| Congresso Brasileiro de Microbiologia 2023 | Resumo: 712-2 | ||||
Resumo:Bovine leptospirosis is a critical reproductive disease. Abortion is a major sign and leads to an important economic impact. Since bovine abortion has a multifactorial etiology, the proper diagnosis of its etiology is crucial to provide preventive measures in a herd. The necropsy of the aborted fetuses followed by molecular analysis is suggested for diagnosis, and kidneys and liver are the main recommended sites for investigation. However, this may not be valid for all strains causing bovine leptospirosis. This study aimed to analyze unconventional sites for the presence of leptospiral DNA in bovine anicteric aborted fetuses. Five fetuses of the same dairy herd were received for necropsy and diagnosis. Kidneys, livers, lungs, hearts, spleens, subcapsular kidney content, abomasal fluids, and the cavity’s hemorrhagic contents were collected for molecular analysis. The DNA extraction proceeded using DNeasy Blood and Tissue Kit (QIAamp, Qiagen) according to the manufacturer's protocol. Conventional PCR targeted the lipL32 gene, exclusive of pathogenic and intermediate leptospires. PCR-positive samples were submitted to a nested PCR of the secY gene and intended for BigDye sequencing. Sequences were analyzed and compared to other sequences previously deposited in GenBank. In necropsy, four out of five (4/5, 80%) fetuses showed hemorrhagic and anicteric gross lesions, while one fetus had no macroscopic alteration. All fetuses were PCR-positive and the positive sites were the heart, lungs, subcapsular kidney content, thymus, kidneys, liver, and abomasal fluid. Only one (1/5, 20%) fetus presented positive results in the kidney and liver, while four fetuses (4/5, 80%) in cardiopulmonary tissues and three fetuses (3/5, 60%) in the abomasal fluid. Of one fetus, two sequences were obtained and identified as Leptospira interrogans serogroup Sejroe serovar Hardjoprajitno, with 99-100% of homology with UF24. If only the conventional samples (kidney and liver) were tested, leptospiral infection would be misdiagnosed in the majority of the fetuses analyzed herein. Abomasal fluid is composed of the amniotic liquid ingesta of the fetus and reflects the placentary environment. This sample is used for the diagnosis of other abortifacient agents and can also be used to diagnose abortions due to leptospiral infection. Besides abomasal fluid, cardiopulmonary tissues also played a role as unconventional samples, being positive organs in fetuses in which the conventional organs were negative. The presence of L. interrogans serovar Hardjoprajitno was already associated with hemorrhagic and anicteric bovine abortions. The results found herein highly encourage testing multiple organs by PCR to investigate abortions suspected of bovine leptospirosis, particularly in anicteric fetuses Palavras-chave: Abortion, abomasal liquid, lipL32, PCR, nucleotide sequencing Agência de fomento:Fundação Carlos Chagas de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ) e Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) | |||||