Use of whole-genome sequencing and evaluation of the apparent sensitivity and specificity of antemortem tuberculosis tests in the investigation of an unusual outbreak of Mycobacterium bovis infection in a Michigan dairy herd
Use of whole-genome sequencing and evaluation of the apparent sensitivity and specificity of antemortem tuberculosis tests in the investigation of an unusual outbreak of Mycobacterium bovis infection in a Michigan dairy herd
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DOI：
10.2460/javma.251.2.206
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发表时间：
2017-07-15
影响因子：
1.9
通讯作者：
Marks, David
中科院分区：
文献类型：
--
作者：
Bruning-Fann, Colleen S.;Robbe-Austerman, Suelee;Marks, David
目的描述全基因组测序（WGS）的使用，并在密歇根州奶牛群中牛分枝杆菌感染的不寻常爆发的调查过程中评估死前结核病测试的表观灵敏度和特异性。方法牛结核病（bTB）爆发调查。动物：牛、猫、狗和野生动物。方法用尾褶试验（CFT）筛选索引奶牛群中的所有牛的bTB，和牛>= 6月龄也用γ-干扰素（γ IFN）测定筛选。将索引牛群中的所有家猫和一只犬（饲喂来自牛群的未经巴氏灭菌的牛奶）沿着减少。对来自索引牛群和其他bTB感染牛群的牛支原体感染动物的选择分离株进行WGS。对所有受影响场所周围的野生动物进行了bTB检查。在检查的任何野生动物中均未发现bTB的证据。在索引牛群中，确认53/45 I（11.8%）牛和12/2 I（57%）猫感染牛支原体。牛支原体感染牛的患病率在4- 7月龄小牛中最高（16/49 [33%]），其次是成年母牛（36/203 [18%]）。CFT的表观灵敏度和特异性分别为86.8%和92.7%，γ IFN检测的表观灵敏度和特异性分别为80.4%和96.5%，当这些检测结果分别解释时，表观灵敏度和特异性分别为96.1%和91.7%。WGS结果显示，牛支原体感染家猫和牛从索引牛群和6个牛肉操作被感染牛支原体相同的菌株。在调查过程中确定的6个bTB影响牛肉操作，3只与指标群的WGS结果，有没有记录的牲畜或废牛奶从指标群的这些operation.CONCLUSIONS和临床relevanceWhole基因组测序增强了流行病学调查，并应在所有疾病的调查。平行进行CFT和γ IFN测定提高了检测牛支原体感染动物的死前能力。与牛支原体感染的牛和受污染的牛奶接触是这次暴发的牛群内和牛群之间传播bTB的主要危险因素。
OBJECTIVETo describe use of whole-genome sequencing (WGS) and evaluate the apparent sensitivity and specificity of antemortem tuberculosis tests during investigation of an unusual outbreak of Mycobacterium bovis infection in a Michigan dairy herd.DESIGNBovine tuberculosis (bTB) outbreak investigation.ANIMALSCattle, cats, dog, and wildlife.PROCEDURESAll cattle in the index dairy herd were screened for bTB with the caudal fold test (CFT), and cattle >= 6 months old were also screened with gamma-interferon (gamma IFN) assay. The index herd was depopulated along with all barn cats and a dog that were fed unpasteurized milk from the herd. Select isolates from M bovis-infected animals from the index herd and other bTB-affected herds underwent WGS. Wildlife around all affected premises was examined for bTB.RESULTSNo evidence of bTB was found in any wildlife examined. Within the index herd, 53 of 45I (11.8%) cattle and I2 of 2I (57%) cats were confirmed to be infected with M bovis. Prevalence of M bovis-infected cattle was greatest among 4- to 7-month-old calves (16/49 [33%]) followed by adult cows (36/203 [18%]). The apparent sensitivity and specificity were 86.8% and 92.7% for the CFT and 80.4% and 96.5% for the gamma IFN assay when results for those tests were interpreted separately and 96.1% and 91.7% when results were interpreted in parallel. Results of WGS revealed that M bovis-infected barn cats and cattle from the index herd and 6 beef operations were infected with the same strain of M bovis. Of the 6 bTB-affected beef operations identified during the investigation, 3 were linked to the index herd only by WGS results; there was no record of movement of livestock or waste milk from the index herd to those operations.CONCLUSIONS AND CLINICAL RELEVANCEWhole-genome sequencing enhanced the epidemiological investigation and should be used in all disease investigations. Performing the CFT and gamma IFN assay in parallel improved the antemortem ability to detect M bovis-infected animals. Contact with M bovis-infected cattle and contaminated milk were major risk factors for transmission of bTB within and between herds of this outbreak.