Evolución funcional tras un ictus en mayores de 85 años / Functional outome in stroke patients older than 85 years

Introducción. El ictus constituye la primera causa de discapacidad en el adulto y la segunda de mortalidad, siendo más frecuente en pacientes ancianos. El objetivo de este trabajo es conocer la evolución funcional al año de todos los pacientes mayores de 85 años que fueron valorados por el Servicio de Rehabilitación tras ingresar por un ictus en nuestro hospital durante el año 2014. Material y métodos. Estudio prospectivo longitudinal, observacional realizado en 41 pacientes. Se analizaron: datos sociodemográficos, características clínicas del ictus, situación neurológica al ingreso (NIHSS), situación funcional (Índice Barthel, Escala Rankin) y capacidad de marcha, al ingreso, al alta de rehabilitación y al año. Todos los análisis estadísticos se realizaron mediante el IBM SPSS Statistics 19 para Windows y se fijó como valor de significación estadística 0,05. Resultados. La edad media fue 88,6 años (85-97), 56% mujeres. El valor medio del NIHHS en la 1ª semana fue de 11,2. Estancia media hospitalaria, 15 días. El Índice de Barthel previo al ictus fue de 80,6 y el Rankin 1,51, al año del ictus, 54,5 y 2,79 respectivamente. Fallecieron 18 pacientes (41,8%). Los factores que influyeron de forma significativa en la recuperación funcional fueron: la mejor situación funcional previa, el NIHSS < a 10, la ausencia de fibrilación auricular, la menor comorbilidad y la no afasia. Conclusión. Al año de haber sufrido un ictus los pacientes muy ancianos presentan una gran mortalidad y los que sobreviven tienen una pérdida funcional importante (AU)

Introduction. Stroke is the main cause of disability in adults and the second cause of mortality, being more common in elderly people. The aim of this study was to determine the functional outcome at 1 year in all patients older than 85 years who were evaluated by the Rehabilitation Therapy Service after being admitted for stroke in 2014. Materials and methods. A longitudinal, observational, prospective study was conducted in 41 patients. We analysed sociodemographic information, the clinical characteristics of the strokes, neurological status at admission (NIHSS), functional status (Barthel Index and Rankin Scale) and walking capacity at admission, at rehabilitation discharge, and after one year. All statistical test were conducted with IBM SPSS Statistics 19 for Windows and statistical significance was set at a p-value of 0.05. Results. The mean age of the patients was 88.6 years (85-97) and 56% were women. The average NIHSS score in the first week was 11.2. The mean length of hospital stay was 15 days. The initial Barthel score was 80.6 and initial Rankin score was 1.51; these scores were 54.5 and 2.79, respectively, at 1 year after stroke. Eighteen patients (41.8%) died. The factors that significantly influenced functional recovery were a better previous functional status, NIHSS score <10, the absence of atrial fibrillation, having fewer comorbidities and the absence of aphasia. Conclusions. One year after a stroke, elderly patients showed a high mortality rate, and those who survived had substantial functional loss(AU)

Utilización de la prótesis en amputados de miembro inferior / Use of prostheses in lower limb amputees

Introducción. El proceso de protetización del amputado de miembro inferior es un reto para el médico rehabilitador, dada la complejidad del mismo. El objetivo de este estudio es averiguar el tiempo de utilización de las prótesis en los amputados de miembro inferior de nuestro Hospital, así como conocer qué factores pueden influir en su uso. Material y métodos. Hemos realizado un estudio longitudinal, observacional de los pacientes protetizados de extremidad inferior en nuestro centro en los últimos 3 años. Se han recogido datos demográficos y características de la amputación. Para conocer el tipo de deambulación con la prótesis hemos utilizado la escala de Houghton. Para valorar el nivel de independencia, las comorbilidades y la calidad de vida se utilizaron los índices de Barthel, Charlson y el cuestionario SF-12 respectivamente. Resultados. Se obtuvo una muestra de 30 pacientes con 60 años de edad media. Veintidós amputados transtibiales y 8 transfemorales. La rehabilitación fue satisfactoria (al menos 9 puntos en la escala Houghton) en el 73% de los pacientes. El nivel de independencia fue alto, con una media en el índice de Barthel de 87,82. Encontramos una moderada correlación negativa (-0,41) entre el índice de Charlson y las horas de uso diarias. La calidad de vida fue superior entre los pacientes con amputación transtibial. Conclusión. El nivel de uso de la prótesis de los pacientes de nuestro centro se puede considerar bueno, siendo la comorbilidad asociada un factor limitante en cuanto a las horas de uso (AU)

Introduction. The process of fitting a prosthesis in a lower limb amputee is a challenge for physiatrists due to the complexity of prosthetic management. The purpose of this study was to determine the actual time of usage of lower limb prostheses in our hospital and to identify the factors that can influence adherence to use. Methods and materials. We conducted an observational study of all patients fitted with a lower limb prosthesis in our hospital during the last 3 years. We gathered demographic data and the characteristics of the amputations. The Houghton scale was used to the classify walking ability of the amputees in our study. To evaluate the level of independence, comorbidities and quality of life, we used the Barthel Index, Charlson Comorbidity Index and the SF-12 questionnaire, respectively. Results. The sample consisted of 30 patients with a mean age of 60 years. Amputations were transtibial in 22 and transfemoral in 8. The rehabilitation process was considered satisfactory (at least 9 points in the Houghton scale) in 73% of the patients. The level of independence achieved was high, with a mean of 87.82 in the Barthel Index. We found a moderate negative correlation (-0.41) between the Charlson Comorbidity Index and the daily number of hours of prosthesis use. Quality of life was higher in patients with transtibial amputations. Conclusions. In our centre, lower limb prostheses were used for an adequate amount of time. A limiting factor for the number of hours of use was associated comorbidity (AU)

Long-term RNA persistence of porcine rubulavirus (PorPV-LPMV) after an outbreak of a natural infection: the detection of viral mRNA in sentinel pigs suggests viral transmission.

The persistence of porcine rubulavirus (PorPV-LPMV) in five pigs that had survived an outbreak of a natural infection was determined. After the resolution of the outbreak, each animal was housed in an isolation pen together with one sentinel pig. Approximately every 2 months thereafter one group of animals was euthanized and tissue samples taken for virological and serological analysis. Infectious virus was not isolated from any samples; antibodies to PorPV-LPMV were detected in convalescent pigs by virus neutralisation test and blocking ELISA but not in sentinel pigs. PorPV-LPMV mRNA of the nucleoprotein (NP) and phosphoprotein (P) genes was detected by a nested polymerase chain reaction (nPCR) in samples of trigeminal and optic nerves, cervical spinal cord, tonsils, salivary gland, lung and pancreas from convalescent pigs. mRNA was also detected in the midbrain, corpus callosum, or olfactory bulb in four out of five pigs by nRT-PCR, this result was confirmed by the sequencing of a 260bp PCR product of P gene region. The highest average viral copies/µg of total RNA occurred in the olfactory bulb and pancreas tissues of convalescent pigs and midbrain, tonsil and pancreas of sentinel pigs housed with the convalescent pigs. Satellitosis and gliosis of the midbrain, olfactory bulb, corpus callosum, medulla oblongata or choroid plexus were microscopically observed in four convalescent pigs. The control pig remained negative in all tests. The results indicate that PorPV-LPMV mRNA persists and induces a durable humoral immune response in pigs that have recovered from a natural infection. After a possible reactivation of the virus, it was transmitted to sentinel pigs in contact with the convalescent pigs.

Laparoscopic versus open total mesorectal excision: a nonrandomized comparative prospective trial in a tertiary center in Mexico City.

Because definitive long-term results are not yet available, the oncologic safety of laparoscopic surgery in rectal cancer remains controversial. Laparoscopic total mesorectal excision (LTME) for rectal cancer has been proposed to have several short-term advantages in comparison with open total mesorectal excision (OTME). However, few prospective randomized studies have been performed. The main purpose of our study was to evaluate whether relevant differences in safety and efficacy exist after elective LTME for the treatment of rectal cancer compared with OTME in a tertiary referral medical center. This comparative nonrandomized prospective study analyzes data in 56 patients with middle and lower rectal cancer treated with low anterior resection or abdominoperineal resection from November 2005 to November 2007. Follow-up was determined through office charts or direct patient contact. Statistical analysis was performed using chi2 test and Student's t test. Twenty-eight patients underwent LTME and 28 patients were in the OTME group. No conversion was required in the LTME group. Mean operating time was shorter in the laparoscopic group (LTME) (181.3 vs 206.1 min, P < 0.002). Less intraoperative blood loss and fewer postoperative complications were seen in the LTME group. Return of bowel motility was observed earlier after laparoscopic surgery. There was no 30-day mortality and the overall morbidity was 17 per cent in the LTME group versus 32 per cent in the OTME group. The mean number of harvested lymph nodes was greater in the laparoscopic group than in the OTME group (12.1 +/- 2 vs 9.3 +/- 3). Mean follow-up time was 12 months (range 9-24 months). No local recurrence was found. LTME is a feasible procedure with acceptable postoperative morbidity and low mortality, however it is technically demanding. This series confirms its safety, although oncologic results are at present comparable with the OTME published series with the limitation of a short followup period. Further randomized studies are necessary to evaluate long-term clinical outcome.

Self-clearance from BVDV infections--a frequent finding in dairy herds in an endemically infected region in Peru.

In this cross-sectional study, a stratified two-stage random sampling procedure was employed to select 221 dairy herds for bulk tank milk (BTM) sampling, and a subset of 55 dairy herds for individual blood sampling of a number of young animals (spot test), to predict presence or absence of current BVDV infection, and for data collection. The prediction was based on the high probability of seropositivity in groups of animals where PI animals are present because of the efficient spread of virus from PI animals to the surrounding group. BTM samples were collected in August 2003 (n=192) and February 2004 (n=195), and the 55 herds selected for spot testing and data collection were visited in December 2003. All samples were tested for presence of BVDV specific antibodies using a commercial indirect ELISA (SVANOVA Biotech AB, Uppsala, Sweden). The results demonstrated a very high level of exposure to BVDV in the region, and the proportion of herds with high antibody levels in the BTM was above 95% on both occasions. Despite this, almost two thirds of the herds had spot test results indicating absence of current infection, suggesting a high probability of self-clearance. A logistic regression model with the results from the spot tests as dependent variable was used to investigate possible herd and management factors associated with self-clearance, and suggested that this may occur regardless of herd size. Even though it is well established that the process of identification and elimination of PI animals is required within a systematic BVDV eradication programme, the present study strongly suggests that many herds may be cleared without intervention even in regions with high cattle density and high BVDV prevalence. Consequently, in any BVDV infected population (regardless of the herd-level BVDV seroprevalence), and at any given point of time, a large proportion of the herds will be free from infection due to self-clearance. Self-clearance is therefore a process that works in favour of any effort to control BVDV, which should be taken into account when planning and assessing the cost-effectiveness of a systematic control programme.

[Safety and efficacy of the MARS therapy applied by continuous renal replacement therapy (CRRT) monitors]. / Seguridad y eficacia de la terapia MARS aplicada mediante monitores de TCRR.

OBJECTIVE: Analyze the utility and safety of MARS therapy applied with the CRRT monitor. DESIGN: Prospective study of cohorts. SCOPE: Polyvalent ICU in tertiary university hospital with hepatic transplantation program. PATIENTS: Thirty one patients: 9 (22.6%) with acute liver failure (ALF) (1 hepatic surgery, 1 primary graft failure, 7 other causes) and 22 (71%) with acute-on-chronic failure (AoCLF). INTERVENTIONS: For the treatment, the patients with ALF are maintained in the ICU but those with AoCLF are admitted for the performance of the different sessions, that are programmed for a duration of at least 15 hours in AoCLF and in ALF are maintained continuously, changing the circuit every 24 hours. VARIABLES OF INTEREST: Metabolic control and complications registered in 75 sessions on 31 patients. RESULTS: Urea decrease was 33.5 (29-38%), creatinine 36 (31-41%), total bilirubin 29 (25-33%) and direct bilirubin 34 (30-38%). Clearance was slower, but sustained, after the first 4 hours of each session both for urea (p<0.001) as well as for bilirubin (p<0.05). The hemodynamic parameters improved and the hematological ones were not altered. We detected decrease in platelets (131 to 120x109/L, p<0.01). In 95 of the sessions in which heparin was used and in 6% where epoprostenol was used, we observed mild bleeding. We cultured albumin of the circuit at the end of the session in 50 occasions and only obtained growth in 3 cases (6%) (2 Staphylococcus epidermidis, 1 S. haemolyticus) without signs of contamination in the patients. CONCLUSIONS: The MARS system applied by CRRT monitors provide adequate bilirubin clearance percentages and is safe, even in serious patients. Prolongation of the duration of the sessions was not accompanied by an increase in the risk of infection secondary to the albumin contamination.

Full-length genome sequence and genetic relationship of two paramyxoviruses isolated from bat and pigs in the Americas.

Mapuera virus (MPRV) was isolated from a fruit bat in Brazil in 1979, but its host range and disease-causing potential are unknown. Porcine rubulavirus (PoRV) was identified as the aetiological agent of disease outbreaks in pigs in Mexico during early 1980s, but the origin of PoRV remains elusive. In this study, the completed genome sequence of MPRV was determined, and the complete genome sequence of PoRV was assembled from previously published protein-coding genes and the non-coding genome regions determined from this study. Comparison of sequence and genome organization indicated that PoRV is more closely related to MPRV than to any other members of the genus Rubulavirus. In the P gene coding region of both viruses, there is an ORF located at the 5' end of the P gene overlapping with the P protein coding region, similar to the C protein ORF present in most viruses of the subfamily Paramyxovirinae, but absent in other known rubulaviruses. Based on these findings, we hypothesise that PoRV may also originate from bats, and spillover events from bats to pigs, either directly or via an intermediate host, were responsible for the sporadic disease outbreaks observed in Mexico.

A prospective study of the effect of Neospora caninum and BVDV infections on bovine abortions in a dairy herd in Arequipa, Peru.

We used a prospective seroepidemiological approach to investigate endemic abortion in a dairy herd in Arequipa, Peru, and its association with Neospora caninum and bovine viral-diarrhoea virus (BVDV) infections. Between January 2002 and March 2004, 1094 pregnancies were confirmed in 538 cows. Of these, 137 pregnancies (13%) in 121 cows ended in abortion. The serological status to N. caninum was assessed using a single serological screening, whereas BVDV status was assessed at the herd level through consecutive samplings of young stock. Cox proportional-hazards models were used to estimate the effect of N. caninum and BVDV on the hazard of early (between day 42 and day 100 in gestation), and late (after day 100) abortions, respectively. Serological status to N. caninum was included as a dichotomous variable, and the effect of BVDV estimated at the herd level, as a time-dependent seasonal effect. Because data from repeated pregnancies were included, we considered possible lack of independence between observations and included frailty effects into the models. Our models also considered the possible confounding by parity and animal origin. Only multiparity was associated with the hazard of early abortion (HR=2.8 compared to nulliparous heifers). N. caninum seropositivity significantly affected the hazard of late abortion, but interacted with parity. The HRs for Neospora-positive animals were 6.4, 3.7 and 1.9, respectively, for nulliparous heifers, first-lactation cows and multiparous cows. Evidence of BVDV circulating (or not) among the young stock was not associated with abortions, but few cows in this herd were susceptible to incident infection.

Experimental porcine rubulavirus (La Piedad-Michoacan virus) infection in pregnant gilts.

Porcine rubulavirus (La Piedad-Michoacan virus) (PoRV-LPMV) is a member of the Paramyxoviridae family that causes encephalitis in young piglets and infertility in adult sows and boars. Infertility in sows naturally infected by PoRV-LPMV is characterized by an increased number of returns to oestrus, stillbirths and mummified fetuses. In this study, nine seronegative gilts were inoculated intranasally with the PAC-3 strain of PoRV-LPMV at week 6 or 10 of gestation. These animals were then killed at weeks 8 or 15 of gestation (seven gilts) or after natural parturition (two gilts). Four control gilts were mock-infected at gestation week 6 or 10 and killed between 2 and 4 weeks later. Gross lesions of focal congestion and haemorrhage were seen in the placenta and endometrium of one gilt infected at gestation week 6 and one infected at gestation week 10. PoRV-LPMV was isolated, at 2-6 weeks post-inoculation (pi), from lung, tonsils, ovary, placenta, uterus and lymph nodes of three of the gilts infected at gestation week 6 and at 2-3 weeks pi from lung, tonsil and ovary of two gilts infected at gestation week 10. Many of the fetuses of eight infected gilts were smaller than normal and had dermal ecchymoses. Dehydrated or mummified fetuses were present in six of the infected gilts but not in any control animal. PoRV-LPMV was isolated from brain, lung and liver of fetuses from two gilts infected at gestation week 6, and from two infected at gestation week 10. These results indicate that, after experimental infection, PoRV can replicate in tissues of seronegative pregnant gilts, cross the placenta, and cause fetal death and mummification.

BVDV and BHV-1 infections in dairy herds in northern and northeastern Thailand.

Bulk milk samples from 220 dairy herds were collected at 9 public milk collection centres in the northeastern and northern Thailand, and a subset of 11 herds was selected for individual testing. The samples were tested for presence of antibodies to BVDV and BHV-1 using an indirect ELISA. The results from the bulk milk testing demonstrated a moderate level of exposure to BVDV and BHV-1 (73% and 67%, respectively). However, the low proportion of herds with high BVDV antibody-levels (13%) and the low within-herd seroprevalence of BVDV and BHV-1 in the 11 herds (24% and 5%, respectively), particularly among the young stock (15% and 0%, respectively), demonstrated a low prevalence of active BVDV infection and a low rate of reactivation of latent BHV-1. The presence of a self-clearance process was also indicated by the results from the individual testing. Moreover, a surprisingly low prevalence of BVDV and BHV-1 antibody-positive herds at one of the milk centres was found. This centre was established 5-10 years before the others. Our impression is that this reflects the self-clearance process, where consecutive replacement of imported infected animals without further spread has resulted in a nearly total elimination of the infections. Based on our experiences and on these results we are convinced that this process can continue if there is awareness of herd biosecurity. This is especially important in the context of a future intensification of the dairy production.

Apoptosis in lymph nodes and changes in lymphocyte subpopulations in peripheral blood of pigs infected with porcine rubulavirus.

In a first experiment, five pigs were inoculated intranasally with porcine rubulavirus (PoRV) at 5 days of age and killed 7 days post-infection (pi). In a second experiment, four pigs were infected with the same virus at 17 days of age and killed at 9 or 15 days pi. Control piglets in each experiment received uninfected cell culture supernate. All PoRV-infected pigs developed respiratory and nervous signs, and histological lesions of non-suppurative encephalitis and interstitial pneumonia. All control pigs remained clinically normal and did not have histological lesions. Significantly increased numbers of apoptotic cells were detected by terminal deoxynucleotidyl transferase biotin-dUTP nick end labelling (TUNEL) in tonsil and lymph nodes of the pigs infected at 7 days of age and killed at 7 days pi. Significantly increased percentages of CD2(+) and CD8(+) T lymphocytes were also found in peripheral blood of these animals at this time, while the percentages of CD4(+) and MHC class II lymphocytes were significantly reduced. Significantly increased numbers of apoptotic cells were detected in lymphoid tissues of the pigs infected at 17 days of age and killed at 9 days pi. The percentages of CD2(+), CD8(+) and MHC class II lymphocytes in peripheral blood were also significantly increased at this time; the percentage of MHC class II lymphocytes remained elevated at 15 days pi. These results indicate that induction of apoptosis is an important mechanism in the pathogenesis of PoRV infection in young pigs, and that this virus induces changes in lymphocyte subpopulations in peripheral blood.

Bulk milk testing for antibody seroprevalences to BVDV and BHV-1 in a rural region of Peru.

Bulk milk from 60 herds of dairy cattle in a rural region in the central highlands of Peru was tested for antibodies to bovine viral-diarrhoea virus (BVDV) and bovine herpesvirus type 1 (BHV-1). None of the herds had been vaccinated against BVDV or BHV-1. Commercially available indirect ELISA-kits were used for antibody detection. True prevalences of BVDV and BHV-1 antibody-positive herds were 96 and 51%, respectively. A relatively low proportion of strongly positive herds suggests, however, a low prevalence of active BVDV infection. BVDV optical densities (ODs) in bulk milk increased with herd size--indicating a higher within-herd prevalence in the larger herds (probably, in part a consequence of a higher rate of animal movement into these herds). For BHV-1, this pattern was not found; a relatively high proportion of the herds was free from BHV-1 infection in each size category. This could indicate a low rate of reactivation of latent BHV-1 infection.

Contaminants in feed for food-producing animals.

Outbreaks of Bovine Spongiform Encephalopathy (BSE) and food borne microbial infections, dioxin contaminated animal products, the presence of veterinary drug residues, microbial resistance to antibiotics, mycotoxins, agricultural and industrial chemicals, etc. are serious concerns for the food industry in many countries. Since the direct links between feed safety and safety of foods of animal origin are obvious, feed production and manufacture should be considered as an integral part of the food production chain. Industry is responsible for the quality and safety of food and feed that is produced. This paper is a brief review of some microorganisms as source of infections for farm animals that could result in human illnesses. These include Salmonella enterica, Bacillus anthracis, Toxoplasma gondii, Trichinella spiralis, prions, Listeria monocytogenes, EHEC, Campylobacter, Clostridium botulinum, Hog Cholera virus, Foot and Mouth Disease virus, etc. as well as other contaminants associated with animal feed such as mycotoxins, veterinary drugs, dioxins and PCB and Genetically Modified Organisms.

Occurrence of clinical and sub-clinical mastitis in dairy herds in the West Littoral Region in Uruguay.

Twenty-nine dairy farms were selected to determine the incidence of clinical mastitis, prevalence of sub-clinical mastitis and bacterial aetiology in the West Littoral Region of Uruguay. In samples taken by the owner and frozen at -20 degrees C during a week the incidence rate of clinical mastitis was determined as 1.2 cases per 100 cow-months at risk. Staphylococcus aureus was the most common isolated pathogen in 37.5% of 40 milk samples from clinical cases obtained in 1 month. No bacteria grew in the 32.5% of the total samples. A sub-sample including 1077 dairy cows from randomly selected farms was used to determine the prevalence of sub-clinical mastitis. These samples were taken on one visit to each farm. The prevalence was 52.4% on a cow basis and 26.7% on an udder quarter basis. In 55.1% of the quarters of the selected animals with more than 300,000 cells/ml there was no growth. The isolated pathogens from sub-clinical cases and their relative frequencies were: Staphylococcus aureus 62.8%, Streptococcus agalactiae 11.3%, Enterococcus sp. 8%, coagulase-negative staphylococci 7.4%, Streptococus uberis 6.4%, Streptococcus dysgalactiae 1.8%, Escherichia coli 1.5% and Staphylococcus hyicus coagulase-positive 0.6%.

Uptake of porcine rubulavirus (LPMV) by PK-15 cells.

BACKGROUND: The porcine virus denominated La Piedad Michoacan Virus (LPMV) is a member of the family Paramyxoviridae and is the cause of a disease in pigs present only in Mexico. The disease is characterized by meningoencephalitis and respiratory distress in young pigs, epididymitis and orchitis in boars, and reproductive failure and abortion in sows. METHODS: The cytopathology, morphology, and distribution of the hemagglutination neuraminidase (HN) and nucleoprotein (NP) proteins of LPMV were investigated following inoculation into PK-15 cells. The cytopathic effect was characterized by cytoplasmic vacuolation and the formation of syncytia and cytoplasmic inclusion bodies. RESULTS: In immunofluorescence assays using a monoclonal antibody (MAb) against the HN protein at 5-60 min post-infection (early infection), a diffuse immunofluorescence was observed near the cell membrane and adjacent to the nuclear membrane. At 24 h post-infection (late infection), a dust-like immunofluorescence was observed throughout the cytoplasm. LPMV-infected cells incubated with the MAb against the NP protein showed punctate cytoplasmic fluorescence during the early stages of infection. At the late infection stage, these fluorescent particles became larger and were seen predominantly in the cytoplasm of syncytia. This pattern was also apparent by immunohistochemical labeling and immunogold electron microscopy. The latter technique revealed that HN protein was diffusely distributed throughout the cytoplasm. When using the MAb against the NP protein, nucleocapsid organization was the most prominent feature and resulted in the formation of cytoplasmic inclusion bodies visible by light and electron microscopy. Immunogold labeling of purified nucleocapsids was shown by electron microscopy. Virus particles and nucleocapsids were morphologically similar to members of the Paramyxoviridae family. CONCLUSIONS: The morphologic characteristics of the virions and the distribution patterns of the HN and NP proteins in PK-15 infected cells indicate that the mechanisms of LPMV replication are generally similar to those of the members of the Paramyxoviridae family.

Serological and molecular diagnosis of bovine viral diarrhoea virus and evidence of other viral infections in dairy calves with respiratory disease in Venezuela.

An investigation based on 2 studies was carried out to assess the involvement of bovine virus diarrhoea virus (BVDV), bovine herpesvirus type 1 (BHV-1), and bovine respiratory syncytial virus (BRSV) in calf respiratory disease in dairy farms in Venezuela. In the first study, 8 farms were selected and paired serum samples from 42 calves with respiratory disease were tested by ELISA for antibodies to the 3 viruses. Seroconversion to BVDV, BHV-1, and BRSV was found to 5, 2, and 6 farms out of the 8, respectively. The proportion of calves that showed seroconversion to BVDV, BHV-1, and BRSV were 19%, 14%, and 26%, respectively. In the second study, another farm having previous serological evidence of BVDV infection was selected. The decline of maternal antibodies against BVDV was monitored in 20 calves and the half-life of maternal antibodies was 34 +/- 12 days presumably indicating an early natural infection with BVDV. Furthermore, sera free of BVDV antibodies that were collected in studies 1 and 2 and were assayed for the presence of BVDV by nested RT-PCR. Two BVDV strains were detected and compared to those of ruminant and porcine pestiviruses. Both strains were assigned to subgroup Ib of type I BVDV. This investigation provides information on BVDV genotypes circulating in Venezuela and may contribute to the establishment of official control programmes against the viruses studied.

Seroprevalence to bovine virus diarrhoea virus and other viruses of the bovine respiratory complex in Venezuela (Apure State).

Six hundred and fifteen serum samples obtained from cows in five districts of Apure State, Venezuela, were tested by ELISA for antibodies to bovine virus diarrhoea virus (BVDV). The same samples were also ELISA-tested for antibodies to bovine herpesvirus type 1 (BHV-1) and bovine respiratory syncytial virus (BRSV). Additionally, the haemagglutination-inhibition (HI) test was used for detecting antibodies to parainfluenza virus type 3 (PIV-3). Overall, seroprevalence to BVDV was 36+/-7% (SE); seroprevalence varied by district (19-42%). BHV-1 seroprevalence was 67+/-4%; variation by district was similar to that of BVDV. However, the first 80 serum samples tested by BHV-1 ELISA all had a strong background reaction with the control antigen. Therefore, these sera were adsorbed to a homogenate of non-infected bovine kidney cell line (MDBK) and retested by ELISA. The non-specific reactivity was significantly reduced (p<0.001 by Wilcoxon's signed-rank test). Compared to the virus-neutralisation (VN) test, the adsorbed BHV-1 ELISA showed 94% agreement and gave a kappa value of 0.84, indicating that the adsorption did not interfere with test accuracy. Seroprevalence against BRSV was 85+/-3%, and showed differences across districts. Most of the cows (94+/-2%) were seropositive to PIV-3, and there were no significant differences among districts.

Development of a blocking ELISA for screening antibodies to porcine rubulavirus, La Piedad Michoacan Virus.

A blocking enzyme-linked immunosorbent assay (ELISA) was developed to detect antibodies to porcine rubulavirus (La Piedad Michoacan Virus [LPMV]) in serum samples from pigs. The test, based on a monoclonal antibody against the LPMV hemagglutinin-neuraminidase glycoprotein, had a sensitivity of 99% and a specificity of 97%. The results of this test were in agreement with those obtained by an indirect ELISA and hemagglutination inhibition, indirect immunofluorescence, and virus neutralization tests. The blocking ELISA is considered the most suitable test for routine screening for antibodies against LPMV.

Porcine rubulavirus LPMV RNA persists in the central nervous system of pigs after recovery from acute infection.

In order to study persistence of the porcine rubulavirus LPMV, we examined tissue samples collected from pigs 53 days after experimental infection. These pigs survived the initial infection and could clinically be considered to have recovered from the infection. Two of the pigs used in this study were chemically immunosuppressed during the last 4 days before necropsy. No infectious virus or viral antigen could be detected in any tissue using standard methods for virus isolation and detection. However, the presence of viral genomic RNA and mRNA could be demonstrated in the mid brain of the convalescent pig using an optimised RT-nested PCR. Mid brain, forebrain and lung were all shown to contain LPMV RNA in the immunosuppressed convalescent pigs. In addition we examined the P-gene editing in the recovered pigs and conclude that the viral genome is transcriptionally active in these pigs. The relevance of the persistence of LPMV for maintenance and spread within and/or between pig populations is discussed.

Multiple factors including subgenomic RNAs and reduced viral protein expression are associated with a persistent infection by porcine rubulavirus (LPMV).

The synthesis of virus specific RNA and the expression of viral proteins in PK-15 cells persistently infected with the porcine rubulavirus LPMV have been studied at two different cell-passages following establishment of persistency (passages 25 and 65). Protein analysis of persistently infected cells and the virus particles released from these failed to demonstrate the presence of the polymerase (L) protein. A decrease in the amount of the phospho- (P) protein was also noted. The genome and mRNAs, both mono- and bicistronic, could readily be identified in the persistently infected cells with the exception of the L mRNA. By analysis of transcription gradients generated using the NIH Image analysis software, as well as analysis of the editing frequency, it was concluded that the changes in viral protein levels in persistently infected cells could be associated with a reduction in the amount of L mRNA and a shift in editing of the P gene. In addition, several large subgenomic RNAs of both the internally deleted and copy-back type were found in the persistently infected cells. The relevance of these findings to the persistent state is discussed.