Parasitic diseases remain as a major public health problem worldwide, not only based on their historically high morbidity and mortality rates, but also because risk factors associated with their transmission are increasing. Laboratory diagnosis and particularly immunodiagnosis is a basic tool for the demonstration, clinical management and control of these infections. Classically, the serological tests for the detection of antibodies or antigens are based on the use of crude and purified antigens. Synthetic peptides have opened a new field and perspectives, as the source of pure epitopes and molecules for diagnosis of malaria, Chagas' disease, leishmaniasis, schistosomiasis, hidatidosis, cysticercosis and fasciolosis based on the detection of antibodies and circulating antigens. Herein, are critically reviewed the relevant advances and applications of the synthetic peptides on immunodiagnosis of parasitic diseases. A variety of sequences, constructs (monomers, polymers, MAPs), immunological methods and samples have been used, demonstrating their diagnostic potential. However, in most parasitic infections it is necessary to use more than a single peptide in order to avoid the genetic restriction against certain epitopes, as well as to test them in well characteized groups of patients, in order to confirm their sensitivity and specificity. The concept of multidiagnosis with synthetic peptides, using a novel multi-dot blot assay is introduced. Finally, the chemical imitation of antigens, offers a tremendous posibilities in the diagnosis of parasitic infections in developing countries since this strategy is cheaper, simpler, reproducible, useful for large scale testing and in most cases, specific and sensitive.

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This study evaluates five synthetic peptides derived from four, potentially protective, Taenia saginata oncosphere molecules for the serodiagnosis of T. solium cysticercosis/neurocysticercosis in three distinct Venezuelan endemic regions. The peptides, all of which have been described previously, are designated HP6-3, Ts45W-1, Ts45W-5, Ts45S-10 and TEG-1. In clinically verified and seropositive hospital cases, combining the results of three of the individual peptide-based ELISAs (HP6-3, Ts45W-1 and Ts45W-5) afforded the best balance between sensitivity (85%) and specificity (83.5%), a significant improvement on the 63.6% specificity obtained with the routinely employed T. solium cyst-fluid-based ELISA. Similarly, in the seropositive Venezuelan endemic zone samples, 89.09% of Amerindians, 77.27% of symptomatic rural subjects and 67.83% of non-symptomatic rural subjects were also classed as seropositive by the combined peptide-based ELISAs. The profile of antibody recognition to individual peptides varied between the different groups of samples examined. The relevance of the above findings for the serology and prognosis of T. solium cysticercosis/neurocysticercosis in hospital- and field-based situations is discussed.

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An extensive malacological survey was carried out between [2005][2006][2007][2008][2009] Fascioliasis is a parasitosis mainly infecting cattle, but it is now considered to be an emergent disease in humans in many countries over the world (Mas-Coma 2005). In the New World, it is considered as a serious health problem in several Andean countries. Bolivia is even described as a hyperendemic area and one of its epidemiological characteristics is its very high altitude at more than 4,000 m . The timing of the emergence of human foci in the Altiplano Region corresponds to the invasion by the European intermediate snail host Lymnaea truncatula (Jabbour-Zahab et al. 1997, Meunier et al. 2001. In Venezuela, human fascioliasis was first reported in 1910 and only eight sporadic cases were detected in the following decades (Risquez 1929, Rodríguez & González 1975, Abdul-Hadi et al. 1996, Scorza et al. 1999, Incani et al. 2002, Alarcón de Noya et al. 2006). However, in 2005 five children belonging to the same family were detected with fascioliasis in Timotes, in the Venezuelan Andes, at an altitude of 2,230 m (Alarcón de Noya et al. 2007). The same year a malacological survey carried out in the Timotes area found only a single lymnaeid species, the European L. truncatula. In this paper we present the results of an extensive malacological survey which was carried out A malacological survey was carried out between 2005-2009 across the whole country. A total of 298 sites were sampled (see the inserts in the maps showing all the sampling sites). Snails were sampled from different vegetation either by hand or sampled using a scoop mounted with a wooden handle, depending on the type of site. These sites include the following main habitat types: springs, ditches, brooks, canals, rivers, swamps, tanks, ponds and lakes. Following field collection lymnaeid snails were allowed to relax overnight using menthol. They were then immersed for 40 s in water at 70°C, from which they were transferred to water at RT. The soft parts were drawn from the shell with small forceps and fixed in slightly modified Railliet-Henry fluid (distilled water 930 mL, sodium chloride 6 g, formalin 50 mL, glacial acetic acid 20 mL). Shells were measured to the nearest 1 mm using callipers. Snails preserved in Railliet Henry's fluid were dissected under a stereoscopic microscope and drawings of the reproductive system were made using a camera lucida attachment. Snails were identified according to conchological and anatomical characteristics