Resumo

FERELLA, Alejandra et al. Dynamics of neutralizing antibodies against Bovine respiratory syncytial virus in a dairy herd from Santa Fe Province, Argentina. Rev. argent. microbiol. [online]. 2020, vol.52, n.4, pp.111-120. ISSN 0325-7541.

Bovine respiratory syncytial virus (BRSV) is one of the most relevant agents responsi-ble for respiratory disease in cattle from both dairy and beef farms. BRSV is spread by horizontalcontact causing a constant presence of seropositive animals that favors viral circulation throughout the year. Moreover, reinfections with BRSV are frequent between animals regardless of theirage as BRSV does not confer long-lasting protective immunity. Several studies have demonstrated the circulation of BRSV in cattle from different regions of the world; however, little isknown about the dynamics of BRSV infection in cows before and after they begin lactation. Theaim of this work was to study the dynamics of BRSV neutralizing antibodies from birth up to36 months of age in a closed dairy herd of Argentina specifically around the lactation period. Passive maternal antibodies against BRSV started to decrease monthly and became almost undetectable at 8 months of age. We detected two potential infection points at months 11 and 27after birth, in which 30% and 45% of the animals showed seroconversion, respectively. Specifically, an increase in the proportion of seropositive cows after the start of lactation suggests thatthey became reinfected around the time they began lactating. We demonstrate the importanceof understanding BRSV dynamics in a closed dairy herd to review the vaccination schedule ofthe animals to achieve protection against BRSV infection.

Palavras-chave : Bovine respiratory syncytial virus; Dairy herd; Viral circulation; Lactation period.

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