Seroprevalence and associated risk factors of bovine brucellosis in Addis Ababa dairy farms

A cross-sectional study was carried out on bovine brucellosis in Addis Ababa dairy farms from November 2003 to April 2004. A total of 1,202 blood samples were collected from non-vaccinated, cross-bred dairy cattle. The Rose Bengal plate test (RBPT) was used as a screening test. Those serum samples reacting positively to RBPT were subjected to the complement fixation test (CFT) for confirmation. The RBPT detected 30 of 1,202 (2.5%) of the samples as brucellosis positive. The positive sera when further retested using CFT, 18 out of the 30 RBPT positive sera were confirmed to be positive. The prevalence of brucellosis based on CFT in the study area was 1.5%, and all positive sera were from female cattle. Result of the questionnaire survey revealed that percentage of 4.4% abortion and 9.5% retained fetal membranes. Abortion and retained fetal membranes were associated with Brucella antibodies (P?相似文献   

宁夏吴忠地区规模化奶牛场流产牛病原血清学调查

为了调查宁夏吴忠地区奶牛场因传染性因素造成流产的基本情况,应用酶联免疫吸附试验(ELISA)对可能造成感染流产的牛传染性鼻气管炎病毒、新孢子虫、牛病毒性腹泻病毒的抗体及布鲁菌的抗原进行了血清学检测。结果显示,牛传染性鼻气管炎病毒抗体阳性率为48.84%,新孢子虫抗体阳性率为30.23%,牛病毒性腹泻病毒抗体阳性率为19.77%,布鲁菌抗原阳性率为24.42%。牛场阳性率高达100%。根据统计显示,不同妊娠胎次的奶牛流产率差异显著(P0.05),其中第1胎流产率与其他胎次间差异极显著(P0.01)。不同妊娠时间的奶牛流产率差异不显著(P0.05)。调查表明,宁夏部分奶牛场存在不同程度的牛传染性鼻气管炎病毒、新孢子虫、牛病毒性腹泻病毒和布鲁菌感染。     

Prevalence of bovine herpesvirus 1 (BHV-1) infection in Hungarian cattle herds.

Hungarian cattle herds were surveyed for bovine herpesvirus 1 (BHV-1) infection by ELISA of milk and serum samples. In 1993, 75% of the large cattle herds (consisting of more than 50 cattle) and all small herds (small-scale producers' stocks), while in 1997 90% of the small herds were included in the survey. In the case of large herds, 79.3% of the herds and 64.1% of the samples tested were found to be positive. Of the small herds, 13.5% and 15.7% tested positive in 1993 and 1997, respectively. The majority of large herds were Holstein-Friesian dairy stocks. Small herds with an infection rate markedly exceeding the average were found in those counties where the small herds had been in close contact with the large-scale farms, or where new herds were established by using animals of uncontrolled infectious bovine rhinotracheitis (IBR) status originating from large farms. Attention is called to the importance of maintaining the IBR-free status of small herds that constitute one-third of the Hungarian cattle population.     

A survey for BVDV antibodies in cattle farms in Slovakia and genetic typing of BVDV isolates from imported animals

A serological survey for bovine viral diarrhoea virus (BVDV) antibodies on a collection of 1295 serum samples obtained from 6-12 months old cattle originating from 45 farms in Slovakia was carried out. On 13 farms more than 90% of the examined animals were seropositive, on 14 farms 71-90% seroprevalence was observed, on 13 farms only 50-70% animals were found to be positive for BVDV antibodies, while the remaining 5 farms showed fewer than 50% seropositive animals. The average incidence of BVDV antibodies (around 70%) was similar as determined 30 years ago. Of 84 serum samples from seronegative animals originating from 14 farms in which 70-98% seropositivity was observed, six were positive in Ag-BVDV ELISA indicating persistently infected (PI) cattle. On a farm to which animals were imported from abroad, a BVD outbreak was observed. Of 110 animals tested, four were positive in Ag-ELISA indicating the presence of PI cattle on this farm. Genetic typing of two isolates from imported animals performed by RT-PCR (324/326 primers from 5'-UTR), sequencing of PCR products and computer-assisted phylogenetic analysis revealed that they belong to BVDV-1 h group.     

Prevalence of antibodies to infectious bovine rhinotracheitis, parainfluenza 3, bovine respiratory syncytial, and bovine viral diarrhea viruses in cattle in Saskatchewan and Alberta

A total of 1745 healthy cattle from 295 farms in Saskatchewan and Alberta was tested by ELISA for antibodies to four viruses. Antibodies to infectious bovine rhinotracheitis (IBR) virus were found in 37.8% of sera (59.5% of properties), to parainfluenza 3 (PI3) virus in 93.9% of sera (99.7% of properties), to bovine respiratory syncytial (BRS) virus in 78.5% of sera (86.6% of properties), and to bovine viral diarrhea (BVD) virus in 40.6% of sera (66.7% of properties)

The prevalence of PI3 viral antibodies among Saskatchewan cattle was not affected by district of origin, breed, sex, age, or vaccination practices, though BRS viral antibodies appeared less frequent in young, male, and unvaccinated animals. Antibodies to IBR and BVD viruses were less prevalent in the Prince Albert/Tisdale districts and in young, male, and unvaccinated animals, but were more common in Holstein cattle. Antibodies to IBR virus appeared less frequent in Herefords. Antibodies were more prevalent in cattle which had been vaccinated against IBR, BRS, and BVD virus infections.

The relatively small number of cattle sampled from Alberta had a similar prevalence of antibodies to PI3 and BRS viruses to that seen in cattle in Saskatchewan, though IBR and BVD prevalence rates were lower.

     

Assessment of cattle grub (Hypoderma spp.) prevalence in northeastern Italy: an immunoepidemiological survey on bulk milk samples using ELISA

Hypodermosis is a myiasis of cattle mainly found in the Northern Hemisphere. In Italy it has been reported primarily in southern regions with a farm prevalence reaching a peak of 85%, while few data are available in the north of the country.This paper reports the results of a serological survey carried out on hypodermosis in Vicenza province (northeastern Italy). During January and February 1999, bulk milk samples were collected from 224 dairy farms and tested, using an hypodermosis ELISA kit. Epidemiological data, such as farm location, herd size, number of cows, grazing management, treatments against Hypoderma larvae, presence of imported animals, were gathered and statistically analysed in relation to the serological results. In 15 farms the presence of warbles was monitored by manual palpation and larvae collected for identification.Ninety-seven (43.3%) samples were detected as positive, whereas 12 (5.4%) and 115 (51.3%) were inconclusive and negative, respectively.Thirteen farms were positive upon parasitological examination and the larvae collected were identified as Hypoderma bovis.Seroprevalence was highly correlated with the practice of free grazing and slightly, but significantly, correlated with the number of cows on the farm. The mean antibody level of positive herds was significantly higher on farms without imported animals. On farms with warbled animals there was a high inverse correlation between antibody level and quantity of milk in the tanks and the number of lactating cows.The ELISA test on bulk milk samples has been shown, under field conditions, to be a useful, cost-effective and easy test for the diagnosis of bovine hypodermosis.     

Periocular dermoid cyst in a calf

Serum samples (n = 1,146) representing 100 species of exotic ruminants now captive in United States zoos were assayed for neutralizing antibody to infectious bovine rhinotracheitis (IBR) virus (bovine herpesvirus 1). Thirty-four animals (3%) of 11 species had antibody to IBR virus. Because of the low prevalence of IBR antibody found, it was concluded that vaccination against IBR virus probably is not necessary for captive wild ruminants in United States zoos.     

新疆某规模化奶牛场牛传染性鼻气管炎病毒抗体水平检测

为了调查新疆地区某规模化奶牛场牛传染性鼻气管炎（IBR）发病情况,通过采集不同生长阶段牛群血清共计362 份,使用牛传染性鼻气管炎病毒gB（IBR-gB）抗体检测试剂盒检测牛传染性鼻气管炎病毒（IBRV）抗体效价,评估该奶牛场IBRV疫苗免疫效果。结果显示,后备牛中犊牛和青年牛IBRV抗体阳性率分别为88.57%（31/35）、75.00%（21/28）;成年母牛中泌乳期母牛、干奶期母牛IBRV抗体阳性率分别为81.46%（145/178）、95.04%（115/121）。阴性数共44 份,可疑数8 份,IBRV抗体平均阳性率为88.38%;结果表明,疫苗接种后,不同生产阶段牛群均可产生不错的抗体保护效果,为奶牛场防控IBR提供依据。     

Apparent seroprevalence,isolation and identification of risk factors for brucellosis among dairy cattle in Goa,India

Brucellosis is a highly contagious zoonotic infection affecting livestock and human beings. The disease has been reported worldwide except in few countries where it has been eradicated. The prevalence of brucellosis among cattle from 11 farms having a history of abortions was studied. A total of 481 samples comprising of blood, milk, vaginal swabs, vaginal discharges, placental tissues and fetal tissues were collected from 296 animals. Clinical samples were processed for the isolation of Brucella. Serum samples (n = 296) were tested by Rose Bengal Plate Test (RBPT) and indirect ELISA. A total of 90 (30.40%) and 123 (41.55%) samples were positive by RBPT and indirect ELISA, respectively. Also 27.02% samples were positive by both the tests. Brucella isolates (n = 8) were recovered from clinical samples using Brucella selective media. All the isolates demonstrated PCR amplification for the bcsp31 and IS711 genes. Amplification of Brucella abortus specific primer was demonstrated by all the isolates in AMOS PCR indicating isolates to be of either B. abortus biotype 1, 2 or 4. Risk factors for transmission of brucellosis among cattle population were studied by field surveys. It was observed that lack of awareness about brucellosis (OR = 8.739, P = 0.138) and inadequate floor space (OR = 0.278, P = 0.128) were crucial risk factors for transmission of bovine brucellosis.     

内蒙古地区部分奶牛场牛传染性鼻气管炎的血清学调查

为了解内蒙古地区牛传染性鼻气管炎在奶牛场的流行情况,对内蒙古地区的16个大、中、小型奶牛养殖场的2 321头奶牛,应用ELISA方法进行牛传染性鼻气管炎的血清流行病学调查。结果显示,5个大型奶牛场牛传染性鼻气管炎的阳性率在68.5%~100%之间,5个中型奶牛场的阳性率在34.0%~84.2%之间,6个小型奶牛场的阳性率在32.6%~89.3%之间,平均阳性率为75.7%。     

Infectious bovine rhinotracheitis (IBR) in the canton of Jura: an epidemiological outbreak investigation

Following an abortion in a beef herd in the summer of 2009, three outbreaks of infectious bovine rhinotracheitis (IBR) were diagnosed in the cantons of Jura and Neuchatel. An epidemiological outbreak investigation was conducted with the aims to identify the source of introduction of the bovine herpes virus 1 (BoHV-1) into the affected herds and to prevent further spread of the disease. The attack rates in the three outbreak farms were 0.89, 0.28 and 0, respectively. BoHV-1 could be isolated from nasal swabs of two animals originating from one of the affected farms. Comparative restriction enzyme analysis revealed slight differences between the isolates of the two animals, but a high similarity to previous BoHV-1 isolates from the canton of Jura, as well as to a French BoHV-1 isolate. This IBR outbreak has shown the importance of reporting and analyzing abortions. The current disease outbreaks recall the main risk factors for the spread of IBR in Switzerland: purchase and movement of bovines and semen of often unknown IBR status.     

Dynamics of infection and immunity in a dairy cattle population undergoing an eradication programme for Infectious Bovine Rhinotracheitis (IBR)

Several countries within the European Union (EU) have successfully eradicated Infectious Bovine Rhinotracheitis (IBR), while others (e.g. Germany) are making efforts to achieve IBR-free status. EU member states IBR eradication programmes must meet Community legislation requirements that ban breeding farms from purchasing positive animals, from using whole-virus IBR vaccines, and from inseminating cows with semen from positive bulls. A follow-up study from 2002 to 2005 was carried out in the province of Trento (Italy), where a compulsory programme for IBR eradication was started in 1998. IBR outbreaks (identified on the basis of seroconversion of sentinel animals) were concentrated in larger positive herds. A higher incidence was recorded between 2003 and 2004. An association between markedly high temperatures in the summer of 2003 and virus reactivation has been suggested but is yet to be confirmed. The practice of driving cattle to common alpine pastures for the summer season did not play a significant epidemiological role in IBR transmission. Premising that only seronegative animals are allowed to enter dairy farms, animal movement increases the infection risk to a moderate extent. The long-term persistence of IBR antibodies was more pronounced in animals positive for antibodies to the glycoprotein E (gE). Scattered seroconversions, occurring mostly in positive herds, require careful interpretation in order to avoid overestimating the incidence of the infection at herd level.     

Seroprevalence of infectious bovine rhinotracheitis and bovine viral diarrhea virus type 1 and type 2 in non-vaccinated cattle herds in the Pacific Region of Central Costa Rica

The objectives of this cross-sectional study were to estimate the seroprevalence of infectious bovine rhinotracheitis (IBR, BHV-1) and bovine viral diarrhea virus (BVDV) in a population of non-vaccinated, double purpose, dairy and beef herds in the Pacific Region of Central Costa Rica. Blood samples were collected from a total of 496 animals from 35 herds. Sera were tested for antibodies against BHV-1(IBR) and BVDV types 1 and 2 using serum neutralization test. The average number of animals tested in each herd for each of the viruses was 14. Overall individual seroprevalence was 48%, 27%, and 19% for IBR, BVDV type 1, and BVDV type 2, respectively. Median within-herd seroprevalence for IBR, BVDV type 1 and type 2 were 43%, 27%, and 24%, respectively.     

Evaluation of the critical parameters of a sensitive ELISA test using purified infectious bovine rhinotracheitis virus antigens

An enzyme-linked immunosorbent assay (ELISA) for the survey or titration of bovine sera for the presence of IgG antibodies against infectious bovine rhinotracheitis (IBR) virus was developed. The optimal conditions of serum dilution, antigen concentration, conjugate dilution, substrate concentrations, and reaction time were established using the signal/ noise (S/N) ratio as the determining criterion. Equilibrium density gradient purified IBR virus was used as antigen at an optimal concentration of 0.60 μg/cuvette. The use of purified antigen allowed the testing of sera at a 1 : 10 dilution without nonspecific reaction.The conditions of conjugate dilution, substrate concentration and reaction time were shown to have significant effects on the ELISA test. Results from 35 sera showed this optimized ELISA procedure to be as much as 1000-fold more sensitive than the serum neutralization plaque reduction assay. Numerous sera showing no neutralizing titer to IBR virus were found to be positive when examined by this ELISA method.     

Cost-effectiveness of bulk-tank milk testing for surveys to demonstrate freedom from infectious bovine rhinotracheitis and bovine enzootic leucosis in Switzerland

In Switzerland, annual surveys to substantiate freedom from infectious bovine rhinotracheitis (IBR) and enzootic bovine leucosis (EBL) are implemented by a random allocation of farms to the respective survey as well as blood sampling of individual animals at farm level. Contrary to many other European countries, bulk-tank milk (BTM) samples have not been used for active cattle disease surveillance for several years in Switzerland. The aim of this project was to provide a financial comparison between the current surveillance programme consisting of blood sampling only and a modified surveillance programme including BTM sampling. A financial spreadsheet model was used for cost comparison. Various surveillance scenarios were tested with different sample sizes and sampling frequencies for BTM samples. The costs could be halved without compromising the power to substantiate the freedom from IBR and EBL through the surveillance programme. Alternatively, the sensitivity could be markedly increased when keeping the costs at the actual level and doubling the sample size. The risk-based sample size of the actual programme results in a confidence of 94,18 % that the farm level prevalence is below 0,2 %. Which the doubled sample size, the confidence is 99,69 % respectively.     

蚌埠市某奶牛场IBRV和BVDV的血清学调查

本试验对蚌埠市一家未进行牛传染性鼻气管炎及病毒性腹泻免疫的规模化奶牛场的94份奶牛血清样品,分别使用牛传染性鼻气管炎及病毒性腹泻抗体ELISA试剂盒进行检测,共检出牛传染性鼻气管炎阳性血清65份,阳性检出率为69．15％;病毒性腹泻阳性血清83份,阳性检出率为88．30％。结果表明,该规模化奶牛场存在牛传染性鼻气管炎及病毒性腹泻的感染和接触史,应采取净化措施进行控制。     

Brucella melitensis infection in dog: a critical issue in the control of brucellosis in ruminant farms

Canine brucellosis is a contagious disease associated with health implications for humans as well as for a wide range of wild and domesticated animals. In this study, 173 dog blood specimens were sampled from herding dogs in three different provinces including Tehran (n = 127), Qom (n = 40) and Alborz (n = 6) provinces. The presence of Brucella antibodies was determined using Rose Bengal plate test (RBPT), slow agglutination test (SAT) and 2-mercaptoethanol (2-ME), respectively. The seropositive samples were further screened using blood culture and PCR tests to identify and differentiate the implicated Brucella species. According to our results, 24.3% (42/173), 13.8% (24/173) and 6.3% (11/173) of blood samples were tested positive using RBPT, SAT and 2-ME, respectively. However, among 42 seropositive samples, only 38.1% (16/42) and 14.2% (6/42) were positive by PCR and culture, respectively. Brucella melitensis biovar 1 and biovar 2 was isolated from the bacterial cultures of 6 blood samples and confirmed by biotyping, AMOS PCR and Bruce-ladder PCR assays. These findings highlight the potential risk of Brucella transmission from dog to humans along with other livestock and reflect the critical role of infected dogs in the persistence of Brucella infections among ruminant farms. This study stresses the need for further epidemiological investigations on canine brucellosis among herding dogs and suggests the systematic screening of the disease among companion animals such as dogs in order to improve brucellosis surveillance and control programs.     

Investigation of causative agents of bovine respiratory tract disease in a beef cow-calf herd with an early weaning program.

Serum samples were collected from early weaned fall calves shortly after the onset of respiratory tract disease. Antibody titers to infectious bovine rhinotracheitis (IBR) virus, parainfluenza type 3 (PI-3) virus, bovine viral diarrhea (BVD) virus, bovine adenovirus type 3 (BAV-3), and bovine respiratory syncytial virus (BRSV) were determined on paired (acute and convalescent) serums. Seroconversion rate (a fourfold or greater rise in antibody titer) for IBR virus was 4.3%, PI-3 virus--16.3%, BVD virus--9.6%, and BAV-3--2.2%. Seroconversion for BRSV was 45.4%. An increased rate of seroconversion for IBR, PI-3, and BVD viruses and BAV-3 was observed in the presence of BRSV seroconversion. These results suggest that BRSV may facilitate infection by other viruses. Results of virus isolation procedures from these calves were negative.     

Brucellosis of camels in Kuwait

This study investigated the presence of Brucella antibodies in serum and milk obtained from camels in Kuwait. Brucella strains were also isolated from the foetus using standard technique (Webridge Lab Techniques). Three serological tests for serum were adopted. These tests were Rose Bengal Plate Test (RBPT), the Serum Tube Agglutination Test (SAT) and the Complement Fixation Test (CFT). The RBPT was used for all sera samples, and both SAT and CET were used for the positive RBPT. Camels that showed a titer of 1:40 in SAT or 1:5 in CFT or greater were considered positive. Thirteen of the samples examined were found positive by CFT (at 1:5); by SAT, they showed a titer of 1:20. One serological test, the Milk Ring Test (MRT), was used for milk. Here 3 and 2 were considered positive reactors but 1+ was considered suspicious. We were unable to isolate the Brucella organism from Sedemine and Cream of milk, but we isolated them from Foetus Brucella abortus and it is confirmed by Webridge Laboratory, U.K. It is Brucella abortus (Biovar 1). The prevalence rate was 14.8% from serum by the CFT and RBPT methods and 10.8% by the SAT method. For milk, the prevalence rate was 8.0%. Two Brucella abortus were isolated from 5 foetuses.     

Herd-level risk factors for bovine viral diarrhea infection in cattle of Tamil Nadu

A cross-sectional study was carried out to identify risk factors for bovine viral diarrhea virus (BVDV) infection in 62 randomly selected dairy herds which were tested for BVD serum antibodies by using an indirect ELISA kit (IDEXX). Results from the chi-square test analysis were interpreted by analyzing by chi-square test. A sum of 500 sera samples were screened and 66 animals (13.20%) showed positive for BVDV antibody. Within herd, BVD seroprevalence was 12–65%. This study concluded that epidemiological risk factors like location, herd size, housing patterns like, tail to tail system, roofing pattern, distance between the manure pit and farm, and distance between farms were significantly associated with BVDV serological status (P?<?0.05).