scholarly journals Influence of category, herd size, grazing and management on epidemiology of bovine viral diarrhoea in dairy herds

2013 ◽  
Vol 82 (2) ◽  
pp. 125-130 ◽  
Author(s):  
Tomislav Bedeković ◽  
Nina Lemo ◽  
Ljubo Barbić ◽  
Željko Cvetnić ◽  
Ivana Lojkić ◽  
...  
Keyword(s):  
Immunosorbent Assay ◽  
Production Management ◽  
Herd Size ◽  
Enzyme Linked Immunosorbent Assay ◽  
Dairy Herds ◽  
Bovine Viral Diarrhoea ◽  
Tissue Samples ◽  
Persistently Infected ◽  
Diarrhoea Virus ◽  
High Prevalence

The aim of this study was to estimate the influence of category, herd size, common grazing and management as risk factors in maintaining bovine viral diarrhoea infection in dairy herds. A total of 987 sera samples obtained from 202 heifers, 653 cows and 132 calves from 103 herds in Croatia were examined by enzyme-linked immunosorbent assay. In order to establish the prevalence of persistently infected cattle, 35 herds were selected. Ear notch tissue samples from all animals in selected herds (n = 2284) were collected and analyzed by antigen enzyme-linked immunosorbent assay. The true prevalence of specific antibodies was 61.61% and the estimated prevalence of exposure to bovine viral diarrhoea virus at the herd level was 100%. The prevalence of persistently infected animals was 0.53% and the prevalence of persistently infected herds was 20%. The antibodies prevalence was higher in cows, in herds that use common pasture and in larger herds (P < 0.001). The prevalence of persistently infected animals was not connected with the herd size but production management on big farms contributed to maintaining the virus. The obtained results suggest that production management was an important risk factor in bovine viral diarrohea epidemiology. High prevalence of antibodies and high prevalence of persistently infected herds requires implementation of control and eradication programs at a national or even regional level. The presented data complete the BVD epidemiological investigations from this part of Europe.

scholarly journals Evaluation of the effects of long-term storage of bovine ear notch samples on the ability of 2 diagnostic assays to identify calves persistently infected with bovine viral diarrhoea virus

2011 ◽  
Vol 82 (1) ◽  
Author(s):  
F. Khan ◽  
J. H. Vorster ◽  
M. Van Vuuren ◽  
P. Mapham
Keyword(s):  
Bovine Viral Diarrhoea Virus ◽  
Enzyme Linked Immunosorbent Assay ◽  
Bovine Viral Diarrhoea ◽  
Persistently Infected ◽  
Diagnostic Assays ◽  
Long Term Storage ◽  
Diarrhoea Virus ◽  
Significant Difference ◽  
Term Storage

Research aimed at optimising diagnostic laboratory procedures is central to the development of effective bovine viral diarrhoea virus (BVDV) control programmes. BVDV is a singlestranded RNA virus that crosses the placenta to infect foetuses, resulting in reproductive losses due to foetal death or persistently infected calves that die early in life. Persistently infected animals are widely accepted to be the primary reservoir of BVDV and the largest source of infection. This poses important challenges to overall animal/herd health and can cause major losses to the cattle industry. Long-term storage of bovine ear notch samples from calves persistently infected with BVDV may adversely affect the ability of diagnostic assays to detect the virus efficiently. In order to test this hypothesis, ear notch samples from 7 animals were divided into 2 groups. One set was subjected to prompt formalin fixation and the other set stored either as fresh samples without preservatives at –2 °C, or soaked overnight in phosphate buffered saline followed by freezing of the supernatant fluid at –2 °C. Frozen ear notches and ear notch supernatant yielded positive results with an antigen- capture, enzyme linked immunosorbent assay (AC-ELISA) for the duration of the study (6 months) and optical density (OD) values remained significantly within range. There was no significant difference between storing fresh ear notch samples or PBS at –2 °C. However, positive immunohistochemistry (IHC) staining on formalin fixed ear notches started to fade between Day 17 and Day 29 when stored at room temperature. It was concluded that fresh ear notches could safely be stored at –2 °C for a period of 6 months prior to testing for BVD viral antigens.

scholarly journals Serological survey of bovine viral diarrhoea virus in Namibian and South African kudu (Tragelaphus strepsiceros) and eland (Taurotragus oryx)

2013 ◽  
Vol 84 (1) ◽  
Author(s):  
Terence P. Scott ◽  
Eleanor Stylianides ◽  
Wanda Markotter ◽  
Louis Nel
Keyword(s):  
South Africa ◽  
South African ◽  
Southern Africa ◽  
Bovine Viral Diarrhoea Virus ◽  
Enzyme Linked Immunosorbent Assay ◽  
Bovine Viral Diarrhoea ◽  
Serum Samples ◽  
Diarrhoea Virus ◽  
Central Regions ◽  
Tragelaphus Strepsiceros

Bovine viral diarrhoea virus (BVDV) is a pestivirus that affects members of the order Artiodactyla, including members of the subfamily Bovinae. Little is known about the seroprevalence of BVDV in southern Africa, especially the prevalence in wild ruminant populations such as kudu (Tragelaphus strepsiceros). A handful of random surveys suggested that seroprevalence ranged between 6% and 70% in southern African wild ruminants. The present study aimed to determine the seroprevalence of BVDV amongst kudu and eland (Taurotragus oryx) from Namibia and South Africa. A BVDV-specific enzyme-linked immunosorbent assay was performed on 50 serum samples from kudu and eland from South Africa and Namibia. The seroprevalence of BVDV in South African kudu was 71%, identical to that in Namibian kudu. The seroprevalence in Namibian eland was 40%. The kudu and cattle farming (free ranging) regions in Namibia predominantly overlap in the central regions, ensuring ample opportunity for cross-species transmission of BVDV. It is therefore important to determine the true prevalence of BVDV in southern Africa in both domesticated and wild animals. In addition, a potential link between BVDV incidence and a devastating rabies epidemic in Namibian kudu was proposed and such a notion could be supported or discredited by comparative prevalence data.

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