A predictive Fasciola hepatica model, based on the growing degree day-water budget (GDD-WB) concept and the known biological requirements of the parasite, was developed within a geographical information system (GIS) in Colombia. Climate-based forecast index (CFI) values were calculated and represented in a national-scale, climate grid (18 x 18 km) using ArcGIS 9.3. A mask overlay was used to exclude unsuitable areas where mean annual temperature exceeded 25 °C, the upper threshold for development and propagation of the F. hepatica life cycle. The model was then validated and further developed by studies limited to one department in northwest Colombia. F. hepatica prevalence data was obtained from a 2008-2010 survey in 10 municipalities of 6,016 dairy cattle at 673 herd study sites, for which global positioning system coordinates were recorded. The CFI map results were compared to F. hepatica environmental risk models for the survey data points that had over 5% prevalence (231 of the 673 sites) at the 1 km2 scale using two independent approaches: (i) a GIS map query based on satellite data parameters including elevation, enhanced vegetation index and land surface temperature day-night difference; and (ii) an ecological niche model (MaxEnt), for which geographic point coordinates of F. hepatica survey farms were used with BioClim data as environmental variables to develop a probability map. The predicted risk pattern of both approaches was similar to that seen in the forecast index grid. The temporal risk, evaluated by the monthly CFIs and a daily GDD-WB forecast software for 2007 and 2008, revealed a major July-August to January transmission period with considerable inter-annual differences.

Experiments on hybridization between Fasciola hepatica and Fasciola gigantica were carried out to clarify whether a reproductive isolating mechanism appears between the two Fasciola species. Molecular evidence for hybridization was based on the DNA sequence of the internal transcribed spacer 1 (ITS1) region in nuclear ribosomal DNA, which differs between the species. The results suggested that there were not pre-mating but post-mating isolating mechanisms between the two species. However, viable adults of the hybrids F1 and F2 were produced from both parental F. hepatica and F. gigantica. The hybrids inherited phenotypic characteristics such as ratio of body length and width and infectivity to rats from parental Fasciola hepatica and F. gigantica. These findings suggest that reproductive isolation is incomplete between Fasciola hepatica and F. gigantica. Adults of the hybrids F1 and F2 were completely different in mode of reproduction from aspermic Fasciola forms that occur in Asia and seem to be offspring originated from hybridization between F. hepatica and F. gigantica and to reproduce parthenogenetically.

A gene coding for a calmodulin was synthesized and cloned. The chemical synthesis of the gene, coding for 149 amino acids, was achieved by the enzymatic ligation of 61 chemically synthesized DNA fragments. The DNA fragments were synthesized using a solid support with a diisopropyl phosphoramidite intermediate and in situ activation. The automated standard cycle time was 10 min/addition. The synthesizer was designed and constructed from inexpensive, readily available parts and controlled by a Commodore 64 computer. The gene possesses 27 unique, regularly spaced, restriction endonuclease cleavage sites to facilitate gene mutagenesis.

Los errores innatos del metabolismo (EIM) son más de 550 enfermedades en las que se presenta una deficiencia o ausencia de proteínas con actividad enzimática, transportadora, receptora o estructural. Cada una de estas enfermedades es rara, pero su gran variedad hace que, consideradas en conjunto, sean la principal patología neonatal. Para la detección de los metabolitos producidos en los EIM se pueden utilizar pruebas cualitativas. Su utilidad radica en que son muy rápidas y de fácil acceso, y en que sirven como pruebas presuntivas para proceder a hacer exámenes más especializados o para enfocar el diagnóstico. Teniendo en cuenta su importancia para un diagnóstico temprano de los EIM, el objetivo del presente artículo es describir el funcionamiento de las pruebas bioquímicas de resorcinol, dinitrofenilhidrazina, nitrosonaftol, nitroprusiato y Hoesch, haciendo énfasis en los metabolitos que detectan.

Se ha incrementado el uso terapéutico de las sanguijuelas y se ha demostrado que ellas pueden inocular bacterias causantes de infecciones en el 20% de los pacientes. El hallazgo en Antioquia de dos especies de sanguijuelas promisorias para hirudoterapia motivó este estudio para identificar las bacterias en la superficie, la probóscide y el intestino de estos anélidos y evaluar su sensibilidad a antibióticos. Las sanguijuelas estudiadas se identificaron como Haementeria sp., y Oxytychus ornatus. Muestras de la superficie, boca e intestino de ambos anélidos se inocularon en agar sangre, agar sangre con ampicilina y agar eosina azul de metileno. La identificación de las bacterias y su sensibilidad a antibióticos se evaluaron por el método automatizado Vitek (Biomerieux®). Se hicieron en total 26 aislamientos pertenecientes a 12 especies de nueve géneros. Enterobacter cloacae fue la especie más frecuente en ambos anélidos. Las bacterias fueron sensibles a los antibióticos comúnmente empleados en las infecciones causadas por este tipo de microorganismos. Se sugiere hacer profilaxis con antibióticos en los pacientes que reciban terapia con los anélidos investigados e implementar los protocolos estandarizados para el lavado de los animales antes de su uso y para el aseo de los acuarios en donde se los mantenga.