Emergence of Echinococcus multilocularis among Red Foxes in northern Germany, 1991--2005

The parasite Echinococcus multilocularis is currently of great concern in Europe because of its spreading behavior, which has public health implications. This study investigates the spatiotemporal distribution of Echinococcus multilocularis in Red Foxes. The infection status of 8459 foxes was sampled from 43 regions in the north German province of Lower Saxony over three investigation periods 1991--1994, 1994--1997 and 2003--2005. Linear empirical Bayesian smoothing within the binomial model was used to produce smoothed choropleth maps. Geostatistical kriging was applied to generate prevalence risk maps. Further geostatistical modeling of the prevalence difference between study periods facilitated spatiotemporal trend investigations. The spatial scan statistic was used for cluster detection analysis. The average prevalence risk for Lower Saxony increased from about 12 to 20% during 1991--2005. Specifically the increases from first to second and to third study periods were estimated by 3.3% (CI 95%: 0.6%-5.9%) and 8.5% (CI 95%: 5.2%-11.8%), respectively. Infections in foxes were clustering and a location stable disease cluster was detected in the south of the province. This study is the first showing evidence for steady emergence of Echinococcus multilocularis in Red Foxes. First cases of human Alveolar Echinococcosis were recorded recently.     

Bluetongue sentinel surveillance program and cross-sectional serological survey in cattle in Belgium in 2010-2011

Bluetongue virus serotype 8 (BTV-8) emerged in Central Western Europe in 2006 causing a large scale epidemic in 2007 that involved several European Union (EU) countries including Belgium. As in several other EU member states, vaccination against BTV-8 with inactivated vaccines was initiated in Belgium in spring 2008 and appeared to be successful. Since 2009, no clinical cases of Bluetongue (BT) have been reported in Belgium and BTV-8 circulation seemed to have completely disappeared by spring 2010. Therefore, a series of repeated cross-sectional surveys, the BT sentinel surveillance program, based on virus detection in blood samples by means of real-time RT-PCR (RT-qPCR) were carried out in dairy cattle from the end of 2010 onwards with the aim to demonstrate the absence of BTV circulation in Belgium. This paper describes the results of the first two sampling rounds of this BT sentinel surveillance program carried out in October-November 2010 and January-February 2011. In addition, the level of BTV-specific maternal antibodies in young non-vaccinated animals was monitored and the level of herd immunity against BTV-8 after 3 consecutive years of compulsory BTV-8 vaccination was measured by ELISA. During the 1st sampling round of the BT sentinel surveillance program, 15 animals tested positive and 2 animals tested doubtful for BTV RNA by RT-qPCR. During the 2nd round, 17 animals tested positive and 5 animals tested doubtful. The positive/doubtful animals in both rounds were re-sampled 2-4 weeks after the original sampling and then all tested negative by RT-qPCR. These results demonstrate the absence of BTV circulation in Belgium in 2010 at a minimum expected prevalence of 2% and 95% confidence level. The study of the maternal antibodies in non-vaccinated animals showed that by the age of 7 months maternal antibodies against BTV had disappeared in most animals. The BTV seroprevalence at herd level after 3 years of compulsory BTV-8 vaccination was very high (97.4% [95% CI: 96.2-98.2]). The overall true within-herd BTV seroprevalence in 6-24 month old Belgian cattle in early 2011 was estimated at 73.4% (95% CI: 71.3-75.4).     

The estimated prevalence of Johne's disease infected sheep flocks in Australia

OBJECTIVE: To estimate the likely geographical distribution and flock-prevalence of ovine Johne's disease (OJD) in Australia. DESIGN: A cross-sectional study design was used. PROCEDURE: The results of abattoir surveillance for OJD carried out during 2000 were analysed to estimate the prevalence of infected flocks in three regions of New South Wales and in other States. A Bayesian approach was used to adjust apparent prevalence estimates for the assumed flock-sensitivity and flock-specificity of abattoir surveillance, and to allow for uncertainty about the true values of these measures. RESULTS: The 95% probability limits for flock-prevalence at 31 December 2000 were 0.04%-1.5%, 8%-15% and 29%-39% for low, moderate and high prevalence regions of New South Wales respectively. The other States generally had an upper 97.5% probability limit of about 1% or less. Based on these estimates about 6 to 10% of flocks in New South Wales and 2.4 to 4.4% of flocks Australia-wide are likely to be infected. CONCLUSION: This study suggests that OJD has a highly clustered distribution in Australia, and provides estimates of the prevalence of infected flocks by State or region. Based on this analysis there were probably between 2000 and 3700 infected flocks in Australia at 31 December 2000, with more than 80% of these in a relatively small geographic area of central and southern New South Wales. Some States, such as Queensland and Western Australia, may have a prevalence equal or close to 0%, however the technique used was unable to demonstrate the absence of infection in these States with the intensity of surveillance undertaken to date.     

Meta-analysis of the prevalence of mastitis and associated risk factors in dairy cattle in Ethiopia

Mastitis is among the most prevalent disease that contributes for the reduction of milk production in dairy herds. Although several published studies have estimated the prevalence of mastitis, variation among studies is great. The objective of the present meta-analysis was to provide a pooled estimate of the prevalence of overall, clinical, and subclinical mastitis in dairy cattle in Ethiopia. A pooled estimate was also conducted by potential risk factors. The literature search was restricted to studies published in English language from January 2002 to June 2016. Meta-analysis of 39 studies was done under random effects model using metafor package in R software. The pooled estimate of the overall prevalence of mastitis on cow-basis was found to be 47.0% (95% confidence interval [CI]?=?42.0, 52.0). The pooled prevalence with the 95% CI for clinical and subclinical mastitis was 8.3% (95% CI?=?6.5, 10.3) and 37% (95% CI?=?32.9, 40.7) respectively. There is a statistically significant and high heterogeneity of the prevalence estimates between published studies. The odds of occurrence of mastitis were higher in cows at early (odds ratio [OR]?=?1.6; 95% CI?=?1.4, 1.8) and late lactation (OR?=?1.3; 95% CI?=?1.2, 1.5) than mid lactation, in cows with 3–4 (OR?=?1.5; 95% CI?=?1.4, 1.7) and >4 parity number (OR?=?2.9; 95% CI?=?2.6, 3.4) than those with 1–2 parity number. Previous history of mastitis, floor type, milking hygiene, and udder injury had also statistically significant effect on pooled prevalence of mastitis (P?<?0.05). The present study reported that there is high prevalence of mastitis in dairy cows in Ethiopia, which could contribute to the low productivity in lactating cows. The statistically significant association of risk factors such as floor type, milking hygiene, and presence of udder injury with mastitis may suggest that dairy farmers can reduce the occurrence of the disease by improving their management practices.     

Updated prediction for the BSE epidemic in dairy cattle in Japan

Following the detection of the first case of Bovine spongiform encephalopathy (BSE) in Japan in September 2001, nine million cattle were tested for BSE up to the end of 2008. As a result, a further 28 cases were detected in dairy cattle. Using the mathematical model previously developed and surveillance data up to the end of 2008, we estimated the prevalence of BSE-infected animals within each birth cohort for the years 1995–2001. We predicted historic and future trends in the number of BSE-infected animals to be culled and anticipated BSE cases from each birth cohort. The results indicate that more infected animals (428 (95% CI: 59–727)) than previously estimated would have been culled from 1995 to 2001, and more cases (53 (95% CI: 25–101)) than previously predicted would have been detected during this period with a higher peak in 2001, if a BSE surveillance program as comprehensive as the present one was applied. In and after 2009, 0–2 cases of BSE would likely to be detected. As previously predicted, the BSE epidemic should be eradicated by 2012.     

Establishing a cost-effective national surveillance system for Bluetongue using scenario tree modelling

Vector-borne diseases pose a special challenge to veterinary authorities due to complex and time-consuming surveillance programs taking into account vector habitat. Using stochastic scenario tree modelling, each possible surveillance activity of a future surveillance system can be evaluated with regard to its sensitivity and the expected cost. The overall sensitivity of various potential surveillance systems, composed of different combinations of surveillance activities, is calculated and the proposed surveillance system is optimized with respect to the considered surveillance activities, the sensitivity and the cost. The objective of this project was to use stochastic scenario tree modelling in combination with a simple cost analysis in order to develop the national surveillance system for Bluetongue in Switzerland. This surveillance system was established due to the emerging outbreak of Bluetongue virus serotype 8 (BTV-8) in Northern Europe in 2006. Based on the modelling results, it was decided to implement an improved passive clinical surveillance in cattle and sheep through campaigns in order to increase disease awareness alongside a targeted bulk milk testing strategy in 200 dairy cattle herds located in high-risk areas. The estimated median probability of detection of cases (i.e. sensitivity) of the surveillance system in this combined approach was 96.4%. The evaluation of the prospective national surveillance system predicted that passive clinical surveillance in cattle would provide the highest probability to detect BTV-8 infected animals, followed by passive clinical surveillance in sheep and bulk milk testing of 200 dairy cattle farms in high-risk areas. This approach is also applicable in other countries and to other epidemic diseases.     

The seroprevalence of foot-and-mouth disease in the sedentary livestock herds in four districts of Bhutan

Cross sectional serological surveys were conducted between March and December 2009 to determine the distribution of foot-and-mouth disease and also to validate the current passive surveillance system in Bhutan. A total of 1909 sera collected from cattle, goats, sheep, and pigs, from 485 herds in 106 villages, were tested using a foot-and-mouth disease non-structural protein 3ABC ELISA. The true prevalence at the animal-level for all species was 15% (95% CI: 13.5, 16.7) using the sensitivity (97.2%) and specificity (99.5%) for cattle. The true prevalence for cattle, goats, sheep and pigs were 17.6 (95% CI: 15.6, 19.5), 11.9% (95% CI: 5.6, 18.3), 11.9% (95% CI: 1.3, 25.1), and 1.9% (95% CI: 0.0, 3.8), respectively. The sub-districts that shared border with India had significantly (p=0.03) higher seroprevalence than the interior sub-districts. Villages located in the sub-tropical zone had significantly (p<0.0001) higher seroprevalence than those located at high altitude zones. Herds with known outbreaks of FMD were 3.6 times more likely (p<0.001) to be seropositive than those with no history of outbreaks of FMD. The study showed the usefulness of population-based serological surveys in detecting circulation of active infection in populations which were, until now, considered to be free of disease based on a passive surveillance system. The study also highlighted the benefits of conducting serological and questionnaire surveys, simultaneously, to ascertain the infection status of herds and animals. Some of the findings from this study could be considered for strengthening of the current FMD control program in Bhutan.     

Establishment of an early warning system against bluetongue virus in Switzerland

Bluetongue (BT) is a vector-borne animal disease of economical importance due to the international trade restrictions likely to be put into place in a country once the infection is discovered. The presence of BT and its vectors in countries adjacent to Switzerland stresses the need of implementing a surveillance system and to raise disease awareness among potential stakeholders. A national survey in Switzerland 2003 indicated freedom of Bluetongue virus (BTV), although a single individual of the main BT vector Culicoides imicola was caught in the canton of Ticino. The survey also demonstrated that potential BT vectors, C. obsoletus and C. pulicaris are locally abundant in Switzerland. Therefore, a new surveillance method based on sentinel herds in high risk areas was implemented in 2004 for the early detection of both an incursion of BT vectors into Switzerland, and potential virus circulation among cattle.     

青藏高原牦牛感染BVDV和BEV的分子流行病学调查

为了解青藏高原地区牦牛牛病毒性腹泻病毒(BVDV)和牛肠道病毒(BEV)的感染情况,应用RT-PCR对青藏高原地区(西藏、青海、四川和云南)共计222份出现腹泻症状的牦牛粪便样品开展了分子流行病学调查。从222份样品中,检出44份BVDV阳性,BVDV阳性检出率为20%(95%CI:15.5%~25.6%);检出65份BEV阳性,BEV阳性检出率为29.4%(95%CI:24.1%~35.0%);BVDV/BEV混合感染阳性率为4.8%(95%CI:2.5%~8.0%)。结果表明,所有被检地区牦牛均存在BVDV和BEV感染,且部分地区感染较为严重,有混合感染的情况。研究结果旨在为青藏地区牦牛腹泻的综合防控措施提供基本数据,丰富BVDV和BEV的分子流行病学调查资料。     

Prevalence and distribution of paratuberculosis (Johne's disease) in cattle herds in Ireland

A simple random survey was conducted in Ireland during 2005 to estimate the ELISA-prevalence of paratuberculosis, commonly called Johne's disease (JD), in the cattle population. Serum samples were collected from all 20,322 females/breeding bulls over 12 months-of-age in 639 herds. All samples were tested using a commercially available absorbed ELISA. The overall prevalence of infected herds, based on the presence of at least one ELISA-positive animal, was 21.4% (95% CI 18.4%-24.9%). Herd prevalence levels amongst dairy herds (mean 31.5%; 95% CI: 24.6%, 39.3%) was higher than among beef herds (mean 17.9%; 95% CI: 14.6%-21.8%). However, the animal level prevalence was similar. The true prevalence among all animals tested, was calculated to be 2.86% (95%CI: 2.76, 2.97) and for animals >= 2 yrs, it was 3.30% (95%CI: 3.17, 3.43). For animals in beef herds, true prevalence was 3.09% (95%CI: 2.93, 3.24), and for those in dairy herds, 2.74% (95%CI: 2.59, 2.90). The majority of herds had only one ELISA-positive infected animal. Only 6.4% (95% CI 4.7%-8.7%) of all herds had more than one ELISA-positive infected animal; 13.3% (CI 8.7%-19.7%) of dairy herds ranging from two to eight ELISA-positive infected animals; and, 3.9% beef herds (CI 2.4%-6.2%) ranging from two to five ELISA-positive infected animals. The true prevalence of herds infected and shedding Mycobacterium avium subspecies paratuberculosis is estimated to be 9.5% for all herd types; 20.6% for dairy herds; and 7.6% for beef herds. If ELISA positive animals <2-years-of-age are excluded, the true herd prevalene reduces to: 9.3% for all herd types; 19.6% for dairy herds; and 6.3% for beef herds based on a test specificity (Sp) of 99.8% and test sensitivity (Se) (i.e., ability to detect culture-positive, infected animals shedding at any level) of 27.8-28.9%.     

Geographic distribution of BSE in Switzerland

Visual evaluation of the occurrence of BAB (born after ban) cases pointed towards spatial clustering. Therefore a statistical analysis of spatial case clustering was conducted using GIS technology. In the initial analysis, all 376 cases (135 BAB, 241 BBB/born before ban) diagnosed through mid of March 2001 were investigated using the spatial scan statistic. Two clusters of BBB cases were identified in the western part of Switzerland, and two clusters of BAB cases in the eastern part. Epidemiological investigations performed within the BAB clusters showed an increased pig density in these cluster regions. Pig density is considered an indicator for the probability of contamination of cattle feed with feed containing meat-and-bone meal that is intended for other species (cross-contamination). In an updated cluster analysis including all cases reported until end of June 2002 (data set B), clusters were identified in the same regions as previously. It was shown that the BAB clusters occurred in different time periods. The small scale differences in cluster size and location are discussed, with an emphasis on the implications for following epidemiological investigations.     

Spatial distribution of Trichinella britovi, T. pseudospiralis and T. spiralis in red foxes (Vulpes vulpes) in Hungary

The red fox (Vulpes vulpes) is considered one of the main reservoir of Trichinella spp. in Europe. As limited information on Trichinella infection in wildlife of Hungary is available, 2116 red foxes, representing more than 3% of the estimated fox population of the country, were screened to detect Trichinella larvae by a digestion method. Trichinella larvae from the 35 positive foxes were identified by a multiplex PCR as Trichinella britovi (30 isolates, 85.7%), Trichinella spiralis (4 isolates, 11.4%), and Trichinella pseudospiralis (1 isolate, 2.9%). The true mean intensity of T. britovi, T. spiralis and T. pseudospiralis larvae in lower forelimb muscles was 23.6, 3.5 and 13.5larvae/g, respectively. T. spiralis was detected only in the southern and eastern regions. The non-encapsulated T. pseudospiralis was recorded for the first time in Hungary. Although the overall true prevalence of Trichinella infection in foxes was only 1.8% (95% confidence interval, CI=1.5-2.1%), the spatial analysis reveals different risk regions. In the north-eastern counties bordering Slovakia and Ukraine (21% of the Hungarian territory), the true prevalence of Trichinella infection is significantly higher than that observed in other regions (6.0%, CI=4.8-7.1%). In the southern counties bordering Croatia, Serbia and Romania (41% of the Hungarian territory), the true prevalence of Trichinella infection is moderate (1.4%, CI=1.0-1.8%). In the north-western and central counties (38% of Hungarian territory), the prevalence of Trichinella infection is significantly lower (0.2%, CI=0.1-0.4%) than that of the other regions. Based on the statistical analysis and the evaluation of epidemiological data, none of the counties can be considered free of Trichinella infection. In the past decade, Trichinella infection has been detected only in few backyard pigs, and only few wild boar-related autochthonous infections in humans were described. Nevertheless, these results highlight the need of the maintenance of a strict monitoring and control programmes on Trichinella infection in farmed and hunted animals of Hungary.     

Pig and herd level prevalence of Toxoplasma gondii in Ontario finisher pigs in 2001, 2003, and 2004

The objective of this study was to estimate the apparent and true prevalence of exposure to Toxoplasma gondii in Ontario finisher pigs. During the study period (2001 to 2004), sera from 6048 pigs were tested with a commercial enzyme-linked immunosorbent assay (ELISA); 103 farms were included 1 to 3 times in the study. True prevalence was estimated using a Bayesian approach. Apparent prevalence at the pig level was 1.59% [95% confidence interval (CI): 0.45, 2.99] in 2001, 0.06% (95% CI: 0.00, 0.46) in 2003, and 0.26% (95% CI: 0.00, 0.82) in 2004. Apparent prevalence at the herd-level was 13.7% (95% CI: 7.5, 22.3) in 2001; 1.25% (95% CI: 0.03, 6.77) in 2003, and 3.75% (95% CI: 0.78, 10.6) in 2004. Similarly, posterior Bayesian estimates of true prevalence at the pig level were 1.7% [95% probability interval (PI): 1.2, 2.2] in 2001, 0.2% (95% PI: 0.04, 0.4) in 2003, and 0.3% (95% PI: 0.1, 0.7) in 2004. At the herd level, posterior estimates of prevalence were 11.6% (95% PI: 7.4, 16.8) in 2001, 0% (95% PI: 0.0, 2.5) in 2003, and 1.2% (95% PI: 0.0, 5.0) in 2004 when a herd cut-point > or = 1 was used. Exposure to T. gondii in finishing pig farms in Ontario appears to be infrequent.     

A Bayesian zero-truncated approach for analysing capture-recapture count data from classical scrapie surveillance in France

Capture-recapture (CR) methods are used to study populations that are monitored with imperfect observation processes. They have recently been applied to the monitoring of animal diseases to evaluate the number of infected units that remain undetected by the surveillance system. This paper proposes three bayesian models to estimate the total number of scrapie-infected holdings in France from CR count data obtained from the French classical scrapie surveillance programme. We fitted two zero-truncated Poisson (ZTP) models (with and without holding size as a covariate) and a zero-truncated negative binomial (ZTNB) model to the 2006 national surveillance count dataset. We detected a large amount of heterogeneity in the count data, making the use of the simple ZTP model inappropriate. However, including holding size as a covariate did not bring any significant improvement over the simple ZTP model. The ZTNB model proved to be the best model, giving an estimation of 535 (CI(95%) 401-796) infected and detectable sheep holdings in 2006, although only 141 were effectively detected, resulting in a holding-level prevalence of 4.4‰ (CI(95%) 3.2-6.3) and a sensitivity of holding-level surveillance of 26% (CI(95%) 18-35). The main limitation of the present study was the small amount of data collected during the surveillance programme. It was therefore not possible to build complex models that would allow depicting more accurately the epidemiological and detection processes that generate the surveillance data. We discuss the perspectives of capture-recapture count models in the context of animal disease surveillance.     

Prevalence and genotypes of Toxoplasma gondii in feline faeces (oocysts) and meat from sheep, cattle and pigs in Switzerland

The protozoan parasite Toxoplasma gondii infects almost all warm blooded animal species including humans, and is one of the most prevalent zoonotic parasites worldwide. Post-natal infection in humans is acquired through oral uptake of sporulated T. gondii oocysts or by ingestion of parasite tissue cysts upon consumption of raw or undercooked meat. This study was undertaken to determine the prevalence of oocyst-shedding by cats and to assess the level of infection with T. gondii in meat-producing animals in Switzerland via detection of genomic DNA (gDNA) in muscle samples. In total, 252 cats (44 stray cats, 171 pet cats, 37 cats with gastrointestinal disorders) were analysed coproscopically, and subsequently species-specific identification of T. gondii oocysts was achieved by Polymerase Chain Reaction (PCR). Furthermore, diaphragm samples of 270 domestic pigs (120 adults, 50 finishing, and 100 free-range animals), 150 wild boar, 250 sheep (150 adults and 100 lambs) and 406 cattle (47 calves, 129 heifers, 100 bulls, and 130 adult cows) were investigated by T. gondii-specific real-time PCR. For the first time in Switzerland, PCR-positive samples were subsequently genotyped using nine PCR-restriction fragment length polymorphism (PCR-RFLP) loci (SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1 and Apico) for analysis. Only one of the cats shed T. gondii oocysts, corresponding to a T. gondii prevalence of 0.4% (95% CI: 0.0-2.2%). In meat-producing animals, gDNA prevalence was lowest in wild boar (0.7%; 95% CI: 0.0-3.7%), followed by sheep (2.0%; 95% CI: 0.1-4.6%) and pigs (2.2%; 95% CI: 0.8-4.8%). The highest prevalence was found in cattle (4.7%; 95% CI: 2.8-7.2%), mainly due to the high prevalence of 29.8% in young calves. With regard to housing conditions, conventional fattening pigs and free-range pigs surprisingly exhibited the same prevalence (2.0%; 95% CI: 0.2-7.0%). Genotyping of oocysts shed by the cat showed T. gondii with clonal Type II alleles and the Apico I allele. T. gondii with clonal Type II alleles were also predominantly observed in sheep, while T. gondii with mixed or atypical allele combinations were very rare in sheep. In pigs and cattle however, genotyping of T. gondii was often incomplete. These findings suggested that cattle in Switzerland might be infected with Toxoplasma of the clonal Types I or III, atypical T. gondii or more than one clonal Type.     

四川地区藏猪戊型肝炎病毒的检测和遗传演化分析

旨在调查四川地区藏猪戊型肝炎病毒（hepatitis E virus,HEV）的流行情况和遗传演化,作者用RT-PCR法对2018—2020年采集自四川省甘孜藏族自治州和阿坝藏族自治州的22个藏猪场332份藏猪粪便样本进行HEV检测,并对阳性样本进行基因分型。RT-PCR检测结果表明HEV核酸阳性率为20.48%（68/332,95% CI=16.3%~25.2%）,22个规模藏猪场中HEV猪场阳性率为77.27%（17/22,95% CI=54.6%~92.2%）,健康样本阳性率为2.86%（3/105,95% CI=0.6%~8.1%）,腹泻样本阳性率为28.63%（65/227,95% CI=22.8%~35.0%）,系统进化分析显示所有阳性株均为G4型。为了进一步研究该地区流行毒株的演化过程,以贝叶斯进化分析软件进行分歧时间估算,结果表明,藏猪流行毒株的分歧时间最早为1999年,最晚为2016年。并分别从每年的样本中挑选1份阳性样本得到全基因组序列,核酸序列相似性为89.5%~93.1%。通过对3条全基因组重组分析发现SWU/301/2019存在重组现象,SWU/301/2019重组区域位于ORF1的3 746—4 655 bp。本研究首次对四川地区藏猪源HEV进行调查,结果表明四川藏猪中存在一定程度的HEV感染,为四川地区对藏猪感染HEV的防治以及深入研究四川藏猪源HEV遗传变异及生物学特性提供了参考依据。     

Cross-sectional prevalence of Fasciola gigantica infections in beef cattle in Botswana

A cross-sectional study was carried out to determine the prevalence and distribution of Fasciola gigantica infections in communally grazed and ranch-grazed beef cattle through coprological examination. A total of 8646 cattle (4618 adults, 2843 weaners and 1185 calves) faecal samples were collected during the 24 months of study. Results from this study indicated that only 64 (0.74%; 95% CI 0.57, 0.94%) of the samples were positive for F. gigantica eggs. The positive samples were detected in one (Central) of the six study districts and was restricted to the Tuli Block (commercial) farms in Machaneng village in eastern Botswana. The prevalence of fluke eggs was significantly higher in adult cattle (12.85%; 95% CI 9.72, 16.54%) than weaners (6.49%; 95% CI 3.40, 11.06%) and calves (0.79%; 95% CI 0.02, 4.31%), (χ²(2)?=?19.01, p?<?0.001). Thus, adults (OR?=?18.57; 95% CI 2.54, 135.81%) were approximately 20 times more likely to be infected than calves. By taking liver inspection as a gold standard for diagnosis of fasciolosis, the sensitivity of the sedimentation technique was found to be 72.41% and the specificity 100%, with moderate relationship (κ?=?0.53; 95% CI 0.31–0.75) between the two methods. This study has demonstrated that infection of cattle from Botswana, with F. gigantica, was low and distribution of the fluke appeared to be linked to suitable environmental conditions for the intermediate host snail. However, detailed surveillance studies, involving more cattle and areas, are required to verify the true prevalence. Such information would assist in the design of appropriate, strategic and effective fluke control programmes.

     

藏猪源捷申病毒的检测和遗传演化分析

旨在调查四川地区藏猪捷申病毒（porcine teschovirus,PTV）的流行及分子特征和遗传演化。用RT-PCR法对2017-2018年采自四川省甘孜藏族自治州康定市14个藏猪场96份粪便样品进行检测,并对全基因组进行序列分析和基因分型。PCR检测结果表明,PTV核酸阳性率为20.8%（20/96,95% CI=13.2%~30.3%）,14个规模藏猪场中PTV猪场阳性率为57.1%（8/14,95% CI=28.9%~82.3%）,并从2份阳性样本中获得了2条近似全长的PTV全基因组序列,分别命名为SWU-E5-2018和SWU-ZG2-2018,核苷酸序列相似性为83.1%。通过VP1序列分析发现2条序列的血清型分别为3型和6型。通过基因重组分析发现SWU-E5-2018存在重组现象,重组区域位于衣壳蛋白基因P1的552-3 082 nt处。为了进一步研究2条PTV序列的演化过程,以贝叶斯进化分析软件进行分歧时间估算,结果表明,SWU-E5-2018的分歧时间约为2010年,SWU-ZG2-2018的分歧时间约为2011年。本研究首次对藏猪源PTV进行了初步调查,结果表明藏猪中存在一定程度的PTV感染,为深入研究藏猪源PTV遗传变异及其生物学特性提供了参考依据。     

The prevalence of verotoxins, Escherichia coli O157:H7, and Salmonella in the feces and rumen of cattle at processing.

Fecal samples collected from cattle at processing during a 1-year period were tested for verotoxins (VT1, VT2), Escherichia coli O157:H7, and Salmonella. Verotoxins were detected in 42.6% (95% CI, 39.8% to 45.4%), E. coli O157:H7 in 7.5% (95% CI, 6.1% to 9.1%), and Salmonella in 0.08% (95% CI, 0.004% to 0.5%) of the fecal samples. In yearling cattle, the median within-lot prevalence (percentage of positive samples within a lot) was 40% (range, 0% to 100%) for verotoxins and 0% for E. coli O157:H7 (range, 0% to 100%) and Salmonella (range, 0% to 17%). One or more fecal samples were positive for verotoxins in 80.4% (95% CI, 72.8% to 86.4%) of the lots of yearling cattle, whereas E. coli O157:H7 were detected in 33.6% (95% CI, 26.0% to 42.0%) of the lots. In cull cows, the median within-lot prevalence was 50% (range, 0% to 100%) for verotoxins and 0% (range, 0% to 100%) for E. coli O157:H7 and Salmonella (range, 0% to 0%). Verotoxins were detected in one or more fecal samples from 78.0% (95% CI, 70.4% to 84.2%) of the lots of cull cows, whereas E. coli O157:H7 were detected in only 6.0% (95% CI, 3.0% to 11.4%) of the lots of cull cows. The prevalence of verotoxins in fecal samples was lower in yearling cattle than in cull cows, whereas the prevalence of E. coli O157:H7 in fecal samples was higher in yearling cattle than in cull cows. The prevalence of E. coli O157:H7 in fecal samples was highest in the summer months. Rumen fill, body condition score, sex, type of cattle (dairy, beef), and distance travelled to the plant were not associated with the fecal prevalence of verotoxins or E. coli O157:H7. The prevalence of verotoxins in fecal samples of cull cows was associated with the source of the cattle. It was highest in cows from the auction market (52%) and farm/ranch (47%) and lowest in cows from the feedlot (31%). In rumen samples, the prevalence of verotoxins was 6.4% (95% CI, 4.2% to 9.4%), and it was 0.8% (95% CI, 0.2% to 2.3%) for E. coli O157:H7, and 0.3% (95% CI, 0.007% to 1.5%) for Salmonella.