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Featured researches published by Jorun Jarp.


Veterinary Microbiology | 1991

Classification of coagulase-negative staphylococci isolated from bovine clinical and subclinical mastitis

Jorun Jarp

One hundred and forty eight strains of coagulase-negative staphylococci (CNS) from bovine clinical and subclinical mastitis were classified by conventional biochemical testing. Staphylococcus simulans was the most frequently isolated species. The distribution of CNS species in the two groups was similar regardless of whether the cow suffered from clinical or subclinical mastitis. There was no significant difference between the grades of severity of the clinical mastitis associated with the various CNS. The small difference in pathogenicity observed between species in this study, and the similarity of distribution in the various species of clinical and subclinical mastitis could indicate that the species per se is of minor importance in the development of mastitis.


Preventive Veterinary Medicine | 2000

A space-time cluster investigation of an outbreak of acute respiratory disease in Norwegian cattle herds.

Madelaine Norström; Dirk U. Pfeiffer; Jorun Jarp

Outbreaks of acute respiratory disease occurred in several cattle herds in the south-east regions of Norway during the winter and spring of 1995. The present study was conducted to investigate the temporal and spatial dynamics of the occurrence of acute respiratory disease between January and April 1995 in the affected cattle herds, in two neighbouring counties in Norway. This was done to assess the possible role of an infectious agent in these outbreaks, as well as to investigate the possibility of transmission between neighbouring herds. During the study period, a total of 190 (19.8%) outbreaks occurred in 955 cattle herds located in the defined study area. Descriptive maps of the spatial and spatio-temporal patterns of the outbreak were generated, and two different statistical tests of space-time interaction (the Knox test and k-nearest neighbour test) and a cluster-detection test (the space-time scan statistic) were used. The results of all the space-time interaction tests strongly suggested that the case herds were clustered in time as well as in space. In addition, the space-time scan statistic defined the most-likely cluster to be located within the second veterinary district (Toten where the disease occurred) during 9-15 weeks in 1995. The relative risk of a herd being infected inside the most-likely cluster compared with the surrounding study area was estimated to be 3.59 (p=0.001). The transmission rate between neighbouring farms therefore appeared to have been higher within this cluster than in the surrounding study area. This study supports the hypothesis that one common source of infection was involved in the outbreaks during the study period.


Preventive Veterinary Medicine | 2002

Factors associated with mortality in Norwegian broiler flocks

B.T Heier; H.R Høgåsen; Jorun Jarp

Our aim in this longitudinal study (covering years from 1996 to 1999) was to use data regularly recorded in a production database, to identify farm- and flock-level factors associated with cumulative mortality in broiler flocks during: (a) the 1st week after housing and (b) the rest of the growout (2nd to 5th week). A total of 1664 broiler flocks kept in 132 broiler farms were included. The average weekly cumulative mortality was 1.54% (95% CI: 1.46, 1.62%) during the 1st week and 0.48% (95% CI: 0.47, 0.49%) during the rest of the growout. The final least-squares regression model of cumulative mortality during the 1st week identified the following significant factors: study year, flock size, stocking density, use of paper underlay for feeding during the 1st week, and the interaction terms between type of ventilation, drinking system and floor insulation. The final model for the 2nd to 5th week demonstrated that the factors age of the broiler house, heating system and control system for the air intake were associated with cumulative mortality, but the effects of the two latter variables were significantly modified by age of the broiler house. A significant difference in mortality between flocks delivered from various hatcheries was found in both analyses. Our results suggest that changes in several housing factors and management routines might reduce the mortality losses, but the relationship depends on the stage of production.


Preventive Veterinary Medicine | 2001

A case-control study on scrapie in Norwegian sheep flocks.

Petter Hopp; M.J. Ulvund; Jorun Jarp

Scrapie first was detected in indigenous sheep in Norway in 1981, and from 1995 to 1997 an increase in the number of flocks with scrapie cases was recorded. These flocks were mainly in one geographical region. A study to identify risk factors for scrapie was conducted. The study had three frequency-matched controls selected for every case within the same Veterinary District. A questionnaire was submitted to 176 sheep flocks (42 had been scrapie flocks). The data obtained by the questionnaire were linked to data collected from governmental and industry registers. After imputing missing data using single random imputation, the statistical analysis was performed using multivariable conditional logistic regression. Purchase of female sheep from scrapie flocks, sharing of rams, or sharing of pastures between different flocks were the risk factors associated with the occurrence of scrapie. Of factors potentially sustaining and promoting the infection in the flock, number of winter-fed sheep, number of buildings for housing sheep, rams and ewes shared room during mating period and increase in the flock size were associated with scrapie. We interpret these findings to show that factors involving transfer of sheep between flocks or direct contact between sheep of different flocks are important for the spread of scrapie. Management factors are important for the development of scrapie. However, it was not possible to discriminate between the different management factors in this study at the flock level. Also, factors indicating awareness and interest of the farmer (as well as willingness to contact a veterinarian for diseased sheep) were related to the detection of scrapie in the flock.


Preventive Veterinary Medicine | 2000

Risk factors for epidemic respiratory disease in Norwegian cattle herds.

Madelaine Norström; Eystein Skjerve; Jorun Jarp

An epidemic of acute respiratory disease associated with bovine respiratory syncytial virus (BRSV) occurred during the winter and spring of 1995 in two neighbouring veterinary districts in the south-eastern part of Norway. The objective of this study was to describe the time course of the outbreak associated with BRSV in the cattle herds, and to determine the association between selected herd factors and the risk of experiencing a herd outbreak of acute respiratory disease. Data from 431 cattle herds on the dates of disease occurrence, location of the farms, herd size, age profile and production type were collected retrospectively for 1995. The risk of acute respiratory disease occurring in a cattle herd was related to the herd size as well as the type of production, with an expressed interaction between these two variables. From the Cox proportional-hazards model, the risk of a herd outbreak in a mixed herd of 20 animals was estimated to be 1.7-times greater than in a dairy herd and 3.3-times greater than a beef herd (reference category) of a comparable size. On increasing the herd size to 50 animals, the risk increased 1.3-fold for a mixed herd, 3.3-fold for a dairy herd, and 2.1-fold for a beef herd, compared to the risk for a corresponding type of herd of 20 animals.


International Journal of Food Microbiology | 2002

An evaluation of the Norwegian Salmonella surveillance and control program in live pig and pork.

Marianne Sandberg; Petter Hopp; Jorun Jarp; Eystein Skjerve

Population data and apparent prevalence data from the Salmonella surveillance and control program in pigs (NSSCP) from 1998 and 1999 were used in a simulation model to evaluate the efficacy of the program. The model consists of three parts: modelling of individual prevalence at the abattoir (abattoir part), modelling of the number of sampled herds of different sizes when carcasses are randomly sampled at the abattoir (sampling strategy part) and finally, modelling of the within herd prevalence (within herd part). A total of 136,550 sows and 2,866,550 finishing pigs slaughtered, 4446 herds and 11 herds positive for Salmonella in 1994/1995-2000 were included in the abattoir part, sampling strategy part and the within herd part of the model, respectively. The abattoir part showed an average estimated prevalence of Salmonella in sows and finishing pigs of (median) 0.4% (5-95 percentiles = 0.03-2%) and 0.1% (0.04-0.2%) respectively. The estimated number of infected sow carcasses that entered the market was 502 (37-2157) while the estimated number of finishing pig carcasses was 2919 (1218-5771). The probability of being sampled for the 10% smallest herds was (mean) 1.9% (1.6-2.2), to 25% (24.7-26.5%) for the 10% largest herds. The within herd prevalence was estimated to be from 1% to 4% for Norwegian pig herds. The conclusions drawn from this evaluation are that the NSSCP does not have any significant consumer protection effect, and that the documentation could be done more effectively using the herd rather than the individual animal as the unit of sampling. Sampling should focus on the larger herds supplying most of the meat on the market and on herds that produce breeding sows and piglets and thus can contribute to the spread of Salmonella among herds.


Apmis | 1988

A rapid assay for protein-A in Staph, aureus strains, using immunomagnetic monosized polymer particles

Berit Johne; Jorun Jarp

Monosized magnetic polystyrene beads, Dynabeads M‐450, coated with sheep IgG were used in an agglutination test for the detection of cell‐surface protein‐A, based on Fc‐protein‐A binding. Ninety‐three per cent of the bovine Staphylococcus aureus strains isolated from clinical mastitis expressed surface protein‐A. The agglutination test was rapid compared to FITC‐labelled IgG binding or dog‐serum agar precipitation test for protein‐A, and was significantly correlated with these methods. Scanning electron micrographs demonstrated binding of protein‐A positive bacteria to the particle surface, thus bridging the beads and forming the agglutination lattice. The microsphere agglutination assay described is a quick, simple and reproducible method for detecting surface protein‐A in staphylococci.


Preventive Veterinary Medicine | 2001

A retrospective analysis of the infectious bovine rhinotracheitis (bovine herpes virus-1) surveillance program in Norway using Monte Carlo simulation models

Larry Paisley; Jorun Tharaldsen; Jorun Jarp

Serological surveillance for antibodies against bovine herpes virus type I (BHV-1) which causes infectious bovine rhinotracheitis and infectious pustular vulvovaginitis has been carried out since 1992 in Norway. Since 1993 (when a single infected herd was detected) all bulk-milk and pooled-serum samples have been negative for BHV-1 antibodies. This paper describes the use of Monte Carlo simulation models for the analysis and interpretation of the results of the surveillance and provides support for the contention that the Norwegian cattle population is not infected by BHV-1.


Preventive Veterinary Medicine | 2000

A simulated surveillance program for bovine paratuberculosis in dairy herds in Norway.

Larry Paisley; Jorun Tharaldsen; Jorun Jarp

Monte Carlo simulation models were used to evaluate the feasibility and potential results of a proposed national survey of the prevalence of bovine paratuberculosis (PTB) in dairy herds in Norway. The expected herd prevalence was assumed to be 0.2% in the simulations. The low sensitivity of the ELISA test, the assumed low herd prevalence, the typical low within-herd prevalence of PTB and the small herd sizes all present problems in detection of the disease. Simulations with 500, 1000, 2500 and 6000 herds tested were done. Our results suggest that a national survey would not be feasible at present, due to the low probability of detecting infected herds and because of the high number of false-positive reactions that would be expected to occur.


Preventive Veterinary Medicine | 2001

The effect of an outbreak of respiratory disease on herd-level milk production of Norwegian dairy farms

Madelaine Norström; Victoria L. Edge; Jorun Jarp

This study was done to evaluate the effect of an outbreak of acute respiratory disease associated with bovine respiratory syncytial virus (BRSV) on the daily milk yield per cow in Norwegian dairy-cattle farms. Retrospective data from 184 dairy herds located in two neighbouring veterinary districts during the study period (December 1994-May 1995, during which an epidemic of acute respiratory disease associated with BRSV occurred in this area) were analysed. Data on the bulk-milk deliveries and the date of the outbreak were collected at herd level, whereas information on calving dates and parity was collected at cow-level. The effect of the herd outbreaks on the daily milk yield was analysed with a repeated-measurement approach. The average daily milk loss was estimated to be 0.70kg per cow for 7 days after a herd outbreak (compared with the period >1 week prior to an outbreak), adjusted for the herd-level lactation stage, parity and their interaction term. We consider the estimated milk loss associated with a herd outbreak of epidemic respiratory disease to be of minor importance.

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Petter Hopp

National Veterinary Institute

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B.T Heier

National Veterinary Institute

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Madelaine Norström

National Veterinary Institute

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Jorun Tharaldsen

National Veterinary Institute

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Larry Paisley

National Veterinary Institute

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Eystein Skjerve

Norwegian University of Life Sciences

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Berit Johne

National Veterinary Institute

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G Schaller

National Veterinary Institute

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H.R Høgåsen

National Veterinary Institute

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