Quantitative risk assessment of introduction of BVDV and BoHV-1 through indirect contacts based on implemented biosecurity measures in dairy farms of Spain

A stochastic quantitative risk assessment model was developed to estimate the annual probability of introduction of bovine viral diarrhea virus (BVDV) and bovine herpesvirus 1 (BoHV-1) on 127 dairy farms through indirect contacts. Vehicles transporting calves, cattle to slaughterhouse, dead animals, and mixture of feed, as well as visits by veterinarians and hoof trimmers, farm workers and contacts with neighbors were considered in the model. Data from biosecurity questionnaires of each farm, scientific literature and expert opinion from field veterinarians, animal vehicle drivers, hoof trimmers and personnel from rendering transport companies were used to estimate values for input parameters. Results showed that the annual probability of introducing BVDV or BoHV-1 through indirect contacts was very heterogeneous. The overall distribution of median values for each farm ranged from 0.5 to 14.6% and from 1.0 to 24.9% for BVDV and BoHV-1, respectively. The model identified that providing protective clothing and boots to visits, not allowing the animal vehicle driver to come into contact with animals present on the farm and ensuring that calf vehicles arrived empty, were the measures with the highest impact on the probability of infection for most farms. This model could be a useful tool to show the impact of the measures to farmers and veterinarians, thus increasing their awareness on biosecurity. In addition, it could support decision making on which measures should be prioritized in dairy cattle herds to reduce the probability of introduction of diseases.

Short communication: Risk factors associated with Mycobacterium avium ssp. paratuberculosis introduction into dairy herds in Galicia, northwestern Spain

This study assessed potential risk factors associated with introduction of Mycobacterium avium ssp. paratuberculosis (MAP) into dairy cattle herds in the Galicia region, northwestern Spain. The study was carried out with data collected from 93 dairies enrolled in a voluntary MAP control program. Information on potential risk factors was obtained through personal interviews with the farmers and veterinarians in charge of the control program of each farm. In addition, blood samples were taken annually over 2 years from cows on the farms in the program, and analyzed with a commercial ELISA to detect antibodies to MAP. Fecal samples of all ELISA-positive cows were analyzed using PCR. Based on χ² test and Fisher's exact test, purchase practices, shared manure truck, shared materials, and visitors per month who contacted animals were found to be significantly associated with farm MAP infection status. Multiple logistic regression indicated that purchase practices and herd size (included as a potential confounder) are the variables that best predict MAP status.

Development of a quantitative risk assessment of bovine viral diarrhea virus and bovine herpesvirus-1 introduction in dairy cattle herds to improve biosecurity

A quantitative risk assessment model was developed to estimate the annual probability of introducing bovine viral diarrhea virus (BVDV) and bovine herpesvirus 1 (BoHV-1) at the farm level through animal movements. Data from 2017 official animal movements, biosecurity questionnaires, scientific literature, and expert opinion from field veterinarians were taken into consideration for model input parameters. Purchasing or introducing cattle, rearing replacement heifers offsite, showing cattle at competitions, sharing transport vehicles with other herds, and transporting cattle in vehicles that have not been cleaned and disinfected were considered in the model. The annual probability of introducing BVDV or BoHV-1 through infected animals was very heterogeneous between farms. The median likelihoods of BVDV and BoHV-1introduction were 12 and 9%, respectively. Farms that purchased cattle from within their region (i.e., local movements) and shared transport with other farms had a higher probability for BVDV and BoHV-1 introduction. This model can be a useful tool to support decision-making on biosecurity measures that should be prioritized to reduce the probability of introduction of these 2 diseases in dairy herds.

Identification of the Photoreceptor Transcriptional Co-Repressor SAMD11 as Novel Cause of Autosomal Recessive Retinitis Pigmentosa

Retinitis pigmentosa (RP), the most frequent form of inherited retinal dystrophy is characterized by progressive photoreceptor degeneration. Many genes have been implicated in RP development, but several others remain to be identified. Using a combination of homozygosity mapping, whole-exome and targeted next-generation sequencing, we found a novel homozygous nonsense mutation in SAMD11 in five individuals diagnosed with adult-onset RP from two unrelated consanguineous Spanish families. SAMD11 is ortholog to the mouse major retinal SAM domain (mr-s) protein that is implicated in CRX-mediated transcriptional regulation in the retina. Accordingly, protein-protein network analysis revealed a significant interaction of SAMD11 with CRX. Immunoblotting analysis confirmed strong expression of SAMD11 in human retina. Immunolocalization studies revealed SAMD11 was detected in the three nuclear layers of the human retina and interestingly differential expression between cone and rod photoreceptors was observed. Our study strongly implicates SAMD11 as novel cause of RP playing an important role in the pathogenesis of human degeneration of photoreceptors.

[Control of arterial hypertension by means of a regimen of hemodialysis on alternate days (HDAA or EODD: "Every Other Day Dialysis") versus 2 conventional regiments of 4 and 5 hours per session 3 times a week with 72 hours without sessions during the weekends]

An increase in the frequency of hemodialysis sessions improves control of extracellular volume and blood hypertension and consequently reduces the mortality related to cardiovascular aetiology in hemodialysis patients.We report the evolution of the blood hypertension depending on the need for antihypertensive drugs in a group of 38 prevalent patients that were included in a every-other-day dialysis schedule (EODD), and compare it with the results in two other groups of prevalent patients that were dialyzed in conventional, previously employed schedules without week-end sessions 4 hours x 3 x week and 5 hours x 3 x week. All three groups received hemodialysis treatment for more than 6 months.A 68% (26/38) of the patients received antihypertensive treatment at the beginning the EODD schedule and, after 16 months, only 7.9% (3/38) of them required antihypertensive treatment (p < 0.001) with reduction in two of the three remanent patients; hypertension control in those 25 patients took an average of 100 +/- 15 days. The final frequency of hypertension in EODD was lower (p < 0.002) than the frequency registered in the 84 prevalent patients in 4h x 3 x week schedule, and also lower (p = 0.065) than the frequency of the 56 prevalent patients in 5h x 3 x week schedule. There is a significant difference (p < 0,05) between EODD and 4h x 3 x week schedule as regards average figures of: increase in weight, decrease in dry-weight, blood pressure levels and hypotension incidence. EODD also produced better results than 5h x 3 x week schedule in this regard although statistics did not reflect it. The results using the every-other-day hemodialysis schedule support previous experiences(Lecce, Columbia) which achieved a good control of the dry-weight by means of suppressing the volume overload gained during the weekend and consequently obtaining adequate ultrafiltration rates and high reduction both of the hypertension and of the symptoms of intolerance to hemodialysis, which are so frequent in conventional schedules with 72 hours without hemodialysis sessions.

[Systemic arterial hypertension in primary chronic glomerulonephritis: prevalence and its influence on the renal prognosis]

Nowadays, glomerulonephritis is one of the most common causes of End-stage Renal Disease and starting point of dialysis in Spain. Several factors may influence negatively in this prognosis; among them, we may show up the systemic arterial hypertension. Though its prevalence in the glomerulonephritis is considered higher than in other nephropathies, with variations among series, probably due to difference in ages, in geographical areas, in histological types, in time on evolution of the nephritis ... and because it is difficult to distinguish if the hypertension is a consequence of the nephritis or a consequence of the renal failure that can be present in several cases. In the same way, its negative influence in the renal prognosis may be influenced more by this renal failure, which can be its cause when it is quite severe, than by the hypertension itself. Our aims were to analyse, on the one hand the prevalence of hypertension in the 394 patients diagnosed of primary glomerulonephritis by means of a renal biopsy during two decades in the Bay of Cadiz, as well as its influence in the renal prognosis since the moment of the diagnosis, even with the absence of severe renal failure. We gathered demographic, clinical, analytical and histological data, as well as the situation of the renal function and the survival period of it at the end of each patient study. For the analysis prognosis and renal survival, Kaplan-Meier curves and the long-rank test were used. Of the 394 patients, 247 are men and 147 are women, with an average age of 36.7 +/- 17.7 years old. The global prevalence of hypertension was 39%, with a higher frequency in older patients. The gathered rate of renal survival for hypertensive patients was 54%, 28%, 20% and 4% at 5, 10, 15 and 20 years respectively; while for non-hypertensive patients, it was 83%, 75%, 66% and 62% for the same periods of time (p < 0.001). This worse tendency for hypertensive patients is observed too in each particular histological type, especially in the IgA nephropathy and membranous nephropathy. These results were the same for the patients who did not have severe renal failure in the moment of the biopsy.

CONCLUSIONS

Hypertension is a common fact in the primary glomerulonephritis, which also conditions, in an important way, the renal prognosis itself in a long term, from the moment of diagnosis and even before the existence of a significant renal failure.

[Benefits of every other day dialysis (EODD) without rest for 72 hours in patients with symptomatic cardiovascular disease]

With the purpose to improve the clinical situation of nine hemodialysis patients who suffer from severe cardiovascular disease and are highly symptomatic after weekends without dialysis because of fluid overload, their dialysis schedule was changed from 5 hours in 3 sessions per week to 4 hours every other day sessions (EODD), avoiding 72 hours of interdialitic weekend period. In each patient, during 38 sessions previous to starting the EODD (stage 1: 3 months) and the 38 sessions in EODD, which followed the first month of this dialysis regime (stage 2), the frequency of the next incidences was registered (ratio in 348 sessions, in every stage, of this patients group): presence of dysnea and/or hypertension pre dialysis session, pre or intra dialysis angor, emergency sessions with hypotension and sessions without achieving predetermined dry-weight. During the EODD stage, sessions, with dysena, hypertension and pre or intra dialysis angor were reduced in 80% (p < 0.001); the incidence of sessions with hypotensive episode or sessions without achieving dry-weight decreased in a third. All patients experimented a considerable improvement in their clinical situation. In addition, the whole group reduced dry-weight and later regained it without presenting symptoms which had motivated EODD schedule. EODD schedule improves the clinical situation in patients with cardiopathy who would not do so when following previous schedule (which includes 48 hours without dialysis).

Detection of hepatitis G virus (HGV) RNA and antibodies to the HGV envelope protein E2 in a cohort of hemodialysis patients

An analysis of the evolution of hepatitis G virus (HGV) infection markers was performed for a cohort of 58 hemodialyzed patients. During follow-up (4.88 +/- 0.42 years), a group of these patients cleared their antibodies against the envelope protein E2 with (4 of 29 cases; 13.8%) or without (9 of 29 cases; 31%) the reappearance of viremia. This finding implies a temporally limited protection in patients previously infected with HGV.

A 3-year follow-up of HCV-RNA viraemia in haemodialysis patients

BACKGROUND

Hepatitis C virus (HCV) infection in a population of haemodialysed patients was studied over a 3-year follow-up period in order to evaluate the changes in viral RNA, diversity of genotypes, and serological response to synthetic HCV peptides.

METHODS

Twenty-eight (32.9%) patients with anti-HCV antibodies from a total of 85 patients assigned to a haemodialysis unit were studied. The serological response to immunopeptides was evaluated by immunoblotting, viral RNA in serum was detected using the polymerase chain reaction (RT-PCR), and genotyping was carried out by hybridization with probes fixed to nitrocellulose paper.

RESULTS

Of the 28 haemodialysis patients who had anti-HCV antibodies, three (10.7%) were always RNA negative, six (21.4%) were always RNA positive, and 19 (67.8%) were variable RNA. There was an incomplete antibody response to non structural antigens in non-viraemic patients. Genotype was determined in 23 patients, and the other two could not be genotyped. The most common genotype was 1b (69.4%), followed by 1a (17.4%), and 2a, 3a, and 4a (each 4.4%).

CONCLUSIONS

Haemodialysis patients, when followed up for a long time, frequently show an intermittent HCV viraemia state, suggesting that HCV cannot be evaluated adequately by isolated RNA determinations.