Muuka Geoffrey, Otina Beatrice, Wesonga Hezron, Bowa Benson, Gicheru Nimmo, Stuke Kristin, Poole E Jane, Salt Jeremy, Colston Angie
Central Veterinary Research Institute (CVRI), Ministry of Fisheries and Livestock, Lusaka, Zambia.
Faculty of Veterinary Medicine, University of Nairobi, Nairobi, Kenya.
BMC Vet Res. 2019 Dec 12;15(1):451. doi: 10.1186/s12917-019-2197-x.
Contagious bovine pleuropneumonia (CBPP) caused by Mycoplasma mycoides subspecies mycoides (Mmm) is an important disease of cattle that causes serious economic losses. With the known effectiveness of new generation macrolides, tulathromycin and gamithromycin were assessed in comparison with oxytetracycline as a positive control and saline as a negative control for effectiveness in inhibiting lung lesion development, promoting resolution, preventing spread and bacteriological clearance in susceptible local cattle breeds in two separate studies in Kenya and Zambia. Animals were monitored for clinical signs, sero-conversion as well as detailed post-mortem examination for CBPP lesions.
Using the Hudson and Turner score for lesion type and size, tulathromycin protected 90%, gamithromycin 80%, and oxytetracycline 88% of treated animals in Kenya. In Zambia, all animals (100%) treated with macrolides were free of lung lesions, while oxytetracycline protected 77.5%. Using the mean adapted Hudson and Turner score, which includes clinical signs, post-mortem findings and serology, tulathromycin protected 82%, gamithromycin 56% and oxytetracycline 80% of the animals in Kenya whereas in Zambia, tulathromycin protected 98%, gamithromycin 94% and oxytetracycline 80%. The saline-treated groups had 93 and 92% lesions in Kenya and Zambia respectively, with Mmm recovered from 5/14 in Kenya and 10/13 animals in Zambia. Whereas the groups treated with macrolides were free from lesions in Zambia, in Kenya 5/15 tulathromycin-treated animals and 6/15 gamithromycin-treated animals showed lesions. Oxytetracycline-treated animals showed similarities with 3/14 and 4/15 showing lesions in Zambia and Kenya respectively and Mmm recovery from one animal in Kenya and six in Zambia. In both studies, lesion scores of saline-treated groups were significantly higher than those of the antibiotic treated groups (p < 0.001). In sentinel animals, CBPP lesions were detected and Mmm recovered from one and two animals mixed with the saline-treated groups in Kenya and Zambia respectively.
This study demonstrated that tulathromycin, a mycoplasmacidal, can achieve metaphylactic protection of up to 80%, while non-recovery of Mmm from sentinels suggests macrolides effectiveness in preventing spread of Mmm. It is recommended that further studies are conducted to evaluate strategies comparing vaccination alone or combining vaccination and antibiotics to control or eradicate CBPP.
由丝状支原体丝状亚种（Mmm）引起的牛传染性胸膜肺炎（CBPP）是牛的一种重要疾病，会造成严重经济损失。鉴于新一代大环内酯类药物已知的有效性，在肯尼亚和赞比亚分别开展的两项独立研究中，对妥拉霉素和加米霉素与作为阳性对照的土霉素以及作为阴性对照的生理盐水进行了比较，以评估其在抑制易感本地牛品种肺部病变发展、促进病变消退、防止传播和细菌清除方面的有效性。对动物进行临床症状、血清转化监测以及针对CBPP病变的详细尸检。
在肯尼亚，使用哈德森和特纳病变类型及大小评分标准，妥拉霉素保护了90%的治疗动物，加米霉素保护了80%，土霉素保护了88%。在赞比亚，所有接受大环内酯类药物治疗的动物（100%）均无肺部病变，而土霉素保护了77.5%的动物。使用包括临床症状、尸检结果和血清学的平均调整后哈德森和特纳评分标准，在肯尼亚，妥拉霉素保护了82%的动物，加米霉素保护了56%，土霉素保护了80%；而在赞比亚，妥拉霉素保护了98%，加米霉素保护了94%，土霉素保护了80%。在肯尼亚和赞比亚，生理盐水治疗组分别有93%和92%出现病变，在肯尼亚从14只动物中的5只分离到Mmm，在赞比亚从13只动物中的10只分离到Mmm。在赞比亚，接受大环内酯类药物治疗的组无病变，而在肯尼亚，15只接受妥拉霉素治疗的动物中有5只、15只接受加米霉素治疗的动物中有6只出现病变。接受土霉素治疗的动物在赞比亚和肯尼亚分别有3/14和4/15出现病变，且在肯尼亚有1只动物、赞比亚有6只动物分离到Mmm。在两项研究中，生理盐水治疗组的病变评分均显著高于抗生素治疗组（p < 0.001）。在哨兵动物中，在肯尼亚和赞比亚分别检测到CBPP病变，且从与生理盐水治疗组混养的1只和2只动物中分离到Mmm。
本研究表明，具有杀支原体作用的妥拉霉素可实现高达80%的群体预防保护效果，而哨兵动物未分离到Mmm表明大环内酯类药物在预防Mmm传播方面有效。建议开展进一步研究以评估单独接种疫苗或联合接种疫苗与抗生素来控制或根除CBPP的策略。
