| dc.description.abstract | Soil-transmitted helminths is among the most prevalent tropical diseases in the world,
affecting approximately 1.5 billion people. Among the species of epidemiological
importance, Ascaris lumbricoides, Trichiuris trichiura, Ancylostoma duodenale, Necator
americanus and Strongyloides stercoralis stand out. These helminths are easily
transmitted through ingestion of eggs or exposure to larvae, which are released into the
feces of infected individuals. Helminthiasis has a major impact on public health, affecting
the learning and development of children in school and pre-school age. In this context,
the control of these parasites becomes necessary and the accurate diagnosis of these
infections assumes a fundamental role in this process. The diagnosis of soil-transmitted
helminths has been based on parasitological, molecular and immunological techniques.
However, the available methods have proven to be flawed and difficult to apply in the
field, requiring the improvement of current techniques and the search for new diagnostic
methods that are sensitive, specific and that do not require specialized equipment. In the
immunodiagnosis specific antibodies, pure or fractionated antigens of the parasite are
used to detect infections. In recent years, the use of extract of pathogen antigens in
immunodiagnostic assays has been replaced by peptides or recombinant proteins that
have greater diagnostic specificity. The aim of the present study was to select conserved
targets for the serological diagnosis of nematodes, as well as specific targets for
epidemiologically relevant species in human infection. The predicted proteome was
analyzed using in silico tools, based on the genes identified in the genome sequences of
the nematodes of interest. From these analyzes, 1160 peptides were identified that showed
a high score prediction for linear B cell epitopes, among which specific targets were
selected and conserved among the species of interest and absent in other helminths. These
peptides were subjected to reactivity tests by immunoblotting, with sera from individuals
known to be positive for the species of interest, confirmed by parasitological techniques,
in order to filter the most promising targets. In total, 107 target peptides were selected,
80 of which were specific (13 for hookworms, 41 for Ascaris sp., and 26 for S. stercoralis)
and 27 conserved in more than one species. The various targets identified have great
potential for improving the diagnosis of soil-transmitted helminths. | |
