Bovine respiratory syncytial virus seroprevalence and risk factors in non-vaccinated dairy cattle herds in Brazil

Ingrid Bortolin Affonso Lux Hoppe,Samir Issa Samara,Clarice Weis Arns,Andréa Souza Ramos De Medeiros

doi:10.1186/s12917-018-1535-8

Ingrid Bortolin Affonso Lux Hoppe, Samir Issa Samara + Show 2 more

Open Access

https://doi.org/10.1186/s12917-018-1535-8

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Abstract

BackgroundThe 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).ResultsVNT 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.ConclusionsThe 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.

Highlights

The cattle industry is one of the most important Brazilian agribusiness sectors and is a strong contributor to the national economy
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 bovine respiratory syncytial virus (BRSV), while natural suckling was considered a protective factor
The study showed that adult animals over 1 year old are an important risk factor for the high seroprevalence of BRSV in herds

Summary

Introduction

The cattle industry is one of the most important Brazilian agribusiness sectors and is a strong contributor to the national economy. 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. 1243 blood samples were collected of animals from 26 farms and a questionnaire about possible risk factors for BRSV prevalence was performed. Bovine respiratory syncytial virus (BRSV) is an economically significant pathogen in cattle production [1], as it is one of the most important causes of lower respiratory tract infections in calves [2]. BRSV infection usually occurs in young calves aged between 2 weeks and 9 months [3]. Mainly in calves, an acute and severe onset is observed, due to maternal antibodies not effectively protect against BRSV infection [3]

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