Stochastic model to assess bioeconomic impact of PRRS on pig farms in Costa Rica.

Despite the economic importance of PRRS and its high prevalence in Costa Rica, there are no studies on the bioeconomic impact of the disease in the country or, even, in Central America. Such studies are essential in finding cost-effective preventive measures tailored for different production circumstances. Therefore, the objective of this study was to evaluate economic and production parameters of a PRRSV-infection for a medium-sized farrow-to-finish pig farm system in Costa Rica with a farm-level stochastic Monte Carlo simulation model. The effect of PRRS was assessed by scenario analysis, in which a baseline PRRS-free situation was compared against three alternative scenarios that assumed low, medium and high PRRS effects. The PRRS effects were based on data from local farms, scientific literature and expert opinion. Sensitivity analyses were performed to assess the impact of key input parameters on output variables. Results show that at the animal level, changes between the baseline and the PRRS-high scenario were estimated as: + 25 d in age to slaughter, - 9.9 pigs to slaughter (per breeding sow/yr), + 6% annual replacement rate, - 255 d in sow productive lifetime, - 6.9 mo in age at culling of sows, and + 24 non- productive days. For a medium size local farm (n = 588 sows), a reduction of 5826 fat pigs to slaughter per farm/yr from baseline compared to PRRS-high scenario was observed. PRRS-induced loss per farm per year was estimated at -US $142,542, US $180,109 and -US $524,719 for PRRS-low, medium and high scenarios, respectively. Revenues/costs ratio changed from 1.12 in the baseline to 0.89 in the PRRS-high scenario. The production cost per kg carcass weight increased from US $2.63 for the baseline to US $3.35 in the PRRS-high scenario. PRRS-induced loss was estimated at US $77.1 per slaughtered pig/yr and US $892 per breeding sow/yr for the PRRS-high scenario. Results from the model indicate that pig farms with medium to high prevalence of PRRS will require optimal market conditions in order to have positive economic outcomes. These results can be helpful in the design of better control strategies for PRRS.

Comparative productive performance of cows born through embryo transfer, artificial insemination and natural mating in dairy and dual-purpose herds raised in tropical conditions.

A populational, observational and longitudinal-retrospective study with records of 28 dairy-specialized and dual-purpose farms was carried out to compare the productive performance of cows born by embryo transfer (ET), artificial insemination (AI) and natural mating (NM), using the database of Centro Regional de Investigación para la Producción Animal Sostenible (CRIPAS) of cattle herds in Costa Rica. Herds (system × altitude), conception method (ET, AI and NM), genetic background (DSpB: specialized dairy breeds [Bos taurus] and crosses, GYR × HOL: Gyr × Holstein Crossbred and DSpB × BI: crosses between dairy breeds and Bos indicus), year of birth (or at calving), lactation number and days in milk were evaluated for the productive parameters age at first calving (AFC), calving to conception interval (CCI) and lactation milk yield (LMY) using a GLIMMIX procedure on SAS. The AFC, CCI and LMY were affected (p < .0001) by all factors considered in each parameter. ET has lower (p < .0001) AFC in months (33.1) than AI (35.2) and NM (36.44). NM had lower (p = .004) CCI (110 days) than AI or ET (121 days) values which were similar (p > .05). The higher LMY (p < .0001) was observed in ET (4140 kg), compared to AI (3706 kg) and NM (3595 kg). There was no difference between AI and NM. In conclusion, the method of conception in calves affected their future reproduction and production during puberty, postpartum and lactation. The effects on management decisions will require a rigorous economical study to discern whether ET would be a cost-effective alternative to AI or NM.

Additive genetic and heterosis effects for milk fever in a population of Jersey, Holstein × Jersey, and Holstein cattle under grazing conditions.

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.

Risk factors associated with milk fever occurrence in grazing dairy cattle.

The aim of this study was to determine risk factors associated with milk fever (MF) occurrence in Costa Rican grazing dairy cattle. A total of 69,870 cows from 126 dairy herds were included in the study. Data were collected in the Veterinary Automated Management and Production Control Program software by the Population Medicine Research Program of the Veterinary Medicine School, National University of Costa Rica, from 1985 to 2014. To determine the risk factors for MF, 2 logistic regression mixed models were evaluated. The first model used breed, month of calving, ecological life zone, herd nested within ecological life zone, and parity as fixed effects. The second model excluded first-lactation animals and cows without production information, had the same fixed effects of the first model, and added previous MF case, previous lactation length, previous dry period length, previous corrected 305-d milk yield, and calving interval length as fixed effects. Both models used animal and year as random effects. Of the 235,971 recorded lactations, 4,312 (1.83%) reported MF event. The significantly associated risk factors for MF occurrence, ranked by their highest odds ratio (OR), were parity (OR = 52.59), previous dry period length (OR = 4.21), ecological life zone (OR = 3.20), breed (OR = 3.04), previous corrected 305-d milk yield (OR = 2.39), previous MF case (OR = 2.35), and month of calving (OR = 1.36). The findings of this study are the first data reported using an epidemiological approach to study risk factors for MF in Costa Rican dairy cattle. Some of these results might be used to improve preventive management practices at the farms to reduce the incidence of this metabolic disease in grazing dairy herds.

Environmental factors associated with Dictyocaulus viviparus and Fasciola hepatica prevalence in dairy herds from Costa Rica.

Dictyocaulosis and fasciolosis are parasitic diseases that cause considerable economic losses for owners of farm animals worldwide, with special relevance on fasciolosis because it is an emerging zoonosis. Indirect diagnosis of these diseases through analyses of bulk milk tank samples has allowed carrying out large-scale prevalence studies, while the use of geographical information systems has helped to visualize and determine those variables that affect distribution of these pathogens. This study is intended to describe the spatial distribution of Dictyocaulus viviparus and Fasciola hepatica in dairy herds from Costa Rica, as well as their associated environmental factors. Bulk milk tank samples from 526 dairy herds in the three most important dairy regions of Costa Rica were analyzed using enzyme immunoassays. Results from the farms were subjected to spatial analyses using Holdridge's life zones, relief and soil type environmental layers. Of the total bulk milk tank samples analyzed, 3.8% (n=20) and 3.6% (n=19) were positive for D. viviparus and F. hepatica, respectively. Moran's I analysis revealed the existence of potential cluster (Moran's I=1.789, z=12.726 p<0.05) for D. viviparus. Consequently, Getis-Ord General G analysis showed that the spatial distribution of positive farms in the dataset was clustered (Observed General G=0.015, variance=0.000001, z=12.823, p<0.05). No significant positive spatial autocorrelation (Moran's I=0.038, z=0.286, p>0.0.5) was observed for F. hepatica. Furthermore, a significant difference was detected in the spatial locations of both parasites (latitude p<0.05, longitude p<0.05), and about the spatial distribution of both D. viviparus negative and positive farms (latitude p<0.05, longitude p<0.05), as well as in F. hepatica negative and positive farms regarding on latitude (p<0.05), but not on longitude (p>0.05). In the case of environmental factors, significant differences were found for D. viviparus and F. hepatica with respect to types of soil, precipitation, altitudinal belts, life zones, biotemperature, and elevation.

Detection of antibodies against Chlamydophila abortus in Costa Rican sheep flocks.

A total of 359 sheep samples from 15 flocks were analyzed for the presence of antibodies against Chlamydophila abortus using a commercial Enzyme linked Immunosorbent Assay (ELISA). Antibodies were detected in 19 (5.29%) sheep from 12 (80%) flocks. Seropositive animals were found in all analyzed regions (Central, Chorotega, Atlantic Huetar, North Huetar and Central Pacific) determining prevalence between 0.28% and 4.4%, and intra-flock positivity between 3.7% and 25.0%. The survey revealed two risk factors associated with seropositivity; introducing animals (males and females), embryos, or semen from other farms or from abroad without any sanitary certification, and flocks not having quarantine areas or separated boxes for diseased animals. No clinical signs of disease were observed in positive seroreactors. C. abortus seems to be present in Costa Rica in a very low prevalence in sheep flocks. Further studies, to isolate the bacteria are required. Finally, implementation of control measures to prevent the spread of C. abortus is recommended.

Serosurveillance of infectious agents in equines of the Central Valley of Costa Rica.

Blood samples from 181 equines from the Central Valley of Costa Rica were collected in the year 2012 to determine the presence of antibodies against selected infectious agents in horses and to determine the risk factors associated with these agents. The presence of antibodies against Equine Infectious Anemia Virus (EIAV), Equine Herpes Virus 1 and 4 (EHV-1 and EHV-4), West Nile Virus (WNV), Influenza A Virus (IAV), Equine Viral Arteritis Virus (EVAV), Babesia caballi, Theileria equi, Neospora caninum and Chlamydia abortus was determined using commercial assays, and risk factors associated with seropositivity to the different infectious agents was established. The most seroprevalent agent detected was EHV-4 (96.7%), followed by WNV (44.2%), and IAV (41.8%). Horses >3 years, used for work or sports, and with access to pastures, had significantly increased probability to be seropositive to WNV, whereas horses used for breeding and recreational purposes, being stabled, and without access to pastures, had significantly greater probability to be seropositive to IAV. Seroprevalence to B. caballi (19.9%) was lower than to T. equi (38.1%). For B. caballi, access to pastures was determined as a risk factor, whereas being older than 3 years was established as a risk factor for T. equi. Low seroprevalences were determined for EHV-1 (5.0%), EVAV (5.0%), C. abortus (4.8%), and N. caninum (4.4%). Mares having history of abortion were more likely to be seropositive to EHV-1, whereas horses >3 years, used for work and sports, and mares having multiple parturitions, were more likely to be seropositive to N. caninum. None of the horses were seropositive to EIAV. Earlier, only diseases caused by EIAV, WNV and piroplasmosis were reported in Costa Rica. The present study however, determined the presence of carriers for EHV-1, EHV-4, and EIAV.

Factores de riesgo para el desarrollo de infecciones intrahospitalarias en pacientes quemados. Hospital S. Juande Dios, Costa Rica: Enero 2003-Diciembre 2005. Parte II / Risk factors for development of intrahospitalary infections in burned patients. Hospital S. Juan de Dios, Costa Rica: January 2003-December 2005. Part II

En los pacientes quemados, existen diferentes factores como la edad, sexo y días de estancia hospitalaria entre otros, que influyen en el desarrollo de infección intrahospitalaria (IIH). Debido a la mayor frecuencia de este tipo de infecciones en los pacientes quemados, pretendemos identificar qué factores influyen en la presentación y predicción de la infección intrahospitalaria en el sitio de la quemadura (IISQ).El presente estudio es una cohorte retrospectiva, sobre 298 registros de expedientes clínicos de pacientes ingresados en la Unidad Nacional de Quemados del Hospital San Juan de Dios (UNQ-HSJD) en Costa Rica, continuando otra investigación del mismo grupo de autores publicada anteriormente en Cirugía Plástica Ibero latinoamericana. A cada factor de riesgo estudiado se le calcularon los dos ratio crudos en un análisis univariado definiendo como variables de exposición principal la superficie corporal total quemada (SCTQ) y la profundidad de la quemadura (PQ). Observamos con este cálculo que el tipo de accidente no presentaba asociación cola IISQ. Después, realizamos un modelo multivariado logístico, no condicional, en el que se introdujeron los siguientes factores de riesgo: SCTQ,PQ, edad, número de segmentos corporales quemados (NSCQ), días de estancia hospitalaria previos a la infección intrahospitalaria en el sitio de la quemadura (DEHP-IISQ) y el agente causal de la quemadura. Consideramos variables confesora y modificadora de efecto al NSCQ y DEHP-IISQ. Determinamos que las principales variables predictoras para la IISQ fueron SCTQ (OR=3.02; 1.20-7.84), PQ (OR=11.44; 4.90-26.71),NCSQ (OR=2.80; 1.13-6.95), y DEHP-IISQ (9 a 14 días: OR=2.43; 0.52-11.29, >19 días: OR=31.89; 2.17-467.68). Pese a que no mostró significancia estadística, también se introdujo la edad en el modelo, debido a la tendencia aumentar el riesgo conforme ésta aumentaba ( >64 años: OR=3.15; 0.61-16.29) (..) (AU)

In burn victims, different factors such as age, gender and days of hospitalization among others, are influential in the development of inner-hospital infections (IHI). Due to a higher incidence of IHI in burn victims, it is pretended to identify which factors influence the presence and prediction of inner-hospital infections in the burned area (IHIBA).This study is a retrospective cohort that recruited 298 registries of medical reports from patients admitted into the National Burn Victims Unit as an Juan de Dios Hospital (NBVU-HSJD), Costa Rica, and following previous report in this journal. The odds ratio (OR) were calculated for each risk factor in a univariated analysis, and defined as principal exposition variables were the total burn surface (TBS) and the depth of the burn (DB).It was deduced from this calculation that the type of accident did not show any association with IHIBA. Subsequently, a multivariate logistic not conditioned study was carried out, in which, the following risk factors were introduced: TBS, DB, age, number of burnt body segments (NBBS), days of hospital stay previous to the IHIBA (DHSP-IHIBA) and the burn’s causing agent. Confusing and modifying variables of effect were also considered, respectively, for the NBBS and the DHSP-IHIBA. It was concluded that the main predicting variables for the IHIBA were (..) (AU)

Factores de riesgo para el desarrollo de infecciones intrahospitalarias en pacientes quemados. Hospital S. Juan de Dios, Costa Rica: Enero 2003-Diciembre 2005. Parte I / Risk factors for development of intrahospitalary infections in burned patients. Hospital S. Juan de Dios, Costa Rica: January 2003-December 2005. Part I

La infección intrahospitalaria es una de las principales causas de morbilidad y mortalidad en los pacientes quemados. El presente estudio caracteriza a los ingresados por quemadura(s) y la presencia de esta clase de infección en la Unidad Nacional de Quemados del Hospital San Juan de Dios, en Costa Rica, entre los años 2003y 2005.Realizamos un análisis descriptivo de la infección intrahospitalaria en el sitio de la quemadura según las características de los pacientes y de la quemadura así como el total de días de estancia hospitalaria, utilizando para ello un diseño de estudio tipo cohorte retrospectiva. La incidencia acumulada de la infección intrahospitalaria en el sitio de la quemadura fue de 19.0%. Los meses posteriores al ingreso clases presentaron un mayor número de hospitalizaciones por quemaduras. La edad, la superficie corporal total quemada, el número de segmentos corporales quemados, la profundidad de la quemadura y los días de estancia hospitalaria presentaron diferencias significativas entre los individuos infectados y no infectados. El tipo de accidente que produjo la quemadura y el sexo no presentaron diferencias significativas entre ambos grupos de pacientes. La electricidad fue el agente causal más frecuente en los pacientes con infección, mientras que el agua caliente lo fue en los pacientes sin infección. Concluimos que las características fisiopatológicas de las quemaduras favorecen infección en los pacientes quemados; asimismo, existen factores que pueden y deben ser tomados en cuenta para controlar y prevenir la infección y sus efectos (AU)

Intrahospitalary infection in burned patients is one of the most important causes of morbidity and mortality. This study characterizes the admitted burn victims and the presence of inner-hospital infection at the National Burn Victims Unit , San Juan de Dios Hospital, Costa Rica, between 2003 and 2005.We made a descriptive analyze of intrahospital infection in the burned area according characteristics of the patients and their burn(s), as well as the total number of days of hospital stay, using prospective cohort. The accumulated incidence for intra hospital infection in the burned area was 19.0%. In the months following the beginning of the school year, the number of burn victims admitted in the hospital increased. Age, total burnt surface, the number of burnt body segments, the depth of the burn and the days of hospital stay varied significantly between infected and not infected individuals. Theca use of the burn and the victim’s gender did not reveal any relevant differences between the groups of patients. For patients that developed intrahospital infection in the burned area, electricity was the most frequent causing agent, as was hot water for patients without intra hospital infection in the burned area. As a conclusion, physiopathology characteristics of the burns favour the occurrence of the intra hospital infection in the burned area; furthermore, there are factors than can and must be taken into account to control and prevent intrahospital infection in the burned area and its effects (AU)

Prevalence of Toxocara spp., Toxascaris leonina and ancylostomidae in public parks and beaches in different climate zones of Costa Rica.

This epidemiological study was conducted in different regions of Costa Rica to determine the prevalence of the developmental stages of potential zoonotic intestinal helminths of dogs and cats in public places. Samples were collected within three main climate zones including rural and urban areas during both the rainy and the dry season. Faecal and environmental samples were taken from 69 parks and beaches. Of the faecal samples 3% contained Toxascaris spp. eggs, 7% Toxocara spp. eggs and 55% contained ancylostomidae eggs. Of the soil samples, 2% contained ancylostomidae eggs and 0.8% contained ascarid eggs. Significant differences in the presence of parasites were found in faecal samples of dry, moist and wet climate zones and between the dry and rainy seasons. Significant differences in the presence of eggs and larvae were also found in the grass samples in the dry, the moist and the wet climate zones and between the different seasons. No significant differences were found between rural and urban areas.

Comparison among DNA polymerases 1, 2 and 3 from maize embryo axes. A DNA primase activity copurifies with DNA polymerase 2.

Three DNA polymerase activities, named 1, 2 and 3 were purified from maize embryo axes and were compared in terms of ion requirements, optimal pH, temperature and KCl for activity, response to specific inhibitors and use of templates. All three enzymes require a divalent cation for activity, but main differences were observed in sensitivity to inhibitors and template usage: while DNA polymerases 1 and 2 were inhibited by N-ethyl maleimide and aphidicolin, inhibitors of replicative-type enzymes, DNA polymerase 3 was only marginally or not affected at all. In contrast, DNA polymerase 3 was highly inhibited by very low concentrations of ddTTP, an inhibitor of repair-type enzymes, and a 100-fold higher concentration of the drug was needed to inhibit DNA polymerases 1 and 2. Additionally, DNA polymerases 1 and 2 used equally or more efficiently the synthetic template polydA-oligodT, as compared to activated DNA, while polymerase 3 used it very poorly. Whereas DNA polymerases 1 and 2 shared properties of replicative-type enzymes, DNA polymerase 3 could be a repair-type enzyme. Moreover, a DNA primase activity copurified with the 8000-fold purified DNA polymerase 2, strengthening the suggestion that polymerase 2 is a replicative enzyme, of the alpha-type. This DNA primase activity was also partially characterized. The results are discussed in terms of relevant data about other plant DNA polymerases and primases reported in the literature.

Arthroscopic use of the Herbert screw in osteochondritis dissecans of the knee.

This article describes repair of osteochondritis dissecans of the knee by arthroscopic Herbert screw fixation and reports the healing response and clinical results. Eleven patients were subjected to surgery using arthroscopy and all were affected by symptomatic osteochondritis dissecans of the medial femoral condyle. Average follow-up time was 16.3 months (13-29). One to four Herbert screws were used, either as the only fixation method or in conjunction with absorbable pins [poly (p-dioxanone)], depending on size and fragmentation of the injury. The patients were non-weight bearing for 10 weeks. The radiographic evidence of healing was correlated with the clinical outcome. The results were excellent or good in 81.8% of the patients. Arthroscopic Herbert screw fixation is an effective and safe method of repair for osteochondritis dissecans of the knee.

Osteochondritis dissecans of the anterior tibial spine.

A 12-year-old boy had a history of pain in the right knee for 2 months, mainly pain in extension. He could not recall any trauma to the knee. The radiograph suggested osteochondritis dissecans in the anterior spine. An arthroscopy was performed and a prominence in the tibial insertion of the anterior cruciate ligament in the anterointernal area was observed, and the fragment resected. The diagnosis of osteochondritis dissecans was confirmed by pathological study. As far as we are aware, this is the first case describing this new location.