Erdachew Yitagesu1,2, Wendi Jackson3, Nigatu Kebede4, Woutrina Smith3, Tsegaw Fentie5. 1. Debre Birhan Agricultural Research Centre, Debre Birhan, Ethiopia. erdutella@gmail.com. 2. University of Gondar, College of Veterinary Medicine and Animal Sciences, Gondar, Ethiopia. erdutella@gmail.com. 3. University of California, School of Veterinary Medicine, One Health Institute, Davis, CA, USA. 4. Addis Ababa University, Aklilu Lemma Institute of Pathobiology, Addis Ababa, Ethiopia. 5. University of Gondar, College of Veterinary Medicine and Animal Sciences, Gondar, Ethiopia.
Abstract
BACKGROUND: Bovine Viral Diarrhea virus (BVDV) is one of important diseases of cattle worldwide causing economic losses to the cattle industry primarily due to increased premature culling and decreased reproductive performance. The virus can cross the placenta during early pregnancy and result in the birth of persistently infected (PI) calves that are efficient transmitters of BVDV and serving as the primary reservoirs for BVDV. Relatively few studies have focused on understanding BVDV seroprevalence, virus detection, genotyping and its distribution in Africa. Most BVDV research in Ethiopia has involved serologic surveys in adult cattle, rather than the identification of PI calves, despite their role in viral shedding and recurring infections. A cross-sectional study was undertaken in three different livestock production systems of Ethiopia with the objective to estimate the prevalence of bovine abortion, calf mortality, and BVDV persistently infected calves. RESULTS: Ear notch samples (882) collected from calves in 349 households were tested for BVDV antigen using antigen capture enzyme-linked immunosorbent assay (ACE). All samples tested were negative for BVDV antigen. The overall animal level crude abortion and calf mortality prevalence were 4.0% (95% CI: 2.9-5.2) and 9.2% (95% CI: 7.7-11.0) respectively. The lower BVDV PI prevalence may be due to a lower effective contact rate between cattle reared in small-scale extensive production systems in Ethiopia. CONCLUSIONS: This is the first report of BVDV Ag test in Ethiopia and no PI was detected in calves in the study areas. Since BVDV is a disease of great economic importance, this study finding must be interpreted with care since absence of evidence is not evidence of absence and even a single BVDV infected animal can serve as source of infection and contribute to the persistent spread of the virus. Greater attention needs to be given to screening for PI animals through testing large number of animals and culling positive animals. Hence, future research should focus on regions and production systems with high BVDV seroprevalence followed by antigen ELISA or BVDV real-time PCR to detect persistently infected and acutely viremic animals.
BACKGROUND:Bovine Viral Diarrhea virus (BVDV) is one of important diseases of cattle worldwide causing economic losses to the cattle industry primarily due to increased premature culling and decreased reproductive performance. The virus can cross the placenta during early pregnancy and result in the birth of persistently infected (PI) calves that are efficient transmitters of BVDV and serving as the primary reservoirs for BVDV. Relatively few studies have focused on understanding BVDV seroprevalence, virus detection, genotyping and its distribution in Africa. Most BVDV research in Ethiopia has involved serologic surveys in adult cattle, rather than the identification of PI calves, despite their role in viral shedding and recurring infections. A cross-sectional study was undertaken in three different livestock production systems of Ethiopia with the objective to estimate the prevalence of bovine abortion, calfmortality, and BVDV persistently infectedcalves. RESULTS: Ear notch samples (882) collected from calves in 349 households were tested for BVDV antigen using antigen capture enzyme-linked immunosorbent assay (ACE). All samples tested were negative for BVDV antigen. The overall animal level crude abortion and calfmortality prevalence were 4.0% (95% CI: 2.9-5.2) and 9.2% (95% CI: 7.7-11.0) respectively. The lower BVDV PI prevalence may be due to a lower effective contact rate between cattle reared in small-scale extensive production systems in Ethiopia. CONCLUSIONS: This is the first report of BVDV Ag test in Ethiopia and no PI was detected in calves in the study areas. Since BVDV is a disease of great economic importance, this study finding must be interpreted with care since absence of evidence is not evidence of absence and even a single BVDVinfected animal can serve as source of infection and contribute to the persistent spread of the virus. Greater attention needs to be given to screening for PI animals through testing large number of animals and culling positive animals. Hence, future research should focus on regions and production systems with high BVDV seroprevalence followed by antigen ELISA or BVDV real-time PCR to detect persistently infected and acutely viremic animals.
Authors: Beate Pinior; Clair L Firth; Veronika Richter; Karin Lebl; Martine Trauffler; Monika Dzieciol; Sabine E Hutter; Johann Burgstaller; Walter Obritzhauser; Petra Winter; Annemarie Käsbohrer Journal: Prev Vet Med Date: 2016-12-23 Impact factor: 2.670
Authors: Todd E Cornish; Alberto L van Olphen; Jacqueline L Cavender; Joan M Edwards; Paula T Jaeger; Leslie L Vieyra; Lynn F Woodard; Dan R Miller; Donal O'Toole Journal: J Vet Diagn Invest Date: 2005-03 Impact factor: 1.279
Authors: Rebecca L Smith; Michael W Sanderson; David G Renter; Robert Larson; Bradley White Journal: Prev Vet Med Date: 2010-03-20 Impact factor: 2.670