Proposta de um iELISA para diagnóstico de Mycoplasma bovis em bovinos leiteiros e fatores de risco associados

D.R Pires,L.F.C Barbosa,A.C.N Morais,L.S Machado,M.F.A Balaro,M.L Barreto,J.P.C Santos,N.C Cunha,J.F.M Mendonça,E.R Nascimento,G.N Souza

doi:10.1590/1678-4162-12140

D.R Pires, L.F.C Barbosa + Show 9 more

Open Access

https://doi.org/10.1590/1678-4162-12140

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Abstract

ABSTRACT Mycoplasma bovis is a highly contagious agent associated with several pathologies in cattle. The detection of reactive antibodies to M. bovis by Indirect Enzyme-Linked Immunosorbent Assay (iELISA) identifies if there was an exposure to the microorganism. The current study aimed to optimize an iELISA from M. bovis total cell antigen, applying it to bovine serum samples, and to evaluate risk factors. Serum samples were obtained from 400 cows from 17 herds from Southeast Brazil. In the optimization of iELISA, the following was established: 2 μg/mL of antigen, sera dilution 1:300, and conjugate dilution 1:15000. The frequency was 62.3% (249/400) of reactive animals and 100% (17/17) of reactive herds. Risk factors were: herds with more than 100 animals (OR= 3.1; CI= 95%); Holstein breed (OR= 72.5; CI= 95%); cows (OR= 29.7; CI= 95%); intensive breeding system (OR= 3.3; CI= 95%); associated small ruminant production (OR= 4.4; CI= 95%); milk production above 500L (OR= 2.9; CI= 95%); no quarantine (OR= 1.5; CI= 95%); mechanical milking (OR= 5.5; CI= 95%) and cases of mastitis (OR= 5.5; CI= 95%). The proposed iELISA was able to detect antibodies reactive to M. bovis in bovine serum. Knowledge of these risk factors can assist in the implementation of prophylactic measures.

Highlights

Mycoplasma species can cause a variety of diseases in cattle, such as mastitis, otitis media, conjunctivitis, endocarditis, respiratory, joint, brain and reproductive disorders
This study was approved by the Ethics Committee on the Use of Animals (CEUA) of Universidade Federal Fluminense (UFF), under certificate number 987/2017
The pellet was resuspended in phosphate-buffered saline (PBS) solution pH 7.2 and centrifuged once again as before

Summary

Introduction

Mycoplasma species can cause a variety of diseases in cattle, such as mastitis, otitis media, conjunctivitis, endocarditis, respiratory, joint, brain and reproductive disorders. Mycoplasma bovis is highly contagious and the leading agent involved in cases of mastitis in dairy cattle. It can cause outbreaks in the clinical form with a decrease in milk production and quality, leading to the early culling of animals, while in the subclinical form, it is responsible for the maintenance and dissemination of the agent in the herd (Maunsell et al, 2011; Fox, 2012; Arede et al, 2016; Rosales et al, 2017; Kanda et al, 2019). Once established in the herd, it is difficult to eradicate, due both to its invasion of epithelial and immune cells and dissemination to inaccessible parts of the organism, making treatment with antibiotics difficult. M. bovis has great antigenic variation, which hinders the development of vaccines for its control (Pretto et al, 2001; Burki et al, 2015; Perez-Casal et al, 2017)

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