Prevalence of Zoonotic Bacterial Pathogens and Associated Risk Factors among Cage-Cultured Nile Tilapia (Oreochromis Niloticus) in Mwanza Gulf of Lake Victoria, Tanzania
| dc.contributor.author | Komba, Richard | |
| dc.date.accessioned | 2026-01-30T16:16:29Z | |
| dc.date.issued | 2025-08 | |
| dc.description | SDG: 2- Zero Hunger SDG:3 - Good Health and Well-Being | |
| dc.description.abstract | Aquaculture has the potential to improve global food and nutrition security, but climate change and poor practices can lead to chemical accumulation and zoonotic bacterial pathogens. This study aimed to identify the prevalence of zoonotic bacterial pathogens and associated risk factors in cage-cultured Nile tilapia in Mwanza Gulf, Lake Victoria, Tanzania. A total of 210 Nile tilapia (Oreochromis niloticus) samples were collected from cages distributed in three districts: Nyamagana (60), Ilemela (70) and Misungwi (80). Tissue samples from the gills, skin, kidney and liver were examined for zoonotic pathogenic bacterial infections. Bacterial isolation and identification were performed using standard conventional bacteriological methods. Additionally, a structured questionnaire was administered to 120 fish farmers to gather information on aquaculture practices, fish health status, and disease management. Water and sediment quality in cage-cultured and control sites were assessed using established physicochemical and sediment analysis procedures. Nine genera of bacteria were identified, including Salmonella spp. (12.5%), Klebsiella spp., Pseudomonas spp. (23.5%), Lactococcus spp. (16.9%), Bacillus spp. (14.7%), Shigella spp., E. coli, Streptococcus spp., and Staphylococcus spp. (16.7%). The gills had the highest bacterial prevalence (28.6%), followed by the liver (16.7%), skin (12.9%) and kidney (6.7%). Bacterial isolates were most prevalent in cages in Ilemela (44.1%), followed by Misungwi (34.6%) and Nyamagana (21.3%), and with significant differences noted (p < 0.001). Additionally, analysis showed that most farms had high stocking densities (> 8 fish/m², 44.4%) and reared Nile tilapia (Oreochromis niloticus) (67.7%). Few farmers regularly measured water quality (16.7%) or removed dead fish daily (20.8%). Key factors influencing total mortality included stocking density (p = 0.013), fish species (p = 0.031), dead fish disposal methods (p = 0.023), and predator bird control (p = 0.016). Water samples from both cage-cultured and control sites showed no significant differences in quality (p > 0.05). Farmed fish and their aquatic environments harbor potentially pathogenic and zoonotic bacteria, posing significant risks to public health and leading to considerable economic losses. Therefore, the implementation of optimal management practices, along with strict biosafety and biosecurity measures, is essential. | |
| dc.identifier.uri | https://dspace.nm-aist.ac.tz/handle/123456789/3669 | |
| dc.language.iso | en | |
| dc.publisher | NM-AIST | |
| dc.title | Prevalence of Zoonotic Bacterial Pathogens and Associated Risk Factors among Cage-Cultured Nile Tilapia (Oreochromis Niloticus) in Mwanza Gulf of Lake Victoria, Tanzania | |
| dc.type | Thesis |