Physicochemical Water Quality Influence on the Parasite Biodiversity in Juvenile Tilapia (Oreochromis spp.) Farmed at Valle Del Mezquital in the Central-Eastern Socioeconomic Region of Mexico.

Aquaculture parasite biodiversity dependents on multiple environmental characteristics, including water quality. The analysis of this relationship aims to support improvements in the production management of tilapia. For this purpose, a total of 100 juvenile fishes (Oreochromis spp.) and 30 water samples were collected at Valle del Mezquital in the Central-Eastern socioeconomical region of Mexico. A study of parasite biodiversity was carried out and water quality parameters were determined. Biodiversity in the habitat was measured using the Simpson diversity index, which considers the number of species present and the abundance of each one; we also calculate the Berger-Parker index to estimate the proportional importance of the most abundant species. In general, it was found that 86% of the examined specimens were parasitized. Parasite biodiversity was 11 genera (Simpson index = 0.55). Trichodina spp. (Ciliophora) was the dominant genus (Berger-Parker index = 0.51). The protozoa Apiosoma spp. was associated with the water hardness (Berger-Parker index = 0.57). Furthermore, the presence of monogeneans showed a positive correlation with the levels of nitrites and ammonium in the water (Berger-Parker index = 0.06-0.55). This characterization may represent a useful tool in the comprehensive management of parasites that affect the farmed tilapia. However, new data is necessary to expand the knowledge about the environment-host-parasite relationship.

Prevalence of Parasitic Infections with Zoonotic Potential in Tilapia: A Systematic Review and Meta-Analysis.

Tilapia has a high socioeconomic value in many countries worldwide. However, it has been identified as a zoonotic parasite reservoir. A systematic literature search and meta-analysis were carried out in order to estimate the global prevalence of zoonotic parasites that affect tilapia. The search was performed by three field experts to avoid reviewer bias. Polled prevalence was estimated using a logistic-normal random-effect regression model in the R software. We dealt with the heterogeneity among studies through subgroup analysis, taking into account the continent, country, genus of the host, parasite taxonomic group, sample origin, and type of diagnostic test as moderator variables. Fifty-two eligible articles were identified covering five tilapia genera with a pooled prevalence of 0.14 (95% CI: 0.10−0.20) showed significant heterogeneity (I2 = 98.4; p < 0.001). The subgroup analysis revealed that the most affected host was Sarotherodon, with a prevalence of 0.42 (95% CI: 0.22−0.65). Cestode was the taxonomic group with the largest prevalence (0.40; 95% CI:0.32−0.48), followed by amoeba (0.24; 95% CI: 0.16−0.35) and nematode (0.22; 95% CI: 0.11−0.38), among which, Schyzocotyle spp., Opistorchis spp., Gnathostoma spp. and Vermamoeba spp. have an impact on public health. Significant differences (p < 0.004) were found among continents and countries, with the highest value of prevalence detected in the African continent (0.28; 95% CI: 0.20−0.37), specifically in Tanzania (0.56; 95% CI: 0.22−0.87) and Egypt (0.43; 95% CI: 0.20−0.55). The origin of samples had a significant effect (p < 0.0001) on the detected prevalence, especially from those that showed the highest prevalence (0.24; 95% CI: 0.17−0.33). Finally, there were no differences in prevalence according to the diagnostic test (p = 0.97). Our results provide useful information on the development of epidemiological programs for the control of zoonoses associated with parasites in tilapia and in the design, planning, and implementation of future research.