PDF(Pubmed)
Abstract：
Bovine ischaemic teat necrosis (ITN) is a disease affecting the skin of the teats of dairy cows with an unknown aetiopathogenesis. Digital dermatitis (DD)-associated treponemes have previously been suggested as a potential aetiological agent in ITN, although the sample size was small. The current study, using established PCR techniques, aimed to examine the association with the presence of DD-associated treponemes in a large number of ITN samples from a wider geographical area, and surveyed the potential of milk as an infection reservoir. From 95 ITN lesions, 35.8% (n = 34) were positive for at least one DD-associated treponeme compared with only 5.6% (n = 1) of 18 non-lesioned teats from cows with ITN lesions on a different teat using a nested PCR approach. All 10 age- and production-matched control cows were negative for DD-associated treponemes via PCR. No DD-associated treponemes could be detected from foremilk of cows with (n = 19) and without (n = 31) a DD lesion on the hind feet. DD-associated treponemes could be detected via PCR after incubation in milk for up to 2 h. Therefore, milk does not appear to be a competent reservoir for transmission of DD-associated treponemes. Moreover, in the current study DD-associated treponemes were only detected in a subset of ITN samples, so it is unlikely these opportunistic skin-associated pathogens are the major or sole agent of ITN.
摘要：
牛缺血性乳头坏死（ITN）是一种影响奶牛乳头皮肤的疾病，其病因未知。数字皮炎（DD）相关的螺旋体以前被认为是ITN的潜在病因，虽然样本量很小。目前的研究,使用已建立的PCR技术，旨在检查与来自更广泛地理区域的大量ITN样本中DD相关螺旋体的存在的关联，并调查了牛奶作为感染宿主的潜力。从95个ITN病变中，35.8％（n=34）的至少一个DD相关的螺旋体为阳性，而使用巢式PCR方法在不同的乳头上有ITN病变的奶牛的18个未病变乳头中只有5.6％（n=1）。所有10只年龄和产量匹配的对照母牛通过PCR对DD相关的螺旋体呈阴性。在后足有（n=19）和没有（n=31）DD病变的奶牛的前乳中，未检测到与DD相关的螺旋体。在牛奶中孵育2小时后，可以通过PCR检测DD相关的螺旋体。因此，牛奶似乎不是传播DD相关螺旋体的有效水库。此外，在当前的研究中，仅在ITN样本的一部分中检测到DD相关的螺旋体，因此，这些机会性皮肤相关病原体不太可能是ITN的主要或唯一病原体。
