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| Author(s): |
Amanda Barbosa Garcia
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Jaboticabal. 2020-05-18. |
| Institution: | Universidade Estadual Paulista (Unesp). Faculdade de Ciências Agrárias e Veterinárias. Jaboticabal |
| Defense date: | 2020-04-08 |
| Advisor: | Rosangela Zacarias Machado |
| Abstract | |
Anaplasma marginale is a Gram-negative, obligatory intracellular erythrocyte parasite and the main agent of bovine Anaplasmosis. This disease causes severe anemia, causing a reduction in weight gain and milk production and generating major economic losses in livestock worldwide. The genetic diversity of this bacterium has been characterized based on the sequence of surface proteins (MSPs), mainly in the protein MSP1α, making it possible to identify the different geographical strains according to the differences in the amino acid sequences. The present study aimed to investigate the genetic diversity of A. marginale in Angus beef cattle naturally infected during an outbreak of the disease. Twenty cattle, aged 6 to 9 months, from a farm in the city of Itú, state of São Paulo, were followed for four months and four blood samples were taken. Serum samples were subjected to the Indirect Immunoenzymatic Assay (iELISA) to detect antibodies IgG anti-A. marginale. The eighty whole blood samples obtained were subjected to DNA extraction, quantitative real-time PCR (qPCR) for the msp1β gene, semi-nested PCR (snPCR) for the msp1α gene, cloning of the target fragment and sequencing by the Sanger method. The obtained sequences were subjected to genetic diversity analysis using the RepeatAnalyzer software. The Indirect Immunoenzymatic assay (iELISA) revealed low seroprevalence in the sampled animals despite 100% positivity in the qPCR, with quantification between 103 and 107 number of DNA copies/μL, showing a possible immunosuppression caused by the presence of the pathogen. In snPCR, based on the msp1α gene, 57.5% (46/80) of the samples were positive. Microsatellite analysis of 36 sequences obtained showed the presence of genotype H (58.3%), F (25%), E (19.4%), C (2.7%) and G (2.7%). Through the RepeatAnalyzer software, several strains were identified in the studied region, some of them never before described in the literature, such as 13 27 13 27 13 F; 16 F F; τ 27; 63 29 104 29; LJ1 13 LJ1 13; 16 F 17; 16 F 91 among others. High genetic diversity of A. marginale bacteria was found circulating in the animals studied, identifying more than one circulating strain in the same animal. (AU) | |
| FAPESP's process: | 18/05366-7 - Genetic diversity of Anaplasma marginale in bovines sampled in ITU, State of São Paulo |
| Grantee: | Amanda Barbosa Garcia |
| Support Opportunities: | Scholarships in Brazil - Master |