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K L Morgan

Publications and source records attributed to K L Morgan.

At least 37 records · Page 2Linked to original sources
PubMed2004

Molecular epidemiology of foot-and-mouth disease viruses in the Adamawa province of Cameroon.

Foot-and-mouth disease virus (FMDV) causes a highly contagious viral disease of even-toed ungulates and is one of the most important economic diseases of livestock. Most studies of FMDV are done in countries where control measures are being implemented. In contrast, in areas such as sub-Saharan Africa, where FMDV is endemic and new strains are likely to emerge, there are only sporadic submissions to the World Reference Laboratory, Pirbright, United Kingdom. This paper describes the molecular epidemiology of FMDV in the Adamawa province of Cameroon based on a population sample of cattle herds. Serotypes SAT2 and A were isolated in the cross-sectional study. SAT2 isolates were all similar, with phylogenetic distances of <6%, and were most closely related to published sequences of isolates from Eritrea and Saudi Arabia. Serotype A isolates were more variable, with phylogenetic distances of 0 to 11%, and were most closely related to historic isolates from Cameroon. Use of a population-based sample gives a representative sample of virus diversity and will improve our understanding of the evolution of FMDV and its epidemiology. A supplementary study of pigs passing through the railhead collection yard at Ngaoundere detected a serotype O virus. A third pilot longitudinal study monitored viral persistence in three cattle herds over 12 months, and serotype O and A viruses were recovered from a herd 12 months after it was first recorded as being infected with SAT2 virus. The pig type O isolate was not closely related to that recovered from the cattle, suggesting that the pigs had not introduced the O virus into the cattle herds.

Animals↗
PubMed2004

A prospective cohort study to investigate risk factors for horse falls in UK hurdle and steeplechase racing.

REASONS FOR PERFORMING STUDY: Equine fatalities during racing continue to be a major welfare concern and falls at fences are responsible for a proportion of all equine fatalities recorded on racecourses. OBJECTIVES: To identify and quantify risk factors for horse falls in National Hunt (NH) racing and to report the frequency of falling and falling-associated fatalities. METHODS: A prospective cohort study was conducted on 2879 horse starts in hurdle and steeplechase races on 6 UK racecourses. Any horse that suffered a fall at a steeplechase or hurdle fence during the race was defined as a case. Data were obtained by interview and observations in the parade ring and from commercial databases. Multivariable logistic regression models, allowing for clustering at the level of the track, were used to identify the relationship between variables and the risk of falling. RESULTS: There were 124 falling cases (32 in hurdling and 92 in steeplechasing) identified. The injury risk of fallers was 8.9% and fatality risk 6.5%. Duration of journey to the racecourse, behaviour in the parade ring and weather at the time of the race were associated with falling in both hurdle and steeplechase racing. Age, amount of rainfall and going were also associated with falling in steeplechase racing. CONCLUSIONS: Falls at fences are significant contributors to equine fatalities during NH racing. Potentially modifiable risk factors identified were the condition of track surfaces and journey time to the racecourse. POTENTIAL RELEVANCE: It is hoped that information from this study may be used in future interventions to improve horse and jockey safety in racing. The study has also identified areas requiring further research, such as equine behaviour and its effect on racing performance, and the effect of light conditions on jumping ability.

Accidental Falls↗
PubMed2004

Whip use and race progress are associated with horse falls in hurdle and steeplechase racing in the UK.

REASONS FOR PERFORMING STUDY: Falls during racing present a risk of injury to both horse and jockey and a risk of fatality to horses. OBJECTIVES: To use video recordings of races to describe the circumstances surrounding horse falls at hurdle and steeplechase fences and to identify and quantify within-race risk factors for horse falls in National Hunt racing in the UK. METHODS: A retrospective, matched, nested case-control study using video recordings of races was conducted on 6 UK racecourses. Cases and controls were matched on both race type and jump number at which the fall occurred. Conditional logistic regression analysis was used to examine the univariable and multivariable relationship between predictor variables and the risk of falling. RESULTS: The risk of falling was significantly associated with whip use and race progress. Horses which were being whipped and progressing through the race were at greater than 7 times the risk of falling compared to horses which were not being whipped and which had no change in position or lost position through the field. CONCLUSIONS: This study has identified whip use and the position of the horse with respect to others in the field as potential risk factors for horse falls. POTENTIAL RELEVANCE: If these findings are confirmed by the use of intervention trials (e.g. with whip-free or restricted whip use races), modifications could be introduced which would reduce the frequency of horse falls, leading to improved equine welfare.

Accidental Falls↗
PubMed2004

Race- and course-level risk factors for fatal distal limb fracture in racing Thoroughbreds.

REASONS FOR PERFORMING STUDY: Considerable variation in the rates of equine fatality at different racecourses draws attention to probable risk factors at the level of course or race that might be partly responsible. Distal limb fractures are the most common cause of equine fatality on UK racecourses and identification of risk factors for such injuries and subsequent implementation of intervention strategies could significantly reduce the total number of racecourse fatalities. OBJECTIVES: To identify race- and course-level risk factors for fatal distal limb fracture in Thoroughbreds on UK racecourses. METHODS: A case-control study design was used. Case races were defined as those in which one or more horses sustained fatal fracture of the distal limb. Controls were selected in 2 different ways. Firstly, 3 races in which no fracture occurred were selected from all races of the same type held within 5 days of the case race (Analysis 1). Secondly, 3 control races were selected for each case race from all races of the same type held in the same year (Analysis 2). One hundred and nine cases were included in the study. Information about the race and the racecourses was collected from Computer Raceform. Conditional logistic regression was used to identify the relationship between a number of independent variables and the likelihood of fracture in a race. RESULTS: Longer races with a larger number of runners were more likely to contain a fracture. Firmer going and fewer days since the last race on the same course were associated with an increased risk of fracture. The going at the course at the previous race meeting was also associated with the likelihood of fracture. CONCLUSIONS: Modifications to the going on the day of a race and greater emphasis on ground maintenance between race meetings may have an impact on the risk of fatal distal limb fracture during racing. POTENTIAL RELEVANCE: Modification of risk factors such as the going and number of days since the last race meeting could reduce the number of equine fatalities on UK racecourses. The condition of the racecourse may be an important risk factor and future research should focus on the identification of course maintenance techniques that produce the safest possible racing surfaces.

Animals↗
PubMed2004

Horse-level risk factors for fatal distal limb fracture in racing Thoroughbreds in the UK.

REASONS FOR PERFORMING STUDY: Fractures below the level of the radius or tibia (distal limb fractures) are the most common cause of equine fatality on UK racecourses; however, little is known about their epidemiology or aetiology. Identification of risk factors could enable intervention strategies to be designed to reduce the number of fatalities. OBJECTIVES: To identify horse-level risk factors for fatal distal limb fracture in Thoroughbreds on UK racecourses. METHODS: A case-control study design was used. Fractures in case horses were confirmed by post mortem examination and 3 matched uninjured controls were selected from the race in which the case horse was running. One hundred and nine cases were included and information was collected about previous racing history, horse characteristics and training schedules. Conditional logistic regression was used to identify the relationship between a number of independent variables and the likelihood of fracture. RESULTS: Horses doing no gallop work during training and those in their first year of racing were at significantly increased risk of fracture on the racecourse. Case horses were also more likely to have trained on a sand gallop, i.e. a gallop described by trainers as being primarily composed of sand. CONCLUSIONS: Modifications to training schedules, specifically within the first year of racing, may have a large impact on the risk of fatal distal limb fracture on the racecourse. Horses should do some gallop work in training and our results suggest that the minimum distance galloped should be between 805-2012 m (4-10 furlongs)/week. POTENTIAL RELEVANCE: The information from this study can be used to alter training schedules in an attempt to reduce the incidence of fatal distal limb fracture in Thoroughbred racehorses. Training should include some gallop work, and further studies, recording the exact level of work, will help to identify an optimum range of training speeds and distances which will reduce the liklihood of catastrophic fracture on the racecourse.

Animals↗
PubMed2003

Case-control study to investigate risk factors for horse falls in hurdle racing in England and Wales.

Between March 1, 2000 and August 31, 2001, a case-control study was conducted on 12 racecourses in England and Wales to identify and quantify the risk factors associated with horse falls in hurdle races. The cases and controls were defined so that variables relating to the horse, the jockey, the race and racecourse, and the jump could be considered. The cases were defined as a jumping effort at a hurdle flight that resulted in a fall, and the controls were defined as a successful jump over a hurdle at any of the 12 racecourses within 14 days before or after the case fall. Conditional logistic regression was used to examine the univariable and multivariable relationships between the predictor variables and the risk of falling. The risk of falling was significantly associated with the position of the jump in the race, and with the distance and speed of the race. A horse's previous racing experience and history were also significantly associated with the risk of falling and horses participating in their first hurdle race were at almost five times greater risk of falling than horses that had hurdled before.

Accidental Falls↗
PubMed2003

Factors related to the risk of neonatal mortality, birth-weight and serum immunoglobulin concentration in lambs in the UK.

Neonatal-lamb mortality represents an economic loss and welfare concern. Two factors often associated with the risk of mortality are birth-weight and serum immunoglobulin concentration. We used data from two studies to investigate risk factors for mortality between 2 and 14 days of age and factors affecting birth-weight and serum immunoglobulin concentration at 48h of age. Dataset 1 included 1339 lambs born on eight farms during the 1995 spring lambing season; dataset 2 included 3172 lambs on seven farms during the 1991 spring lambing season. To account for some of the potential clustering within the data, multilevel models were used. Most (>75%) of the variation in the risk of mortality was at the lamb level. In dataset 1, factors significantly associated with increased odds of lamb mortality included low birth-weight and low serum immunoglobulin concentration. In dataset 2, significant risk factors for mortality included low birth-weight, ewe body-condition score, being born late in the season (relative to other lambs on the farm) and being born in multiple litters. There was a significant interaction between the effects of litter size and birth-weight. (Serum immunoglobulin concentration was not available for dataset 2.) More than half of the variation in birth-weight was at the ewe level, 27% at the lamb level, and 18% at the farm level (dataset 1). Single birth and being male were associated with increased birth-weight in both datasets. In dataset 2 only, increasing ewe condition score and birth early in the study period were also associated with increased birth-weight. Fifty-six percent of the variation in immunoglobulin concentration was at the lamb level, 36% at the ewe level and only 7% at the farm level. Factors associated with reduced serum immunoglobulin concentration included early or late birth in the lambing season, being born later than 14 days after the first lamb born on the farm, multiple-birth litters and maternal mastitis.

Animal Husbandry↗
PubMed2003

Relationship between white spot syndrome virus and indicators of quality in Penaeus monodon postlarvae in Karnataka, India.

White spot disease (WSD) is a viral disease of shrimp caused by white spot syndrome virus (WSSV). Stocking WSSV-infected seed has been implicated as a major risk factor for outbreaks of WSD. In addition, the quality of postlarvae batches has been proposed as a predictor for good crops. This paper describes the relationship between indicators of quality and WSSV in postlarvae (PL) of Penaeus monodon from Karnataka, India, over the period September 1999 to January 2000. Three outcome variables were considered: the WSSV status of the PL, as determined by PCR, and 2 subjective assessments of PL quality, namely the activity of the PL and the quality of the PL as determined by research assistants and farmers, respectively. Of the 73 batches of PL, 49.3% from a random sample of farms tested positive for WSSV. After adjusting for confounding, stocking earlier in the growing season and duration of transportation were the main risk factors for the presence of WSSV. The quality assessed by farmers and the PL activity assessed by research assistants showed only fair agreement (kappa 0.252) reaffirming the subjective nature of such techniques. The only variables consistently associated with either assessment of quality in univariate analysis were PL length, number per bag and salinity of the water in the delivery bags. After adjusting for confounding, no single variable was consistently associated with PL quality and activity. The research assistants' assessment of PL activity was also associated with the hatchery and a brown-orange hepatopancreas in univariate analysis. After adjusting for confounding, a brown-orange hepatopancreas was still significant and fitted into the model together with the salinity of the water in the PL bags. The farmers' assessment of quality was associated with PL length, date of stocking and duration of transportation in both univariate and multivariable analyses. There was no relationship between quality assessment and WSSV in PCR-positive PL.

Animals↗
PubMed2003

Foot and mouth disease and livestock husbandry practices in the Adamawa Province of Cameroon.

Foot and mouth disease (FMD) is a highly contagious viral disease of even-toed ungulates and is endemic in most of the tropics. A cross-sectional study using a stratified, two-stage random sample design was undertaken in the Adamawa Province of Cameroon. The objectives were to measure the reported herd-level prevalence of FMD and a range of husbandry practices important for its transmission. The owner-reported prevalence for the previous 12 months was 57.9% (50.4-65.4%), although there was a significant variation across the Province. During the previous dry season, 46.5% (38.6-54.4%) of herds had gone on transhumance. Herds had high numbers of contacts with other herds while on transhumance (98.6%), at pasture (95.8%) and at night (74.4%), with medians of 7-10, 4-6 and 1-3 daily contacts, respectively. The high level of endemic FMD and potential for disease spread presents a significant challenge for control and eradication. Locally sustainable methods need to be developed upon which larger regional control programmes could be built in the future.

Animal Husbandry↗
PubMed2002

Risk factors and sources of variation in horse falls in steeplechase racing in the UK.

We identified risk factors associated with falling during steeplechase racing. We used retrospective data from all steeplechase runs on UK racecourses during 1999: 10,866 starts with 647 horse falls. The relationship between continuous variables and falling was assessed using generalised additive models (GAMs). Polynomial fits then were included in a multilevel, multivariable logistic-regression model. The number of runners had a linear, positive association with the risk of falling. The distance of the race had a non-linear relationship with the risk of falling; the risk steadily increased in races up to 23 furlongs (1furlong approximately equals 198 m), and then decreased in longer races. Age also had a significant, non-linear relationship with the risk of falling: a decreasing risk up to 12 years of age followed by an increasing risk in older horses. Horses that wore visors and had raced previously were associated with a decrease in the risk of falling. Intra-class correlation coefficients (ICCs) showed that although most of the variation resided at the start (level 1), a proportion of variation in the risk of falling could be attributed to horse and race. Trainer and jockey contributed very little to the variation in the risk of falling.

Accidental Falls↗
PubMed2002

Usefulness of dead shrimp specimens in studying the epidemiology of white spot syndrome virus (WSSV) and chronic bacterial infection.

This paper describes the utility of dead shrimp samples in epidemiological investigations of the white spot syndrome virus (WSSV) and chronic bacterial infections. A longitudinal observational study was undertaken in shrimp farms in Kundapur, Karnataka, India, from September 1999 to April 2000 to identify risk factors associated with outbreaks of white spot disease (WSD) in cultured Penaeus monodon. As a part of the larger study, farmers were trained to collect and preserve dead and moribund shrimp (when observed) during the production cycle. At the end of the production cycle, 73 samples from 50 ponds had been collected for histopathology and 55 samples from 44 ponds for PCR. Intranuclear viral inclusion bodies diagnostic of WSSV infection were detected in dead samples from 32 ponds (64 %). Samples of dead shrimp from 18 ponds (36%) showed no histopathological evidence of WSSV infection. However, of these, samples from 13 ponds (26%) showed clear evidence of shell, oral, enteric and systemic chronic inflammatory lesions (CIL) in the form of haemocytic nodules, typical of bacterial infection. Samples from 5 ponds (10%) were negative for both WSSV and CIL. Samples from 8 ponds had dual WSSV and CIL, although both WSSV and CIL were only observed in the same shrimp from 1 pond. Useful information was obtained from these shrimp despite the presence of post-mortem changes. Samples from 19 ponds (43%) tested positive for WSSV by 1-step PCR and samples from an additional 10 ponds (22.7%) were positive by 2-step nested PCR. Samples from 15 ponds (34.1%) were negative for WSSV by 2-step nested PCR. There was moderate to substantial agreement between PCR and histopathology in the diagnosis of WSSV infection in dead shrimp. WSSV infection in dead shrimp was significantly associated with crop failures as defined by a shorter length of the production cycle (<90 d) and lower average weight at harvest (<22 g). WSSV infection was also associated with lower survival (<50%), but this was not significant. Ponds with CIL did not experience any crop failures, and the presence of CIL was significantly associated with successful crops. The study demonstrates that samples of dead shrimp can provide useful information for disease surveillance and epidemiological investigations of WSSV and chronic bacterial infections.

Animals↗
PubMed2002

Estimation of prevalence of white spot syndrome virus (WSSV) by polymerase chain reaction in Penaeus monodon postlarvae at time of stocking in shrimp farms of Karnataka, India: a population-based study.

White spot disease (WSD) is at present the most serious viral disease affecting cultivated shrimp species globally. The causative agent, white spot syndrome virus (WSSV), is extremely virulent, has a wide host range and can also be transmitted from broodstock to their offspring. The shrimp postlarvae (PL) act as asymptomatic, latent carriers of the virus, and stocking of WSSV-infected PL has been reported as a risk factor for WSD outbreaks in culture ponds. However, there is no population-based study on WSSV prevalence in PL of shrimp. The present manuscript documents the approaches and the results in the estimation of prevalence of WSSV in PL populations of Penaeus monodon at the time of stocking. A maximum of 300 PL from each of the 73 batches of PL stocked at various farms in the west coast of India during September 1999 to January 2000 were tested for the presence of WSSV by 2-step nested PCR. Thirty-six (49%) of the 73 batches tested positive for WSSV either by 1-step alone (3 batches) or after 2-step nested PCR (33 batches). Sub-samples of 5 PL each or 1 PL each tested to quantify the proportion of infected PL within batches showed that WSSV prevalence was very high in 1-step PCR-positive batches and low in 2-step PCR-positive batches. The study also showed that appropriate sampling and sample size were major factors in determining the prevalence of WSSV in PL populations, underlining the need for testing large samples of PL to reduce errors from falsely negative results.

Animals↗
PubMed2002

Problems and solutions with the design and execution of an epidemiological study of white spot disease in black tiger shrimp (Penaeus monodon) in Vietnam.

White spot disease (WSD) is caused by white spot syndrome virus (WSSV) and is an acutely fatal pandemic disease of crustaceans. It has resulted in massive losses to the shrimp-farming industry in Asia and has now spread to the Americas. This paper reports the problems and solutions associated with the design and execution of a longitudinal epidemiological study of shrimp (Penaeus monodon) health on farms practising a crop rotation of rice and shrimp in the Mekong Delta of Vietnam. The pre-sampling phase of the project involved selecting an appropriate site and sampling variables, obtaining permission and establishing the necessary laboratory and logistic facilities. At the start of the sampling phase, 40 farmers were selected and 32 of these were visited and interviewed. This resulted in the enrolment of only 17 farmers. A further seven had to be enrolled to obtain the maximum number of farmers that could be sampled by the study team. Compliance was enhanced through meetings, regular visits by senior members of the project team and ensuring that visits were punctual and that all information was treated confidentially. The production cycle began in January 1998 and lasted for approximately 5 months. An attempt was made to collect 500 post larvae (PL) before each pond was stocked to assess the health of the batch and to test for the presence of WSSV by one-step PCR. After stocking, the wild crustaceans also were sampled from the pond for PCR analyses. Information was collected on the management practices and samples of water, pond bottom, feed and shrimp collected throughout the production cycle. Water quality variables with predictable diurnal variation were sampled in the morning and afternoon, twice a week. Two months after stocking, the first outbreak of WSD occurred; subsequently, 18 farms conducted a complete emergency harvest due to the actual or perceived presence of a WSD outbreak. Detectable mortalities were reported from 19 farms, and moribund shrimps were collected from four of these for PCR and histological analyses.

Animals↗
PubMed2002

Optimization of a culture technique for the isolation of Listeria monocytogenes from faecal samples.

A culture technique employing cold enrichment at 4 degrees C followed by selective enrichment and plating at higher temperatures (30 degrees C) was used to isolate Listeria monocytogenes from faecal samples. The samples were held at 4 degrees C for 15 weeks and cultured weekly to assess the sensitivity of the culture after cold storage for different lengths of time. No media, Listeria selective enrichment broth (LSEB), nutrient broth (NB) and saline were used as cold storage medium. Cold storage increased the frequency of Listeria positive samples. The sensitivity of the culture for Listeria spp. and L. monocytogenes was 72 and 94%, and 56 and 61% after third and seventh week of cold storage, respectively. When the results of third and seventh week of cold storage were combined, the sensitivity was 100% for Listeria spp. and 94% for L. monocytogenes. LSEB and NB as storage medium increased Listeria positive samples after the first week of cold storage but did not maintain the increase thereafter while saline had an adverse effect on the growth of the bacteria. However, samples held in no media in a pilot study involving monthly sampling of a herd revealed better results. Detection limit of the culture media was also investigated. The lowest concentration detected by culture media was 3.17 organisms/ml. This was seven organisms/g for known Listeria positive sample. The faecal samples spiked with 10-fold dilutions of L. monocytogenes and held at 4 degrees C revealed that the sample spiked with 3.17 x 10-1 cfu/ml organisms resulted in growth after the second week of cold storage. The results suggest that the culture technique employing cold enrichment followed by selective enrichment and plating is more sensitive, the storage of faecal samples in no media when compared with the samples in storage medium, LSEB, NB and saline, during cold enrichment is a better application and culture of faeces, immediately after collection, at third and seventh week of cold enrichment produce more satisfactory results.

Animals↗
PubMed2001

Risk factors associated with white spot syndrome virus infection in a Vietnamese rice-shrimp farming system.

White spot disease (WSD) is a pandemic disease caused by a virus commonly known as white spot syndrome virus (WSSV). Several risk factors for WSD outbreaks have been suggested. However, there have been very few studies to identify risk factors for WSD outbreaks in culture systems. This paper presents and discusses the risk factors for WSSV infection identified during a longitudinal observational study conducted in a Vietnamese rice-shrimp farming system. A total of 158 variables were measured comprising location, features of the pond, management practices, pond bottom quality, shrimp health and other animals in the pond. At the end of the study period WSSV was detected in 15 of the 24 ponds followed through the production cycle (62.5%). One hundred and thirty-nine variables were used in univariate analyses. All the variables with a p-value < or = 0.10 were used in unconditional logistic regression in a forward stepwise model. An effect of location was identified in both univariate and multivariate analyses showing that ponds located in the eastern portion of the study site, closer to the sea, were more likely to test positive for WSSV by 1-step PCR at harvest. Ponds with shrimp of a smaller average size 1 mo after stocking tended to be positive for WSSV at the end of the production cycle. Average weight at 1 mo was also highlighted in multivariate analyses when considered as either a risk factor or an outcome. Other risk factors identified in univariate analyses were earlier date of stocking and use of commercial feed. A number of variables also appeared to be associated with a reduced risk of WSSV at harvest including the presence of dead post larvae in the batch sampled at stocking, presence of Hemigrapsus spp. crabs during the first month of production, feeding vitamin premix or legumes, presence of high numbers of shrimp with bacterial infection and the presence of larger mud crabs or gobies at harvest. No associations were detected with WSSV at harvest and stocking density, presence, or number or weight of wild shrimp in the pond. The multivariate model to identify outcomes associated with WSSV infection highlighted the presence of high mortality as the main variable explaining the data. The results obtained from this study are discussed in the context of WSD control and areas requiring further investigation are suggested.

Animal Feed↗
PubMed2001

Establishment and maintenance of a longitudinal study of bovine spongiform encephalopathy (the ULiSES scheme).

This paper addresses the issues of tracing and compliance encountered in setting up and maintaining a UK-wide 5-year observational study of beef cattle. The 5-year prospective study was initiated in 1997 to investigate the occurrence of bovine spongiform encephalopathy (BSE) in a single herd of pedigree Aberdeen Angus cattle, in which BSE had been detected at low prevalence. The study was given the acronym ULiSES (University of Liverpool Spongiform Encephalopathy Scheme). All cattle present on the farm at the start of the scheme were registered as members of the study population (n=320), as were all calves subsequently born on the farm (n=350). Animals that were sold (n=291) were traced and monitored at destination farms. Farmers were requested to give advance notification of slaughter of any ULiSES animal and an attempt was made to collect post-mortem samples of nervous tissue, peripheral lymphoid tissue and striated muscle from all animals in the scheme at the time of slaughter, death or euthanasia. Sections of medulla were examined (by standard histopathological techniques) for the presence of spongiform change. Remaining samples were stored at -70 degrees C for future investigation by alternative tests. At the halfway point of the scheme in October 1999, 75.2% (506/673) of the study population was still alive; 42% (284) of the population was still alive on the study farm and 33% (222) was distributed on other farms throughout the UK. Complete sets of specimens had been recovered from 77% (129/167) of dead animals. All brainstem sections were negative by histopathological examination. No suspect cases of BSE were reported in ULiSES animals. Failure to recover specimens occurred principally in animals which had left the study farm. The main cause of specimen loss was a failure of compliance in a small number of individuals who had purchased large numbers of ULiSES animals, and subsequently slaughtered them without contacting the University. Despite this, farmer compliance was generally high. The ULiSES scheme shows the feasibility of a country-wide longitudinal observational study spanning a period of several years and indicates the large impact of small numbers of non-compliant individuals.

Animals↗
PubMed2001

Prevalence, incidence, signs and treatment of clinical listeriosis in dairy cattle in England.

The prevalence, incidence and clinical signs of listeriosis in dairy cattle in England were investigated by means of a postal questionnaire survey of 1500 dairy farmers. The response rate was 64.1 per cent. Overall the farm prevalence of listeriosis was 11.7 per cent, 9.3 per cent for milking cows, 5.0 per cent for replacement heifers and 1.4 per cent for dairy calves. The within-herd incidence rate per thousand animal-years was 51.4 for all cases, 39.7 for milking cows, 86.6 for replacement heifers and 73.7 for dairy calves. Most cases of clinical listeriosis were reported between December and May, and the most common signs were silage eye, followed by nervous signs. The results of the questionnaire were validated internally by re-estimating the farm prevalence by including only those cases diagnosed by a veterinarian or veterinary investigation centre; the prevalence did not change significantly. The proportion of cases which were culled or died of encephalitic listeriosis was compared with the proportion diagnosed during statutory BSE reporting. The fact that the two proportions were similar provided external validation for the results of the questionnaire.

Animals↗