青海省猪囊尾蚴病血清学调查

猪囊尾蚴病又称猪囊虫病,是由人的有钩绦虫(猪带绦虫)的幼虫——猪囊尾蚴寄生在猪的肌肉中所引起一种人畜共患寄生虫病。为了摸清青海省猪囊尾蚴感染情况,对来自10个县市的788份猪血清样品采用ELISA方法进行了血清学检测,结果检出阳性样品17份,阳性率为2.16%。     

广西山羊蓝舌病血清学调查及流行区域分布的影响因素分析

为了解广西地区山羊蓝舌病(BT)流行现状,本研究采用免疫扩散试验对采自广西11个地区的3 646份山羊血清进行BT血清学调查,结果表明,广西地区山羊群普遍存在BT感染,并且血清阳性率存在地域性差异,阳性率为6.3%～45.1%,平均阳性率为20.5%。对不同生长阶段山羊的血清阳性率进行统计,结果显示成年羊的阳性率高于羔羊,分别为22.1%和17.4%,这可能与成年羊接触媒介昆虫的机会较多有关。对BT流行区域分布与地理位置和气候等自然因素之间的相关性分析表明,广西山羊BT血清阳性率与地理位置有一定相关性,与年平均气温显著相关,与年平均降雨量无显著相关性,由此可见,地理位置和气温是BT流行病学的影响因素。     

规模化猪场脑心肌炎病毒感染的血清学调查

脑心肌炎病毒(EMCV)可引起猪的脑炎、心肌炎和母猪繁殖障碍,该病已在世界上多个国家暴发和流行。我国对EMCV及其所致疾病的研究工作还处于起步阶段,为了揭示EMCV在我国规模化猪场的感染情况,我们应用酶联免疫吸附试验(ELISA)对2005-2006年间采集自全国13个省市46个规模化猪场的3250份血清样本进行了EMCV抗体检测,结果显示,各省阳性率在39.64%~90%之间,平均抗体阳性率为72%,监测的46个猪场都存在EMCV感染,猪场感染阳性率为100%;对不同生长阶段猪群检测结果表明,EMCV抗体阳性率随猪龄的增长而升高,且不同生长阶段猪抗体阳性率差异极显著;成年公猪的抗体阳性率高于成年母猪。本项调查表明,我国规模化猪场已经普遍感染EMCV,这应引起我国养猪业警惕,并做好该病的综合防控。     

Serosurvey and Observational Study of US Army Veterinary Corps Officers for Q Fever Antibodies from 1989 to 2008

Since World War II, the military has experienced outbreaks of Q fever among deploying units including recent case reports of Q fever in US military personnel returning from serving in the Middle East during Operation Iraqi Freedom and Operation Enduring Freedom. Occupational exposure and prevalence of Q fever among US Army Veterinary Corps officers have not been examined. A retrospective serosurvey and observational study of 500 military veterinarians were conducted using archived serum specimens from military veterinarians who entered and served between 1989 and 2008 and were tested for exposure to Coxiella burnetii. Corresponding longitudinal health‐related, demographic, medical and deployment data were examined. A total of 69 (13.8%) individuals at military entry and 85 (17%) had late career positive titres. A total of 18 (3.6%) individuals showed seroconversion. Women were more likely to be seropositive after military service [prevalence ratio (PR) 1.96; 95% confidence interval (CI) 1.15–3.35] and were also more likely to seroconvert (incidence rate ratio 3.55; 95% CI 1.19–12.7). Women who deployed to Operation Iraqi Freedom were more likely to be seropositive (PR 3.17; 95% CI 1.03–9.71). Veterinarians with field service and pathology specialties had the highest incidence rates (7.0/1000 PY; 95% CI 4–12 and 3–19, respectively). This is the first report documenting US military veterinarians' exposure to C. burnetii. Military veterinarians are at risk prior to service, with moderate number of new cases developing during service and most maintaining titres for long periods of time. Women consistently demonstrated higher seroprevalence and incidence levels. As increasing numbers of women enter the veterinary profession and subsequently the US Army, this may warrant close monitoring. This study likely underestimates exposure and risk and does not address chronic health effects, which may be valuable to explore in future health studies.     

The association between antibody titres againstCampylobacter fetus and reproductive efficiency in dairy cattle

The relationship between the antibody titres againstCampylobacter fetus and various indices of reproductive efficiency was studied in a cross-sectional study of 178 dairy cows from three California Dairy Herd Improvement Association herds. Blood samples were collected from the lactating cows during December 1986. Enzyme-linked immunosorbent assays were used to determine the antibody titres of the cow againstCampylobacter fetus, Haemophilus somnus andLeptospira hardjo and were classified as either negative or positive. The status of a cow as either negative or positive againstCampylobacter fetus andHaemophilus somnus represents serological evidence of natural exposure to the corresponding bacterial agents. However, the status againstLeptospira hardjo was assumed to reflect a vaccinal titre since all the cows studied had been routinely vaccinated against this organism in September 1986. The data on demographic and reproductive parameters pertained only to the current lactation of the cows and were obtained from Dairy Herd Improvement Association individual cow records of December 1986. Five indices of reproductive efficiency were used, namely the recent calving interval, the calving-to-conception interval, the calving-to-last-service interval, the number of services per conception, and the number of services since last calving. The serological status againstHaemophilus somnus, Leptospira hardjo and other covariates suggested by the results of previous studies were included in modelling the relationships of interest. Stepwise multiple linear regression analyses were carried out to study the adjusted relationship ofCampylobacter fetus with each measure of reproductive efficiency.Multivariate analyses revealed that the adjusted relationship forCampylobacter fetus with all five measures of reproductive efficiency was non-significant (p > 0.05). Among the covariates,Leptospira hardjo had a strong and independent relationship with recent calving interval, the unstandardized partial regression coefficient being -0.77. The possible biological mechanisms of these associations are discussed.Abbreviations BMDP biomedical computer programs - DHIA dairy herd improvement association - ELISA enzyme-linked immunosorbent assay - ICR individual cow record - PSS physiological saline solution - SD standard deviation; Other abbreviations are shown in Table I     

The association between antibody titres againstCampylobacter fetus and milk production efficiency in dairy cattle

The association between serological evidence of exposure toCampylobacter fectus and milk production performance was studied in 178 lactating cows from three California Dairy Herd Improvement Association herds using a cross-sectional study design in December 1986. ELISAs were used to determine the antibody titres againstCampylobacter fetus, Haemophilus somnus andLeptospira hardjo, which were classified as either negative or positive. The status of a cow as negative or positive againstC. fetus andH. somnus represents the serological evidence of natural exposure to the corresponding bacteria. However, the status againstL. hardjo was assumed to be the level of vaccinal titre against this organism since all the cows studied had been vaccinated against this agent. The data on demographic and productivity variables relating to the current lactation of the cows were obtained from Dairy Herd Improvement Association individual cow records for December 1986. Four measures of milk production efficiency for the current lactation were used. The status againstL. hardjo and other covariates suggested by previous studies were included in modelling the relationships of interest. Stepwise multiple linear regression was used to study the adjusted relationship ofC. fetus with each measure of milk production efficiency.Multivariate analyses revealed that the adjusted relationships ofC. fetus with the test-day's milk production, the extended 305-day milk production and the relative value of milk production were not significant (p>0.1). However, after adjusting for possible covariates,C. fetus-positive cows had an average of 7.43% lower mature equivalent milk production thanC. fetus-negative cows (p=0.02). Among the covariates, the serological status againstL. hardjo had a strong and independent relationship with the percentage mature equivalent milk production, the unstandardized partial regression coefficient being 4.53.We conclude from this cross-sectional study that the association ofC. fetus seropositivity with one index of milk production is the first indication that latentC. fetus infection may be associated with subclinical mastitis, perhaps through a hypersensitivity reaction. However, this needs further investigation.Abbreviations BMDP Biomedical Computer Programs - DHIA California Dairy Herd Improvement Association - ELISA enzyme-linked immunosorbent assay; other abbreviations are shown in Table I     

Seroepidemiologic survey for Coxiella burnetii among hospitalized US troops deployed to Iraq

Q fever is a zoonotic illness which frequently has a non-specific clinical presentation. Cases among deployed US military personnel have been reported in increasing numbers indicating an emerging at-risk occupational group. Banked serum specimens were utilized to estimate seroprevalence and risk factors among military personnel deployed to Iraq. Coxiella burnetii antibody testing was performed and epidemiologic data were analysed from 909 servicemembers. The overall number who seroconverted to Q fever was 88 (10%). The most common ICD-9 code assigned to Q fever cases was fever not otherwise specified (NOS) (45%). A combat occupational specialty was a risk factor for Q fever seroconversion (OR = 1.8, 95% CI: 1.1-2.8) as well as receiving a primary diagnosis of fever NOS (OR = 2.6, 95% CI: 1.6-4.1). These findings indicate that Q fever is a significant infectious disease threat to military personnel deployed to Iraq. A heightened awareness among physicians is necessary to ensure prompt diagnosis and treatment.     

大理地区散养户猪伪狂犬病病毒野毒株感染的血清学分析

为了解云南大理地区散养户猪伪狂犬病病毒(PRV)野毒感染的情况,从大理地区30多个散养户6月龄及6月龄以上猪群中随机采集了共112份血清,采用间接ELISA方法对血清样本进行PRVgE抗体检测。结果显示,112份血清中抗PRVgE抗体阳性率为8.04%。结果表明,大理地区散养户6月龄及6月龄以上猪只猪伪狂犬病病毒野毒株感染率较低。     

散养户猪群细小病毒感染的血清学调查

为了解大理地区猪细小病毒(PPV)感染的情况,从大理地区58个散养户采集了243份猪血清,采用间接ELISA方法对血清样本进行细小病毒抗体检测。结果显示,243份猪血清中抗PPV抗体阳性率为85.60%,表明大理地区散养户猪群细小病毒病已经普遍流行,结果值得关注。