De la Torre Euclides, Moreira Nixon, Saegerman Claude, De Clercq Kris, Salinas María, Maldonado Alex, Jarrín David, Sol Vaca María, Pachacama Silvia, Espinoza Jorge, Delgado Hipatia, Barrera Maritza
Animal Diagnostic Laboratory, Agencia Ecuatoriana para el Control Fito y Zoosanitario (AGROCALIDAD), Quito 170184, Ecuador.
Dirección Distrital Manabí, Agencia Ecuatoriana para el Control Fito y Zoosanitario (AGROCALIDAD), Portoviejo 130105, Ecuador.
Pathogens. 2021 Nov 6;10(11):1445. doi: 10.3390/pathogens10111445.
Bluetongue (BT) is a viral disease transmitted by (Diptera: ) to domestic and wild ruminants. Infections in cattle are mainly subclinical, but severe necrotic and hemorrhagic illness and death may occur depending on the strain of the virus and other factors; cattle act as a reservoir for the virus. Although the Ecuadorian coast has climatic conditions that favor the presence of the vector, there are few serologic or virologic BTV studies available. Manabí is a coastal province in which livestock farming is mostly implemented in the northern part. We conducted two studies to assess, for the first time, the presence of active BTV infections in Manabí province. We collected 430 serum samples from 38 randomly selected farms between March and July 2019 to perform BTV competitive ELISA. In addition, six seropositive farms were selected to place eight sentinel BTV-naive calves. All these calves were blood sampled and the presence of BTV RNA and antibodies was tested for by RT-PCR and competitive ELISA, respectively, once a week for 6-8 weeks until seroconversion was evidenced. A high individual seroprevalence (99%) was obtained, and all investigated farms had BTV seropositive animals. All sentinel calves became BTV viremic and seroconverted. The first viremia appeared after 2-5 weeks from arrival at the farm; they seroconverted 1-3 weeks later. We demonstrate for the first time that there is a high level of BTV circulation north of Manabí, with active infections on these farms. Integrated control strategies such as hygienic measures on farms to reduce midge populations would be advisable for the owners as mitigation measures.
蓝舌病（BT）是一种由库蠓（双翅目：蠓科）传播给家养和野生反刍动物的病毒性疾病。牛的感染主要为亚临床感染，但根据病毒株和其他因素的不同，可能会出现严重的坏死性和出血性疾病甚至死亡；牛是该病毒的储存宿主。尽管厄瓜多尔海岸的气候条件有利于传播媒介的生存，但关于蓝舌病病毒（BTV）的血清学或病毒学研究却很少。马纳比是一个沿海省份，其畜牧业主要集中在北部地区。我们开展了两项研究，首次评估马纳比省是否存在活跃的BTV感染。2019年3月至7月期间，我们从38个随机选取的农场采集了430份血清样本，用于进行BTV竞争ELISA检测。此外，我们选择了6个血清学阳性农场，放置8头未感染BTV的哨兵小牛。所有这些小牛每周采血一次，持续6 - 8周，直至出现血清转化，期间分别通过RT-PCR和竞争ELISA检测BTV RNA和抗体的存在情况。个体血清阳性率很高（99%），所有调查的农场都有BTV血清学阳性动物。所有哨兵小牛都出现了BTV病毒血症并发生了血清转化。首次病毒血症在到达农场后2 - 5周出现；1 - 3周后它们发生了血清转化。我们首次证明，马纳比以北地区存在高水平的BTV传播，这些农场存在活跃感染。对于农场主来说，采取综合控制策略，如农场卫生措施以减少蠓虫数量，作为缓解措施是可取的。
