Vaccination for the prevention of cysticercosis.
ABSTRACT Several species of taeniid cestode parasites cause cysticercosis in their intermediate hosts. The most important species is Taenia solium, which infects pigs as the natural animal intermediate host but also may infect humans as intermediate hosts, leading to the disease known as neurocysticercosis. T. solium has been identified as a potentially eradicable disease and increasing attention is being placed on efforts to control transmission of the parasite. One option to assist with control of the disease is to prevent infection occurring in pigs by vaccination, thereby breaking the parasite's life-cycle and removing the source of infection for humans. Several approaches are being examined towards development of vaccines against T. solium, one of which is the application of recombinant oncosphere antigens. Two different oncosphere antigens, designated TSOL18 and TSOL45, have been evaluated, each of which has been shown to induce complete or near complete protection against experimental challenge infection in four separate vaccine trials in pigs. Investigations have begun towards characterising various aspects of this vaccine before undertaking controlled field trials. The TSOL18/TSOL45 vaccine has the potential to make a substantial contribution to the control and, potentially, the eradication of human neurocysticercosis.
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ABSTRACT: Neurocysticercosis is a disease caused by the oral ingestion of eggs from the human parasitic worm Taenia solium. Although drugs are available they are controversial because of the side effects and poor efficiency. An expressed sequence tag (EST) library is a method used to describe the gene expression profile and sequence of mRNA from a specific organism and stage. Such information can be used in order to find new targets for the development of drugs and to get a better understanding of the parasite biology. Here an EST library consisting of 5760 sequences from the pig cysticerca stage has been constructed. In the library 1650 unique sequences were found and of these, 845 sequences (52%) were novel to T. solium and not identified within other EST libraries. Furthermore, 918 sequences (55%) were of unknown function. Amongst the 25 most frequently expressed sequences 6 had no relevant similarity to other sequences found in the Genbank NR DNA database. A prediction of putative signal peptides was also performed and 4 among the 25 were found to be predicted with a signal peptide. Proposed vaccine and diagnostic targets T24, Tsol18/HP6 and Tso31d could also be identified among the 25 most frequently expressed. An EST library has been produced from pig cysticerca and analyzed. More than half of the different ESTs sequenced contained a sequence with no suggested function and 845 novel EST sequences have been identified. The library increases the knowledge about what genes are expressed and to what level. It can also be used to study different areas of research such as drug and diagnostic development together with parasite fitness via e.g. immune modulation.PLoS Neglected Tropical Diseases 01/2010; 4(12):e919. · 4.57 Impact Factor
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ABSTRACT: In many developing and transition countries, parasitic zoonoses such as cysticercosis and echinococcosis cause serious human suffering and considerable losses in agricultural and human productivity, thus posing a significant hindrance to their development. Although, effective and reliable tools for the diagnosis, prevention and control of parasitic zoonoses are now available, their implementation has not always been successful in many countries. This is primarily due to the lack of awareness on the presence or impact of the causing parasites (Taenia saginata, Taenia solium and Echinococcus spp.). In addition, often the needed intersectorial cooperation, resource management and political commitment for their control are (also) absent. FAO's regular programme has established a global network of professionals directly involved in zoonotic and food-borne diseases. The network provides a basic framework for the spread of information related to the diagnosis, prevention and control of major zoonotic diseases including cysticercosis and echinococcosis.Parasitology International 02/2006; 55 Suppl:S305-8. · 2.30 Impact Factor
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ABSTRACT: BACKGROUND: Neurocysticercosis is a leading cause of preventable epilepsy in the developing world. Sustainable community-based interventions are urgently needed to control transmission of the causative parasite, Taenia solium. We examined the geospatial relationship between live pigs with visible cysticercotic cysts on their tongues and humans with adult intestinal tapeworm infection (taeniasis) in a rural village in northern Peru. The objective was to determine whether tongue-positive pigs could indicate high-risk geographic foci for taeniasis to guide targeted screening efforts. This approach could offer significant benefit compared to mass intervention. METHODS: We recorded geographic coordinates of all village houses, collected stool samples from all consenting villagers, and collected blood and examined tongues of all village pigs. Stool samples were processed by enzyme-linked immunosorbent assay (ELISA) for presence of Taenia sp. coproantigens indicative of active taeniasis; serum was processed by enzyme-linked immunoelectrotransfer blot for antibodies against T. solium cysticercosis (EITB LLGP) and T. solium taeniasis (EITB rES33). FINDINGS: Of 548 pigs, 256 (46.7%) were positive for antibodies against cysticercosis on EITB LLGP. Of 402 fecal samples, 6 (1.5%) were positive for the presence of Taenia sp. coproantigens. The proportion of coproantigen-positive individuals differed significantly between residents living within 100-meters of a tongue-positive pig (4/79, 5.1%) and residents living >100 meters from a tongue-positive pig (2/323, 0.6%) (p = 0.02). The prevalence of taeniasis was >8 times higher among residents living within 100 meters of a tongue-positive pig compared to residents living outside this range (adjusted PR 8.1, 95% CI 1.4-47.0). CONCLUSIONS: Tongue-positive pigs in endemic communities can indicate geospatial foci in which the risk for taeniasis is increased. Targeted screening or presumptive treatment for taeniasis within these high-risk foci may be an effective and practical control intervention for rural endemic areas.PLoS Neglected Tropical Diseases 12/2012; 6(12):e1953. · 4.57 Impact Factor