A four year longitudinal sero-epidemiological study of bovine herpesvirus type-1 (BHV-1) in adult cattle in 107 unvaccinated herds in south west England

Abstract

BackgroundBovine herpesvirus type-1 (BHV-1) is an important pathogen of cattle that presents with a variety of clinical signs, including the upper respiratory tract infection infectious bovine rhinotracheitis (IBR). A seroepidemiological study of BHV-1 antibodies was conducted in England from 2002 – 2004: 29,782 blood samples were taken from 15,736 cattle from 114 herds which were visited on up to three occasions. Antibody concentration was measured using a commercial ELISA. Farm management information was collected using an interview questionnaire, and herd size and cattle movements were obtained from the cattle tuberculosis testing database and the British Cattle Movement Service. Hierarchical statistical models were used to investigate associations between cattle and herd variables and the continuous outcome percentage positive (PP) values from the ELISA test in unvaccinated herds.ResultsThere were 7 vaccinated herds, all with at least one seropositive bovine. In unvaccinated herds 83.2% had at least one BHV-1 seropositive bovine, and the mean cattle and herd BHV-1 seroprevalence were 42.5% and 43.1% respectively. There were positive associations between PP value, age, herd size, presence of dairy cattle. Adult cattle in herds with grower cattle had lower PP values than those in herds without grower cattle. Purchased cattle had significantly lower PP values than homebred cattle, whereas cattle in herds that were totally restocked after the foot-and-mouth epidemic in 2001 had significantly higher PP values than those in continuously stocked herds. Samples taken in spring and summer had significantly lower PP values than those taken in winter, whereas those taken in autumn had significantly higher PP values than those taken in winter. The risks estimated from a logistic regression model with a binary outcome (seropositive yes/no) were similar.ConclusionThe prevalence of BHV-1 seropositivity in cattle and herds has increased since the 1970s. Although the study population prevalence of BHV-1 was temporally stable during study period, the associations between serological status and cattle age, herd size, herd type, presence of young stock and restocked versus continuously stocked herds indicate that there is heterogeneity between herds and so potential for further spread of BHV-1 within and between herds.

Serological evidence and risk factors associated with Caprine herpesvirus 1 in dairy goat flocks in a semiarid region of northeastern Brazil

“…18 It is well known that animals on farms located in colder areas are more prone to herpesvirus infections. 3,22 The high prevalences of positive flocks found in the present study for CpHV-1 (89.1%) and BoHV-1 (80.0%) infections was surprising because the climate in the region is hot (temperature is approximately 31°C during the day). However, conditions of high temperature and humidity may cause heat stress in the animals, thus decreasing the immune response and predisposing the animals to infections.…”

Risk factors for herd breakdown with bovine tuberculosis in 148 cattle herds in the south west of England

“…One explanation for this could be that these farms 273 had a period of time without any cattle and that the infectious load on the farm, both from slurry (less 274 produced and so less spread) and excretion of M. bovis by cattle, decreased temporarily. It is also possible 275 that cattle in these newly formed herds had less M. bovis infection initially (from undetected infected cattle) 276 than cattle in continuously stocked herds in this endemic area if they were, on average, sourced from herds 277 with a lower prevalence of bTB; this has been reported for IBR (Woodbine et al, 2009a) and Johnes disease 278 (Woodbine et al, 2009b). It is also possible (given the test sensitivity and cessation of testing for bTB in 279 2001) that continuously stocked herds had undetected infected cattle that were restricted on the farm and 280 untested because of FMD and so transmission of bTB was greater that usual in continuously stocked herds.…”

“…One hundred and fourteen farmers (all except 33 which were only rearing beef cattle and one that left the 141 study after completing the questionnaire), also participated in a study of five other endemic diseases, where 142 blood samples were taken from cattle >2 years old (Woodbine et al, 2008(Woodbine et al, , 2009a2009b). These farmers 143…”

Herd-level prevalence of selected endemic infectious diseases of dairy cows in Great Britain

“…In addition to these ongoing recording systems, oneoff surveys are often carried out (Davison et al, 2005;Salimi-Bejestani et al, 2005;Woodbine et al, 2009b); although useful, their results should be interpreted with caution because of issues such as nonprobabilistic selection of studied farms (Paton et al, 1998;Woodbine et al, 2009b;Williams and Winden, 2014) and failure to adjust prevalence estimates for the study design (Paton et al, 1998) or for test performance (Davison et al, 2005;Woodbine et al, 2009a;Williams and Winden, 2014). Furthermore, one-off studies are only useful for a limited period of time, as the prevalence can change as a result of the implementation of control measures and changes in the dairy industry, the more apparent of which are increased herd size, genetic selection, and application of new technological innovations (Barkema et al, 2015).…”