河南洛阳地区流产奶牛感染性病原的分子检测

为调查洛阳地区引起奶牛流产的主要病原,于2013年7月至2014年3月,收集该地区6个奶牛场(或小区)共42头新鲜流产胎牛,及其母体的血液、阴道分泌物和鼻腔分泌物,计为42例样本,采用PCR或RT-PCR方法对所采集样本进行新孢子虫、弓形虫、胎儿三毛滴虫、布鲁菌、牛传染性鼻气管炎病毒(IBRV)和牛病毒性腹泻病毒(BVDV)6种常见流产病原的核酸检测。结果显示,被检样本总感染率为42.9%(18/42),其中新孢子虫感染率最高,为40.5%(17/42);:IBRV次之,为11.9%(5/42);胎儿三毛滴虫、布鲁菌、弓形虫和BVDV感染率分别为2.4%、2.4%、2.4%和0。14.3%(6/42)的被检样本存在混合感染,其中以新孢子虫十IBRV混合感染为主(50%,3/6)。结合被检流产奶牛的临床特征及饲养管理等因素,推断新孢子虫是导致该地区奶牛流产的最主要病原,本研究结果将为该地区有效防控奶牛流产提供科学依据。     

某规模化奶牛场牛流产病原的血清学调查

为了摸清某规模化奶牛场50头奶牛流产的原因,对可能造成感染流产的布氏杆菌、衣原体、弓形虫和新孢子虫抗体进行了血清学检测。结果显示,流产奶牛布氏杆菌、弓形虫和新孢子虫抗体阳性率依次为28%、10%和8%;布氏杆菌抗体和弓形虫抗体均为阳性2头,占被检头数4%;衣原体抗体全部阴性。调查结果表明,布氏杆菌、弓形虫和新孢子虫感染是造成该规模化牛场奶牛流产的主要原因。     

温泉县部分奶牛的新孢子虫病和布氏杆菌病血清学调查

为了探究温泉县奶牛流产病因,对采自温泉县4个不同地区的81份血清样品分别进行新孢子虫病和布氏杆菌病检测,其中新孢子虫病应用rELISA方法检测,布氏杆菌病的检测参照国标,被检的81份血清样品中8份血清呈新孢子虫抗体阳性,阳性率为9.88%。其中安格里格乡感染率为18.75%,哈日布呼镇感染率为7.14%,蒙进感染率为0%,塔秀乡感染率为13.04%。没有检出布氏杆菌阳性血样和新孢子虫和布氏杆菌病二者混合感染的流产奶牛血样。检测结果表明:新孢子虫是导致该地区奶牛流产的重要原因之一。     

4 种呼吸道疫病血清学调查分析——以凯里市A奶牛场为例

[目的]为了解凯里市A奶牛场牛呼吸道疫病的流行情况。[方法]本次采用酶联免疫吸附试验（ELISA）对142 份奶牛血清样品进行牛呼吸道合胞体病毒（BRSV）、牛病毒性腹泻（BVDV）、牛传染性鼻气管炎（IBRV）、牛支原体感染抗体检测。[结果]凯里市A奶牛场4 种呼吸道疾病病原普遍存在,BRSV阳性率为41.5%（59/142）;BVDV阳性率为40.1%（57/142）;IBRV阳性率为45.0%（64/142）;支原体阳性率为33.8%（48/142）。犊牛4 种呼吸疾病单一感染率为15.1%~45.5%;BVDV感染最严重,为45.5%;成年牛单一感染率为33.8%~45.1%。此外,奶牛场存在IBRV、BRSV、BVDV、支原体多种病原体混合感染,二重感染率为18.3％~30.2％;BVDV+IBRV感染率最高,为30.2%;三重感染以BVDV+支原体+IBRV感染率最高,为19.7%;四重感染率为9.9%。[结论]凯里市A奶牛场存在4 种疫病,有不同程度的病原体感染,应加强对上述病原体的流行控制,提高奶牛场管理水平,减少奶牛场疫病发生和经济损失。     

河北省部分地区致犊牛腹泻主要病原分布特征

为了明确河北省内致犊牛感染性腹泻主要病原,本研究自河北省8个地区采集775份犊牛腹泻粪便样品,根据GenBank中登录的牛病毒性腹泻病毒(BVDV)5′UTR基因、牛冠状病毒(BCoV)N基因、牛轮状病毒(BRV)VP6基因和牛传染性鼻气管炎病毒(IBRV)gB基因序列设计特异性引物,参照文献合成隐孢子虫18S rRNA和大肠杆菌16S rRNA引物,利用PCR方法对BVDV、BCoV、BRV、IBRV、隐孢子虫和大肠杆菌进行检测。结果显示,775份犊牛腹泻临床样品中,BVDV的阳性率为27.11%(205/775);BCoV的阳性率为17.52%(137/775);BRV的阳性率为9.85%(77/775);IBRV的阳性率为3.71%(29/775);隐孢子虫的阳性率为12.28%(96/775);大肠杆菌的阳性率为20.46%(160/775);还有9.10%的样品未检测出病原。在河北省部分地区采集的犊牛腹泻粪便样品中,BVDV检测阳性率最高为27.11%,在冬季犊牛BVDV的感染率最高为40.21%,且唐山和张家口地区奶牛场BVDV的感染率高于其他6个地区。本研究明确了河北省内...     

2022年宁夏固原市肉用流产母牛病原血清学调查分析

[目的]为了明确宁夏固原地区肉用流产母牛4种流产相关病原的流行情况。[方法]试验选择宁夏固原市5个地区不同规模化肉牛养殖场,采集131份有流产史的母牛血清样品,采用酶联免疫吸附试验（ELISA）分别对流产相关病原抗体/抗原进行检测和分析。[结果]采集的131份血清样品中共检出109份阳性血清,阳性率为83.2%。其中BVDV抗体阳性率为62.6%（82/131）、流产衣原体抗体阳性率为59.5%（78/131）、IBRV抗体阳性率为13.7%（18/131）,布鲁氏菌抗体阳性率为0%（0/131）。结果表明,采集的131份血清样品中共检出109份阳性血清,阳性率为83.2%。其中BVDV抗体阳性率为62.6%（82/131）、流产衣原体抗体阳性率为59.5%（78/131）、IBRV抗体阳性率为13.7%（18/131）,布鲁氏菌抗体阳性率为0%（0/131）。109份阳性样品中,最多出现3种病原混合感染。其中单一病原感染阳性样品占42.2%（46/109）,以BVDV感染比例最大,与流产衣原体阳性率相比差异显著（P＜0.05）;2种病原混合感染样品占56.9%（62/109）,以BVDV和流产衣原体混合感染比例最大,与流产衣原体和IBRV混合感染阳性率、BVDV和IBRV混合感染阳性率差异极显著（P＜0.01）;3种病原混合感染样本占4.6％（4/109）,主要以BVDV、流产衣原体和IBRV混合感染为主。[结论]宁夏固原地区流产母牛均存在以上3种疫病感染,其中主要以BVDV和流产衣原体单独或混合感染为主。     

我国北方4省部分规模奶牛场牛呼吸道疾病综合征主要病原血清体检测

为了解我国牛呼吸道疾病综合征（BRDC）主要病原牛传染性鼻气管炎病毒（IBRV）、牛病毒性腹泻病毒（BVDV）、牛副流感病毒3型（BPIV3）与牛呼吸道合胞体病毒（BRSV）的血清流行情况,使用抗体检测试剂盒,对4个省份的28家奶牛场采集的1 601份血清样品进行ELISA抗体检测。结果显示：奶牛IBRV、BVDV、BPIV3和BRSV抗体阳性率分别为76.2%、60.5%、63.2%和45.4%,奶牛场抗体阳性率分别为82.2%、75.0%、85.7%和89.3%。不同省份奶牛IBRV、BVDV、BPIV3和BRSV抗体阳性率分别为25.1%~90.3%、42.3%~81.3%、26.9%~81.1%和32.2%~51.9%,奶牛场抗体阳性率分别为20.0%~100%、57.2%~100%、75.0%~100%和75.0%~100%。奶牛IBRV、BVDV、BRSV抗体阳性检出率在3—5月最高,BPIV3抗体阳性检出率在12月到次年2月最高。奶牛场存在IBRV、BVDV、BPIV3和BRSV多种病原的混合感染,且各病原流行存在一定的地区和季节性差异。结果提示应加强对上述病原流行的控制,提高奶牛场管理水平。本研究为奶牛场呼吸道相关病毒病防控提供了数据参考。     

规模化奶牛场牛传染性鼻气管炎与牛病毒性腹泻的流行病学调查

为初步了解上海市崇明岛地区奶牛养殖场IBRV和BVDV的流行情况,在两个规模化养殖场共采集385份血清样品,进行IBRV和BVDV抗体的检测与BVDV病原的检测。结果显示,两个规模化养殖场BVDV的抗体阳性率分别为97.4%和96.7%,IBRV的抗体阳性率分别为41.2%和74.3%。1号牛场BVDV病原阳性率为1.3%,检测到一头BVD持续感染牛(BVD-PI)牛。2号牛场没有检测到BVD-PI牛。数据表明,两个规模化养殖场存在IBRV和BVDV感染史和接触史,应采取防控净化措施。     

引起部分奶牛场呼吸道疾病的主要病毒性病原检测

近年来,我国部分地区奶牛场发生了以流黏性鼻液为主要症状的呼吸道疾病,经检测,排除牛支原体、牛巴氏杆菌感染。为探究其主要病毒性病原,从山东等4省(市)5家表现临床症状的奶牛场采集发病牛与无症状牛鼻拭子样品298份,开展牛传染性鼻气管炎病毒(IBRV)、牛病毒性腹泻病毒(BVDV)和牛副流感病毒3型(BPIV3)PCR检测。结果显示:发病奶牛场IBRV与BVDV阳性率分别为28.9%、7.1%,BPIV3未检出;发病牛与无症状牛IBRV阳性率分别为42.6%、10.9%,BVDV阳性率分别为11.3%、1.6%;IBRV、BVDV混合感染率为5.7%,IBRV、BVDV混合感染占IBRV总感染数的19.8%,占BVDV总感染数的81.0%。结果表明,引起这些奶牛场呼吸道症状的主要病原可能为IBRV、BVDV,且混合感染较严重。本研究为奶牛场呼吸道疾病防控提供了依据。     

吉林省部分牛场BVDV、IBRV、BRSV的感染情况调查

为了解吉林省牛病毒性腹泻(BVD)、牛传染性鼻气管炎(IBR)、牛呼吸道合胞体病(BRS)的流行及其病原混合感染情况,在吉林省的9个地区随机采集了325份血清样品,采用ELISA血清抗体检测试剂盒与新型纳米PCR方法检测所采集样品。结果显示,ELISA检测BVDV抗体阳性243份,阳性率为74.77%,IBRV抗体阳性186份,阳性率为57.23%,BRSV抗体阳性90份,阳性率为27.69%,BVDV与IBRV混合感染率为31.69%;BVDV与BRSV混合感染率为9.54%,IBRV与BRSV混合感染率为1.54%,3种病毒混合感染率为17.23%。采用纳米PCR方法检测所有血清显示,BVDV抗原阳性42份,阳性率12.92%,未检出IBRV抗原阳性;BRSV抗原阳性29份,阳性率8.92%。BVDV与BRSV混合感染率为1.85%。     

Clinical signs and diagnosis of a severe primary infection with BVDV subtype 1b in a dairy herd

As a result of a BVDV infection in a herd consisting of 95 adult cattle 17 cows aborted their calves within a period of 3.5 months, one third got severe diarrhoea, 3 cows died and an increased percentage of the cattle got lochiometra after calving or abortion. The disease was diagnosed by paired serological testing of cattle with diarrhoea or abortion and post mortem examination of several aborted calves. From one foetus BVDV virus was isolated and subsequently subtyped by sequencing. Of aborting cattle, the testing results were influenced by the interval between infection and abortion. These results indicate that a primary infection with BVDV subtype 1b can cause severe clinical symptoms in a dairy herd.     

Efficacy of viral components of a nonabortigenic combination vaccine for prevention of respiratory and reproductive system diseases in cattle

Efficacy and safety of components of an IM-administered vaccine for prevention of infectious bovine rhinotracheitis virus (IBRV), parainfluenza type-3 (PI-3) virus, bovine viral diarrhea virus (BVDV), and respiratory syncytial virus (RSV) infections and campylobacteriosis and leptospirosis were evaluated in cattle, including calves and pregnant cows. Challenge of immunity tests were conducted in calves for IBRV, PI-3 virus, or BVDV vaccinal components. All inoculated calves developed serum-neutralizing antibodies and had substantially greater protection (as measured by clinical rating systems) than did controls after challenge exposure to virulent strains of IBRV, PI-3 virus, BVDV, or RSV. In in utero tests, IBRV or bovine RSV vaccinal strains were inoculated into fetuses of pregnant cows. Histologic changes or abortions did not occur after fetal inoculation of the RSV vaccinal strain, and 10 of 14 fetuses responded serologically. Of 9 fetuses, one responded serologically to the IBRV vaccinal strain after in utero inoculation and was aborted 3 weeks later. In an immunologic interference test, 10 calves vaccinated with 2 doses of the multivalent vaccine, containing the 4 viral components and a Campylobacter-Leptospira bacterin, developed serum-neutralizing antibodies to IBRV, PI-3 virus, BVDV, and RSV without evidence of serologic interference. Under field conditions, 10,771 cattle, including 4,543 pregnant cows, were vaccinated. Vaccine-related abortions did not occur.     

Neospora caninum and bovine virus diarrhoea virus infections in Swedish dairy cows in relation to abortion

The protozoan parasite Neospora caninum and bovine virus diarrhoea virus (BVDV) are recognized as important causes of bovine abortion and congenital disease worldwide. In this study, serological investigations were performed to estimate the prevalence of N. caninum infection in Swedish dairy cattle, to assess to what extent it may affect abortion rates, and to determine possible effects of coinfection with BVDV. The overall N. caninum seroprevalence in Swedish dairy cows was estimated at 2% (16/780), and the BVDV seroprevalence was 32% (249/780). Among aborting cows from herds with abortion problems, 7% (26/378) had antibodies to N. caninum and 42% (153/378) to BVDV. Seventeen of the N. caninum positive animals also had antibodies to BVDV. There was a statistically significant (P = 0.013) association between presence of antibodies to N. caninum and BVDV. In a case-control study comprising sera from cows in herds without recognized abortion problems, 6% (5/89) and 1% (1/89) of sera from aborting and non-aborting cows, respectively, had antibodies to N. caninum. Two of the N. caninum seropositive aborting cows also had antibodies to BVDV. These results confirm that N. caninum infection is associated with bovine abortion in Sweden and also indicate that there might be concurrent effects of N. caninum and BVDV. It is concluded that Swedish dairy cows have a low prevalence of N. caninum infection which is favourable in relation to possible future control programmes.     

Survey of nine abortifacient infectious agents in aborted bovine fetuses from dairy farms in Beijing, China, by PCR

Abortion in dairy cattle causes considerable economic losses to the dairy industry. Aborted fetuses and samples from the corresponding aborting dams from 12 dairy herds in Beijing were tested for 9 abortifacient infectious pathogens by PCR between 2008 and 2010. From a total of 80 abortion cases collected during this period, infectious agents were detected in 45 (56.3%) cases, 22 (48.9%) of which represented co-infections with two or three infectious agents. The detected pathogens included infectious bovine rhinotracheitis virus (36.3%) and Neospora caninum (31.3%), followed by bovine viral diarrhoea virus (7.5%), Brucella abortus (6.3%), Tritrichomonas foetus (5%) and Toxoplasma gondii (1.3%). Campylobacter fetus, Coxiella burnetii and Chlamydophila psittaci were not detected in any abortion case. Findings from this study indicated that infectious bovine rhinotracheitis virus and Neospora caninum were the main potential causes of abortions in Beijing dairy herds, whereas the bacterial pathogens were not, in contrast to reports from other countries. This is the first study to test nine abortifacient infectious agents by PCR at the same time, and it is also the first time to report the involvement of a variety of infectious agents in bovine abortion cases in China.     

A farming systems study of abortion in dairy cattle on the Atherton Tableland: 2. The pattern of infectious diseases

The role of infectious agents on dairy farms on the Atherton Tableland in tropical north Queensland was studied as part of a comprehensive investigation into the causes of bovine abortion. The prevalence of antibody in serums collected from 7 herds whose annual abortion rates ranged from 3% to 21% were as follows: Leptospira hardjo 49.9% (426/853), L. pomona 0.4% (3/851), bovine virus diarrhoea (BVD) 33.7% (35/104). Infectious bovine rhinotracheitis virus (IBR) 11.5% (12/105), Akabane virus 92.2% (95/103), Aino virus 62.1% (64/103), Chlamydia psittaci 3.1% (37/1004), Brucella abortus 0% (0/851), and Toxoplasma gondii 0% (0/105). Testing of serums against a wide range of leptospiral serotypes indicated that reactions occurring in the Hebdomadis and Sejroe serogroups were probably cross reactions with L. hardjo. Infection with L. hardjo and Akabane virus occurred prior to first mating and contact with Aino virus occurred during first pregnancy. Infection with BVD and IBR viruses was sporadic. The pathology and microbiology of 32 aborted foetuses from 24 Tableland herds (10 from the group of 19 farms under more intense study) were performed. Lesions associated with a Sarcocystis-like agent were present in 6, leptospires in 1, suspected toxic hepatosis in 2 and purulent bronchopneumonia (Staphylococcus aureus) in 1 foetus. No diagnoses were made in the remaining 22 foetuses (69%). Evidence for a common infectious cause of abortion in the population was inconclusive.     

A prospective study of the effect of Neospora caninum and BVDV infections on bovine abortions in a dairy herd in Arequipa, Peru

We used a prospective seroepidemiological approach to investigate endemic abortion in a dairy herd in Arequipa, Peru, and its association with Neospora caninum and bovine viral-diarrhoea virus (BVDV) infections. Between January 2002 and March 2004, 1094 pregnancies were confirmed in 538 cows. Of these, 137 pregnancies (13%) in 121 cows ended in abortion. The serological status to N. caninum was assessed using a single serological screening, whereas BVDV status was assessed at the herd level through consecutive samplings of young stock.

Cox proportional-hazards models were used to estimate the effect of N. caninum and BVDV on the hazard of early (between day 42 and day 100 in gestation), and late (after day 100) abortions, respectively. Serological status to N. caninum was included as a dichotomous variable, and the effect of BVDV estimated at the herd level, as a time-dependent seasonal effect. Because data from repeated pregnancies were included, we considered possible lack of independence between observations and included frailty effects into the models. Our models also considered the possible confounding by parity and animal origin.

Only multiparity was associated with the hazard of early abortion (HR = 2.8 compared to nulliparous heifers). N. caninum seropositivity significantly affected the hazard of late abortion, but interacted with parity. The HRs for Neospora-positive animals were 6.4, 3.7 and 1.9, respectively, for nulliparous heifers, first-lactation cows and multiparous cows. Evidence of BVDV circulating (or not) among the young stock was not associated with abortions, but few cows in this herd were susceptible to incident infection.     

Occurrence of Neospora caninum and Toxoplasma gondii infections in ovine and caprine abortions

Neospora caninum and Toxoplasma gondii are closely related cyst-forming apicomplexan parasites identified as important causes of reproductive failure in cattle and small ruminants, respectively. Protozoan abortion in small ruminants is traditionally associated with T. gondii, but the importance of N. caninum remains uncertain. The aim of this study was to investigate the presence of N. caninum and T. gondii infections in abortion cases in small ruminants submitted for diagnosis. For this purpose, 74 ovine and 26 caprine aborted foetuses were recovered from different areas in Spain. Foetal histopathology was used to detect the presence of protozoal-associated lesions in brain. The presence of N. caninum and T. gondii was confirmed by PCR. Protozoal infection was detected in 17 out of 100 (17%) foetuses examined by at least one of the diagnostic techniques used. Lesions suggestive of protozoal infection were observed in 10.8% (8/74) and 15.4% (4/26) of the ovine and caprine abortions respectively. N. caninum and T. gondii infection was detected by PCR in 6.8% (5/74) and 5.4% (4/74) of sheep foetuses, respectively, of which five showed protozoal-associated lesions. N. caninum DNA was detected in 11.5% (3/26) of goat foetuses, of which two showed protozoal-associated lesions, whereas T. gondii DNA was detected in one goat foetus with no lesions. The simultaneous presence of N. caninum and T. gondii DNA was detected in one sheep foetus with severe lesions. This study demonstrates that N. caninum plays a significant role in abortion in small ruminants in the studied population. In addition, our results highlight the importance of differentiating between protozoa whenever characteristic lesions are observed.     

Evaluation of the rabbit as a laboratory model for infectious bovine rhinotracheitis virus infection

Experimental infection of rabbits with infectious bovine rhinotracheitis virus (IBRV) produced diverse manifestations of disease which included abortion, conjunctivitis, dermatitis, vulvovaginitis, systemic infection, neonatal death and respiratory tract infection. Each disease syndrome was studied using virus isolation, fluorescent antibody examination and histologic examination. Conjunctivitis, dermatitis and vulvovaginitis lesions were characterized by edema, infiltration of mucosa and submucosa with inflammatory cells and ulceration of epithelium. Systemic infection resulted in severe necrosis of liver and adrenal glands with large numbers of cells containing intranuclear inculsions. Pregnant rabbits aborted within 48 hours following inoculation of IBRV. Virus infection and viral lesions were not demonstrated in aborted fetuses.