Molecular prevalence of Anaplasma marginale and associated risk factors in beef cattle herds from Ohio: a cross-sectional study

Abstract

OBJECTIVE To estimate the prevalence of Anaplasma marginale, the causative agent of bovine anaplasmosis, in beef herds from Ohio; evaluate farm identity and animal age as risk factors; and examine serologic cross-reactivity with Anaplasma phagocytophilum, an emerging disease agent. ANIMALS 4 beef cattle herds (n = 327) sampled between December 2020 and December 2021. PROCEDURES To address the broader investigation of characterizing Anaplasma spp and genotypes in Ohio, herds with a history of clinical anaplasmosis were targeted. Blood was screened for antibodies to Anaplasma spp using a competitive enzyme-linked immunosorbent assay with seropositive samples tested for A marginale using real-time PCR. If negative, samples were also tested for A phagocytophilum. RESULTS We estimated a statewide molecular prevalence of 38.53% (95% CI, 33.26% to 43.81%), with some farms exhibiting higher prevalence than others (19.40% to 56.86%). Accounting for farm identity, the odds of an animal becoming infected increased by 1.41 (95% CI, 1.28 to 1.58) for every year in age. Forty-four animals tested seropositive but PCR negative for A marginale. Out of these, 2 tested positive for A phagocytophilum. CLINICAL RELEVANCE Our study was the first to report prevalence estimates for bovine anaplasmosis in Ohio. Although prevalence was higher than other states, this is most likely due to our sampling approach. Our results suggested that older animals are more likely to be infected with A marginale, and when animals are instead infected with A phagocytophilum, serology alone can be misleading wherever the 2 species co-occur. Our study can guide wider epidemiological studies for informing management in Ohio.

Describing the experience of livestock producers from Ohio, USA with ticks and associated diseases

“…These results generally agree with other U.S. studies, which showed that the public is familiar with Lyme disease, but not other TBDs, such as Rocky Mountain spotted fever, anaplasmosis, babesiosis, and ehrlichiosis [5,7]. In our study, it is concerning that 32 producers (56.1%) were unsure or thought animal anaplasmosis was absent given that bovine anaplasmosis, an economically devasting disease, has been detected in at least four beef production farms in Ohio [30]. Perhaps more alarming is that 12 producers (21.1%), seven of which identified as swine producers, reported that African swine fever was present in Ohio, because this is a foreign animal disease that will present a significant economic challenge for the swine industry if it were to invade [31].…”

A survey of knowledge, attitudes, and practices of veterinary professionals regarding ticks and tick-borne diseases: Insights from Ohio, USA

“…1 , Table S3). Although many TBDs occur in Ohio [e.g., [ 26 ]], Lyme disease was the only TBD thought by most (52.2%) to occur (Table S4).

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Molecular prevalence of Anaplasma spp. in cattle and assessment of associated risk factors in Northeast Thailand

“…In addition, this study notices that good management practices on the farm have been observed to be the key factor in the infection rate. In other counties, the prevalence of anaplasmosis in cattle varies from 8.7% in Mongolia [ 19 ], 9% and 17% in Punjab (Pakistan) [ 20 ], 11.1% in Pakistan [ 21 ], 15.7% in India [ 22 ], 38.53% in Ohio [ 23 ], 49.1 % in Nigeria [ 24 ], and 68.3% in Egypt [ 25 ]. The prevalence of bovine anaplasmosis in this study is reliable in range with previous epidemiological studies.…”