Mendonça Filipe Lucas de Melo, Coelho Matheus Figueiredo, Bastos Camila Valgas, da Silveira Júlia Angélica Gonçalves, Nicolino Rafael Romero, Uribe Jose Azael Zambrano, Ribeiro Múcio Flávio Barbosa, Silvestre Bruna Torres, Meneses Rodrigo Melo, de Carvalho Antônio Último, Moreira Tiago Facury, Facury-Filho Elias Jorge
Veterinary Clinic and Surgery Department, Veterinary School, Universidade Federal de Minas Gerais, Minas Gerais, 31270-901, Brazil.
Veterinary Clinic and Surgery Department, Veterinary School, Universidade Federal de Minas Gerais, Minas Gerais, 31270-901, Brazil; Animal Production Department, Instituto Federal de Minas Gerais (IFMG) Campus São João Evangelista, Minas Gerais, 39705-000, Brazil.
Ticks Tick Borne Dis. 2025 Jan;16(1):102394. doi: 10.1016/j.ttbdis.2024.102394. Epub 2024 Sep 20.
Bovine anaplasmosis is endemic and is of fundamental importance worldwide. Therefore, measures for controlling and preventing clinical diseases are warranted to ensure the reduction of associated economic losses. The objective of the present study was to assess the post-inoculation effects and protection conferred by three different protocols of inoculation of low-virulence live strains of Anaplasma marginale (UFMG1 and UFMG3) in field-challenged cattle. Sixty-eight Holstein calves with an average age of 17 days were randomly divided into four groups. The groups received two subcutaneous administrations spaced 40 days apart, at a dosage of 2 × 10 infected erythrocytes of the following A. marginale strains: G1 (UFMG1 + UFMG1); G2 (UFMG3 + UFMG3); G3 (UFMG1 + UFMG3); and G4 (control). Every two days, the animals were evaluated for rectal temperature, Packed Cell Volume (PCV), and blood smears. Blood samples were collected prior to inoculation, before the field challenge, and after the challenge period, nPCR and IFAT techniques were performed. There were no significant differences in rickettsemia levels, reduction in PCV, or antibody detection among the different inoculation strategies. Forty days after the second inoculation, 90 %, 84.6 %, and 90.9 % of the animals in G1, G2, and G3, respectively, tested positive using nPCR. After inoculation, the group G2, which received the UFMG3 inoculum, had a higher frequency of treatment (odds ratio of 6.7; 1.198-38.018 CI; p = 0.03), while groups G1 and G3 demonstrated similar treatment frequencies compared to the control. During the natural challenge phase, 13.3 % of animals in group G1 required treatment (odds ratio of 0.108; 0.018-0.635 CI; p = 0.014) compared to 58.8 % of the control group. Considering the results collectively, the protocol using the UFMG1 strain (G1) stands out for its potential to be safe and induce some degree of immunization against A. marginale, reducing the incidence of clinical disease and the need for treatment during natural challenge.
牛无形体病呈地方性流行，在全球范围内具有至关重要的意义。因此，有必要采取控制和预防临床疾病的措施，以确保减少相关经济损失。本研究的目的是评估三种不同接种低毒力边缘无浆体活菌株（UFMG1和UFMG3）方案在经田间攻毒的牛中接种后的效果和保护作用。68头平均年龄为17天的荷斯坦犊牛被随机分为四组。这些组接受两次皮下给药，间隔40天，剂量为2×10个以下边缘无浆体菌株的感染红细胞：G1（UFMG1 + UFMG1）；G2（UFMG3 + UFMG3）；G3（UFMG1 + UFMG3）；以及G4（对照组）。每隔两天，对动物的直肠温度、红细胞压积（PCV）和血涂片进行评估。在接种前、田间攻毒前和攻毒期后采集血样，进行巢式PCR（nPCR）和间接荧光抗体试验（IFAT）技术检测。不同接种策略之间在立克次体血症水平、PCV降低或抗体检测方面没有显著差异。第二次接种后40天，G1、G2和G3组分别有90%、84.6%和90.9%的动物使用nPCR检测呈阳性。接种后，接受UFMG3接种物的G2组治疗频率较高（优势比为6.7；95%置信区间为1.198 - 38.018；p = 0.03），而G1组和G3组与对照组相比治疗频率相似。在自然攻毒阶段，G1组13.3%的动物需要治疗（优势比为0.108；95%置信区间为0.018 - 0.635；p = 0.014），而对照组为58.8%。综合考虑结果，使用UFMG1菌株（G1）的方案因其安全性潜力以及诱导对边缘无浆体一定程度免疫的能力而突出，可降低临床疾病的发生率以及自然攻毒期间的治疗需求。
