IDENTIFICATION OF HELMINTH PARASITES OF THREE ECONOMICALLY IMPORTANT FISH SPECIES AND PUBLIC AWARENESS ON THEIR ZOONOTIC POTENTIAL IN SELECTED RIFT VALLEY LAKES, OROMIA, ETHIOPIA

Abstract

Fishes are important for human nutrition and livelihood. However, their production may be affected by parasites and, the identification those parasites is crucial in desiging an effective control method. Therefore, a cross-sectional study was carried out on fishes caught from lake Dambal, Koka reservoir and lake Langano from September 2022 to March 2023 with the objectives of identifying helminth parasites of three commerciallyy important fish species in selected Rift Valley lakes of Oromia and to assessing public awareness on fish-borne parasitic zoonoses in communities living surrounding the lakes. The collected data was analysed using Stata version 14 statistical software. The proportion of fish caught and infected were depicted with percentages while the association between infection and the supposed risk factors was assessed with a chi-square test as well as a univariable and multivariable logistic regression analysis.The difference in mean intensity and abundance berween groups were assessed using student t-test and One way ANOVA. A total of 574 fish caught from the selected lakes consisting of Nile tilapia (Oreochromis niloticus) (274), Common carp (Cyprinus carpio) (174) and African catfish (Clarius gariepinus) (126) were examined and 110 key informant stakeholders involved in fishing activity were included. From 574 sampled fish (213 from lake Dambal (lake Ziway), 168 from lake Langano and 193 from Koka reservoir), 129 were found infected with helminths with an overall prevalence of 22.47% [95% confidence interval (CI): 19.12%–26.11%]. The prevalence of helminth infection was 27.46% in Koka reservoir 26.76% lake Dambal and 11.31% in lake Langano. The highest infection rate occurred in African catfish (28.57%) followed by the common carp (25.86%) and Nile Tilapia (17.52%). On assessment of the percentage of helminth infection among the sampled species of fish a difference was observed within the respective study sites (p<0.05). Fish caught from Koka reservoir (OR=2.59; 95% CI=1.45-4.65; p<0.001)) and lake Dambal (OR=2.85; 95% CI=1.45-4.65) were more likely to be highly infected than those fish in lake Langano. In addition, African catfish (OR=1.76; 95% CI: 1.06-2.94; p<0.030) were more infected compared to Nile tilapia. Furthermore, male fish (OR=2.09; 95% CI: 1.39-3.15; p<0.001) were observed highly infected with helminths than that of females. Helminths belonging to the genus Contracaecum, Clinostomum, Eustrongyloides and Diplostomum were identified at different infection rate. A statistically significant difference in mean parasite intensity was seen between males and females (t = 12.13; p<0.001) and fish that were 10-30 cm long and >30-to 60 cm long (t=2.07; p=0.040). Likewise, the mean abundance also showed significant difference between males and females (t = -6.83; p<0.001) and fish that were 10-30 cm long and those >30-to 60 cm long (t=2.07; p=0.040). From 110 respondents, 50 (45.45%) consume raw fish meat, 33 (30%) had the knowledge about fish diseases, 24.55% knew that fish are affected by parasites and 19.09% disclosed fish parasites are transmissible to humans. Only 6.36% of the respondents disclosed they have been infected with fish parasites and 4.55% and 1.82% of the participants mentioned they took traditional treatment. In coclusion:implementing lake management, identification of parasites to the species level, capacity building in fish parasitology and pathology and health education should be considered