Heinemann Lisa, Methner Ulrich, Donat Karsten, Moog Udo
Thüringer Landesamt für Verbraucherschutz, Bad Langensalza.
Friedrich-Loeffler Institut - Bundesforschungsinstitut für Tiergesundheit (FLI), Institut für bakterielle Infektionen und Zoonosen, Jena.
Tierarztl Prax Ausg G Grosstiere Nutztiere. 2023 Jun;51(3):135-143. doi: 10.1055/a-2097-7085. Epub 2023 Aug 11.
Infections with subspecies serovar 61: k: 1, 5, (7) (SASd) are widespread in sheep. SASd is considered as host associated with low virulence. The aim of the study was to determine the time of infection of lambs after birth with consideration of the status of the mother.
Fecal and nasal swabs from 88 ewes of a flock with known SASd status but unknown intraherd prevalence were examined for SASd in the period of 6 weeks before the beginning of the lambing period. Fecal and nasal swabs from one female lamb from each of these ewes were also examined for SASd at 4-6 time points between the 4th and 50th day of life and at 7, 30 and 40 months of age.
In the first two weeks after birth, significantly more lambs were positive in the nasal swab than in the fecal swab. SASd positive nasal swabs were mainly found in lambs originating from ewes also positive in nasal swabs. 43 lambs remained SASd-negative until day 50 of age. There was no correlation between the SASd status of ewes and their off-spring. At 7 months of age, the number of animals with a positive detection of SASd increased significantly. 32% of the nasal swabs and 62% of the fecal samples were positive for SASd.
There is no rapid and intensive transmission of SASd from ewes to their offspring. Most likely, the infection begins by colonising the nasal mucosa of the lambs and does not cause any clinical symptoms.
Even with a high intraherd prevalence, infections with SASd are very unlikely to cause clinical symptoms.
亚种血清型61：k：1，5，（7）（SASd）感染在绵羊中广泛存在。SASd被认为是毒力较低的宿主相关型。本研究的目的是考虑母羊状况来确定羔羊出生后感染的时间。
在产羔期开始前的6周内，对一群已知SASd状况但群体内流行率未知的88只母羊的粪便和鼻拭子进行SASd检测。这些母羊所产的每只雌性羔羊在出生后第4天至第50天之间的4 - 6个时间点以及7、30和40月龄时，也对其粪便和鼻拭子进行SASd检测。
出生后的前两周，鼻拭子检测呈阳性的羔羊显著多于粪便拭子检测呈阳性的羔羊。SASd阳性鼻拭子主要见于其母羊鼻拭子也呈阳性的羔羊。43只羔羊在50日龄前一直为SASd阴性。母羊的SASd状况与其后代之间没有相关性。在7月龄时，SASd检测呈阳性的动物数量显著增加。32%的鼻拭子和62%的粪便样本SASd检测呈阳性。
SASd不会从母羊快速且大量地传播给其后代。感染很可能始于羔羊鼻黏膜的定植，且不会引起任何临床症状。
即使群体内流行率很高，SASd感染也极不可能引起临床症状。
