Abstract
Anaplasma marginale is an obligate intracellular Gram-negative bacterium found in ruminants' erythrocytes and is the etiological agent of bovine anaplasmosis. The bacterium's genetic diversity has been characterized based on sequences of major surface proteins (MSPs), such as MSP1α. The aim of the present study was to investigate the genetic diversity of A. marginale in cattle in the state of Maranhão, northeastern Brazil. To this end, 343 blood samples were harvested and subjected to iELISA assays using the recombinant surface protein MSP5. Out of 343 blood samples, 235 (68.5%) were randomly chosen and submitted to DNA extraction, qPCR and conventional PCR targeting the msp1α gene to determine amino acid sequences and classify the genotypes. The iELISA results showed 81.34% seropositivity (279/343), whereas qPCR revealed 224 positive samples (95.32%). Among these qPCR-positive samples, 67.4% (151/224) were also positive in the cPCR. Among the 50 obtained sequences, 21 strains had not been previously reported. Regarding the genotypes, H (26/50) and E (18/50) were identified most often, while genotypes F and C were only identified twice each and B and G once each. In conclusion, high prevalence and genetic diversity for A. marginale were observed in dairy cattle herds in the state of Maranhão.
Highlights
Anaplasma marginale is an obligate intracellular Gram-negative alpha-proteobacterium of the Anaplasmataceae family that parasites erythrocytes of ruminants. Because it is the etiological agent of bovine anaplasmosis, A. marginale stands out as one of the major causes of diminished bovine beef and milk production
Considering there are no studies reporting the occurrence of A. marginale in Maranhão, and that the Middle region of Mearim, Maranhão has characteristics that favor the spread of the tick R. microplus, the aim of the present study was to investigate the serological and molecular prevalence and genetic diversity of A. marginale in naturally infected cattle in dairy herds in six municipalities in the Médio Mearim microregion, Maranhão, northeastern Brazil
The dairy cattle sampled belonged to Girolando herds on 37 farms located in six municipalities in the Médio Mearim microregion, in Maranhão, northeastern Brazil (Figure 1): 59 animals were sampled on farms 1 to 6 in the municipality of Lima Campos (4°31’14” S and 44°28’2” W); 51 on farms 7 to 12 in Pedreiras (4°34’28” S and 44°35’55” W); 52 on farms 13 to 18 in Trizidela do Vale (4°34’0” S and 44°37’37” W); 58 on farms 30 to 36 in Poção de Pedras (4°43’55” S and 44°53’18” W); 66 on farms 19 to 25 in Bernardo do Mearim (4°36’22” S and 44°46’29” W); and 57 on farms 26 to 30 and farm 37 in Igarapé Grande (4°33’19” S and 44°51’14” W)
Summary
Anaplasma marginale is an obligate intracellular Gram-negative alpha-proteobacterium of the Anaplasmataceae family that parasites erythrocytes of ruminants. Because it is the etiological agent of bovine anaplasmosis, A. marginale stands out as one of the major causes of diminished bovine beef and milk production. It is associated with high herd mortality. This bacterium parasites bovines in tropical, subtropical and temperate regions (Kocan et al, 2010; Aubry & Geale, 2011). Transplacental transmission has been reported previously (Kocan et al, 2004; Silva et al, 2015, 2016)
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