Rose Grogono-Thomas

Dichelobacter nodosus is the causal agent of ovine footrot, a contagious disease of welfare and economic concern worldwide. Damaged feet may be subclinical carriers of D. nodosus and covertly spread infection. Accordingly, we evaluated the risk of misshapen and damaged feet on D. nodosus presence and load in four commercial UK sheep flocks. Foot-level observations and swabs (n = 972) were collected from ewes (n = 85) over 12 months. On average, ewes were sampled three times. Feet were inspected for disease and scored (good/poor) for three hoof conformation traits (sole and heel, wall, and wall overgrowth). Swabs were analysed for presence and load of D. nodosus, and mixed models were constructed. Poor hoof conformation traits were present in 92.5% of foot-level observations. Feet with poor sole and heel conformation were more likely to have higher D. nodosus loads (β = 0.19, 95% CI: 0.04–0.35) than those with good conformation. Furthermore, on feet positive for D. nodosus, wall overgrowth was associated with higher D. nodosus loads (β = 0.27, 95% CI: 0.01–0.52). Feet with aspects of poor conformation covertly harbour D. nodosus and are a source of infection. Flock management should be guided by hoof conformation to reduce disease challenge.

Two dairy goat farms with high level of lameness in lactating animals were presented for further investigation. Farm 1 and Farm 2 presented with 37 and 67 % morbidity, respectively. Both farms had an all year round indoor system, feeding ad libitum concentrate with forage available at all times. The lameness was found to be based in the foot. Previous treatments consisting of biweekly footbathing with zinc sulphate, spraying lesions with oxytetracycline spray and packing lesions with copper crystals on a single occasion and single injections with long acting oxytetracycline had not been successful. Mild cases had signs of haemorrhaging in the white line or on the sole of the foot. Moderate cases showed under running of the wall horn or small areas of exposed sole corium. Severe cases would consist of horn or wall separation with the corium exposed and infected. In extreme cases only the wall horn of the claw remained, with a large area of necrotic tissue in the centre and no healthy corium visible. Only one animal was seen to have interdigital lesions. Polymerase chain reaction (PCR) and culture of swabs taken from exposed corium and the interdigital space were negative for Dichelobacter nodosus but PCR for treponemes were positive in both the adults and the youngstock tested. Due to the high level of concentrate in the diet of these goats, nutrition was thought to contribute to the problem. Transcutaneous rumen fluid samples were taken and pH was measured on both farms, with 35 % of the samples below pH value 5.5. No definite diagnosis could be made. However, the results suggest both treponemes and nutrition play a role in the aetiology of the lameness. The initial sole or wall horn lesions were thought to be secondarily infected by treponemes. Further investigation is needed to definitively diagnose the cause and contributing factors for this lameness.

Five UK goat farms with high levels of lameness (prevalence 14–67 per cent) were investigated. On two farms (farms 1 and 2), the animals presented with typical footrot lesions. The remaining three farms (farms 3, 4 and 5) presented with infected lesions on the foot that did not resemble footrot. These lesions were observed to start from the white line or sole but the interdigital space was rarely affected. Swabs were processed by PCR to assess the presence of Dichelobacter nodosus and three specific treponeme groups (group 1: Treponema medium/Treponema vincentii ‐like, group 2: Treponema phagedenis ‐like and group 3: Treponema denticola/Treponema putidum ‐like) that are reported to be associated with bovine digital dermatitis and contagious ovine digital dermatitis. On farms 1 and 2, 85.7 per cent of samples were found to be positive for D nodosus while only 9.5 per cent were positive for treponeme groups 1, 2 and 3. In contrast, 5.3 per cent of samples from farms 3, 4 and 5 were positive for D nodosus , while 34.2, 68.4 and 36.8 per cent of samples from these farms tested positive for treponeme groups 1, 2 and 3, respectively. T medium/T vincentii ‐like, T phagedenis ‐like and T denticola/T putidum ‐like treponemes were detected on foot lesions of lame goats suggesting that they have a role in the aetiology of this lameness, which has not previously been described in dairy goats.

Q fever, a zoonosis caused by Coxiella burnetii, an obligate intracellular gram-negative bacterium (Arricau-Bouvery and Rodolakis 2005), is currently attracting international attention due to a recent major epidemic (2007–2009) in The Netherlands involving over 3500 reported human cases (Roest and others 2011). Domestic ruminants (goats, sheep and cattle) are the major reservoirs and sources of human infection (Maurin and Raoult 1999); goats are the most susceptible, clinically manifesting with abortion and reproductive problems, followed by sheep and cattle. Humans are affected by acute or chronic influenza-like illness, pneumonia, endocarditis and hepatitis. Shedding of C burnetii differs among ruminant species, milk being the primary route in cattle (Rodolakis and others 2007).

SUMMARY: Enrichment culture is often used to isolateCampylobacter. This study compared isolation ofCampylobacterspp. from 119 broiler chicken environments from two farms, using Preston and modified Exeter (mExeter) and modified Bolton (mBolton) enrichments. mExeter was significantly more effective in isolatingCampylobacterspp. from the environmental samples compared to Preston (PP0·05). Enrichment broth type did not affect isolation from chicken faecal or soil and litter samples.C. jejuniwas isolated from significantly more environmental samples using mExeter broth compared to Preston (PP0·05). OnlyC. coliwas isolated from the soil and litter samples and although bothC. jejuniandC. coliwere recovered from the faecal samples there was no effect of using different enrichment broths. The majority of samples where the same species had been isolated yielded the same or closely related genotypes as defined by pulsed-field gel electrophoresis. Isolates recovered using Preston and mBolton broths were less genetically diverse than those from mExeter broth. We conclude that the enrichment method used affects both the number and species ofCampylobacterisolated from naturally contaminated samples.