Streptococcus suis is an economically important pathogen of pigs as well as a zoonotic cause of human disease. Serotyping is used for further characterization of isolates; some serotypes seem to be more virulent and more widely spread than others. This study characterizes a collection of German field isolates of Streptococcus suis from pigs dating from 1996 to 2016 with respect to capsular genes (cps) specific for individual serotypes and pathotype by multiplex PCR and relates results to the clinical background of these isolates. The most prominent finding was the reduction in prevalence of serotype-2/serotype-1/2 among invasive isolates during this sampling period, which might be attributed to widely implemented autogenous vaccination programs in swine against serotype 2 in Germany. In diseased pigs (systemically ill; respiratory disease) isolates of serotype-1/serotype-14, serotype-2/serotype-1/2, serotype 3 to 5 and 7 to 9 were most frequent while in carrier isolates a greater variety of cps types was found. Serotype-1/serotype-14 seemed to be preferentially located in joints, serotype 4 and serotype 3 in the central nervous system, respectively. The virulence associated extracellular protein factor was almost exclusively associated with invasive serotype-1/serotype-14 and serotype-2/serotype-1/2 isolates. In contrast, lung isolates of serotype-2/serotype-1/2 mainly harbored the gene for muramidase-released protein. Serotype 4 and serotype 9 isolates from clinically diseased pigs most frequently carried the muramidase-released protein gene and the suilysin gene. When examined by transmission electron microscopy all but one of the isolates which were non-typable by molecular and serological methods showed various amounts of capsular material indicating potentially new serotypes among these isolates. Given the variety of cps types/serotypes detected in pigs, not only veterinarians but also medical doctors should consider other serotypes than just serotype 2 when investigating potential human cases of Streptococcus suis infection.
A prevalence study was conducted on German sheep flocks including goats if they cohabitated with sheep. In addition, a novel approach was applied to identify an infection at the herd-level before lambing season with preputial swabs, suspecting venereal transmission and ensuing colonisation of preputial mucosa with Coxiella (C.) burnetii. Blood samples and genital swabs were collected from breeding males and females after the mating season and were analysed by enzyme-linked immunosorbent assay (ELISA) and quantitative polymerase chain reaction (qPCR) respectively. In total, 3367 animals were sampled across 71 flocks. The true herd-level prevalence adjusted for misclassification probabilities of the applied diagnostic tests using the Rogan-Gladen estimator for the prevalence estimate and a formula by Lang and Reiczigel (2014) for the confidence limits, ranged between 31.3% and 33% (95% confidence interval [95% CI] 17.3–45.5) detected by the ELISA and/or qPCR. Overall 26–36.6% (95% CI 13–56.8) were detected by ELISA, 13.9% (95% CI 4.5–23.2) by the qPCR and 7.9–11.2% (95% CI 0.08–22.3) by both tests simultaneously. The range of results is due to data obtained from literature with different specifications for test quality for ELISA. Among eight farms with females shedding C. burnetii, three farms (37.5%) could also be identified by preputial swabs from breeding sires. This indicates less reliability of preputial swabs if used as a single diagnostic tool to detect C. burnetii infection at the herd-level.
Prevalence of Coxiella burnetii in German sheep flocks and evaluation of a novel approach to detect an infection via preputial swabs at herd-level-ERRATUM. Epidemiology and Infection 148,
In Germany, sheep are the main source of human Q fever epidemics, but data on Coxiella burnetii (C. burnetii) infections and related risk factors in the German sheep population remain scarce. In this cross-sectional study, a standardised interview was conducted across 71 exclusively sheep as well as mixed (sheep and goat) farms to identify animal and herd level risk factors associated with the detection of C. burnetii antibodies or pathogen-specific gene fragments via univariable and multivariable logistic regression analysis. Serum samples and genital swabs from adult males and females of 3367 small ruminants from 71 farms were collected and analysed using ELISA and qPCR, respectively. On animal level, univariable analysis identified young animals (<2 years of age; odds ratio (OR) 0.33; 95% confidence interval (CI) 0.13–0.83) to reduce the risk for seropositivity significantly (p < 0.05). The final multivariable logistic models identified lambing all year-round (OR 3.46/3.65; 95% CI 0.80–15.06/0.41–32.06) and purchases of sheep and goats (OR 13.61/22.99; 95% CI 2.86–64.64/2.21–239.42) as risk factors on herd level for C. burnetii infection detected via ELISA and qPCR, respectively.
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