Observations on the indirect transmission of virulent ovine footrot in sheep yards and its spread in sheep on unimproved pasture

Rj, Whittington

doi:10.1111/j.1751-0813.1995.tb15032.x

Cited by 46 publications

(22 citation statements)

References 12 publications

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“…The environment can also be a source for introduction of footrot as reported by Whittington et al [15] where a flock became infected after using the same yard used by an infected flock some hours earlier. The risk of introduction or re-introduction of footrot into a flock can be reduced by some principal preventive strategies as described by Abbott and Lewis [16]: animals should only be purchased from footrot-free flocks, purchased animals should be quarantined, or the flock should be sequestered from outside introduction.…”

Section: Discussionmentioning

confidence: 99%

Development and comparison of a real-time PCR assay for detection of Dichelobacter nodosus with culturing and conventional PCR: harmonisation between three laboratories

et al. 2012

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BackgroundOvine footrot is a contagious disease with worldwide occurrence in sheep. The main causative agent is the fastidious bacterium Dichelobacter nodosus. In Scandinavia, footrot was first diagnosed in Sweden in 2004 and later also in Norway and Denmark. Clinical examination of sheep feet is fundamental to diagnosis of footrot, but D. nodosus should also be detected to confirm the diagnosis. PCR-based detection using conventional PCR has been used at our institutes, but the method was laborious and there was a need for a faster, easier-to-interpret method. The aim of this study was to develop a TaqMan-based real-time PCR assay for detection of D. nodosus and to compare its performance with culturing and conventional PCR.MethodsA D. nodosus-specific TaqMan based real-time PCR assay targeting the 16S rRNA gene was designed. The inclusivity and exclusivity (specificity) of the assay was tested using 55 bacterial and two fungal strains. To evaluate the sensitivity and harmonisation of results between different laboratories, aliquots of a single DNA preparation were analysed at three Scandinavian laboratories. The developed real-time PCR assay was compared to culturing by analysing 126 samples, and to a conventional PCR method by analysing 224 samples. A selection of PCR-products was cloned and sequenced in order to verify that they had been identified correctly.ResultsThe developed assay had a detection limit of 3.9 fg of D. nodosus genomic DNA. This result was obtained at all three laboratories and corresponds to approximately three copies of the D. nodosus genome per reaction. The assay showed 100% inclusivity and 100% exclusivity for the strains tested. The real-time PCR assay found 54.8% more positive samples than by culturing and 8% more than conventional PCR.ConclusionsThe developed real-time PCR assay has good specificity and sensitivity for detection of D. nodosus, and the results are easy to interpret. The method is less time-consuming than either culturing or conventional PCR.

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Section: Discussionmentioning

confidence: 99%

Development and comparison of a real-time PCR assay for detection of Dichelobacter nodosus with culturing and conventional PCR: harmonisation between three laboratories

et al. 2012

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“…D. nodosus has been isolated from clinically normal cattle [20], but cattle is not considered a source of virulent D. nodosus in sheep [10]. Indirect transmission of D. nodosus between sheep on unimproved pasture, which has resulted in virulent ovine footrot, has been reported [21]. Early studies by Egerton & Parsonson indicated that experimental transmission of D. nodosus from cattle to sheep can result in ovine footrot [22].…”

Section: Discussionmentioning

confidence: 99%

Possible cross-infection of Dichelobacter nodosus between co-grazing sheep and cattle

Rogdo¹,

Hektoen

Slettemeås

et al. 2012

Acta Vet Scand

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BackgroundThe aim of this study was to investigate possible cross-infection of Dichelobacter nodosus in Norwegian farms practising co-grazing of sheep and cattle.MethodsThirteen farms practising co-grazing of sheep and cattle were included in this descriptive study: five farms with a history of severe ovine footrot (Group I) and eight farms with free-stall housing of cattle and signs of mild or no footrot in sheep (Group II). Sampling for PCR detection of D. nodosus was performed from animals in all farms, and clinical claw examination of sheep and cattle was performed in Group II. D. nodosus positive samples were analysed by a multiplex PCR method that detects variants of the fimA gene corresponding to D. nodosus serogroups A through I.ResultsD. nodosus serogroup A was identified more frequently in sheep from farms with a history of severe footrot (Group I) versus from Group II, and in most of the farms with a history of severe footrot there was a coexistence of D. nodosus serogroup A in sheep and cattle. In one farm heel horn erosion and dermatitis emerged in cattle after co-grazing with sheep suffering from severe footrot where D. nodosus serogroup A was detected. Six months later heel horn erosion and dermatitis were still diagnosed, and D. nodosus serogroup A was identified. Out of the 16 D. nodosus positive sheep samples from Group II, ten of the samples were positive by the fimA serogrouping PCR. Among these 10 samples all serogroups except G were detected. All the D. nodosus serogroups detected in sheep were also present in the corresponding cattle herds.ConclusionThe clinical findings and the coexistence of the same serogroups in co-grazing sheep and cattle could indicate cross-infection. However, further research including isolation of the bacterial strains, virulence-testing and genetic identification, is needed.

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“…A significant relation was found between the hygiene and management practice categories and disease prevalence (Table 2). Prevalence of footrot depends on the environmental condition and pasture (Reilly et al, 2012;Whittington, 1995). The prevalence is higher in temperate climate with high temperature (Hussain et al, 2013).…”

Section: Resultsmentioning

confidence: 99%

Prevalence of ovine footrot in Brahmaputra Chars (shoals) in Mymensingh

et al. 2016

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A retrospective cohort study was conducted from July 2012 to August 2013 to determine prevalence of ovine footrot in chars (Shoals) of Mymensingh Sadar Upazila, Bangladesh, centred in Paranganj Union Parishad. A field survey used a prepared questionnaire and investigation of farm management. The prevalence of ovine footrot was 4.2% in the study group of 687 sheep, in 106 farms. The prevalence differed according to farm type and housing system. Prevalence of ovine footrot was higher (9.5%) in farms where sheep and other livestock were housed under the same roof. Prophylactic medication and footbath practice were absent. Common care and management practices were sheep bath, house and floor cleaning, deworming, and therapeutic medication. Highest prevalence (7.0%) was recorded in farms where prophylactic medication and deworming was irregular, and antiseptics were not used in sheep bathing and cleaning of sheep house and floor. The results suggest that improvement of the housing environment and management practices are required to control footrot. (Bangl. vet.

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Observations on the indirect transmission of virulent ovine footrot in sheep yards and its spread in sheep on unimproved pasture

Cited by 46 publications

References 12 publications

Development and comparison of a real-time PCR assay for detection of Dichelobacter nodosus with culturing and conventional PCR: harmonisation between three laboratories

Development and comparison of a real-time PCR assay for detection of Dichelobacter nodosus with culturing and conventional PCR: harmonisation between three laboratories

Possible cross-infection of Dichelobacter nodosus between co-grazing sheep and cattle

Prevalence of ovine footrot in Brahmaputra Chars (shoals) in Mymensingh

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