title: Detection of genetic diversity of Anaplasma marginale isolates in Minas Gerais, Brazil.
abstract: Bovine anaplasmosis, caused by the tick-borne rickettsia Anaplasma marginale, is endemic in tropical and subtropical regions of the world and results in economic losses in the cattle industry. Major surface proteins (MSPs) have been used as markers for the genetic characterization of A. marginale strains and demonstrate that many isolates may occur in a given geographic area. However, in Brazil, little is known about the genetic diversity of A. marginale isolates within individual herds. This study was designed to examine the genetic variation among A. marginale infecting calves in a farm in the south of Minas Gerais State, Brazil. Blood samples collected from 100 calves were used to prepare Giemsastained smears that were microscopically examined for the presence of A. marginale. From each blood sample, DNA was extracted and analyzed by a polymerase chain reaction (PCR), followed by sequencing to determine diversity among the isolates. Examination of blood smears showed that 48% of the calves were infected with A. marginale, while the real-time PCR detected 70.2% positivity. Congenital infections were found in four calves. The microsatellite and tandem repeat analyses showed high genetic diversity among the isolates.
authors.forename: Anna Elisabeth
authors.initials: AE
authors.lastname: Pohl
authors.forename: Alejandro
authors.initials: A
authors.lastname: Cabezas-Cruz
authors.forename: Múcio Flávio Barbosa
authors.initials: MF
authors.lastname: Ribeiro
authors.forename: Júlia Angélica Gonçalves da
authors.initials: JA
authors.lastname: Silveira
authors.forename: Cornelia
authors.initials: C
authors.lastname: Silaghi
authors.forename: Kurt
authors.initials: K
authors.lastname: Pfister
authors.forename: Lygia Maria Friche
authors.initials: LM
authors.lastname: Passos
mesh_terms: D042322:Anaplasma marginale / Q000235:genetics* / Q000302:isolation & purification*; D000818:Animals; D001938:Brazil; D002417:Cattle / Q000382:microbiology*; D004269:DNA, Bacterial / Q000032:analysis; D014644:Genetic Variation
chemical_list: D004269:DNA, Bacterial