essential tools for diagnosis, treatment, control of taeniasis/cysticercosis, as well as for identification of parasite-derived immunomodulators that could aid in the treatment of emerging inflammatory diseases worldwide.

Force-of-infection of Taenia solium porcine cysticercosis: a modelling analysis to assess global incidence and prevalence trends

The World Health Organization (WHO) called, in 2012, for a validated strategy towards Taenia solium taeniasis/cysticercosis control and elimination. Estimating pig force-of-infection (FoI, the average rate at which susceptible pigs become infected) across geographical settings will help understand local epidemiology and inform effective intervention design. Porcine cysticercosis (PCC) age-prevalence data (from 15 studies in Latin America, Africa and Asia) were identified through systematic review. Catalytic models were fitted to the data using Bayesian methods, incorporating uncertainty in diagnostic performance, to estimate rates of antibody seroconversion, viable metacestode acquisition, and seroreversion/infection loss. There was evidence of antibody seroreversion across 5 studies, and of infection loss in 6 studies measured by antigen or necropsy, indicating transient serological responses and natural resolution of infection. Concerted efforts should be made to collect robust data using improved diagnostics to better understand geographical heterogeneities in T. solium transmission to support post-2020 WHO targets.

Taenia solium proteins: a beautiful kaleidoscope of pro and anti-inflammatory antigens

Background: Neurocysticercosis (NCC) is an acquired infection of central nervous system associated with epileptic seizures. The parasite 'Taenia solium' causes this disease and has a complex life cycle and molts into various stages that influence the host-parasite interaction. The disease has a long asymptomatic phase with viable cyst and degeneration of cyst and leaking cyst fluid has been associated with symptomatic phase. The parasite proteome holds the answers and clues to this complex clinical presentation and hence unraveling of proteome of parasite antigens is needed for better understanding of host-parasite interactions. Objective: To understand the proteome make-up of T. solium cyst vesicular fluid (VF) and excretory secretory proteins (ESPs). Methodology: The VF and ESPs for the study were prepared from cyst harvested from naturally infected swine. The samples were prepared for nano LC-MS by in-tube digestion of proteins. The spectra obtained were annotated and enrichment analysis was performed and in silico analysis was done. Results: T. solium VF and ESPs have 206 and 247 proteins of varied make-up including pro-inflammatory and anti-inflammatory nature. Conclusions: Due to varied make-up of VF and ESPs it can generate complex humoral and cellular immune response.

TSOL18 vaccine and oxfendazole for control of Taenia solium cysticercosis in pigs: A field trial in endemic areas of Tanzania

A field trial was conducted in Tanzania to determine the effectiveness of TSOL18 vaccine used concurrently with oxfendazole (OFZ), and of OFZ alone, on T. solium cysticercosis determined by organ and half carcase dissection of slaughter age pigs. This study followed a quasi-experimental group design. Suitable trial sites were randomly allocated to either treatment group T1 (OFZ treatment alone [30mg/kg, Paranthic 10%]) or T2 (TSOL18 [1ml, Cysvax] plus OFZ). Three 4-monthly treatments were administered to eligible pigs. A random selection of pigs were necropsied at baseline and at endline, 2–3.5 months after the final treatment. Additionally, untreated pigs from T1 and T2 areas were necropsied at endline to provide contemporaneous comparisons with T1 and T2 pigs. Baseline prevalence of viable T. solium cysticerci for T1 was 25.5% (Exact 95% CI: 13.9, 40.3; n = 12/47), and for T2 was 12.0% (CI: 6.4, 20.0; n = 12/100). At endline, prevalence was 2.8% for T1 (CI: 0.1, 14.5, n = 1/36) and 0% for T2 (CI: 0, 4.7, n = 0/77). Among untreated pigs, three had viable cysticerci, one from T1 area (12.5%, CI: 0.3, 52.7; n = 1/8) and two from T2 area (5.7%, CI: 0.7, 19.2, n = 2/35). Fisher’s exact test showed significant changes in prevalence from baseline to endline in both groups (T1: p = 0.005, T2: p = 0.001). Firth’s penalized Maximum Likelihood method suggested the changes were not significant relative to their controls (T1: p = 0.245, T2: p = 0.076). These findings showed a significant reduction in the prevalence of viable cysticerci from baseline to endline after both interventions. However, the changes could not be definitively attributed to the interventions due, in part, to small numbers of control pigs. Concurrent administration of the TSOL18 and OFZ cleared infection among assessed pigs whereas infection remained after treatment with OFZ only. Further studies including larger sample sizes would be required for more definitive conclusions. A One Health approach is recommended for rapid and sustainable impact.

The pork tapeworm T. solium affects the health and income of poor people in endemic areas. A pig vaccine—TSOL18, and a drug—oxfendazole (OFZ) present options for its control. In this study we assessed the effectiveness of the two tools against the parasite in pigs. We provided one group of pigs (T1) with a concurrent administration of TSOL18 and OFZ, and another group (T2) with OFZ only, in three rounds at 4 months intervals. We compared infection prevalence before and after the interventions by detection of cysticerci through carcase dissections. In addition, untreated pigs from the T1 and T2 areas were also sacrificed to serve as controls. We found a significant reduction in prevalence within the groups after the interventions. However, the reductions were not significant when compared with the reductions in the control groups, hence could not be definitively attributed to the interventions. Further, concurrent administration of TSOL18 and OFZ cleared infection among assessed pigs whereas OFZ alone did not clear the infection. Further studies would be required to make more definitive conclusions. We advocate for a One Health approach for a more rapid and sustainable impact.

Taenia solium insulin receptors: promising candidates for cysticercosis treatment and prevention

Insulin signaling pathway is an ancient and highly conserved pathway known to play critical roles in cell growth, control and metabolic regulation. In this study, we identified and characterized two insulin receptor genes (TsIR-1316 and TsIR-4810) from Taenia solium. TsIR-1316 was grouped with E. multilocularis insulin receptor (EmIR-1) and TsIR-4810 was closer to Taenia pisiformis insulin-like growth factor receptor (TpIR) on the same branch with a very high bootstrap value. TsIR-1316 was located on the integument of larvae and adult worms, as well as the ovary of adults and eggs. Alternatively, TsIR-4810 was located in the parenchyma and reproductive organs of the adult worms. By using in vitro cultivation systems with Cysticercus pisiformis as a model, we demonstrated that anti-TsIRs-LBD antibodies could effectively block the insulin signaling pathway, resulting in reduced phosphorylation of the insulin receptor as well as lower levels of glucose uptake and glycogen synthesis. The rabbits immunized with TsIR-1316-LBD, TsIR-4810-LBD and TsIR-1316-LBD + TsIR-4810-LBD produced protection against infection of T. pisiformis as demonstrated by a 94.6%, 96% and 80% reduction of establishment of larvae, respectively. These data suggested that TsIR-1316-LBD and TsIR-4810-LBD are promising vaccine candidates or novel drug targets against swine cysticercosis.

Mimotope-based antigens as potential vaccine candidates in experimental murine cysticercosis

Human cysticercosis is a public health problem caused by Taenia solium metacestodes; thus, eradication of T. solium transmission by vaccination is an urgent requirement. The Cc48 mimotope from T. solium cysticerci was tested expressed in phage particles (mCc48) and chemically synthesized (sCc48) as a vaccine candidate in experimental murine cysticercosis. For this, BALB/c mice were immunized with mCc48 (G1; n = 40), sCc48 (G2; n = 40) and phosphate-buffered saline (PBS) (G3; n = 40, positive control) and challenged with Taenia crassiceps metacestodes. Another PBS group without parasite challenge was used as a negative control (G4; n = 40). Mice were sacrificed 15, 30, 45 and 60 days post-infection for cysticerci and serum collection. Immunization efficacy was determined by cysticerci counting. Serum samples were tested by ELISA to verify antibody (IgM, IgG, IgA and IgE) and cytokine (IFNγ and IL-4) levels. The sCc48 achieved the highest rates of protection and efficacy (90 and 98%, respectively). The group immunized with mCc48 presented the highest reactivity for IgM, IgG and IgE. All groups presented IL-4, but IFNγ was quite variable among groups. The protection induced by sCc48 synthetic peptide supports further studies of this mimotope as a potential vaccine candidate against cysticercosis.

Use of Veterinary Vaccines for Livestock as a Strategy to Control Foodborne Parasitic Diseases

Foodborne diseases (FBDs) are a major concern worldwide since they are associated with high mortality and morbidity in the human population. Among the causative agents of FBDs, Taenia solium, Echinococcus granulosus, Toxoplasma gondii, Cryptosporidium spp., and Trichinella spiralis are listed in the top global risk ranking of foodborne parasites. One common feature between them is that they affect domestic livestock, encompassing an enormous risk to global food production and human health from farm to fork, infecting animals, and people either directly or indirectly. Several approaches have been employed to control FBDs caused by parasites, including veterinary vaccines for livestock. Veterinary vaccines against foodborne parasites not only improve the animal health by controlling animal infections but also contribute to increase public health by controlling an important source of FBDs. In the present review, we discuss the advances in the development of veterinary vaccines for domestic livestock as a strategy to control foodborne parasitic diseases.

Taenia solium Cysticercosis and Its Impact in Neurological Disease

Taenia solium neurocysticercosis (NCC) is endemic in most of the world and contributes significantly to the burden of epilepsy and other neurological morbidity. Also present in developed countries because of immigration and travel, NCC is one of few diseases targeted for eradication. This paper reviews all aspects of its life cycle (taeniasis, porcine cysticercosis, human cysticercosis), with a focus on recent advances in its diagnosis, management, and control. Diagnosis of taeniasis is limited by poor availability of immunological or molecular assays. Diagnosis of NCC rests on neuroimaging findings, supported by serological assays. The treatment of NCC should be approached in the context of the particular type of infection (intra- or extraparenchymal; number, location, and stage of lesions) and has evolved toward combined symptomatic and antiparasitic management, with particular attention to modulating inflammation. Research on NCC and particularly the use of recently available genome data and animal models of infection should help to elucidate mechanisms of brain inflammation, damage, and epileptogenesis.

Diagnosis of Porcine Cysticercosis at Necropsy: When Is Enough, Enough?

Changes in the incidence of porcine cysticercosis is used commonly in the assessment of efforts to control the transmission of Taenia solium, the cause of human neurocysticercosis. Although cysticerci may occasionally occur in tissues other than the striated muscles, particularly the brain, infection in pigs can be diagnosed reliably by assessment of muscle tissue alone.

Development of multi-epitope chimeric vaccine against Taenia solium by exploring its proteome: an in silico approach

Objective: Taenia solium is a neglected tropical disease; larvae of this parasite infect central nervous system i.e. Neurocysticercosis, and adults mature and survive into intestine i.e. Taeniasis. Globally more than 50 million people are at the risk of infection. This is one of the main etiological agents for onset of new early epilepsy in developing countries. However, there is no vaccine available to protect human from its infection. Hence, there is an urgent need for a good vaccine.Methods: We applied immune-informatics approach to design a multi-epitope chimeric vaccine consisting of both B and T-cell epitopes.Results: From the whole transcriptome of Taenia, we identified five suitable peptides present on cell membrane, epitope identification on these peptides were done by using various immunoinformatic software. Physiochemical properties were determined and the tertiary structure of vaccine was predicted, validated and refined, and to increase antigenicity we added linker to them. Best-modeled protein-complex was used for docking study with TLR1-2, TLR4, TLR3 and TLR7 and stability of molecular complex was determined by molecular dynamics simulation.Conclusions: Overall, we attempted to design an efficient subunit chimeric vaccine, which could stimulate humoral and cellular immune responses and could protect against both neurocysticercosis and taeniasis.

A hyperendemic focus of porcine cystic echinococcosis in the Banke District of Nepal

Detailed post mortem analyses of 68 free-ranging, slaughter-age pigs from two sites in the Banke District of Nepal identified 36% as being infected with Echinococcus granulosus. The cysts ranged from infertile, immature cysts a few millimetres in diameter to fertile cysts >10 cm in diameter. PCR RFLP and DNA sequencing identified the cysts as being E. granulosus sensu stricto. The Banke district has recently been identified as having a high prevalence of porcine cysticercosis. These data suggest that cestode zoonoses in this, and possibly other parts of Nepal may be a serious concern for human health. An assessment of the level of human cystic echinococcosis and neurocysticercosis, in the region is warranted and the introduction of control measures are required to limit the parasites' transmission.

Taeniasis and cysticercosis in Asia: A review with emphasis on molecular approaches and local lifestyles

Taeniasis is an important parasitic condition in Asia, especially since all three human-infecting Taenia spp., Taenia solium, Taenia saginata, and Taenia asiatica are found in this region. These three species are believed to be sympatrically distributed, with the largest disease burden found in remote and rural areas where people raise pigs and cattle in a traditional manner. Recent studies revealed that T. asiatica and T. saginata are genetically-related sister species that are not completely reproductively isolated from each other. Current evidence indicates that most T. asiatica adult worms are hybrid-derived descendants. Moving forward, nuclear DNA analysis will be critical in further assessing the species circulating locally. Lifestyle choices, such as the consumption of undercooked meat, are important in maintaining the life cycles of these parasites. In addition, poor hygiene and sanitation, in highly endemic areas, make disease control difficult, resulting in the need for sustainable education programs. An overview of the present situation of taeniasis and cysticercosis in Asia is provided, followed by a discussion of molecular approaches to species assessment and the impact of human lifestyles on parasite transmission.

Accurate diagnosis of lesions suspected of being caused by Taenia solium in body organs of pigs with naturally acquired porcine cysticercosis

The definitive method for diagnosis of porcine cysticercosis is the detection of cysticerci at necropsy. Cysts are typically located in the striated muscle and brain. Until recently Taenia solium cysticerci have not been definitively identified in other tissue locations, despite several comprehensive investigations having been undertaken which included investigation of body organs other than muscle and brain. Recently a study conducted in Zambia reported 27% infection with T. solium in the liver of pigs with naturally acquired porcine cysticercosis, as well as some T. solium infection in the lungs and spleen of some animals. We investigated the cause of lesions in sites other than the muscle or brain in a total of 157 pigs from T. solium endemic regions of Uganda and Nepal which were subjected to extensive investigations at necropsy. Lesions which had the potential to be caused by T. solium were characterised by macroscopic and microscopic examination, histology as well as DNA characterisation by PCR-RFLP and sequencing. Lesions were confirmed as being caused by Taenia hydatigena (both viable and non-viable), by T. asiatica and Echinococcus granulosus (in Nepal) and nematode infections. No T. solium-related lesions or cysticerci were identified in any tissue other than muscle and brain. It is recommended that future evaluations of porcine cysticercosis in aberrant tissue locations include DNA analyses that take appropriate care to avoid the possibility of contamination of tissue specimens with DNA from a different tissue location or a different animal. The use of appropriate control samples to confirm the absence of cross-sample contamination is also recommended.

Control of Taenia solium; A Case for Public and Private Sector Investment

The zoonotic helminth T. solium is one of the leading causes of acquired epilepsy in endemic countries, resulting in a high burden both in human health and social stigma of affected people (1-3). In 2012 T. solium was highlighted as a priority for control in the World Health Assembly resolution 66.12 (4). Despite a call for validated control strategies by 2015 and a "Tool Kit" of control options being available, relatively few examples of successfully implemented and sustainable control programs are available (5-7). A minimal control strategy focusing solely on the porcine host has also been proposed although the cost-effectiveness of such has yet to be explored (8). Although acknowledgment has been made of the need for initiatives to be sustainable, we are yet to see sufficient consideration of the balance between the provision of public and private goods, and the need for engagement of the people and organizations in the pork value chains within T. solium control strategies. We utilized a food chain risk analysis model to determine the incremental cost-effectiveness ratio (ICER) in terms of $/infective meal avoided, of combining a pharmaceutical intervention in pigs with strengthened meat hygiene services. The addition of a vaccination and treatment protocol, at an additional 10.3% cost, was illustrated to have the potential to improve the ICER of improving meat inspection by 74.6%. The vaccination and treatment protocol also had the potential to reduce the losses borne by the pork industry of condemned meat by 66%, highlighting the potential to leverage private sector investment in T. solium control.

Can We Recommend Practical Interventions to Prevent Neurocysticercosis?

The cystiSim model was used to compare strategies for the control of Taenia solium. A three-monthly intervention in pigs for 3 years was substantially more effective than biannual treatment for taeniasis in the human population for 5 years. The intervention period could be shortened further by combining pig and human interventions.