Seroprevalence to bovine virus diarrhoea virus and other viruses of the bovine respiratory complex in Venezuela (Apure State) (original) (raw)
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Tropical animal health …, 2010
Bovine viral diarrhoea virus (BVDV) and infectious bovine rhinotracheitis virus (IBRV) are important viral diseases around the world. The objective of this study was to estimate the incidence of seroconversion to BVDV and IBRV and to identify associated risk factors in dairy herds of Michoacan, Mexico. The longitudinal study included 62 herds and ran from December 2001 to November 2002. The total number of animals enrolled and completing the study were 392 and 342 animals for BVDV and 925 and 899 animals for IBRV. Animals were tested monthly for 12 months, for the presence of antibodies. Risk factors were: herd size (2-9, 10-25 and 26-55 animals), herd serostatus (seropositive or seronegative, only for IBRV), age group of the animal (6 to 12, 13 to 24, 25 to 48 and > 48 months) and animal origin (born in farm, purchased). The cumulative incidences for BVDV and IBRV were 16.4% and 3.4%, respectively; whereas, the incidence density rates for BVDV and IBRV were 15.9 and 2.9 per 1000 animal-months at risk, respectively. Seroconver-sion curves were statistically different for age group for BVDV and IBRV and for herd status for IBR. The relatively high incidence of seroconversion for BVDV suggests that a successful control programme should be oriented towards the identification and elimination of the PI animals and towards avoiding the introduction of PI cattle to the farm. The scenario of IBRV is favourable to implement a programme directed to reduce the number of new seropositive herds.
Veterinary Record, 2008
Avcı O, Yavru S, Şevik M. İç Anadolu Bölgesi'ndeki doğal enfekte sığırlarda solunum viruslarına karşı gelişen antikor prevalansı. Amaç: Bu çalışma İç Anadolu bölgesindeki sığırlarda major respiratorik viral ajanların seroprevalanslarının belirlenmesi amacı ile yapıldı. Gereç ve Yöntem: Bu çalışmada İç Anadolu Bölgesi'ndeki 5 ilden (Amasya, Çorum, Kayseri, Nevşehir ve Yozgat) solunum sisteminin en önemli enfeksiyöz ajanları olan Bovine Herpesvirus tip 1 (BHV-1), Bovine Viral Diarrhea Virus (BVDV), Bovine Respiratory Syncytial Virus (BRSV), Parainfluenza Virus-3 (PIV-3) ve Bovine Adenovirus-3 (BAV-3)'e karşı herhangi bir aşı uygulaması yapılmamış toplam 500 sığırdan kan örnekleri toplandı. Serum örnekleri BHV-1, BVDV, BRSV, PIV-3 ve BAV-3'e karşı gelişen spesifik antikor varlıkları yönünden serolojik olarak indirekt Enzyme Linked Immunosorbent Assay (ELISA) ile incelendi.
Detection of bovine viral diarrhea virus (BVDV) in seropositive cattle
Preventive veterinary …, 2005
Detection of bovine virus diarrhoea virus (BVDV) in one vaccinated beef cattle and three nonvaccinated dairy herds was investigated on peripheral blood leukocytes (PBL) with or without previous treatment followed by a capture ELISA (cELISA). Using the combination of PHA and polycation treatment, PBL from 229 seropositive cattle were studied and could be classified in four different states of BVDV infection. Lysed PBL from four animals were directly positive in cELISA (Category I), PBL of 17 animals were positive after PHA stimulation (Category II), 15 animals were positive only after PHA stimulation plus polycation treatment (Category III), while virus could not be detected in 193 seropositive cattle. Wild-type BVDV strains were isolated by co-culture on polycation-treated MDBK cells from 11 of these seropositive animals. BVDV antibodies of these same animals were able to neutralize their own virus, indicating that virus persists in PBL in spite of strain-specific antibodies. No apparent change of leukocyte subpopulations could be detected in any category of virus-positive animals. Thus, BVDV may be present in the PBL of some cattle, even in the presence of a specific active immune response. #
CES Medicina Veterinaria y Zootecnia, 2016
Bovine viral diarrhea virus (BVDV), Bovine herpesvirus-1 (BoHV-1) and enzootic bovine leucosis (EBL) are viral infections that cause three of the most important cow diseases in the world. Antibody detection is the quickest and most cost-effective method to detect exposition to the virus. The aim of this study was to determine the seroprevalence and risk factors associated with these diseases in cows from the town of San Pedro de los Milagros, Antioquia. A total of 791 bovines of 24 dairy farms were sampled for blood between may and june of 2014, and analized for antibodies against BVDV and BoHV-1. These 24 farms plus other five were analized for antibodies against EBL for a total of 1003 bovines from 29 farms sampled. All tests were done with ELISA kits commercially available. The risk factors for farm and cow selected were evaluated to analize their relation with the serological state of these three diseases using logistic regression. In general, seroprevalence at the animal level for BVDV BoHV-1 and EBL was 75.7% (95% CI: 68.7-82.6%), 31.1% (95% CI: 22.1-40.1%) and 47.8% (95% CI: 40-55.7%), respectively. The odds ratio of being seropositive for BoHV-1 was significantly higher (OR=3.0) in animals older than 3 years in comparison to bovines younger than a year. Not using disposable needles was associated with prevalence of EBL. In conclusion there was a high seroprevalence of EBL and BVDV, and a lower one for BoHV-1. Seropositivity to BoHV-1 was associated with cows older than 3 years and seropositivity to EBL was associated with not using disposable needles in the farm.
Bovine respiratory syncytial virus seroprevalence and risk factors in endemic dairy cattle herds
Veterinary Research Communications, 2009
Background: The cattle industry is one of the most important Brazilian agribusiness sectors and is a strong contributor to the national economy. Annually about 44.6 million calves are bred, which makes the optimal management of these animals extremely important. Several diseases can affect the initial stages of the bovine production chain, being the bovine respiratory syncytial virus (BRSV) one of the most relevant pathogens. This study aimed to characterize the epidemiology of BRSV infection in dairy cattle herds of São Paulo State, Brazil, using serological and risk factors analyses. For that, 1243 blood samples were collected of animals from 26 farms and a questionnaire about possible risk factors for BRSV prevalence was performed. The obtained blood sera were analyzed using virus neutralization test (VNT). Results: VNT results showed high BRSV prevalence in dairy cattle herds, reaching 79.5% of seropositivity. The BRSV seroprevalence among studied farms ranged from 40 to 100%. The analysis of risk factors indicated that the age group and the occurrence of coinfection with bovine herpesvirus 1 (BoHV-1) and bovine viral diarrhea virus 1 (BVDV-1) should be associated with a higher prevalence of BRSV, while natural suckling was considered a protective factor. Conclusions: The study showed that adult animals over 1 year old are an important risk factor for the high seroprevalence of BRSV in herds. The high BRSV prevalence associated with BoHV-1 and BVDV-1 suggests that biosecurity measures should be applied in order to reduce viral dissemination. Additionally, the natural suckling may be an important management to protect calves from high BRSV seroprevalence.
Preventive veterinary medicine, 2008
Our objective was to determine the prevalence of serum antibodies to bovine herpesvirus-1 (BHV-1) and bovine viral diarrhea (BVD) virus in beef cattle in Uruguay. A random sample of 230 herds selected with probability proportional to population size based on the number of cattle was chosen from a list frame of all registered livestock farms as of June 1999. Sera from up to 10 heifers, cows and bulls (up to 30 sera total per herd) were collected on selected farms between March 2000 and March 2001 and evaluated by means of enzyme-linked immunosorbent assays (ELISAs). Overall, 6358 serum samples were evaluated. We also collected data on previous diagnosis of BHV-1 or BVD infections and on the use of vaccines against these agents. The estimated prevalence of exposure to BHV-1 and BVD at the herd level for the Uruguayan beef population was 99% and 100%, respectively. Approximately 37% of beef cattle in Uruguay have been exposed to BHV-1 and 69% to BVD virus. Only 3% of beef herds in Urug...
Acta Scientiae Veterinariae, 2017
Background: Bovine enterovirus (BEV) and bovine adenovirus (BAV) are widely distributed in cattle population, and are among possible causes of gastroenteritis and respiratory disease, respectively, although the infection is more often subclinical. BAV infection may be also related to conjunctivitis, and may lead to severe infections and death in immunosuppressive calves. BEV infections have been associated with disorders of respiratory and reproductive tracts, and diarrhea. There is little available information about BAV and BEV in Brazil; however the main of the present study was to investigate the presence of antibodies against these viruses in cattle from some counties of the Rio Grande do Sul (RS), Brazil. Material, Methods & Results: A total of 415 bovine serum samples collected in 2015 year to detect neutralizing antibodies against BEV and BAV by Virus neutralization (VN) assay were performed. The serum samples were gently provided from Setor de Virologia da Universidade Federal de Santa Maria (SV-UFSM). The samples came from bovine with a history or report of clinical cases of diarrhea, respiratory and reproducible disorders and/or abortion suggestive of Leucosis, Bovine Viral Diarrhea Virus (BVDV) and/or Bovine herpesvirus type 1 and 5 (BoHV-1 and 5) infections. The samples are originated as from dairy and beef herd cattle in the following regions from RS State: Southwest, Northeast, Northwest, West, Southeast, Midwest and Metropolitan regions; and were classified according to the origin, gender and age. The serum samples were tested against 100 TCID50/mL of (tissue cellular infection dose 50/mL) of previously characterized BEV and BAV-3 isolates. Serial dilution of the serum was performed in duplicate, starting at 1:5 up to > 1:640 for BEV and at 1:2 to > 1:256 for BAV in 96 wells plates. The serum and virus mixture was incubated in 37ºC for 4-6 h and then a suspension of CRIB cells was added to each well. The plates were incubated in 37ºC and 5% CO 2 for three days for BEV and five days for BAV assay. Neutralization titers were calculated as the reciprocal of the highest serum dilution able to avoid the cytopathic effect. A total of 99.7% (414/415) serum samples showed neutralizing antibodies to BAV and/or BEV. 99.2% (411/414) showed neutralizing antibodies against only BEV and 97.3 % (403/414) were seropositive only to BAV-3. Regarding the sex of the analyzed population, males corresponded to 41.6% (173/415) and female 30.3% (126/415) of the total. From BEV seropositive samples, a higher frequency of neutralizing antibodies titers of 1:320, regarding 22.1% (91/411) of samples and for BAV-3 the titers > 1:256 were more prevalent, 72.2% (291/403) of seropositive. Discussion: The data in the present study showed that the frequency of neutralizing antibodies was high for both viruses as well as co-infection was prevalent; demonstrated that both viruses are actively circulating in the bovine population. However reinfections with BEV may be related to a higher proportion of animals presenting strong humoral immunity. Since BAV and BEV are normally related to subclinical infections, in the absence of clinical cases and high levels of herd immunity, it could be inferred that no other preventive measures need to be taken in these herds until no clear overt of clinical signs is noticed. In another hand, is important research these viruses in animals with signs historic of respiratory tract disease, reproductive disorders and diarrhea.
Epidemiology and eradication of bovine viral diarrhoea virus infections
2002
Providing a new generation of methodologies and tools for cost-effective risk-based animal health surveillance systems for the benefit of livestock producers, decision makers and consumers (RISKSUR) View project Abstract . Epidemiology and eradication of bovine viral diarrhoea virus infections. Studies on transmission and prenatal diagnosis of persistent infection. Doctor's dissertation.
American Journal of Animal and Veterinary Sciences, 2013
Bovine respiratory disease is the leading cause of morbidity and mortality in weaned calves. In Argentina, two weaning practices have been implemented. In the early weaning, the calf is removed from the cow at 60-70 days of age while in ultra-early weaning the calf is weaned at 30-45 days of age. The purposes of both systems is to improve cow body condition, calf performance, conception rates and forage availability for the cow. In this study we evaluated the antibody response against BVDV and BoHV1 in early and ultra-early weaned calves that had received a conventional vaccination schedule (first dose at weaning and a booster 21 days post-weaning). Passively acquired immunity may provide protection against disease caused by these viruses. The presence of antibodies against BRSV, a virus that was not present in the vaccines used, was also evaluated as an indirect indicator of viral circulation in the herd. At the time of vaccination, calves presented a wide range of maternallyderived antibody titers. Vaccination against BoHV-1 did not evoke seroconvertion and antibody titers continued to decay throughout the experience. After vaccination, seroconversion to BVDV could be detected in calves with low antibody titers, while higher antibody titers exerted an inhibitory effect of the active humoral response.