Mzula Alexanda, Wambura Philemon N, Mdegela Robinson H, Shirima Gabriel M
Department of Global Health and Biomedical Sciences, School of Life Science and Bioengineering, Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania.
College of Veterinary Medicine and Biomedical Sciences, Sokoine University of Agriculture, Morogoro, Tanzania.
Heliyon. 2019 Aug 7;5(8):e02220. doi: 10.1016/j.heliyon.2019.e02220. eCollection 2019 Aug.
Aeromonads disease outbreaks are now becoming a common phenomenon in freshwater farmed fish worldwide. In Tanzania, the aquaculture field is increasingly growing save to sustain food protein demand and strengthen household income. To avoid losses that tilapia fish farmers might account, information on magnitude of infection and characteristics of the aetiological agent is vital. This study aimed to establish the prevalence of aeromonads infection in farmed tilapia and assess pond and fish health management practices. A cross sectional study was carried out between February 2017 and October 2018 and a total of 816 whole fish samples were aseptically collected from 32 ponds in Ruvuma, Mbeya, Iringa and Kilimanjaro regions. During sampling, water quality parameters were taken and questionnaires to assess the knowledge of farmers were also provided. Isolation and identification of bacteria was conducted using conventional biotyping and molecular techniques. A total of 201 (80.4%) of 250 isolates that were conventionally identified were confirmed to be aeromonads by amplification of 820 bp rpoD gene, making the overall prevalence of 24.6% (201, n = 816). Sequencing of rpoD gene and phylogenetic analysis revealed two aeromonads species, and . To the best of our knowledge this is the first report to establish the prevalence of aeromonads in apparently healthy farmed tilapia in Southern highlands and Northern zone of Tanzania. In addition it was observed that farmers were lacking proper knowledge and awareness on pond management practices and fish health management. In conclusion, the infection rate of aeromonads in apparently health tilapia coupled with lack of proper knowledge and awareness on pond and fish health management by fish farmers in the study area poses risk of diseases outbreaks in their farms in future. Therefore, it is recommended that the farmers should be trained on basic pond and fish health management and control strategies.
气单胞菌病疫情如今在全球淡水养殖鱼类中已成为一种常见现象。在坦桑尼亚，水产养殖领域不断发展，以满足食物蛋白质需求并增加家庭收入。为避免罗非鱼养殖户可能遭受的损失，了解感染程度和病原体特征至关重要。本研究旨在确定养殖罗非鱼中气单胞菌感染的患病率，并评估池塘和鱼类健康管理措施。2017年2月至2018年10月期间开展了一项横断面研究，从鲁伍马、姆贝亚、伊林加和乞力马扎罗地区的32个池塘中无菌采集了总共816份全鱼样本。采样期间，测定了水质参数，并向养殖户发放问卷以评估他们的知识水平。使用传统生物分型和分子技术进行细菌的分离和鉴定。通过扩增820 bp的rpoD基因，在常规鉴定的250株分离株中，共有201株（80.4%）被确认为气单胞菌，总体患病率为24.6%（201株，n = 816）。rpoD基因测序和系统发育分析揭示了两种气单胞菌，即[具体菌名1]和[具体菌名2]。据我们所知，这是第一份确定坦桑尼亚南部高地和北部地区看似健康的养殖罗非鱼中气单胞菌患病率的报告。此外，还观察到养殖户在池塘管理措施和鱼类健康管理方面缺乏适当的知识和意识。总之，研究区域内看似健康的罗非鱼中气单胞菌感染率，加上养殖户在池塘和鱼类健康管理方面缺乏适当的知识和意识，未来其养殖场存在疾病暴发的风险。因此，建议对养殖户进行基本的池塘和鱼类健康管理及控制策略培训。
