High genetic diversity and superinfection by Anaplasma marginale strains in naturally infected Angus beef cattle during a clinical anaplasmosis outbreak in southeastern Brazil

Author(s)

Garcia, Amanda Barbosa ; Jusi, Marcia Mariza Gomes ; Freschi, Carla Roberta ; Ramos, Inalda Angelica Souza ; Mendes, Natalia Serra ; do Amaral, Renan Bressianini ; Gonsalves, Luiz Ricardo ; Andre, Marcos Rogerio ; Machado, Rosangela Zacarias

• Document type: Journal article
• Source: TICKS AND TICK-BORNE DISEASES; v. 13, n. 1, p. 9-pg., 2022-01-01.

Abstract

Anaplasma marginale is an obligate intracellular Gram-negative bacterium that is parasitic to erythrocytes and is the main agent of bovine anaplasmosis. This disease causes severe anemia and reduces weight gain and milk production, thus giving rise to major economic losses relating to livestock worldwide. The genetic diversity of this bacterium has been characterized based on sequences of major surface proteins (MSPs), especially MSP1 alpha. This has enabled identification of several geographical strains, according to different amino acid sequences. The aim of this study was to investigate the genetic diversity of A. marginale in naturally infected Angus beef cattle during a disease outbreak in southeastern Brazil. Four blood samples were collected over a four-month period from each of 20 animals on a cattle farm in Itu, Sao Paulo, Brazil. Serum samples were subjected to indirect ELISA to detect anti-A. marginale IgG antibodies. The 80 whole-blood samples obtained were subjected to DNA extraction, quantitative real-time PCR (qPCR) for the msp1 beta gene, semi-nested PCR (snPCR) for the msp1 alpha gene, cloning of the target fragment and sequencing using the Sanger method. The sequences obtained were analyzed for genetic diversity using the RepeatAnalyzer software. Both iELISA tests, using recombinant MSP5 and the Anaplasma antibody test kit (VMRD), revealed high seroprevalence: 91.25% and 97.5%, respectively. In qPCR, 100% of the samples were positive, with between 10(3) and 10(7) DNA copies/mu L. In the snPCR based on the msp1 alpha gene, 57.5% (46/80) of the samples were positive. Microsatellite analysis on the 36 sequences obtained showed the presence of genotypes H (58.3%), F (25%), E (19.4%), C (2.7%) and G (2.7%). The RepeatAnalyzer software identified 36 strains in the study region, among which some had not previously been described in the literature (13 27 13 27 13 F; 16 FF; tau 27; 63 29 104 29; LJ1 13 LJ1 13; 16 F 17; 16 F 91). High genetic diversity of A. marginale bacteria was found on this farm in Itu, Sao Paulo. (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