Artículos Científicos

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A bvrR/bvrS Non-Polar Brucella abortus Mutant Confirms the Role of the Two-Component System BvrR/BvrS in Virulence and Membrane Integrity
(MDPI, 2023-08-05) Rivas-Solano, Olga; Núñez-Montero, Kattia; Altamirano-Silva, Pamela; Ruiz-Villalobos, Nazareth; BARQUERO-CALVO, ELIAS; Moreno, Edgardo; Chaves-Olarte, Esteban; Guzman-Verri, Caterina
Brucella abortus is a bacterial pathogen causing bovine brucellosis worldwide. This facultative extracellular–intracellular pathogen can be transmitted to humans, leading to a zoonotic disease. The disease remains a public health concern, particularly in regions where livestock farming is present. The two-component regulatory system BvrR/BvrS was described by isolating the attenuated transposition mutants bvrR::Tn5 and bvrS::Tn5, whose characterization led to the understanding of the role of the system in bacterial survival. However, a phenotypic comparison with deletion mutants has not been performed because their construction has been unsuccessful in brucellae and difficult in phylogenetically related Rhizobiales with BvrR/BvrS orthologs. Here, we used an unmarked gene excision strategy to generate a B. abortus mutant strain lacking both genes, called B. abortus ∆bvrRS. The deletion was verified through PCR, Southern blot, Western blot, Sanger sequencing, and whole-genome sequencing, confirming a clean mutation without further alterations at the genome level. B. abortus ∆bvrRS shared attenuated phenotypic traits with both transposition mutants, confirming the role of BvrR/BvrS in pathogenesis and membrane integrity. This B. abortus ∆bvrRS with a non-antimicrobial marker is an excellent tool for continuing studies on the role of BvrR/BvrS in the B. abortus lifestyle.
A cross-sectional survey of gastrointestinal parasites with dispersal stages in feces from Costa Rican dairy calves
(Elsevier B.V, 2010-07-24) Fernández, A; Alfaro, R; Eped, C; Schnieder, T; Jiménez Rocha, Ana Eugenia; Dolz, Gaby; Vargas, Bernardo; Schnieder, T
A cross-sectional study was carried out to determine the prevalence of gastrointestinal parasites and lungworm nematodes in dairy calves from five different ecoclimatic areas of Costa Rica. Also intensity of infection of nematodes was determined. In order to describe management practices and anthelmintic control, a questionnaire was applied in 73 farms. The influence of area, farm, host (breed, age) and ecological factors (low and high rainfall period) upon eggs per gram feces (epg) of gastrointestinal nematodes (GIN) and first larval stage counts (L1) of Dictyocaulus viviparus were investigated. Furthermore, association of host, ecological and management risk factors to the prevalence of gastrointestinal parasites and D. viviparus were analyzed. The most prevalent GIN, cestodes and protozoan identified in dairy farms were similar in all areas studied. Strongylidae was themost prevalent parasite group detected, representedmainly by Haemonchus spp. andCooperia spp., whereas Ostertagia spp. and Mecistocirrus digitatus were barely found. The most prevalent protozoan was Eimeria spp. The questionnaire applied to producers revealed the following management practices: weaning age of calves 1–4 months (52.1%), semi-confinement of calves upon 5–8 months of age (41.1%), number of paddocks used for calves <10 (57.5%), first deworming of calves at ages ≥15 days (74.70%) and deworming of calves at intervals >60 days (52.1%). Anthelmintic products were changed in 56.1% of the farms at intervals between 13 and 24 months. Although 91.8% of the farms had veterinary assistance, the majority performed parasite control regimes according to the criteria of the producers (66.7%). Common practices were the dispersion of animal feces on the pastures (64.4%) and use of disinfectant in the milking room (63.4%). The analyses of variance showed significant influence (p < 0.05) of age, rainfall period, interaction of rainfall period on area (rainfall period × area) and nested effect of farm within area [farm (area)] on epg of Strongylidae; age, area, rainfall period × area and [farm (area)] on epg of Strongyloides papillosus; age, rainfall period and farm (area) on epg of Trichuris spp.; rainfall period, rainfall period × area and [farm (area)] on L1 of D. viviparus. The logistic regression analyses determined area, semi-confinement, management of feces, use of disinfectant in the milking room as risk factors for the presence of Strongylidae, S. papillosus and Trichuris spp; rainfall, age, paddock numbers for D. viviparus; and area, age, veterinary assistance, deworming program, age at first deworming and use of disinfectant in the milking room for Eimeria spp. and Buxtonella sulcata.
A Differential Effect of Indian Ocean Dipole and El Niño on Cholera Dynamics in Bangladesh
(PLoS ONE, 2013-03-29) Moji, K; Hashizume, Masahiro; Chaves, Luis Fernando; Faruque, A. S. G.; Yunus, Md; Streatfield, Kim; Moj, Kazuhiko
Background: A stationary (i.e., constant through time) association between El Niño Southern Oscillation (ENSO), the Indian Ocean Dipole (IOD) and epidemics of cholera in Bangladesh has been widely assumed. However, whether or not elements of the local climate that are relevant for cholera transmission have stationary signatures of the IOD on their dynamics over different time scales is still not clear. Here we report results on the time-varying relationships between the various remote and local environmental drivers and cholera incidence in Bangladesh. Methodology/Principal Findings: We performed a cross wavelet coherency analysis to examine patterns of association between monthly cholera cases in the hospitals in Dhaka and Matlab (1983–2008) and indices for both IOD and ENSO. Our results showed that the strength of both the IOD and ENSO associations with cholera hospitalizations changed across time scales during the study period. In Dhaka, 4-year long coherent cycles were observed between cholera and the index of IOD in 1988–1997. In Matlab, the effect of ENSO was more dominant while there was no evidence for an IOD effect on cholera hospitalizations. Conclusions/Significance: Our results call for the consideration of non-stationary, possibly non-linear, patterns of association between cholera hospitalizations and climatic factors in cholera epidemic early warning systems.
A joint Myxoma in a dog
(Harcourt Publishers Ltd, 2001) Millán, Y; Ordás, J; Martín de las Mulas, J; Berrocal, Alexis
Myxomas of the joints are extremely rare in domestic animals, only four cases, all in dogs, having been reported previously. This paper describes a myxoma originating from the synovium of the right radiocarpal joint of a mature female Dobermann pinscher with right front limb lameness. The tumour was excised surgically and no recurrence was detected during a 2-year follow-up period. Immunohistochemically, the tumour cells reacted with antibodies to vimentin and S100 protein but not with antibodies to cytokeratins (high and low molecular weight) or human callus keratin.
A method to obtain rapid zoosporogenesis of Pythium insidiosum
(Kluwer Academic Publishers, 1988-10) Mendoza, Leonel; Prendas, Jorge
Nine strains of Pythium insidiosum the etiologic agent of pythiosis, were inoculated on 2% water agar plus grass blades and then incubated one day at 25°C, 35°C and 37°C. Sporangium and secondary biflagellate-type zoosporas from the parasitized grass blades were noticed in induction medium after one hour of incubation at 35 °C and 37 °C. The number of sporangia and zoospores were lower at 25 °C, than 35 °C and 37 °C. Increasing the days of incubation of the parasitized grass blades resulted in the increase in the time of incubation in the induction medium. Corn meal agar, Schmitthenner medium and Sabouraud dextrose agar were also tested but the sporangium and zoosporas were always observed after five hours of incubation in induction medium. © 1988 Kluwer Academic Publishers.
A novel host-adapted strain of Salmonella Typhimurium causes renal disease in olive ridley turtles (Lepidochelys olivacea) in the Pacific
(Springer Nature, 2019-06-27) Thierry, Work; Dagenais, Julie; Stacy, Brain; Ladner, Jason; Lorch, Jeffrey; Balazs, George; BARQUERO-CALVO, ELIAS; Breeden, Renee; Corrales Gómez, Natalia; Berlowski-Zier, Brenda; Gonzalez-Barrientos, Rocio; Harris, Heather; Hernández-Mora, Gabriela; Herrera-Ulloa, Ángel; Hesami, Shoreh; Jones, Todd; Morales, Juan Alberto; Norton, Terry M.; Rameyer, Robert A.; Taylor, Daniel; Waltzek, Thomas
Salmonella spp. are frequently shed by wildlife including turtles, but S. enterica subsp. enterica serovar Typhimurium or lesions associated with Salmonella are rare in turtles. Between 1996 and 2016, we necropsied 127 apparently healthy pelagic olive ridley turtles (Lepidochelys olivacea) that died from drowning bycatch in fisheries and 44 live or freshly dead stranded turtles from the west coast of North and Central America and Hawaii. Seven percent (9/127) of pelagic and 47% (21/44) of stranded turtles had renal granulomas associated with S. Typhimurium. Stranded animals were 12 times more likely than pelagic animals to have Salmonella-induced nephritis suggesting that Salmonella may have been a contributing cause of stranding. S. Typhimurium was the only Salmonella serovar detected in L. olivacea, and phylogenetic analysis from whole genome sequencing showed that the isolates from L. olivacea formed a single clade distinct from other S. typhimurium. Molecular clock analysis revealed that this novel clade may have originated as recently as a few decades ago. The phylogenetic lineage leading to this group is enriched for non-synonymous changes within the genomic area of Salmonella pathogenicity island 1 suggesting that these genes are important for host adaptation.
A sensitive blotting system for detection of α-fetoprotein variants with monoclonal and polyclonal antibodies
(Elsevier, 1988-08-19) Sittenfeld, Ana; Moreno, Edgardo
Human α-fetoprotein (AFP) variants from cord sera were separated by isoelectric focusing in agarose gels under native conditions, transferred to nitrocellulose paper and detected with polyclonal and monoclonal antibodies (Moabs). Rabbit anti-AFP recognized up to 9 individual electrophoretic variants in the range of pH 4.5 to pH 5.2. The reactivity of 8 Moabs ranged from weak to strong and showed variability in the pattern of AFP bands recognized. Moabs were separated into 3 groups according to the number of bands detected: group 1 detected 6 to 7 bands; group 2 recognized only one band; and group 3 recognized 4 bands. The sensitivity of the system with polyclonal antibodies was 0.15 ng of AFP in complete cord serum and varied between 300 and 0.2 ng with Moabs.
A sensor histidine kinase from a plant-endosymbiont bacterium restores the virulence of a mammalian intracellular pathogen
(Elsevier, 2023-11-08) Chaves-Olarte, Esteban; Meza-Torres, Jazmín; Herrera-Rodríguez, Fabiola; Lizano-González, Esteban; Suárez-Esquivel, Marcela; Baker, Kate S.; Rivas-Solano, Olga; Ruiz-Villalobos, Nazareth; Villalta-Romero, Fabián; Cheng, Hai-Ping; Walkerf, Graham C.; Cloeckaert, Axel; Thomson, Nicholas R.; Frisan, Teresa; Moreno, Edgardo; Guzman-Verri, Caterina
Alphaproteobacteria include organisms living in close association with plants or animals. This interaction relies partly on orthologous two-component regulatory systems (TCS), with sensor and regulator proteins modulating the expression of conserved genes related to symbiosis/virulence. We assessed the ability of the exoS+Sm gene, encoding a sensor protein from the plant endosymbiont Sinorhizobium meliloti to substitute its orthologous bvrS in the related animal/human pathogen Brucella abortus. ExoS phosphorylated the B. abortus regulator BvrR in vitro and in cultured bacteria, showing conserved biological function. Production of ExoS in a B. abortus bvrS mutant reestablished replication in host cells and the capacity to infect mice. Bacterial outer membrane properties, the production of the type IV secretion system VirB, and its transcriptional regulators VjbR and BvrR were restored as compared to parental B. abortus. These results indicate that conserved traits of orthologous TCS from bacteria living in and sensing different environments are sufficient to achieve phenotypic plasticity and support bacterial survival. The knowledge of bacterial genetic networks regulating host interactions allows for an understanding of the subtle differences between symbiosis and parasitism. Rewiring these networks could provide new alternatives to control and prevent bacterial infection.
A Sinorhizobium meliloti and Agrobacterium tumefaciens ExoR ortholog is not crucial for Brucella abortus virulence
(PLOS ONE, 2021-08-13) Castillo Zeledon, Amanda; Ruiz-Villalobos, Nazareth; Altamirano-Silva, Pamela; Chacón-Díaz, Carlos; BARQUERO-CALVO, ELIAS; Chaves-Olarte, Esteban; Guzman-Verri, Caterina
Brucella is a facultative extracellular-intracellular pathogen that belongs to the Alphaproteo- bacteria class. Precise sensing of environmental changes and a proper response mediated by a gene expression regulatory network are essential for this pathogen to survive. The plant-related Alphaproteobacteria Sinorhizobium meliloti and Agrobacterium tumefaciens also alternate from a free to a host-associated life, where a regulatory invasion switch is needed for this transition. This switch is composed of a two-component regulatory system (TCS) and a global inhibitor, ExoR. In B. abortus, the BvrR/BvrS TCS is essential for intra- cellular survival. However, the presence of a TCS inhibitor, such as ExoR, in Brucella is still unknown. In this work, we identified a genomic sequence similar to S. meliloti exoR in the B. abortus 2308W genome, constructed an exoR mutant strain, and performed its characteri- zation through ex vivo and in vivo assays. Our findings indicate that ExoR is related to the BvrR phosphorylation state, and is related to the expression of known BvrR/BrvS gene tar- gets, such as virB8, vjbR, and omp25 when grown in rich medium or starving conditions. Despite this, the exoR mutant strain showed no significant differences as compared to the wild-type strain, related to resistance to polymyxin B or human non-immune serum, intracel- lular replication, or infectivity in a mice model. ExoR in B. abortus is related to BvrR/BvrS as observed in other Rhizobiales; however, its function seems different from that observed for its orthologs described in A. tumefaciens and S. meliloti.
A survey on Triatoma dimidiata in an urban area of the province of Heredia, Costa Rica
(Mem Inst Oswaldo Cruz, 2005-10) Zeledón, Rodrigo; Calvo, Nidia; Montenegro, Víctor M.; Seixas Lorosa, Elias; Arévalo, Carolina
Triatoma dimidiata has been found in several cities and towns of those countries where the insect is a domestic or peridomestic pest. In Central America, urban infestations occur in the capitals of at least five countries. During 2001 and 2002 a survey was carried out in the county of San Rafael, Heredia province, located 15 km northwest of San José, capital of Costa Rica, in order to determine the degree of infestation by T. dimidiata in an entire city block. Six peridomestic colonies of the insect were detected in the backyards of eight households. The ecotopes occupied by the insects consisted of store rooms with old objects, wood piles or firewood, and chicken coops. A total of 1917 insects were found in the six foci, during two sampling periods, and a mean infection rate by Trypanosoma cruzi of 28.4% was found in 1718 insects examined. The largest colony found in one of the households yielded 872 insects that were thriving mainly at the expenses of two dogs. Opossums and adult insects were common visitors of the houses and it became evident that this marsupial is closely related to the peridomestic cycle of the Chagas disease agent. Lack of colonization of the insect inside the human dwellings is explained by the type of construction and good sanitary conditions of the houses, in contrast to the situ- ation in most peridomiciliary areas. Stomach blood samples from the insects showed that the main hosts were, in order of decreasing frequency: rodents, dogs, fowl, humans, opossums, and cats. The fact that no indication of infection with Chagas disease could be detected in the human occupants of the infested houses, vis a vis the high infection rate in dogs, is discussed.
A two-component regulatory system playing a critical role in plant pathogens and endosymbionts is present in Brucella abortus and controls cell invasion and virulence
(Blackwell Science, 1998-04-08) Sola-Landa, Alberto; Pizarro-Cerdá, Javier; Grilló, Maria Jesus; Moriyón, Ignacio; Blasco, José Maria; Gorvel, Jean Pierre; López Goñi, Ignacio; Moreno, Edgardo
Two mutants showing increased sensitivity to polycations and surfactants were obtained by transposon mutagenesis of virulent Brucella abortus 2308 Nal(r). These mutants showed no obvious in vitro growth defects and produced smooth-type lipopolysaccharides. However, they hardly multiplied or persisted in mouse spleens, displayed reduced invasiveness in macrophages and HeLa cells, lost the ability to inhibit lysosome fusion and were unable to replicate intracellularly. Subsequent DNA analyses identified a two-component regulatory system [Brucella virulence related (Bvr)] with a regulatory (BvrR) and sensory (BvrS) protein. Cloning on bvrR in the BvrR-deficient mutant restored the resistance to polycations and, in part, the invasiveness to polycations and, in part, the invasiveness and the ability to multiply intracellularly. BvrR and BvrS were highly similar (87-89% and 70-80% respectively) to the regulatory and sensory proteins of the chromosomally encoded Rhizobium meliloti Chvl-ExoS and Agrobacterium tumefaciens Chvl-ChvG systems previously shown to be critical for endosymbiosis and pathogenicity in plants. Divergence among the three sensory proteins was located mostly within a periplasmic domain probably involved in stimulus sensing. As B. abortus, R. meliloti and A. tumefaciens are phylogenetically related, these observations suggest that these systems have a common ancestor that has evolved to sense stimuli in plant and animal microbial environments.
Absence of IgG antibodies against Schmallenberg virus in ruminant sera (bovine, goat and sheep) collected in Costa Rica between 2012 and 2014.
(Universidad Nacional, Costa Rica, 2017-07) Villegas-Salas, Marlene; Alvarado, Tara; Trejos-Araya, Carla; Sandí, Alexis; León, Bernal; Jiménez Sánchez, Carlos
Schmallenberg virus affects ruminants, which causes significant economic losses. The virus is transmitted through vectors of the genus Culicoides; however, other studies do not rule out the possibility of sexual transmission due to its presence in semen. For this reason, the National Service of Animal Health of Costa Rica (SENASA) imposed restrictions on the import of semen from animals from the European Union in 2013. Consequently, SENASA conducted a study to determine the presence or absence of antibodies against this virus in bovine, ovine and caprine samples. As a result, no antibodies against this virus were detected in the 748 samples tested. It was concluded that Schmallenberg virus was not circulating in Costa Rican ruminants during the tested period.
Un acercamiento integrado para determinar la sostenibilidad de granjas lecheras de Costa Rica: 1. Desarrollo de una matriz de indicadores
(CIPAV, 2004-12-06) Murillo, L; Villalobos, L; Vargas Leitón, Bernardo; Saenz, Fernando
Se desarrolló una matriz de objetivos e indicadores claves para el monitoreo de la sostenibilidad en sistemas de lechería especializada. Se realizó con información proveniente de diez ganaderías lecheras localizadas en Cartago, Poás y San Carlos; Costa Rica. La metodología desarrollada presenta dos fases: Caracterización del sistema y Desarrollo de una matriz de objetivos e indicadores. La caracterización comprende el diagnóstico estático, el diagrama de flujo y la definición de las fortalezas, oportunidades, debilidades y amenazas (FODA). La matriz de objetivos e indicadores claves se construyó para cada componente dentro de las dimensiones ecológica, económica, social y técnica. El diagrama de flujo indica que existen cinco componentes principales identificados como: animal, vegetal, infraestructura, humano y suelos. El FODA revela que en la dimensión ecológica la principal fortaleza es la existencia de bosques en la ganaderías y la disponibilidad de pastos de buena calidad, originando como objetivo maximizar el uso de forrajes. En la dimensión económica su principal fortaleza es su rentabilidad, generando el objetivo maximizar rentabilidad por área. Su mayor debilidad son costos de producción altos, relacionándose con el objetivo de disminución de costos variables. En la dimensión social sus fortalezas son la estabilidad de la mano de obra y el acceso a servicios sociales; dando origen al objetivo de optimizar la calidad de vida de la mano de obra. En la dimensión técnica su principal oportunidad es aumentar la productividad por área; lo que genera el objetivo maximizar productividad por área. Su mayor debilidad es la dependencia de concentrados, relacionada directamente con el objetivo optimización del uso de concentrados. Es necesario implementar esta metodología a nivel de ganaderías de lechería especializada, con el fin de determinar su operatividad y su posible aplicación para comparar la sostenibilidad de sistemas lecheros con similares niveles de intensificación.
Activation of Rho and Rab GTPases dissociates Brucella abortus internalization from intracellular trafficking
(Blackwell Science, 2002-10-04) Chaves-Olarte, Esteban; Guzman-Verri, Caterina; Méresse, Stephane; Desjardins, Michel; Pizarro-Cerdá, Javier; Badilla, Jenny; Gorvel, Jean-Pierre; Moreno, Edgardo
Brucella abortus is an intracellular pathogen that relies on unconventional virulence factors to infect hosts. In non-professional phagocytes, Rho GTPasesactivation by the Escherichia coli cytotoxic necrotiz ing factor (CNF) promoted massive Brucella entrance by membrane ruffling, a mechanism that differs from the common mode of entrance used by this bacterium in non-treated cells. Cytotoxic necrotizing factor treatment, however, did not alter the intracellular route followed by the wild type or non-virulent defined mutants. In contrast, expression of a constitutively active Rab5Q79L GTPase did not alter cell-invasion by Brucella but hampered its ability to reach the endoplasmic reticulum. The CNF-induced Brucella superinfection did not reduce the ability of host cells to synthesize DNA and progress through the cell cycle. Furthermore, CNF-treatment increased the isolation of Brucella-containing compartments by a factor of 15. These results demonstrate that in nonprofessional phagocytic cells, Brucella manipulates two different sets of GTPases during its biogenesis, being internalization and intracellular trafficking two consecutive but independent processes. Besides, CNF-induced super-infection demonstrates that Brucella does not interfere with crucial cellular processes and has shown its potential as tool to characterize the intracellular compartments occupied by this bacterium.
Actividad gastroprotectora del extracto etanólico de hojas de Licania platypus (Hemsl.) Fritsh.
(Departamento de Farmacología de la Escuela de Medicina de la Universidad de Costa Rica, 2017-04-25) Orozco-Aguilar, Josue; Chavarría Rojas, Marianela; Alvarado Barboza, Gilbert; Cordero García, Eugenia; Morales Acuña, Juan Alberto; Retana Salazar, Axel; González Camacho, Sara
La especie Licania platypusdistribuida en países tropicales. Tradicionalmente, en América Central se han utilizado diferentes partes de la planta para diversos problemas de salud, especialmente gastrointestinales. Objetivo: Investigar la posible actividad antiulcerosa gástrica del extracto etanólico de hojas de platypus. Métodos: Las lesiones gástricas fueron inducidas por los modelos de etanol e indometacinaevaluó el extracto con el modelo modificado de Shay. El extracto se administró por vía oral y se midió el área dañada. Además, se analizaron otros parámetros en el modelo de ligadura pilórica. Resultados: La administración oral de una dosis área de las lesiones gástricas (p < 0.05) en los modelos de inducción de etanol e indometacina. Además, se observó un incremento significativo en la secreción de moco gástrico en el modelo modific0.05). Conclusión: El extracto etanólico de Licania platypus de inducción de úlceras agudas. Este trabajo brinda la primera evidencia de especies pertenecientes al género Licania con actividad gastroprotectora y permite promover la realización de estudios para elucidar un mecanismo de acción específico.
Acurácia da ultrassonografia Modo-B no diagnóstico de gestação e determinação do número de fetos em matrizes suínas
(Ciência Veterinária nos Trópicos, 2009) Passos Pequeno, Andreia; Zúñiga Alfaro, Carlos E.; Wischral, Aurea
Neste trabalho objetivou-se avaliar a acurácia da ultrassonografia Modo- B como método diagnóstico de gestação nos dias 21 e 22 pós-inseminação artifici- al, de acordo com o número de vesículas embrionárias (VEs) contadas, bem como correlacionar o número total de leitões nascidos com o número de vesículas conta- bilizadas, durante o exame ultrassonográfico. Foram utilizadas 79 fêmeas suínas, entre os dias 21 e 22 de gestação, examinadas via transcutânea com aparelho de ultrassom (Aloka SSD 500) equipado com transdutor setorial convexo de 5,0 MHz. A acurácia do diagnóstico (92,1%) não sofreu influência da quantidade de VEs, nem do tamanho da leitegada, apesar de ter sido levemente maior quando o número de VEs e de leitões nascidos foram iguais ou superiores a oito. A correlação entre o número de leitões e o número de vesículas contabilizadas durante o exame ultras- sonográfico foi baixa e não significante. O percentual de acerto foi de apenas 20,5%. Diante do exposto, conclui-se que a ultrassonografia na produção suína é um méto- do eficiente no diagnóstico precoce de gestação. No entanto, o transdutor de 5,0 MHz não é recomendado para a previsão do tamanho da leitegada nestas condi- ções.
Additive genetic and heterosis effects for milk fever in a population of Jersey, Holstein × Jersey, and Holstein cattle under grazing conditions
(FASS Inc. and Elsevier Inc., 2018-10) Saborío Montero, A; Camacho Sandoval, Jorge; Vargas, Bernardo; ROMERO-ZUÑIGA, JUAN JOSÉ
The aim of this study was to estimate additive genetic and heterosis effects for milk fever (MF) in Costa Rican dairy cattle. A farm-based management information software was used to collect 223,783 parity records between years 1989 and 2016, from 64,008 cows, 2 breeds (Jersey, Holstein × Jersey crosses, and Holstein), and 134 herds. The pedigree file comprised 73,653 animals distributed across 10 generations. A total of 4,355 (1.95%) clinical cases of MF were reported within this population, affecting 3,469 (5.42%) cows. Data were analyzed using 2 animal models, both accounting for repeatability and assuming different distributions for MF event: normal (linear model) or binomial (threshold model). The models included parity as fixed effect, breed and heterosis as fixed regressions, and herd-year-season, additive genetic, and permanent environment as random effects. The models were fit using a generalized linear mixed model approach, as implemented in ASReml 4.0 software. We noted significant regression on the percentage of Holstein breed, depicting a −0.0086% [standard error (SE) = 0.0012] decrease in MF incidence for each 1-unit increase in percentage of Holstein breed. A favorable heterosis of 5.9% for MF was found, although this was not statistically significant. Heritability and repeatability were, respectively, 0.03 (SE = 0.002) and 0.05 (SE = 0.002) for the linear model, and 0.07 (SE = 0.007) and 0.07 (SE = 0.007) for the threshold model. The correlation between BLUP (all animals in pedigree) for linear and threshold models, was 0.89. The average accuracy of the estimated BLUP for all animals were 0.44 (standard deviation = 0.13) for the linear model and 0.29 (standard deviation = 0.14) for the threshold model. Heritability and repeatability for MF within this population was low, though significant.
Aerobic bacterial flora of nesting green turtles (Chelonia mydas) from Tortuguero National Park, Costa Rica
(American Association of Zoo Veterinarians, 2006) Santoro, Mario; Hernández, Giovanna; Caballero, Magaly; GarcÍa, Fernando
Bacteriological examination of 70 nesting green turtles (Chelonia mydas) from Tortuguero National Park, Costa Rica was performed to investigate nasal and cloacal aerobic bacteria. A total of 325 bacterial isolates were obtained, including 10 Gram-negative and three Gram-positive genera. Two hundred thirty-nine were Gram-negative and 86 were Gram-positive isolates. Klebsiella pneumoniae was the most common microbe identified in turtle samples: 27/70 (38.5%) in cloacal, and 33/70 (47.1%) in nasal samples. The Enterobacteriaceae family, including Enterobacter agglomerans, E. cloacae, Escherichia coli, Klebsiella oxytoca, K. pneumoniae, and Serratia marcescens, was the largest Gram-negative group of bacteria recovered and comprised 127 of 239 (53.1%) of the Gram-negative isolates. Staphylococcus species was the largest Gram-positive bacteria group, including S. aureus, S. cromogenes, S. epidermis, and S. intermedius, and made up 63 of 86 (73.2%) of the Gram-positive isolates recovered. The results of this study demonstrate that the aerobic bacterial flora of nesting green turtles at Tortuguero National Park is composed of a very wide spectrum of bacteria, including several potential pathogens.
Age and Sexual Maturity Estimation of Stranded Striped Dolphins, Stenella coeruleoalba, Infected with Brucella ceti
(MDPI, 2022-10-31) Roca‑Monge, Karol; González-Barrientos, Rocío; Suárez Esquivel, Marcela; Palacios Alfaro, José David; Castro Ramírez, Laura; Jiménez Soto, Mauricio; Cordero‑Chavarría, Minor; García-Párraga, Daniel; Barratclough, Ashley; Moreno, Edgardo; Hernández-Mora, Gabriela
Age parameters in cetaceans allow examining conservation and studying individuals with growth affection. The age and sexual maturity of 51 stranded Stenella coeruleoalba striped dolphins from the Eastern Tropical Pacific (ETP) of Costa Rica, most suffering brucellosis (95.6%), were assessed. In order to ascertain the dolphins’ ages, we measured the length and growth of dentin-layer group counts (GLGs) and assessed flipper bone radiography without (FBSA) and with a formula (FBF). Sexual maturity was determined through gonadal histology and sexual hormone serum levels. Compared with a model based on S. coeruleoalba ages estimations in other latitudes, the striped dolphin studied displayed deficient growth parameters, with considerable variability in length, teeth, and flippers bone development. Close to 43% (n = 15) of GLGs’ measurements were below the body length average ranges for the predicted age, suggesting developmental abnormalities. Likewise, 34.4% and 31.2% of the dolphins assessed by FBSA and FBF were also below the body length based on age prediction curves, also indicating developmental abnormalities. This information is supported by the poor correlation between GLGs, FBSA, and FBF. Inconsistencies between sexually mature males and females related to GLGs, FBSA, and FBF were evident. Although the different oceanic settings of the ETP, such as contamination, food access, diseases, and other parameters, may influence size variation, our data also suggest that long-lasting debilitating brucellosis may account for detrimental growth in the ETP striped dolphins. Our study highlights the possible deleterious consequences of chronic infectious diseases in the cetacean populations already confronting distressful conditions.
Aislamiento, identificación y caracterización de hongos nematófagos depredadores nativos de Costa Rica
(Museo Nacional de Costa Rica, 2015) Orozco Aceves, Martha; Jiménez Rocha, Ana Eugenia; Acuña Navarro, Oscar; Álvarez Calderón, Víctor
Tropical ecosystems provide biological resources with potential to be used in agricultu- re, for example, the predatory nematophagous fungi (PNF), which can be used as biological control agents of parasitic nematodes of plants and animals. A successful biological control should incorpo- rate locally isolated organisms, for this reason the aim of this study was to investigate the presence of PNF in non-disturbed ecosystems and agroecosystems of Costa Rica. Samples of soil, litter, organic fertilizers, and animal feces were collected across five counties of Costa Rica, and screened for PNF through the soil sprinkling technique. Twenty-seven strains were isolated; 15 Candelabrella musiformis, 11 Arthrobotrys oligospora, and one Dactylella sp. The strains were morphologically characterized both macro and microscopically. Our results indicated that strains of PNF are locally available in Costa Rica, therefore their use as part of a biological control strategy to combat parasitic nematodes is viable.

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