Centrocestus formosanus (Opisthorchiida: Heterophyidae) as a cause of death in gray tilapia fry Oreochromis niloticus (Perciforme: Cichlidae) in the dry Pacific of Costa Rica. Centrocestus formosanus is a zoonotic trematode from Asia and has been mainly associated as cause of death of cultured fish. To identify pathogen trematode species in tilapia fry (Oreochromis niloticus) and to determine mollusks hosting these parasites, freshwater mollusks were collected from tilapia cultured ponds and experimental infections were carried out with tilapia fries and different mollusk species. A total of 907 freshwater mollusks were obtained from tilapia ponds and were identified to species level, four gastropods and one bivalve were determined: Melania tuberculata, Melanoides turricula, Pomacea flagellata, Haitia cubensis and Anodontiles luteola. For the first time, the presence of M. turricula and H. cubensis are reported in Costa Rica. Seven morphotypes of cercariae (Xifiodiocercaria, Equinostoma, Oftalmocercaria, Parapleurolofocercus, Cistocerca, Furcocercaria and Leptocercaria) parasitizing all five species of mollusks were found, all of distome type. Experimental exposure of tilapia fry to M. tuberculata demonstrated that the parapleurolofocercus morphotype found in the mollusk is in accordance with the finding of C. formosanus in tilapia fry. An abundance and mean intensity of 1018-1027 digeneans per gill in each exposed fish was determined. Centrocestus formosanus is reported for the first time in Costa Rica, for which the primary and secondary intermediate hosts were also determined.

<p><strong>Background</strong>. <em>Staphylococcus aureus</em> is considered the main causal agent of mastitis in dairy herds globally, affecting milk production and constituting a potential risk to public health. The presence of virulence factors such as biofilm formation and slime production favor colonization and persistence of the mammary gland infections. <strong>Objective</strong>. The study aims to characterize the phenotypes of slime-producing and biofilm-forming <em>S. aureus</em> associated with subclinical mastitis with different CMT (California Mastitis Test) degrees<strong> </strong>and their relationship with the persistence of infection. <strong>Methodology</strong>. To characterize the slime-producing and biofilm-forming <em>S. aureus</em> phenotypes, 116 individual milk samples were taken from cows with subclinical mastitis through the CMT, obtaining 80 <em>S. aureus</em> isolates. Slime production on Congo Red agar was determined <em>in vitro</em>, and the conformation of bacterial clusters adherent identified biofilm formation to rigid surfaces and crystal violet staining. <strong>Results</strong>. 68.8% (55) of the isolates produced slime, of which 20% (16) were considered as producers and 48.8% (39) as intermediate producers. 82.5% (66) of the total isolates were related to the formation of biofilm in different degrees; 1.25% (1) very high trainer, 41.25% (33) high trainer, and 40.0% (32) moderately trainer. Highly biofilm-forming isolates were associated with subclinical mastitis degrees 2 and 3 of the CMT. <strong>Implications</strong>. The verification of slime and biofilm formation in most of <em>S. aureus</em> isolations obtained from subclinical mastitis may imply that their presence is related to the condition's persistence and severity. <strong>Conclusion</strong>. The association between the phenotypes of slime-producing and biofilm-forming <em>S. aureus</em> was established with high degrees of the CMT and mammary infection persistence in the cows studied.</p>

Necrosis Pancreatic Infectious Virus does not block 701-STAT1 (α/β) tyrosine in Oncorhynchus mykiss (‎Salmoniformes: ‎Salmonidae). Introduction: Infectious pancreatic necrosis virus (IPNV) is a pathogen important that affects predominantly salmonids. The type I interferon alpha system has a crucial role in the first line of defense against IPNV infection. IFN-I(α) activation triggers the signaling pathway JAK-STAT, binding to their receptors results in the rapid phosphorylation of STATs a critical step for the nuclear translocation to induce the interferon stimulated genes (ISGs). The relationship between infectivity level of IPNV strain and pathway signaling of IFN is yet poorly understood. Objective: our purpose was to investigate if the IFN-I(α) signaling pathway is affected by IPNV strains of different infectivity levels. Methods: We used two IPNV isolated (VR-299 and Sp) to infect RTG-2 cells. Total RNA was isolated using the commercial kit for determine to VP2 expression and ISGs using qRT-PCR. Western Immunoblotting analysis was carried out for determine the 701 STAT1(α/β) phosphorylation into infected cells. Results: Hence, a higher virulence strain is not associated with a greater blocking effect for interferon signaling. Furthermore, the activation of Y701-STAT1 (α/β) was significantly increased in serotype Sp virus infected cells compared with serotype VR-299 virus infected cells, indicating that IPNV inhibits IFN signaling pathway. Conclusions: As concluded, IPNV does not block the phosphorylation of 701-tyrosine STAT1 (α/β) stimulated by IFN-I(α), contrary to other RNA viruses.

Abstract:The infectious pancreatic necrosis (IPNV) is the causative agent of an acute illness well characterized in salmonids worldwide. Clinical signs and mortality rates are dependent on several factors such as the viral dose, the age of the fish, the water temperature, among others. An experimental study was conducted to measure the effect of temperature on the gene expression profile of IFN-1(α), STAT-1 and Mx-1 in rainbow trout fry, exposed to IPNV. Fry (n=198) were exposed at 8, 12 and 16°C, and samples were taken for 21 days to determine the virus titer and gene expression. In the first 11 days the greatest viral titer was recorded at 8°C compared with the values obtained at 12 and 16°C. At 8°C, there was a significant increase on day 4 of mRNA Mx-1 (t-test, p<0.05), time in which the viral titer began to decrease. Furthermore, as the viral titer increased, STAT-1 and Mx-1 (r=0.91) and (r=0.96) increased, respectively. The animals were able to recover from day 4 from some of the symptoms of IPN. Clinical disease was developed only in fish exposed to 12°C and all died between days 6 and 14, despite the highly significant increase shown in the average expression level of Mx-1, compared with the values recorded at 8°C and 16°C (Tukey, p<0.0001). Additionally, the expression profiles of IFN-1(α) and STAT-1 decreased completely (~0.016) and (~0.020 times) on day 7. The highest expression level of IFN-1(α), occurred at 16°C (Tukey, p<0.0005). Fry exposed at 16°C were normal during the experiment. IFN-1(α) possibly generated a protector effect from day 2 when they showed a significant expression increase compared with the results at 8°C and 12°C (t-student, p<0.0001); however, STAT-1 was not significantly affected by temperature, although the highest average expression value was recorded at 16°C. Our research supports the expression of relevant anti-viral response genes as IFN-1(α), STAT-1 and Mx-1 are physiologically modulated by the water temperature, directly influencing the development of the IPN disease in rainbow trout. Rev. Biol. Trop. 63 (2): 559-569. Epub 2015 June 01.

Los nematodos de la familia Anisakidae parasitan peces marinos y de agua dulce, abarcan tres génerosde importancia para la salud pública: Anisakis sp., Contracaecum sp., y Pseudoterranova sp., que sehan asociado a ictiozoonosis por el consumo de productos pesqueros contaminados con los estadiosinfectantes (L3). Estas enfermedades son conocidas en su conjunto como anisakidosis. A la fecha, noexisten reportes en Costa Rica sobre la presencia de estos nematodos.El objetivo del estudio fue evidenciar la presencia de parásitos de la familia Anisakidae en peces deagua dulce destinados al consumo humano: Parachromis sp. (Guapotes), Rhamdia sp. (Barbudos) yHoplias sp. (Guabinas). En la investigación, se recolectaron un total de 214 peces procedentes de 6 ríosde la provincia de Guanacaste. Se georreferenciaron los lugares de pesca de los ejemplares y se tomaronparámetros físico-químicos del agua en cada sitio muestreado. Los peces fueron necropsiados, y laslarvas del helminto (L3) caracterizadas por microscopía de luz, microscopía electrónica y se confirmómediante diagnóstico molecular (PCR convencional y secuenciación).Como resultado, se encontró un total de 100 larvas (L3) de nemátodos, las cuales fueron extraídas de35 peces. La identificación y caracterización de las larvas por microscopía y diagnóstico molecular lasdeterminó como Contracaecum multipapillatum, un helminto zoonótico. Se recomienda alertar a lapoblación sobre el hallazgo de este parásito.

En el presente estudio se determinó el grado de bioalfabetización en estudiantes provenientes de escuelas cercanas a la zona de influencia de la Universidad Técnica Nacional, donde participaron diez centros educativos procedentes de cuatro cantones en la provincia de Guanacaste, a saber: Cañas, Tilarán, Bagaces y Abangares. Un total de 141 estudiantes de tercero y cuarto año fueron abordados, el 50,35 % correspondió al género femenino y 49,65 % al masculino. El grupo etario se mantuvo entre los 10 y 11 años de edad. Con la investigación se determinaron los principales factores que influyen sobre las comunidades en cuanto a temas ambientales. El mayor índice de bioalfabetización general lo presentó la escuela San Antonio de Javilla en Cañas (0,96) y el menor índice lo presentó la escuela Celestino Álvarez Ruíz de la comunidad de Montano de Bagaces. Únicamente dos escuelas (San Antonio de Javilla en Cañas y Agua Caliente de Bagaces) presentaron grados altos de bioalfabetización con valores de iguales a 0,96 y 0,80 respectivamente.