Bahonar Alireza, Bahreinipour Akram, Dadar Maryam
Department of Food Hygiene and Quality Control, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran.
Animal and Animal Products-borne Diseases Research Center, IVO, Tehran, Iran.
Vet Res Commun. 2025 Jul 9;49(5):251. doi: 10.1007/s11259-025-10822-9.
Brucellosis remains a significant challenge in Iran's dairy industry, with varying prevalence across provinces. This retrospective study (March 21, 2023-March 20, 2024) assessed bovine brucellosis seroprevalence across all regions of Iran (32 provinces), following Iranian Veterinary Organization (IVO) ethical guidelines. A total of 1,555,086 blood samples were collected from 612,558 dairy cattle at 4,586 industrial dairy farms, indicating that some animals were sampled more than once during the study period. Blood samples were screened using the Rose Bengal Plate Test, confirmed by Wright and 2-ME tests; milk samples were cultured for Brucella. Additionally, 248 milk samples were collected from seropositive farms. Overall, 7.6% (350 farms) had seropositive cases, with the highest rates in Qom (22.8%), Alborz (20.5%), Isfahan (18.1%), and Yazd (14.7%), which showed the highest farm-level prevalence. By contrast, provinces including South Khorasan (0.6%), West Azerbaijan (1%), and Kurdistan (1.1%) showed the lowest farm-level prevalence with positive cases. Provinces with zero positive cases at the farm level include Sistan and Baluchestan, Gilan, South Kerman, Mazandaran, and Hormozgan. Based on our study, the national average prevalence at the animal level in industrial dairy cattle is 0.4%, and the reactor to test percentage is 0.1%. Our analysis showed the highest animal-level prevalence in Qom (2.1%), Yazd (1.6%), and Fars (1.5%). Moreover, the highest reactor to test percentage was in Yazd (1.0%), followed by Qom and Khuzestan (0.5%). Holstein cattle were most affected (76.1%), followed by crossbreds (23%), with minimal infection in Simmental (0.7%) and Jersey (0.1%). Of the infected cattle, 79.6% were born on the farm, and 20.4% came from outside sources. Moreover, 82.2% of reactor cows were nursing, and 49.7% were pregnant at testing. Reproductive issues among positive reactors were noted: 17.1% had abortions, 1.3% had stillbirths, and 4% had weak calves. Vaccination records showed that 68.7% of reactors had received a full dose of the RB51 vaccine, while 31.3% were unvaccinated. Furthermore, 65% had been vaccinated with reduced doses of the RB51 vaccine, and 35% were unvaccinated. Brucella abortus and Brucella melitensis were found in 7.7% and 7.1% of milk samples, respectively. These results highlight the urgent need for stricter biosecurity, movement controls, and better vaccination to manage brucellosis in Iranian dairy farms.
布鲁氏菌病仍然是伊朗乳制品行业面临的重大挑战，各省份的患病率各不相同。这项回顾性研究（2023年3月21日至2024年3月20日）遵循伊朗兽医组织（IVO）的伦理准则，评估了伊朗所有地区（32个省份）的牛布鲁氏菌病血清阳性率。在4586个工业奶牛场，从612558头奶牛中总共采集了1555086份血样，这表明在研究期间有些动物被多次采样。血样采用玫瑰红平板试验进行筛查，通过瑞特试验和2-巯基乙醇试验进行确认；对乳样进行布鲁氏菌培养。此外，还从血清阳性农场采集了248份乳样。总体而言，7.6%（350个农场）有血清阳性病例，其中库姆省（22.8%）、阿尔伯兹省（20.5%）、伊斯法罕省（18.1%）和亚兹德省（14.7%）的患病率最高，显示出农场层面的最高患病率。相比之下，南呼罗珊省（0.6%）、西阿塞拜疆省（1%）和库尔德斯坦省（1.1%）的农场层面患病率最低且有阳性病例。农场层面零阳性病例的省份包括锡斯坦-俾路支斯坦省、吉兰省、南克尔曼省、马赞德兰省和霍尔木兹甘省。根据我们的研究，工业奶牛中全国动物层面的平均患病率为0.4%，检测反应率为0.1%。我们的分析显示，库姆省（2.1%）、亚兹德省（1.6%）和法尔斯省（1.5%）的动物层面患病率最高。此外，检测反应率最高的是亚兹德省（1.0%），其次是库姆省和胡齐斯坦省（0.5%）。荷斯坦奶牛受影响最大（76.1%），其次是杂交品种（23%），西门塔尔牛（0.7%）和泽西牛（0.1%）感染极少。在感染的奶牛中，79.6%出生在农场，20.4%来自外部来源。此外，82.2%的反应奶牛正在产奶，49.7%在检测时怀孕。注意到阳性反应动物存在繁殖问题：17.1%发生流产，1.3%出现死产，4%产下弱犊。疫苗接种记录显示，68.7%的反应动物接受了全剂量的RB51疫苗，而31.3%未接种疫苗。此外，65%接种了减量的RB51疫苗，35%未接种疫苗。在7.7%的乳样中发现了流产布鲁氏菌，在7.1%的乳样中发现了马尔他布鲁氏菌。这些结果凸显了在伊朗奶牛场加强生物安全措施、严格控制动物流动以及改进疫苗接种以管理布鲁氏菌病的迫切需求。
