Standardization of molecular techniques for the detection and characterization of intestinal protozoa and other pathogens in humans.

Background: The intrinsic sensitivity limitations of basic parasitological methods, along with the particular biological characteristics of parasites, make these methods ineffective to differentiate morphologically indistinguishable species. Molecular detection and characterization techniques could be used to overcome these problems. The purpose of this work was to standardize molecular polymerase chain reaction (PCR) techniques, described in the literature, for the detection and molecular characterization of intestinal protozoa and other pathogens in humans.

[[Anti-leishmanial activity in plants from a Biological Reserve of Costa Rica].

Leishmaniosis is an important human disease very difficult to treat. For this reason, many researchers in the world have been look- ing for anti-leishmanial chemical components present in several plant species. In Costa Rica, since no studies have been done in this field, this work aimed at the search of active chemical components in local plants that may have an activity against Leishmania sp.

[Immunosuppressor effect of Trypanosoma musculi (Mastigophora: Trypanosomatidae) on experimental toxoplasmosis].

The immunosuppression caused by species of the gender Trypanosoma has been widely documented. The influence over experimental infections with Toxoplasma gondii is evident when using Trypanosoma lewisi, a natural parasite of white rats. We decided to test the effect of Trypanosoma musculi from mice, an organism with very similar biological characteristics to T.

Molecular characterization of Trypanosoma cruzi and infection rate of the vector Triatoma dimidiata in Costa Rica.

According to the genetic characterization by the analysis of the miniexon gene, strains of Trypanosoma cruzi can be classified into six discrete typing units (DTUs), and the DTU 1 into four distinct genotypes associated with different life cycles. While Chagas disease is endemic in Costa Rica, T. cruzi isolates from this region have never been genetically characterized.

[Natural concentration of antimalaric components in Tropical arthropods (in vitro)].

Alcohol, hexane and dichlorometane extracts of 751 samples of Costa Rican arthropods were studied for the presence of antimalaric components. With Plasmodium berghei we set an in vitro model in which the effect of the extract was determined by staining of the parasites with cresil brilliant blue. Active extracts at concentration of 50 mg or less, were considered positive.